Nutrition and health

Objectives:
New studies indicate that resveratrol can significantly reduce plasma lipids, but the result of randomized clinical trials (RCTs) on resveratrol effect and the serum lipid profile are contradictory. Therefore, this review article (meta-analysis) has been conducted.  

Do resveratrol supplements reduce plasma lipids, like cholesterol levels?

Study design:
This review article included 21 RCTs.

Results and conclusions:
The investigators found resveratrol supplements had no significant effects on both:
-total cholesterol (TC) [WMD = 0.08 mmol/L, 95% CI = -0.23 to 0.08, p = 0.349, I2 = 87.8%];
-low-density lipoprotein (LDL-C or bad cholesterol) [WMD = -0.04 mmol/L, 95% CI = -0.21 to 0.12, p  = 0.620, I2 = 93.4%] and;
-high density lipoprotein (HDL-C or good cholesterol) [WMD = -0.01 mmol/L, 95% CI = -0.04 to 0.02, p = 0.269, I2 = 88.6%].

The investigators found resveratrol supplements had significant effects on
triacylglycerol (TG) [WMD = 0.58 mmol/L, 95% CI = 0.34 to 0.82, p 0.0001, I2 = 99.8%]. But after removing 1 study the significance was eliminated.

The investigators also found that sex, age, BMI, resveratrol dosage and intervention duration could not change the results.

The investigators concluded that resveratrol supplements do not change lipid profile concentration, like cholesterol levels. Confirmation of this conclusion will require more studies exclusively on dyslipidemic patients in which the intake of lipid lowering agents is among the exclusion criteria.

Original title:
Effect of resveratrol on lipid profile: An updated systematic review and meta-analysis on randomized clinical trials by Haghighatdoost F and Hariri M.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29305228

Additional information of El Mondo:
Find more information/studies on resveratrol and cholesterol right here.

Objectives:
Does the consumption of various types of tomato products reduce prostate cancer risk and is there a potential dose-response relationship?

Study design:
This review article included 30 studies, which summarized data from 24,222 cases (subjects with prostate cancer) among 260,461 participants.

Results and conclusions:
The investigators found that higher total tomato consumption was associated with a reduced risk of 19% for prostate cancer [RR = 0.81, 95% CI = 0.71 to 0.92, p = 0.001].

The investigators found in subgroup analysis that higher tomato foods consumption was associated with a reduced risk of 16% for prostate cancer [RR = 0.84, 95% CI = 0.72 to 0.98, p = 0.030].

The investigators found in subgroup analysis that higher cooked tomatoes and sauces consumption was associated with a reduced risk of 16% for prostate cancer [RR = 0.84, 95% CI = 0.73 to 0.98, p = 0.029]. 

The investigators found in subgroup analysis, however, no association between higher raw tomatoes consumption and prostate cancer risk [RR = 0.96, 95% CI = 0.84 to 1.09, p = 0.487].

The investigators found there was a significant dose-response association for total tomato consumption [p = 0.040], cooked tomatoes and sauces [p  0.001] and raw tomatoes [p = 0.037], but there was not a significant association with tomato foods [p-linear = 0.511, p-nonlinear = 0.289].

The investigators concluded that increased tomato consumption, particularly cooked tomatoes and sauces reduces prostate cancer risk. Furthermore, there are dose-response relationships for total tomato consumption and for cooked tomatoes and sauces. Further studies are required to determine the underlying mechanisms of these associations.

Original title:
Processed and raw tomato consumption and risk of prostate cancer: a systematic review and dose-response meta-analysis by Rowles JL, Ranard KM, […], Erdman JW Jr.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29317772

Additional information of El Mondo:
Find more information/studies on tomatoes consumption and cancer right here.

Objectives:
What is the relationship between serum, dietary and urinary potassium and the risk of type 2 diabetes mellitus (T2DM)?  

Study design:
This review article included 8 prospective cohort studies involved 5,053 type 2 diabetes mellitus cases among 119,993 individuals.
The follow-up durations were from 5 to 18.1 years with a baseline age range from 18 to 95 years.
Serum potassium was measured using the ion-selective electrode method. Dietary potassium was estimated from food frequency questionnaire (FFQ). Urinary potassium samples were analyzed by potentiometric methods.
Most of the included studies provided risk estimates adjusted for age, sex, race, BMI and family history of diabetes.

Results and conclusions:
The investigators found in 5 studies involving 28,944 individuals and 3,849 type 2 diabetes mellitus cases, a non-significantly reduced risk of 21% [summary RR = 0.79, 95% CI = 0.60-1.04, I2 = 76.7%] for type 2 diabetes mellitus, when comparing the highest versus lowest serum potassium levels.
However, the sensitivity analysis did show a significant inverse association between serum potassium and type 2 diabetes mellitus risk [RR = 0.63, 95% CI = 0.52-0.73, I2 = 0%].

The investigators found in random dose-response meta-regression analysis a significantly reduced risk of 17% for type 2 diabetes mellitus [RR = 0.83, 95% CI = 0.73-0.95] per 1 mmol/L increase in serum potassium.

The investigators found in 6 studies involving 112,125 individuals and 4,573 type 2 diabetes mellitus cases, a non-significantly reduced risk of 7% [RR = 0.93, 95% CI = 0.81-1.06, I2 = 0.0%, p = 0.52] for type 2 diabetes mellitus, when comparing the highest versus lowest dietary potassium intake.
The sensitivity analysis did not significantly alter the association between dietary potassium and type 2 diabetes mellitus risk.

The investigators found there was no significant dose-response relationship between dietary potassium and type 2 diabetes mellitus risk [RR for every 1000mg increase dietary potassium per day = 1.00, 95% CI = 0.96-1.05].

The investigators found in 3 studies involving 4,376 individuals and 455 type 2 diabetes mellitus cases, a non-significantly reduced risk of 17% [RR = 0.83, 95% CI = 0.39-1.75, I2 = 73.9%, p = 0.02] for type 2 diabetes mellitus, when comparing the highest versus lowest urinary potassium levels.

The investigators found there was no significant dose-response relationship between urinary potassium levels and type 2 diabetes mellitus risk [RR for 10 mmol increase in urinary potassium per 24 hours = 1.00, 95% CI = 0.95-1.05].

The investigators concluded that serum potassium levels are linearly associated with the risk of type 2 diabetes mellitus, with each 1 mmol/L increase in serum potassium lowering the risk by 17%. However, neither dietary potassium nor urinary potassium shows any association with the risk of type 2 diabetes mellitus.

Original title:
Potassium measurements and risk of type 2 diabetes: a dose-response meta-analysis of prospective cohort studies by Peng Y, Zhong GC, […], Yang G.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5725047/

Additional information of El Mondo:
Find more information/studies on type 2 diabetes and potassium right here.
 

Objectives:
There are some indications of regional differences in the association between fish consumption and clinical outcomes. Therefore, this review article (meta-analysis) has been conducted.  

Are there regional differences in the association between fish consumption and risk of all-cause mortality and cardiovascular (CVD) mortality?

Study design:
This review article included 14 prospective cohort studies (10 publications) with 911,348 participants, of which 75,451 incident deaths.

Results and conclusions:
The investigators found dose-response meta-analysis showed a 20 g/d increment in fish consumption significantly reduced risk of cardiovascular mortality with 4% [relative risk = 0.96, 95% CI = 0.94-0.98, I2 = 0%, n = 8]. However, subgroup analysis resulted in a significant association only in Asian studies and not in Western studies.

The investigators found dose-response meta-analysis showed a 20 g/d increment in fish consumption significantly reduced risk of all-cause mortality with 2% [relative risk = 0.98, 95% CI = 0.97-1.00, I2 = 81.9%, n = 14]. However, subgroup analysis resulted in a significant association only in Asian studies and not in Western studies.

The investigators found analysis of Western studies suggested a nearly U-shaped association, with a nadir at fish consumption of 20 g/d in analysis of both outcomes. Meanwhile, the associations appeared to be linear in Asian studies.

The investigators concluded that fish consumption, particularly 20 g/d reduces boh risk of cardiovascular mortality and all-cause mortality. Furthermore, there is potential evidence of regional differences in the association between fish consumption and mortality. Therefore, it may be helpful to examine the associations by considering types of fish consumed and methods of fish preparation.

Original title:
Fish consumption and risk of all-cause and cardiovascular mortality: a dose-response meta-analysis of prospective observational studies by Jayedi A, Shab-Bidar S, […], Djafarian K.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29317009

Additional information of El Mondo:
Find more information/studies on cardiovascular disease and fish consumption right here.

Objectives:
Over the last 7 years there has been intense debate about the advice to reduce saturated fat and increase polyunsaturated fat to reduce cardiovascular (CVD) risk. Therefore, this review article (meta-analysis) has been conducted.

Does replacement of saturated fat with carbohydrate, polyunsaturated fatty acid (PUFA) or monounsaturated fatty acid (MUFA) reduce cardiovascular risk?

Study design:
This review article included cohort studies and intervention studies.

Results and conclusions:
The investigators found replacement of saturated fat with any carbohydrate, polyunsaturated fatty acid (PUFA) and monounsaturated fatty acid (MUFA) is associated with lower mortality with PUFA being more effective than MUFA [19% reduction versus 11%].

The investigators found per 5% of energy (5 En%) replacement of saturated fat with polyunsaturated fatty acid and fish oil significantly lowered risk of cardiovascular mortality with 28%.  

The investigators found replacing saturated fat with PUFA or MUFA was equally effective at reducing coronary heart disease (CHD) events

The investigators found replacement of saturated fat with whole grains significantly lowered coronary heart disease events while replacement with sugar and starch significantly increased coronary heart disease events.

The investigators found replacement of saturated fat with carbohydrate had no effect on coronary heart disease events or death.

The investigators found only PUFA replacement of saturated fat significantly lowered coronary heart disease events and cardiovascular and total mortality.

The investigators concluded reducing saturated fat and replacing it with carbohydrate will not lower coronary heart disease events or cardiovascular mortality although it will reduce total mortality. Replacing saturated fat with PUFA, MUFA or high-quality carbohydrate will lower coronary heart disease events.

Original title:
A systematic review of the effect of dietary saturated and polyunsaturated fat on heart disease by Clifton PM and Keogh JB.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29174025

Additional information of El Mondo:
Find more information/studies on fat, carbohydrates and cardiovascular diseases right here.

Objectives:
What are the cardiovascular benefits of indiscriminate supplementation of omega-3 supplementation?

Study design:
This review article included 8 RCTs.

Results and conclusions:
The investigators found omega-3 supplementation significantly resulted in a 8% decrease of the risk of cardiac death, unless the patients are treated by statins.

The investigators found omega-3 supplementation prolonged quality adjusted life years by about a month. Old people gained less, whereas diabetes mellitus type 2 patients and people with history of cardiovascular events gained more.

The investigators concluded omega-3 supplementation decreases risk of cardiac death, unless the patients are treated by statins.

Original title:
The cardiovascular benefits of indiscriminate supplementation of omega-3 fatty acids; meta-analysis and decision-making approach by Leshno M, Goldbourt U, [...], Lichtenberg D.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29171335

Additional information of El Mondo:
Find more information/studies on omega-3 fatty acids and cardiovascular diseases right here.

Objectives:
What is the relationship between dietary intake of 12 major food groups, including whole grains, refined grains, vegetables, fruit, nuts, legumes, eggs, dairy, fish, red meat, processed meat and sugar-sweetened beverages and colorectal cancer (CRC) risk?

Study design:
This review article included cohort studies.

Results and conclusions:
The investigators found in the linear dose-response meta-analysis, that every 30 g/d whole grains significantly reduced risk of colorectal cancer with 5% [RR = 0.95, 95% CI = 0.93 to 0.97, n = 9 cohort studies].

The investigators found in the linear dose-response meta-analysis, that every 100 g/d vegetables significantly reduced risk of colorectal cancer with 3% [RR = 0.97, 95% CI = 0.96 to 0.98, n = 15 cohort studies].

The investigators found in the linear dose-response meta-analysis, that every 100 g/d fruit significantly reduced risk of colorectal cancer with 3% [RR = 0.97, 95% CI = 0.95 to 0.99, n = 16 cohort studies]. 

The investigators found in the linear dose-response meta-analysis, that every 200 g/d dairy products significantly reduced risk of colorectal cancer with 7% [RR = 0.93, 95% CI = 0.91 to 0.94, n = 15 cohort studies]. 

The investigators found in the linear dose-response meta-analysis, that every 100 g/d red meat significantly increased risk of colorectal cancer with 12% [RR = 1.12, 95% CI = 1.06 to 1.19, n = 21 cohort studies].

The investigators found in the linear dose-response meta-analysis, that every 50 g/d processed meat significantly increased risk of colorectal cancer with 17% [RR = 1.17, 95% CI = 1.10 to 1.23, n = 16 cohort studies].

The investigators found some evidence for a nonlinear relationship between dietary intake of vegetables, fruit and dairy products and risk of colorectal cancer.

The investigators concluded that daily dietary intake of 30g whole grains, 100g vegetables,100g fruit and 200g dairy products reduce risk of colorectal cancer, while daily dietary intake of 100g red meat and 50g processed meat increase risk of colorectal cancer.

Original title:
Food groups and risk of colorectal cancer by Schwingshackl L, Schwedhelm C, [...], Schlesinger S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29210053

Additional information of El Mondo:
Find more information/studies on different food groups and colorectal cancer right here.

Objectives:
Beetroot is considered a complementary treatment for hypertension because of its high content of inorganic NO3.

The aim of this meta-analysis (review article) is to clarify several aspects of beetroot juice supplementation on systolic blood pressure (SBP) and diastolic blood pressure (DBP).

Study design:
This review article included 22 RCTs with a total of 47 intervention (n = 650) and 43 control (n = 598) groups.

Results and conclusions:
The investigators found overall, systolic blood pressure [-3.55 mmHg, 95% CI = -4.55 to -2.54 mmHg] and diastolic blood pressure [-1.32 mmHg, 95% CI = -1.97 to -0.68 mmHg] were significantly lower in the beetroot juice-supplemented groups than in the control groups.

The investigators found the mean difference of systolic blood pressure was larger between beetroot juice-supplemented and control groups in the longer than in the shorter (≥14 compared with 14 days) study durations [-5.11 compared with -2.67 mmHg].

The investigators found the mean difference of systolic blood pressure was larger between beetroot juice-supplemented and control groups in the highest compared with the lowest (500 compared with 70 and 140 mL/d] doses of beetroot juice [-4.78 compared with -2.37 mmHg].

The investigators found a positive correlation between beetroot juice doses and the mean differences of blood pressures.

The investigators found a smaller effect size of blood pressures after supplementation with higher NO3 (milligrams per 100 mL beetroot juice).

The investigators found a weak effect size in a meta-analysis of trials that used NO3-depleted beetroot juice as a placebo compared with other interventions [-3.09 compared with -4.51 mmHg for systolic blood pressure and -0.81 compared with -2.01 mmHg for diastolic blood pressure].

The investigators concluded beetroot juice supplementation, particularly 500 mL/d beetroot juice during at least 14 days, reduces blood pressure.

Original title:
The Nitrate-Independent Blood Pressure-Lowering Effect of Beetroot Juice: A Systematic Review and Meta-Analysis by Bahadoran Z, Mirmiran P, […], Ghasemi A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29141968

Additional information of El Mondo:
Find more information/studies on fruit, hypertension prevention and cardiovascular diseases right here.

Objectives:
Carnitine deficiency has been implicated as a potential pathway for cancer-related fatigue that could be treated with carnitine supplementation. Therefore, this review article (meta-analysis) has been conducted.

Does carnitine supplementation reduce cancer-related fatigue?

Study design:
This review article included 3 RCTs involving a total of 659 participants.

There were not enough studies to conduct sensitivity analyses to isolate potential sources of heterogeneity and test the robustness of findings.

Results and conclusions:
The investigators found in 3 RCTs involving a total of 659 participants that carnitine supplementation did not significantly reduce cancer-related fatigue [SMD = 0.06 points, 95% CI = -0.09 to 0.21, p = 0.45, I2 = 0%].
Clinical heterogeneity was evident from these studies in regards to the dose (2-4 g of carnitine per day), patient demographics (40-100% females included) and carnitine status.

The investigators concluded there is no evidence to support the use of carnitine supplementation (2-4 g of carnitine per day) for cancer-related fatigue.

Original title:
Efficacy and Effectiveness of Carnitine Supplementation for Cancer-Related Fatigue: A Systematic Literature Review and Meta-Analysis by Marx W, Teleni L, [...], Isenring E.

Link:
http://www.mdpi.com/2072-6643/9/11/1224/htm

Additional information of El Mondo:
Find more information/studies on carnitine, randomized controlled trials/cohort studies/subgroup analysis and cancer right here.

Objectives:
What is the relationship of the intake of whole grains, refined grains, vegetables, fruits, nuts, legumes, eggs, dairy, fish, red meat, processed meat and sugar-sweetened beverages (SSBs) and the risk of hypertension?

Study design:
This review article included 28 prospective cohort studies.

Results and conclusions:
The investigators found in dose-response meta-analysis of 4 studies with 28,069 incident hypertension cases, a significantly reduced risk of 8% [RR = 0.92, 95% CI = 0.87-0.98, I2 = 88%, p 0.0001] for hypertension for 30 g/day whole grains. Significant means that there is an association with a 95% confidence.
The reduced risk was highest (15%) at 90 g/day whole grains.

The investigators found in dose-response meta-analysis of 6 studies, a significantly reduced risk of 3% [RR = 0.97, 95% CI = 0.96-0.99, I2 = 64%, p = 0.02] for hypertension for 100 g/day fruits.
The strongest risk reduction was 7% at 300 g/day fruits.

The investigators found in dose-response meta-analysis of 9 studies with 31,509 incident hypertension cases, a significantly reduced risk of 5% [RR = 0.95, 95% CI = 0.94-0.97, I2 = 0%, p = 0.50] for hypertension for 200 g/day dairy products.
The strongest risk reduction was 15% at 800 g/day dairy products.

The investigators found in dose-response meta-analysis of 7 studies with 97,745 incident hypertension cases, a significantly increased risk of 14% [RR = 1.14, 95% CI = 1.02-1.28, I2 = 88%, p 0.001] for hypertension for 100 g/day red meat.
The increased risk was highest (40%) at 200 g/day red meat.

The investigators found in dose-response meta-analysis of 4 studies, a significantly increased risk of 12% [RR = 1.12, 95% CI = 1.00-1.26, I2 = 82%, p 0.001] for hypertension for 50 g/day processed meat.

The investigators found in dose-response meta-analysis of 4 studies, a significantly increased risk of 7% [RR = 1.07, 95% CI = 1.04-1.10, I2 = 64%, p = 0.04] for hypertension for 250 mL/day sugar-sweetened beverages.
The increased risk was highest (13%) at 450 mL/day sugar-sweetened beverages.

The investigators found compared with nonconsumption, an intake of 2 servings red meat/d [170g, RR = 1.35], 1 serving processed meat/d [35g, RR = 1.07], 1 serving fish/d [100g, RR = 1.08] and 2 servings sugar-sweetened beverages/d [500mL, RR = 1.14 was associated with a 78% increased risk of hypertension. On the other hand, a risk reduction by 44% would be achieved by not consuming these foods (red meat, processed meat, fish and sugar-sweetened beverages).

The investigators concluded a daily dietary intake of 30g whole grains, 100g fruits, 200g dairy products reduce risk of hypertension, whereas a daily dietary intake of 100g red meat, 50g processed meat, and 250mL sugar-sweetened beverages increase risk of hypertension. These findings need to be seen under the light of very-low to low credibility of meta-evidence. However, the findings support the current dietary recommendations in the primary prevention of hypertension.

Original title:
Food Groups and Risk of Hypertension: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies by Schwingshackl L, Schwedhelm C, […], Boeing H.

Link:
http://advances.nutrition.org/content/8/6/793.long

Additional information of El Mondo:
Find more information/studies on different food groups, hypertension prevention and cardiovascular diseases right here.

Objectives:
Previous meta‐analyses on meat intake and risk of stroke did not report the effect of white meat (poultry meat, excluding fish) and did not examine stroke incidence and mortality separately. Therefore, this review article (meta-analysis) has been conducted.

What is the relationship of total (red and processed meat), red (unprocessed or fresh red meat) and processed (processed red meat) meat consumption along with white meat on risk of stroke incidence and mortality disease risk?

Study design:
This review article included 15 prospective cohort studies (254,742 participants with 9,522 stroke incidents and 487,150 participants with 12,999 cases of stroke mortality). The follow-up duration varied from 5.5 to 26 years.

There was no significant publication bias based on the Egger test except that the evaluation of total meat with stroke incidence reached the significance threshold.

The average score for study quality assessed by the Newcastle‐Ottawa Scale was 7.29 (range 7-8) for studies on meat consumption and stroke incidence and 6.87 (range 6-8) for those on stroke mortality.

Results and conclusions:
The investigators found that a high total meat (red and processed meat) consumption resulted in a significantly higher risk of 18% [pooled relative risk = 1.18, 95% CI = 1.09-1.28, I2 = 0%] for total stroke incidence. Significantly means that there is an association with a 95% confidence.

The investigators found that a high red meat consumption resulted in a significantly higher risk of 11% [pooled relative risk = 1.11, 95% CI = 1.03-1.20, I2 = 0%] for total stroke incidence.

The investigators found that a high processed meat consumption resulted in a significantly higher risk of 17% [pooled relative risk = 1.17, 95% CI = 1.08-1.25, I2 = 0%] for total stroke incidence.

The investigators found that a high white meat consumption resulted in a significantly lower risk of 13% [pooled relative risk = 0.87, 95% CI = 0.78-0.97, I2 = 0%] for total stroke incidence.

The investigators found, however, no significant associations between consumption of total [RR = 0.97, 95% CI = 0.85-1.11, I2 = 0%] or red meat [RR = 0.87, 95% CI = 0.64-1.18, I2 = 70.9%] and stroke mortality. No significant associations because RR of 1 was found in the 95% CI of 0.64 to 1.18. RR of 1 means no risk/association.

The investigators found that a high total meat consumption was associated with an increased risk of 41% for hemorrhagic stroke [RR = 1.41, 95% CI = 1.08-1.84, I2 = 0%], but no significant association was found between a high total meat consumption and ischemic stroke [RR = 1.16, 95% CI = 0.94-1.43, I2 = 40.6%].

The investigators found a positive association between total meat consumption and stroke incidence, regardless of sex, number of cases and follow‐up duration.

The investigators found when stratified by adjustment variables, studies that adjusted for family history of myocardial infarction, fruit and vegetable intake and use of aspirin showed a statistically significant relationship between total meat intake and risk of stroke compared with other studies that did not include those as adjustment variables.

The investigators found that a high red meat consumption was associated with an increased risk of 24% for ischemic stroke [RR = 1.24, 95% CI = 1.05-1.46, I2 = 17.7%], but no significant association was found between a high red meat consumption and hemorrhagic stroke [RR = 1.11, 95% CI = 0.89-1.38, I2 = 0%].

The investigators found that a high processed meat consumption was linked to neither ischemic [RR = 1.10, 95% CI = 0.96-1.27, I2 = 11.4%] nor hemorrhagic stroke [RR = 1.19, 95% CI = 0.95-1.49, I2 = 8.10%].

The investigators concluded that higher consumption of red or processed meat is associated with an increase in the risk of stroke, while higher intake of white meat is related to a reduction in stroke incidence. Therefore, recommendations for replacing proportions of red and processed meat to white meat for the prevention of stroke may be considered in clinical practice.

Original title:
Role of Total, Red, Processed, and White Meat Consumption in Stroke Incidence and Mortality: A Systematic Review and Meta-Analysis of Prospective Cohort Studies by Kim K, Hyeon J, […], Park SM.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5634267/

Additional information of El Mondo:
Find more information/studies on meat consumption and cardiovascular diseases right here.

Objectives:
Dietary fiber intake, especially viscous soluble fiber, has been established as a means to reduce cardiometabolic risk factors. Whether this is true for blood pressure remains controversial. Therefore, this review article (meta-analysis) has been conducted.

Does viscous soluble fiber supplementation reduce cardiovascular disease risk?

Study design:
This review article included 22 (n = 1430) and 21 RCTs (N = 1343) for systolic blood pressure (SBP) and diastolic blood pressure (DBP), respectively.

5 types of viscous fiber supplementation were β-glucan from oats and barley, guar gum, konjac, pectin and psyllium.

Results and conclusions:
The investigators found viscous soluble fiber supplementation significantly reduced systolic blood pressure [MD = -1.59 mmHg, 95% CI = -2.72 to -0.46, I2 = 72%, p 0.01] and diastolic blood pressure [MD = -0.39 mmHg, 95% CI = -0.76 to -0.01, I2 = 67%, p 0.01] at a median dose of 8.7 g/day (1.45-30 g/day) over a median follow-up of 7-weeks.

The investigators found within the five fiber types, systolic blood pressure reductions were observed only for supplementation using psyllium fiber [MD = -2.39 mmHg, 95% CI = -4.62 to -0.17].

The investigators concluded 8.7 g/day viscous soluble fiber supplementation, particularly psyllium fiber during 7 weeks reduces systolic blood pressure (SBP) and diastolic blood pressure (DBP). Therefore, inclusion of viscous fiber to habitual diets may have additional value in reducing cardiovascular risk via improvement in blood pressure.

Original title:
The effect of viscous soluble fiber on blood pressure: A systematic review and meta-analysis of randomized controlled trials by Khan K, Jovanovski E, […], Vuksan V.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29153856

Additional information of El Mondo:
Find more information/studies on fiber consumption, hypertension and cardiovascular diseases right here.

Objectives:
Elevated cholesterol has been linked to cardiovascular disease in adults and preclinical markers of atherosclerosis in children, thus reducing saturated (SFA) and trans-fatty acids (TFA) intake from an early age may help to reduce cholesterol and the risk of cardiovascular disease later in life. The World Health Organization (WHO) is currently updating its guidance on SFA and TFA intake in adults and children. Therefore, this review article (meta-analysis) has been conducted.

Does a diet with low saturated fatty acids reduce cholesterol and blood pressure in children and adolescents between 2 to 19 years of age?

Study design:
This review article included 8 RCTs (5 trials had a duration of 1 year and 3 had a duration of ≥ 1year with a total of 2,430 individual children and adolescents between 2 to 19 years of age) and 3 cohort studies.

Minimum duration was 13 days for RCTs and one year for cohort studies.

Saturated fatty acids intake was assessed using 24hr dietary recalls in 4 trials, 3-day diet records in 3 trials and food frequency questionnaires and/or checklists in 2 trials.

No trials were identified meeting the inclusion criteria for trans-fatty acids.

Publication bias was not assessed as the number of trials found was not sufficient to conduct funnel plot analyses for any outcome measure.

Results and conclusions:
The investigators found compared with control diets, there was a highly statistically significant effect of reduced saturated fatty acids intake on total cholesterol [MD = -0.16 mmol/L, 95% CI = -0.25 to -0.07, I2 = 64%], LDL cholesterol [MD = -0.13 mmol/L, 95% CI = -0.22 to -0.03, I2 = 77%] and diastolic blood pressure [MD = -1.45 mmol/L, 95% CI = -2.34 to -0.56].
The effects on cholesterol were greatest among those in which saturated fatty acids was replaced primarily with PUFA or MUFA and when the intervention group achieved a reduction in saturated fatty acids to below 10% of total energy intake.

The investigators found subgroup analysis of the effect of the initial lipid status of the participants showed a significantly different effect of saturated fatty acids reduction on total cholesterol [p = 0.05] between trials involving normolipidaemic/mixed status children [MD -0.21 mmol/L, 95% CI = -0.31 to -0.12] vs hyperlipidaemic children [MD = -0.08 mmol/L, 95% CI = -0.15 to -0.01].

The investigators found subgroup analysis of the effect of the initial lipid status of the participants showed the reduction in LDL cholesterol (bad cholesterol) was greater among the trials conducted in normolipidaemic/mixed status [MD -0.21 mmol/L, 95% CI = -0.30 to -0.13] vs hyperlipidaemic children [MD = -0.02 mmol/L, 95% CI = -0.14 to -0.11].

The investigators found there were no significant associations observed for HDL cholesterol (good cholesterol), triglycerides or apolipoproteins A1 or B.

The investigators found there were no significant associations observed between reduced saturated fatty acids intake and weight, height, body mass index (BMI) or waist circumference.

The investigators found there was no evidence of adverse effects of reducing saturated fatty acids intake in children on micronutrient intakes, cognitive development or sexual maturation in the small number of trials reporting these outcomes.  

The investigators concluded a diet with low saturated fatty acids reduces total cholesterol, LDL cholesterol and diastolic blood pressure in children and adolescents between 2 to 19 years of age without evidence of adverse effects on growth and development. The greatest effect on cholesterol occurred when saturated fatty acids was replaced with PUFA or a mixture of PUFA/MUFA and when saturated fatty acids intake was less than 10% of total energy intake. Therefore, dietary guidelines for children and adolescents should continue to recommend diets low in saturated fat.

Original title:
Health effects of saturated and trans-fatty acid intake in children and adolescents: Systematic review and meta-analysis by Morenga L and Montez JM.

Link:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0186672

Additional information of El Mondo:
Find more information/studies on fat consumption, body mass index, hypertension, cholesterol and cardiovascular diseases right here.  

A diet with saturated fatty acids intake less than 10% of total energy intake is a diet with less than 10 En% saturated fat.
A diet with less than 10 En% saturated fat is a diet that is largely made up of meals/products with less than 10 En% saturated fat. Practically, this means that all meals/products that you eat on a daily basis should on average contain less than 10 En% saturated fat. Check here which products contain less than 10 En% saturated fat.

Objectives:
Previous studies regarding the relationship between carrot intake and risk of urothelial cancer have reported conflicting results. Therefore, this review article (meta-analysis) has been conducted.

Does a high consumption of carrot reduce urothelial cancer risk?

Study design:
This review article included a total of 6 epidemiological studies (4 case-control and 2 cohort studies) with 1,523 urothelial cancer cases.

There was no significant publication bias by Begg's test (p = 0.348) or Egger's test (p = 0.130).

Results and conclusions:
The investigators found overall analysis indicated a significantly reduced risk of 37% for urothelial cancer for high intake of carrot [OR = 0.63, 95% CI = 0.44-0.90, I2 = 79.6%, p 0.001].

The investigators found in the subgroup analysis by study design, a significantly reduced risk of 55% for urothelial cancer in case-control studies [OR = 0.45, 95% CI = 0.25-0.81]. However, this reduced risk was not significant in cohort studies [OR = 0.91, 95% CI = 0.67-1.24].
Not significant because OR of 1 was found in the 95% CI of 0.67 to 1.24. OR of 1 means no risk/association.

The investigators found, when separately analyzed by carrot type, a significantly reduced risk of 31% for cooked carrot [OR = 0.69, 95% CI 0.51-0.94], but the reduced risk was not significant for raw carrot [OR = 0.84, 95% CI = 0.37-1.93].

The investigators found in the stratified analysis by geographical region, a non-significantly reduced risk of 38% [OR = 0.62, 95% CI = 0.37-1.06], a non-significantly reduced risk of 30% [OR = 0.70, 95% CI = 0.29-1.67] and a non-significantly reduced risk of 47% [OR = 0.53, 95% CI = 0.22-1.26] for Europe, Asia and USA, respectively.

The investigators also found a non-significantly reduced risk of 44% [OR = 0.56, 95% CI = 0.27-1.17] and a non-significantly reduced risk of 27% [OR = 0.73, 95% CI = 0.12-4.60] for male and female, respectively.

The investigators concluded that a high intake of carrot might be associated with a low incidence of urothelial cancer. Might be associated because the reduced risk was not significant in cohort studies. Considering the limited included studies and huge heterogeneity, further large well-designed prospective cohort studies are warranted to confirm these findings.

Original title:
Carrot intake and incidence of urothelial cancer: a systematic review and meta-analysis by Luo X, Lu H, [...], Wang S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5652827/

Additional information of El Mondo:
Find more information/studies on carrot consumption, randomized controlled trials/cohort studies/subgroup analysis and cancer right here.

Objectives:
Despite growing evidence for food-based dietary patterns' potential to reduce cardiovascular disease risk, knowledge about the amounts of food associated with the greatest change in risk of specific cardiovascular outcomes and about the quality of meta-evidence is limited. Therefore, this review article (meta-analysis) has been conducted.

Which food-based dietary patterns reduce risk of cardiovascular diseases, such as coronary heart disease (CHD), stroke and heart failure (HF)?

Study design:
This review article included 123 prospective cohort studies.

Results and conclusions:
The investigators found whole grains significantly reduced risk of coronary heart disease with 5% [RR = 0.95, 95% CI = 0.92-0.98]. Significantly means that there is an association with a 95% confidence.

The investigators found whole grains significantly reduced risk of heart failure with 4% [RR = 0.96, 95% CI = 0.95-0.97]. Significantly because RR of 1 was not found in the 95% CI of 0.95 to 0.97. RR of 1 means no risk/association.

The investigators found vegetables significantly reduced risk of coronary heart disease with 3% [RR = 0.97, 95% CI = 0.96-0.99]. Significantly means it can be said with a 95% confidence that a intake of vegetables really decreased the risk of getting coronary heart disease with 3%.  

The investigators found fruits significantly reduced risk of coronary heart disease with 6% [RR = 0.94, 95% CI = 0.90-0.97].

The investigators found vegetables significantly reduced risk of stroke with 8% [RR = 0.92, 95% CI = 0.86-0.98].

The investigators found fruits significantly reduced risk of stroke with 10% [RR = 0.90, 95% CI = 0.84-0.97].

The investigators found nuts non-significantly reduced risk of coronary heart disease with 33% [RR = 0.67, 95% CI = 0.43-1.05]. Non-significantly means that there is no association with a 95% confidence.

The investigators found fish consumption significantly reduced risk of stroke with 14% [RR = 0.86, 95% CI = 0.75-0.99].

The investigators found fish consumption significantly reduced risk of heart failure with 20% [RR = 0.80, 95% CI = 0.67-0.95].

The investigators found egg significantly increased risk of heart failure with 16% [RR = 1.16, 95% CI = 1.03-1.31].

The investigators found red meat significantly increased risk of coronary heart disease with 15% [RR = 1.15, 95% CI = 1.08-1.23].

The investigators found red meat significantly increased risk of stroke with 12% [RR = 1.12, 95% CI = 1.06-1.17].

The investigators found red meat significantly increased risk of heart failure with 8% [RR = 1.08, 95% CI = 1.02-1.14].

The investigators found processed meat significantly increased risk of coronary heart disease with 27% [RR = 1.27, 95% CI = 1.09-1.49].

The investigators found processed meat significantly increased risk of stroke with 17% [RR = 1.17, 95% CI = 1.02-1.34].

The investigators found processed meat significantly increased risk of heart failure with 12% [RR = 1.12, 95% CI = 1.05-1.19].

The investigators found sugar-sweetened beverages significantly increased risk of coronary heart disease with 17% [RR = 1.17, 95% CI = 1.11-1.23].

The investigators found sugar-sweetened beverages significantly increased risk of heart failure with 7% [RR = 1.07, 95% CI = 1.02-1.12].

The investigators found sugar-sweetened beverages significantly increased risk of stroke with 8% [RR = 1.08, 95% CI = 1.05-1.12].

The investigators found there were clear indications for non-linear dose-response relationships between whole grains, fruit, nuts, dairy and red meat and coronary heart disease.

The investigators concluded there is a relationship between food-based dietary patterns and risk of cardiovascular diseases, with an increased risk for consumption of eggs, red meat, processed meat and sugar-sweetened beverages and a decreased risk for consumption of whole grains, vegetables, fruit and fish.

Original title:
Food groups and risk of coronary heart disease, stroke and heart failure: A systematic review and dose-response meta-analysis of prospective studies by Bechthold A, Boeing H, […], Schwingshackl L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29039970

Additional information of El Mondo:
Find more information/studies on food groups and cardiovascular diseases right here. 

Objectives:
Surgical resection remains the primary treatment for gastrointestinal (GI) malignancy including early-stage cancer. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been reported to have beneficial clinical and immune-modulating effects in the prognosis of gastrointestinal cancer patients undergoing surgery. Therefore, this review article (meta-analysis) has been conducted.

What is the impact of n-3 PUFA supplementation on postoperative inflammation status and immune function of gastrointestinal cancer patients?

Study design:
This review article included a total of 9 RCTs with 623 participants.

The homogeneous test detected no statistical heterogeneity between studies.

There was no evidence of publication bias following assessment by funnel plot, Egger’s test [p > 0.05] and Begg’s test [p > 0.05].

Results and conclusions:
The investigators found the n-3 PUFAs regime significantly resulted in lower levels of C-reactive protein [p 0.05], interleukin-6 [p 0.01] and higher levels of albumin, CD3+ T cells, CD4+ T cells and CD4+/CD8+ ratio [p 0.05] compared with the isocaloric nutrition regime.

The investigators found, however, no significant difference in the level of tumor necrosis factor-α between the n-3 PUFAs regime and the isocaloric nutrition regime [p = 0.17].

The investigators found that the level of CD8 + T cells significantly decreased compared with the isocaloric nutrition regime [p 0.0001].

The investigators concluded that n-3 PUFAs are effective in improving the nutritional status and immune function of gastrointestinal cancer patients undergoing surgery as they effectively enhance immunity and attenuate the inflammatory response. Although further larger trials are needed, these fatty acids should be widely used in the clinic.

Original title:
Effects of omega-3 fatty acids on patients undergoing surgery for gastrointestinal malignancy: a systematic review and meta-analysis by Yu J, Liu L, [...], Yang F.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5391568/

Additional information of El Mondo:
Find more information/studies on n-3 PUFA consumption and cancer right here.
 

Objectives:
The therapeutic efficacy of coenzyme Q10 on patients with cardiac failure remains controversial. Therefore, this review article (meta-analysis) has been conducted.

Do patients with heart failure benefit from coenzyme Q10 supplements?

Study design:
This review article included a total of 14 RCTs with 1064 patients in coenzyme Q10 (treatment) group and 1085 patients in placebo (control) group.

Egger’s test results showed no significant evidence of publication bias in either endpoint.

Results and conclusions:
The investigators found compared with placebo, coenzyme Q10 supplementation significantly decreased mortality risk with 31% [RR = 0.69, 95% CI = 0.50 to 0.95, p = 0.02, I2 = 0%].

The investigators found a greater improvement in exercise capacity was established in patients who used coenzyme Q10 than in those who used placebo [SMD = 0.62, 95% CI = 0.02 to 0.30, p = 0.04, I2 = 54%].

The investigators found patients who used coenzyme Q10 and placebo associated with similar left heart ejection fraction [SMD = 0.14, 95% CI = -0.08 to 0.37, p = 0.22, I2 = 54%].

The investigators found no significant difference between coenzyme Q10 and placebo for NYHA classification [SMD = -0.70, 95% CI = -1.92 to 0.51, p = 0.26, I2 = 89%].

The investigators concluded in patients with heart failure, the administration of coenzyme Q10 results in lower mortality and improved exercise capacity compared with the effects of placebo treatment.

Original title:
Efficacy of coenzyme Q10 in patients with cardiac failure: a meta-analysis of clinical trials by Lei L and Liu Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5525208/

Additional information of El Mondo:
Find more information/studies on coenzyme Q10 and cardiovascular diseases right here. 

Objectives:
The aim of this review article (meta-analysis) is to compare empirically derived dietary patterns in relation to cancer risk.

Study design:
This review article included observational studies, which evaluated the association with cancer risk between a posteriori derived dietary patterns.

Results and conclusions:
The investigators found a significantly 64% increased risk of cancer for the adoption of high-meat compared to plant-based dietary patterns [RR = 1.64, 95% CI = 1.02-2.63].

The investigators found a significantly 12% lower risk of cancer for individuals adopting a plant-based dietary pattern over a mixed one [RR = 0.88, 95% BI = 0.82-0.95].

The investigators concluded that plant-based dietary patterns decrease cancer risk; meanwhile meat-based dietary patterns increase cancer risk.

Original title:
Differences in the association between empirically derived dietary patterns and cancer: a meta-analysis by Bella F, Godos J, […], Sciacca S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/27894200

Additional information of El Mondo:
Find more information/studies on veganism and cancer right here.
 

Objectives:
Several previous meta-analyses show a consistent inverse association between nut consumption and all-cause mortality, but the associations with cause-specific mortality remain uncertain. Therefore, this meta-analysis (review article) has been conducted.

Does nut consumption reduce all-cause and cause-specific mortality?

Study design:
This review article included 18 prospective cohort studies with 81,034 deaths.

Results and conclusions:
The investigators found random-effects meta-analysis of 18 studies with 81,034 deaths showed a significant reduced risk of 19% [summary RR = 0.81, 95% CI = 0.78-0.84] for all-cause mortality for high compared with low nut consumption. This significant reduced risk was broadly consistent within subgroups according to various study and population characteristics and within sensitivity analyses that took into account potential confounders.

The investigators found random-effects meta-analysis of 17 studies with 20,381 deaths showed a significant reduced risk of 25% [summary RR = 0.75, 95% CI = 0.71-0.79] for cardiovascular mortality for high compared with low nut consumption. This significant reduced risk was broadly consistent within subgroups according to various study and population characteristics and within sensitivity analyses that took into account potential confounders.

The investigators found random-effects meta-analysis of 14 studies with 10,438 deaths showed a significant reduced risk of 27% [summary RR = 0.73, 95% CI = 0.67-0.80] for coronary heart disease mortality for high compared with low nut consumption. This significant reduced risk was broadly consistent within subgroups according to various study and population characteristics and within sensitivity analyses that took into account potential confounders.

The investigators found random-effects meta-analysis of 13 studies with 4,850 deaths showed a significant reduced risk of 18% [summary RR = 0.82, 95% CI = 0.73-0.91] for stroke mortality for high compared with low nut consumption. This significant reduced risk was broadly consistent within subgroups according to various study and population characteristics and within sensitivity analyses that took into account potential confounders.

The investigators found random-effects meta-analysis of 11 studies with 21,353 deaths showed a significant reduced risk of 13% [summary RR = 0.87, 95% CI = 0.80-0.93] for cancer mortality for high compared with low nut consumption. This significant reduced risk was broadly consistent within subgroups according to various study and population characteristics and within sensitivity analyses that took into account potential confounders.

The investigators found peanut (5 studies) and tree nut (3 studies) consumption were similarly associated with mortality risks.

The investigators found dose-response analyses suggested evidence for nonlinear associations between nut consumption and mortality [p-nonlinearity 0.001 for all outcomes except cancer mortality], with mortality risk levelling off at the consumption of about 3 servings per week (12g/day).

The investigators concluded that nut consumption is associated with reduced all-cause and cause-specific mortality, with the strongest reduction for coronary heart disease (CHD) mortality. Both tree nuts and peanuts lower mortality and most of the survival benefits could be achieved at a relative low level of nut consumption (up to 12g/day).

Original title:
Nut consumption in relation to all-cause and cause-specific mortality: a meta-analysis 18 prospective studies by Chen GC, Zhang R, [...], Qin LQ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28875220

Additional information of El Mondo:
Find more information/studies on nut consumption, cancer, cardiovascular disease and stroke right here.
 

Objectives:
Increasing evidence suggests that high consumption of meat is linked to lung cancer but the previous meta-analyses did not properly address the role of tobacco smoking as a potential confounder. Therefore, this review article (meta-analysis) has been conducted.

Does high consumption of meat increase lung cancer risk among never and non-smokers?

Study design:
This review article included 14 independent observational studies and a total of 5,368 subjects with lung cancer.
There was no indication of publication bias.

Results and conclusions:
The investigators found in 11 studies, a statistically significant 24% increased risk of lung cancer for high consumption of red meat [Summary Relative Risk = 1.24, 95% CI = 1.01-1.51, I2 = 31%].

The investigators found no significant associations between high consumption of other types of meat, fish or for heterocyclic amines and lung cancer risk.

The investigators found no significant risk estimates for the increase of one serving per week of any type of meat or fish.

The investigators concluded a high intake of red meat increases the risk of lung cancer among never and non-smokers.

Original title:
Carcinogenicity of High Consumption of Meat and Lung Cancer Risk Among Non-Smokers: A Comprehensive Meta-Analysis by Gnagnarella P, Caini S, […], Gandini S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29016198

Additional information of El Mondo:
Find more information/studies on meat consumption, randomized controlled trials/cohort studies/subgroup analysis and cancer right here.

According to international recommendations, adults should aim to have a maximum of 70g red meat per day or 500g per week (cooked weight).
 

Objectives:
Anthocyanins are of interest due to their anti-oxidative and vasodilatory properties. Earlier reviews have shown that berries and other anthocyanin rich foods or extracts can improve vascular health. However, the effect of anthocyanins on vascular function has not yet been reviewed. Therefore, this review article (meta-analysis) has been conducted.

Does anthocyanin supplementation improve vascular function?

Study design:
This review article included 29 RCTs (15 were parallel and 14 were crossover designs).
Anthocyanin intakes ranged from 1 to 724 mg/day.
Most studies (n = 19) involved participants in the middle to older age group (mean age ≥ 40 years).
The number of participants that completed each study ranged from 10 to 146.
Intervention durations ranged from 1 h to 6 h in the acute studies and one week to six months in the chronic studies.

There was no publication bias.

Results and conclusions:
The investigators found compared to placebo-control, acute anthocyanin supplementation (1-8 h post consumption of anthocyanin doses between 7 and 724 mg) significantly improved FMD [SMD = 3.92%, 95% CI = 1.47 to 6.38, p = 0.002, I2 = 91.8%].
No improvements were observed in PAT-RHI [SMD = 0.08, 95% CI = -0.34 to 0.50, p = 0.71, I2 = 0%].
Collectively, (i.e., the pooling of studies using FMD and/or PAT-RHI) anthocyanins may improve vascular reactivity [overall SMD = 2.41, 95% CI = 0.91 to 3.91, p = 0.002, I2 = 92.6%].

The investigators found compared to placebo-control, acute anthocyanin supplementation (1-8 h post consumption of anthocyanin doses between 7 and 724 mg) also significantly improved arterial stiffness, using PWV [SMD = -1.27 m/s, 95% CI = -1.96 to -0.58, p = 0.000, I2 = 17.9%].

The investigators found pulse wave velocity was improved following acute anthocyanin supplementation only [SMD = -1.27 m/s, 95% CI = -1.96 to -0.58, p = 0.000, I2 = 17.8%]. 

The investigators found compared to placebo-control, chronic anthocyanin supplementation (one week to six months and used anthocyanin doses of 12 to 320 mg/day) significantly improved FMD [SMD = 0.84%, 95% CI = 0.55 to 1.12, p = 0.000, I2 = 62.5%].
Collectively (i.e., the pooling of studies using FMD and/or PAT-RHI), chronic anthocyanin supplementation may improve vascular reactivity [overall SMD = 0.77, 95% CI = 0.37 to 1.16, p = 0.000, I2 = 85.3%].

The investigators concluded that both acute and chronic anthocyanin supplementation improve vascular health, particularly with respect to vascular reactivity measured by FMD. However, more research is required to determine the optimal dosage and the long-term effects of anthocyanin consumption.

Original title:
The Effect of Anthocyanin-Rich Foods or Extracts on Vascular Function in Adults: A Systematic Review and Meta-Analysis of Randomised Controlled Trials by Fairlie-Jones L, Davison K, […], Hill AM.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579701/

Additional information of El Mondo:
Find more information/studies on flavonoids and cardiovascular diseases right here.  

Objectives:
Several studies have investigated the relationship between serum selenium concentration and cervical cancer, but the results were inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Do high serum selenium levels reduce risk of cervical cancer among women?

Study design:
This review article included 12 studies investigating the association by univariate analysis and 5 studies by multivariate analysis.

Results and conclusions:
The investigators found in univariate analysis, that serum selenium levels in women with cervical cancer were significantly lower than in women without cervical cancer [SMD = -4.86, 95% CI = -6.03 to -3.69]. Subgroup analysis showed consistent results.

The investigators found in multivariate analysis, that serum selenium levels in women with cervical cancer were significantly lower than in women without cervical cancer [OR = 0.55, 95% CI = 0.42-0.73].

The investigators found after treatment, the serum selenium levels increased significantly [SMD = 2.59, 95% CI = 0.50-4.69].

The investigators concluded high serum selenium levels reduce risk of cervical cancer among women.

Original title:
Serum Selenium Levels and Cervical Cancer: Systematic Review and Meta-Analysis by He D, Wang Z, […], Chen D.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28255860

Additional information of El Mondo:
Find more information/studies on selenium, randomized controlled trials/cohort studies/subgroup analysis and cancer right here.

Univariate analysis is the simplest form of analyzing data. "Uni" means "one", thus in other words your data has only one variable.

High serum selenium levels can be obtained by consuming selenium-rich food items and/or taking selenium supplements.
 

Objectives:
Several epidemiological studies have suggested that vitamin E could reduce the risk of uterine cervical neoplasm. However, controversial data were presented by different reports. Therefore, this review article (meta-analysis) has been conducted.

Do both high vitamin E intake and circulating vitamin E levels reduce risk of uterine cervical neoplasm?

Study design:
This review article included 15 case-control studies, involving 3,741 cases (those with uterine cervical neoplasm) and 6,328 controls (those without uterine cervical neoplasm).

There was no obvious publication bias.

Results and conclusions:
The investigators found in pooled analysis that the highest intake of vitamin E significantly reduced risk of cervical neoplasia with 42% [OR = 0.58, 95% CI = 0.47-0.72, I2 = 83%]. In addition, both vitamin E intake and blood levels of vitamin E were negatively correlated with cervical neoplasia risk.

The investigators found in subgroup analysis that the highest intake of dietary vitamin E significantly reduced risk of cervical neoplasia with 32% [OR = 0.68, 95% CI = 0.49-0.94, I2 = 70%].

The investigators found in subgroup analysis that the highest vitamin E blood levels significantly reduced risk of cervical neoplasia with 48% [OR = 0.52, 95% CI = 0.40-0.69, I2 = 86%].

The investigators found in subgroup analysis that vitamin E significantly reduced risk of cervical neoplasia with 40% [OR = 0.60, 95% CI = 0.45-0.78, I2 = 84%] in studies conducted in America and Europe.

The investigators found in subgroup analysis that the highest intake of vitamin E significantly reduced risk of cervical neoplasia with 46% [OR = 0.54, 95% CI = 0.39-0.76, I2 = 75%] in studies conducted in Asia.

The investigators found subgroup analysis stratified by different types of cervical neoplasm indicated that the highest intake (or serum level) of vitamin E significantly decreased risk of cervical cancer with 47% [OR = 0.53, 95% CI = 0.390.73, I2 = 77%] and cervical intraepithelial neoplasia (CIN) with 46% [OR = 0.54, 95% CI = 0.43-0.70, I2 = 79%]. Meanwhile, sensitivity analysis to assess the influence of each single study on the pooled ORs by omitting a research in each turn, showed combined ORs were not substantially different, indicating that the results of this meta-analysis were stable and reliable.

The investigators concluded that both vitamin E intake and circulating vitamin E levels could reduce cervical neoplasia risk, including cervical cancer and cervical intraepithelial neoplasia. In other words, sufficient supplementation of vitamin E might reduce the risk of cervical neoplasia. However, more randomized controlled trials and cohort studies with high quality are required to further validate this inverse relationship.

Original title:
Effect of vitamin E supplementation on uterine cervical neoplasm: A meta-analysis of case-control studies by Hu X, Li S, [...], Zhu X.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5567498/

Additional information of El Mondo:
Find more information/studies on vitamin E, randomized controlled trials/cohort studies/subgroup analysis and cancer right here.

Higher intake of vitamin E is an intake which covers the recommended daily allowance of vitamin E of at least 1 day.

Objectives:
Dietary fat may play a role in lung carcinogenesis. Findings from epidemiologic studies, however, remain inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Is there an association between dietary fat intake and the risk of lung cancer?

Study design:
This review article included 10 prospective cohort studies with a total of 1,445,850 participants, of which 18,822 incident cases (subjects with lung cancer).

The mean follow-up was 9.4 years. 

Results and conclusions:
The investigators found high intakes of total fat were associated with a 7% significant increased risk of lung cancer [for highest v lowest quintile: HR = 1.07, 95% CI = 1.00 to 1.15].

The investigators found high intakes of saturated fat were associated with a 14% significant increased risk of lung cancer [for highest v lowest quintile: HR = 1.14, 95% CI = 1.07 to 1.22].

The investigators found high intakes of saturated fat were associated with a 23% significant increased risk of lung cancer among current smokers [for highest v lowest quintile: HR = 1.23, 95% CI = 1.13 to 1.35, p for trend 0.001].

The investigators found high intakes of saturated fat were associated with a 61% significant increased risk of squamous cell lung cancer [for highest v lowest quintile: HR = 1.61, 95% CI = 1.38 to 1.88].

The investigators found high intakes of saturated fat were associated with a 40% significant increased risk of small cell carcinoma lung cancer [for highest v lowest quintile: HR = 1.40, 95% CI = 1.17 to 1.67].

The investigators found a high intake of polyunsaturated fat was associated with a 8% significant decreased risk of lung cancer [for highest v lowest quintile: HR = 0.92, 95% CI = 0.87 to 0.98, p for trend = 0.02].

The investigators found a 5% energy substitution of saturated fat with polyunsaturated fat was associated with a 16% and 17% lower risk of small cell and squamous cell carcinoma, respectively.

The investigators found no associations for monounsaturated fat.

The investigators concluded that high intakes of polyunsaturated fat decrease risk of lung cancer, while high intakes of saturated fat increase risk of lung cancer, particularly among smokers and for squamous cell and small cell carcinoma.

Original title:
Dietary Fat Intake and Lung Cancer Risk: A Pooled Analysis by Yang JJ, Yu D1, […], Shu XO.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28742456

Additional information of El Mondo:
Find more information/studies on fat and cancer right here.

A daily diet with high intakes of saturated fat is a diet that is largely made up of meals/products with more than 10 En% saturated fat, with a small part of meals/products with less than 10 En% saturated fat. Practically, this means that all meals/products that you eat on a daily basis should contain on average more than 10 En% saturated fat.
Check here which products contain more than 10% En% saturated fat.

A daily diet with low intakes of saturated fat is a diet that is largely made up of meals/products with less than 7 En% saturated fat, with a small part of meals/products with more than 7 En% saturated fat. Practically, this means that all meals/products that you eat on a daily basis should contain on average less than 7 En% saturated fat.
Check here which products contain less than 7% En% saturated fat.

Objectives:
Recently, several randomized controlled trials (RCTs) reported the association between the use of vitamin or antioxidant supplements and the risk of bladder cancer. However, those findings remain inconsistent and some studies even reported that vitamin and antioxidant supplements increased the risk of bladder cancer. Therefore, this review article (meta-analysis) has been conducted.

Is there an association between the use of vitamin or antioxidant supplements and the risk of bladder cancer?

Study design:
This review article included 14 RCTs with a total of 147,383 participants, which involved 89,972 in the supplement group and 57,411 in the control group.

The supplementation and follow-up periods ranged between 1 and 13 years.

The types of vitamin and antioxidant supplements were as follows: vitamin A, vitamin B6, vitamin C, vitamin D, vitamin E, beta-carotene, folic acid and selenium.
The dosage regimens in individual trials were as follows: vitamin A (200 mg or 25,000, 36,000 or 40,000 IU daily), vitamin B6 (25 or 100 mg daily), vitamin C (2,000 mg daily), vitamin D (1,600 IU daily), vitamin E (50 mg or 400 IU daily), beta-carotene (20 or 30 mg daily; 50 mg alternate day; 75 mg daily for 3-month cycles), folic acid (1.6 mg daily) and selenium (200 μg daily).

Publication bias was not observed [Begg's funnel plot, symmetrical and Egger's test, p for bias = 0.378].

Results and conclusions:
The investigators found in fixed-effect meta-analysis of all 14 trials that vitamin or antioxidant supplementation was not associated with the risk of bladder cancer [RR = 1.04, 95% CI = 0.92-1.17, I2 = 39.7%].

The investigators found regarding types of supplements, any type of vitamin and antioxidant supplements had no beneficial effect on the risk of bladder cancer:
-vitamin A [RR = 0.86, 95% CI = 0.65-1.13, I2 = 61.7%, n = 5];
-vitamin B6 [RR = 0.77, 95% CI = 0.49-1.20, I2 = 78.8%, n = 3];
-vitamin C [RR = 0.74, 95% CI = 0.36-1.54, I2 = 88.8%, n = 2];
-vitamin D [RR = 1.05, 95% CI = 0.85-1.29, n = 1];
-vitamin E [RR = 0.91, 95% CI = 0.69-1.19, I2 = 60.9%, n = 6];
-beta-carotene [RR = 1.19, 95% CI = 0.96-1.46, I2 = 0.0%, n = 6];
-folate [RR = 1.05, 95% CI = 0.85-1.29, n = 1] and
-selenium [RR = 1.09, 95% CI = 0.81-1.46, I2 = 0.0%, n = 2].

The investigators found overall, there was no significant effect of vitamin and antioxidant supplements in the subgroup meta-analyses by various factors such as dose of supplements, type of cancer prevention, methodological quality, duration of treatment, provider of supplements, type of control and number of participants.
However, the risk of bladder cancer was marginally increased in trials with the use of beta-carotene alone [RR = 1.44, 95% CI = 1.00-2.09, I2 = 0.0%, n = 3].

The investigators concluded that vitamin and antioxidant supplements have no overall preventive effect against bladder cancer. Instead, subgroup meta-analyses showed that beta-carotene supplementation marginally increased the risk of bladder cancer. Even though further large, high-quality trials are required to confirm these associations, the effects (either beneficial or harmful) of vitamin or antioxidant supplements on bladder cancer should not be overemphasized.

Original title:
Effects of Vitamin and Antioxidant Supplements in Prevention of Bladder Cancer: a Meta-Analysis of Randomized Controlled Trials by Park SJ, Myung SK, […], Lee YJ.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5334161/

Additional information of El Mondo:
Find more information/studies on vitamins, selenium, beta-carotene, antioxidants and cancer right here.