Nutrition and health

Objectives:
The association between coffee consumption and the level of C-reactive protein (CRP) has been evaluated in several epidemiological studies with conflicting results. Therefore, this meta-analysis (systematic review) has been conducted.

Does coffee consumption reduce level of C-reactive protein in humans?

Study design:
This review article included a total of 9 cross-sectional studies.

Results and conclusions:
The investigators found according to the combined standard mean difference (SMD) between the highest and the lowest coffee intake category, coffee consumption was associated with a significantly lower level of serum CRP level [SMD = -0.34, 95% CI = -0.62 to -0.06, p = 0.016].

The investigators found subgroup analysis for CRP marker showed that coffee consumption was associated with a significantly lower level of serum high-sensitivity CRP (hsCRP) [SMD = -0.51, 95% CI = -0.88 to -0.14, p = 0.007], but not standard CRP [SMD = 0.02, 95% CI = -0.28 to 0.32, p = 0.913].

The investigators concluded that coffee consumption is associated with a lower level of serum CRP, particularly serum high-sensitivity CRP. However, more well-designed prospective cohort studies are needed to elaborate the concerned issues further.

Original title:
Is coffee consumption associated with a lower level of serum C-reactive protein? A meta-analysis of observational studies by Zhang Y and Zhang DZ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29405789

Additional information of El Mondo:
Find more information/studies on coffee and chronic disease right here.

 

Objectives:
In the past, some observational studies have been carried out on the relationship between milk and dairy intake and risk of acne occurrence. However, their results were conflicting. Therefore, this meta-analysis (systematic review) has been conducted.

Does milk and dairy intake increase risk of acne?

Study design:
This review article included observational studies.

Results and conclusions:
The investigators found for highest compared with lowest category of dairy intake a significantly increased risk of 161% for acne [OR = 2.61, 95% CI = 1.20 to 5.67].

Significant means that there is an association with a 95% confidence.

The investigators found for highest compared with lowest category of total milk intake a significantly increased risk of 48% for acne [OR = 1.48, 95% CI = 1.31 to 1.66].
Significantly means it can be said with a 95% confidence that a high total milk intake really increased the risk of getting acne with 48%. 

The investigators found for highest compared with lowest category of low-fat milk intake a significantly increased risk of 25% for acne [OR = 1.25, 95% CI = 1.10 to 1.43].
Significant because OR of 1 was not found in the 95% CI of 1.10 to 1.43. RR of 1 means no risk/association.

The investigators found for highest compared with lowest category of skim milk intake a significantly increased risk of 82% for acne [OR = 1.82, 95% CI = 1.34 to 2.47].

The investigators found results of dose-response analysis revealed a significant linear relationship between dairy, whole milk and skim milk and risk of acne and a nonlinear association between dairy, milk, low-fat milk and skim milk intake and acne.

The investigators concluded there is a positive relationship between dairy, total milk, whole milk, low-fat and skim milk consumption and acne occurrence. In contrary, there is no significant association between yogurt/cheese and acne development.

Original title:
Dairy intake and acne development: A meta-analysis of observational studies by Aghasi M, Golzarand M, […], Taheri F.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29778512

Additional information of El Mondo:
Find more information/studies on dairy products and chronic disease right here.
 

Objectives:
Epidemiological studies exploring the role of flavonoids intake in preventing type 2 diabetes mellitus (T2DM) showed inconsistent results. Therefore, this review article (meta-analysis) has been conducted.

Does flavonoids intake decrease risk of developing type 2 diabetes?

Study design:
This review article included 10 independent cohorts published between 2002 and 2017 with a total of 312,015 participants, of which 19,953 type 2 diabetes cases were identified during the follow-up periods from 4 to 28 years.
All participants were free of type 2 diabetes at baseline (at the beginning of the study), with age ranging from 28 to 75 years.
Dietary flavonoids intake was evaluated using food-frequency questionnaire and type 2 diabetes was frequently ascertained through medical records.
In the original studies, the median intake level of total flavonoids was 8.9 to 501.8 mg/day for the lowest categories and 33.2 to 1452.3 mg/day for the highest categories.
The most commonly adjusted variables included age, sex, total energy intake, body mass index, smoking, alcohol consumption and physical activity.
All included studies had a NOS score of ≥7, with an average score of 7.9, indicating the presence of high methodological quality.

There was no indication of publication bias from visual inspection of the funnel plot, which was further confirmed by Egger test [p = 0.253].

Results and conclusions:
The investigators found when compared with the lowest intake, the highest intake of total flavonoids was associated with a significantly 9% decreased risk of type 2 diabetes [RR = 0.91, 95% CI = 0.86-0.96, I2  =  21%, p =  0.257].
In stratified analyses, the pooled RR for total flavonoids intake was not modified by sample size, sex, follow-up duration and study location.
Leave-one-out sensitivity analysis showed that no individual study had a significant influence on the final result.

The investigators found in subgroup analyses when compared with the lowest intake, the highest intake of anthocyanidins significantly decreased risk of type 2 diabetes with 11% [RR = 0.89, 95% CI = 0.82-0.95].

The investigators found in subgroup analyses when compared with the lowest intake, the highest intake of flavan-3-ols significantly decreased risk of type 2 diabetes with 14% [RR = 0.86, 95% CI = 0.78-0.95].

The investigators found in subgroup analyses when compared with the lowest intake, the highest intake of flavonols significantly decreased risk of type 2 diabetes with 14% [RR = 0.86, 95% CI = 0.80-0.94].

The investigators found in subgroup analyses when compared with the lowest intake, the highest intake of isoflavones significantly decreased risk of type 2 diabetes with 9% [RR = 0.91, 95% CI = 0.84-0.98].

The investigators found in 9 cohort studies a curvilinear relationship between total flavonoids intake and type 2 diabetes risk [p for nonlinearity = 0.042] with a significant risk reduction at an intake of ≥550 mg/day.

The investigators found when assuming a linear association, the risk of type 2 diabetes was reduced by 5% [RR = 0.95, 95% CI = 0.93-0.97] for each 300-mg/day increment in total flavonoids intake.

The investigators concluded that intakes of total flavonoids, particularly ≥550 mg/day, anthocyanidins, flavan-3-ols, flavonols and isoflavones are associated with significantly decreased risks of type 2 diabetes in the highest versus lowest analyses. Additionally, the dose-response analysis suggest a curvilinear relationship of total flavonoids intake with type 2 diabetes risk; when assuming a linear manner, the risk of type 2 diabetes is reduced by 5% for an increment of 300 mg/day in total flavonoids intake.

Original title:
Flavonoids intake and risk of type 2 diabetes mellitus: A meta-analysis of prospective cohort studies by Xu H, Luo J, [...], Wen Q.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5959406/

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

Objectives:
There is an increasing trend in the consumption of poor-quality diets worldwide, contributing to the increase of non-communicable diseases. Diet directly influences physiological composition and subsequently physical health. Studies have shown that dietary macronutrient and energy content can influence the proportion of intramuscular fat (IMF), which mediates various metabolic and endocrine dysfunction. Therefore, this review article has been conducted.

Do different types of dietary macronutrient intake increase the proportion of intramuscular fat?

Study design:
This review article included 13 trials (RCTs, quasi-RCTs, controlled trials, randomized controlled crossover trials or controlled crossover trials).

High-fat diets were diets with a proportion of fat between 38 and 85 En%. Participants in high-fat diets were all young to middle aged adults with ages varying between 18 and 50 years.

Participants in starvation diets (a decrease of 25% calorie from weight maintenance energy requirements) and hypocaloric diets (890 calories per day, until 15% weight reduction) followed the diet for 8 days with a 3-week washout period in between.

Cohen’s criteria were used to determine the effect size of SMDs, where a SMD between 0.2 and 0.5 is small, a SMD between 0.5 and 0.8 is moderate and a SMD above 0.8 is large. SMDs below 0.2 were considered unsubstantial.

Results and conclusions:
The investigators found in 6 studies with in a total of 134 participants receiving a high-fat intervention and 135 people receiving a control intervention, that high-fat diets (38 and 85 En% fat) significantly increased the proportion of intramuscular fat [SMD = 1.24, 95% CI = 0.43-2.05, p  = 0.003, I2 = 87%].  
Sensitivity analysis (excluding studies with a quality value 20, smallest sample size 8 and those that do not specify participant characteristics) showed a significantly SMD of 1.26 [95% CI = 0.23-2.28, p = 0.02]. 

The investigators found diets with an increased proportion of carbohydrates decreased the proportion of intramuscular fat.
However, increasing caloric intake with carbohydrates compared to a standardized diet (55 En% carbohydrates, 30 En% fat and 15 En% protein) increased the proportion of intramuscular fat.

The investigators found starvation diets (a decrease of 25% calorie from weight maintenance energy requirements) increased intramuscular fat stores and hypocaloric diets (890 calories per day, until 15% weight reduction) did not result in any intramuscular fat proportion changes.

The investigators concluded that high-fat diets (38 y 85 En%), excessive caloric intake in the form of carbohydrates and short-term starvation diets are associated with increases in the proportion of intramuscular fat. However, further studies are needed to assess the effects of macronutrient combinations on intramuscular fat and the influence of diet-induced intramuscular fat alterations on health outcomes. In addition, intramuscular fat poses a possibly effective clinical marker of health.

Original title:
The Effects of Diet on the Proportion of Intramuscular Fat in Human Muscle: A Systematic Review and Meta-analysis by Ahmed S, Singh D, [...], Kumbhare D.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5826234/

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

Higher intramuscular fat levels are positively associated with insulin resistance and an increased risk of developing type 2 diabetes.

Objectives:
The evidence is mixed on the use of long chain omega 3 fatty acids in the prevention and management of childhood asthma. Therefore, this meta-analysis (systematic review) has been conducted.

Does fish consumption reduce risk of childhood asthma?

Study design:
This review article included 23 observational studies on fish intake in association with childhood asthma.

Results and conclusions:
The investigators found in 15/23 studies early introduction of fish (6-9 months) and regular consumption (at least once a week) improved asthma symptoms and reduced risk in children 0-14 years as compared to no fish consumption; 6/23 showed no effect and 2/23 studies suggested adverse effects.

The investigators found a significantly reduced risk of 25% [OR = 0.75, 95% CI = 0.60-0.95] for all fish intake on current asthma in children up to 4.5 years old. 

The investigators found a significantly reduced risk of 38% [OR = 0.62, 95% CI = 0.48-0.80] for all fish intake on current wheeze in children up to 4.5 years old.

The investigators found as compared to no fish intake, a significantly reduced risk of 65% [OR = 0.35, 95% CI = 0.18-0.67] for fatty fish intake on asthma in children 8-14 years old. 

The investigators concluded that introduction of fish early in life (6-9 months) and regular consumption of all fish (at least once a week) reduces asthma and wheeze in children up to 4.5 years old, while fatty fish intake has beneficial effects in older children (8-14 years). Future well-designed clinical trials are recommended to confirm the promising findings documented in this literature analysis.

Original title:
The role of fish intake on asthma in children: A meta-analysis of observational studies by Papamichael MM, Shrestha SK, [...], Erbas B.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29524247

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

Objectives:
Observationally, homocysteine is associated with higher risk of diabetes. Folate, which reduces homocysteine, is promising for the prevention and treatment of diabetes. Previous meta-analysis (review) of 3 trials suggested folate might lower hemoglobin A1c (HbA1c). Therefore, this review article (meta-analysis) has been conducted.

Have folic acid supplementation positive effects on insulin resistance and glycemic control, like HbA1c level and fasting glucose level?

Study design:
This review article included 18 RCTs with in total of 21,081 people with/without diabetes.

Results and conclusions:
The investigators found that folic acid (folate) supplementation significantly reduced fasting glucose level with 0.15 mmol/L [95% CI = -0.29 to -0.01]. Significant means that there is an association with a 95% confidence.

The investigators found that folic acid (folate) supplementation significantly reduced homeostatic model assessment-insulin resistance (HOMA-IR) with 0.83 [95% CI = -1.31 to -0.34].

The investigators found that folic acid (folate) supplementation significantly reduced fasting insulin level with 1.94 μIU/mL [95% CI = -3.28 to -0.61].

The investigators found that folic acid (folate) supplementation had no clear effect on diabetes or HbA1c level.

The investigators concluded that folic acid (folate) supplementation reduces both fasting glucose level, fasting insulin level and homeostatic model assessment-insulin resistance (HOMA-IR) but it has no effect on diabetes or HbA1c level.

Original title:
The effects of folate supplementation on glucose metabolism and risk of type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials by Zhao JV, Schooling CM and Zhao JX.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29501221

Additional information of El Mondo:
Find more information/studies on diabetes and folic acid right here.

Patients with diabetes often have both an increased fasting glucose level, HOMA-IR value and fasting insulin level.

Objectives:
The increasing prevalence of diabetes in the United Kingdom and worldwide calls for new approaches to its management and diets with low glycaemic index have been proposed as a useful means for managing glucose response. However, there are conflicting reports and differences in the results of studies in terms of their effectiveness. Furthermore, the impact of low-glycaemic index diets (low GI-diets) and their long-term use in patients with type 2 diabetes remains unclear. Therefore, this review article (meta-analysis) has been conducted.

Do patients with type 2 diabetes mellitus benefit from low-GI diets?

Study design:
This review article included 6 RCTs.

Results and conclusions:
The investigators found in 2 RCTs that low-glycaemic index (low-GI) diet resulted in a significant improvement in glycated haemoglobin (HbA1c) [0.05]:
low-GI diet Δ = -0.5% [95% CI = -0.61% to -0.39%] vs. high-cereal fibre diet Δ = -0.18% [95% CI = -0.29% to -0.07%] and;
low-GI legume diet Δ = -0.5% [95% = -0.6% to -0.4%] vs. high-wheat fibre diet Δ = -0.3% [95% Cl = -0.4 to -0.2%].

The investigators found in 4 RCTs significant improvements in fasting blood glucose in low-GI diets compared to higher-GI diets or control:
low-GI diet = [150.8 ± 8.7] vs. higher-GI diet = [157.8 ± 10.4 mg/dL, mean ± SD, p = 0.43];
low-GI diet = [127.7] vs. high-cereal fibre diet = [136.8 mg/dL, p = 0.02];
low-GI diet = [6.5 (5.6-8.4)] vs. standard diabetic diet = [6.7 (6.1-7.5 mmol/L), median and interquartile range p > 0.05] and;
low-GI diet = [7.3 ± 0.3] vs. conventional carbohydrate exchange diet = [7.7 ± 0.4 mmol/L, mean ± SEM (Standard Error of Mean), p 0.05].

The investigators concluded that the low-GI diet is more effective in controlling glycated haemoglobin (HbA1c) and fasting blood glucose compared with a higher-GI diet or control in patients with type 2 diabetes. It will useful to evaluate the long-term effectiveness of low-glycaemic index diet in patients with type 2 diabetes.

Original title:
The Effect of Dietary Glycaemic Index on Glycaemia in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials by Ojo O, Ojo OO, [...], Wang XH.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872791/

Additional information of El Mondo:
Find more information/studies on diabetes and GI-diets right here.

A low-GI diet is a diet with a lot of products/meals with a low GI.
Products/meals with a low GI are products/meals with a GI-number of 55 or less.
In daily life, products/meals with a low GI contain at least 1.5 grams fiber per 100 kcal. These products and meals contain at least 1.5 grams fiber per 100 kcal.
 

Objectives:
Type 2 diabetes mellitus (T2DM) is one of the most important public health issues. Vitamin K supplementation might have favorable effect on risk factors of T2DM. Therefore, this review article (meta-analysis) has been conducted.

Have vitamin K supplementation favorable effects on risk factors of type 2 diabetes mellitus?

Study design:
This review article included 5 RCTs with in total of 533 participants.

There was no evidence of publication bias.

Results and conclusions:
The investigators found overall, meta-analysis did not show any beneficial effect of vitamin K supplementation on both:
-fasting blood sugar levels [-0.91 mg/dL, 95% CI = -2.57 to 0.76, p = 0.28];
-fasting insulin levels [-0.35 μIU/mL, 95% CI = -1.70 to 1.00, p = 0.61];
-HOMA-IR [-0.06, 95% CI = -0.32 to -0.19, p = 0.63] and
-2-h oral glucose tolerance test [-4.00 mg/dL, 95% CI = -20.00 to 11.99, p = 0.62].

The investigators found sensitivity analysis showed that overall estimates were not affected by elimination of any study.

The investigators concluded that vitamin K supplementation has no significant effect on glycemic control in healthy subjects. However, further studies should be performed on diabetic and pre-diabetic patients to determine the effect of vitamin K supplementation on impaired glycemic control.

Original title:
Effect of Vitamin K Supplementation on Glycemic Control: A Systematic Review and Meta-Analysis of Clinical Trials by Shahdadian F, Mohammadi H and Rouhani M.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29523009

Additional information of El Mondo:
Find more information/studies on diabetes and vitamin K right here.
 

Objectives:
The actual effects of L-carnitine administration on leptin serum level is inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does L-carnitine supplementation reduce leptin serum level?

Study design:
This review article included 7 RCTs with 325 cases (group with L-carnitine administration) and 330 controls (group without L-carnitine administration).

Subgroup analysis to find the sources of heterogeneity showed that L-carnitine dosage [ 2 g: I2 = 00.0%, p = 0.408] and study population [diabetes: I2 = 46.7%, p = 0.153 and non-diabetes: I2 = 15.1%, p = 0.317] were the potential sources of heterogeneity.

Results and conclusions:
The investigators found that L-carnitine supplementation had no significant effect on serum leptin concentrations [WMD = -0.565 ng/mL, 95% CI = -2.417 to 1.287, p = 0.550, I2 = 84.3%, p  0.0001].

The investigators found in subgroup analysis that  ≥ 2 mg L-carnitine supplementation significantly reduced serum leptin concentrations [WMD = -2.742 ng/mL, 95% CI = -3.039 to -2.444, p  0.001].

The investigators found in subgroup analysis that L-carnitine supplementation significantly reduced serum leptin concentrations in diabetic patients [WMD = -2.946 ng/mL, 95% CI = -3.254 to -2.638, p  0.001].

The investigators found in subgroup analysis that L-carnitine supplementation during 12 weeks significantly reduced serum leptin concentrations [WMD = -2.772 ng/mL, 95% CI = -3.073 to -2.471, p  0.001].

The investigators concluded that at least 3 mg L-carnitine per day in the course of 12 weeks reduce serum leptin concentrations, especially in diabetic patients.

Original title:
The effect of L-carnitine supplementation on serum leptin concentrations: a systematic review and meta-analysis of randomized controlled trials by Nazary-Vannani A, Ghaedi E, […], Varkaneh HK.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29453657

Additional information of El Mondo:
Find more information/studies on diabetes and L-carnitine and diabetes right here.

L-carnitine is a non-essential amino acid, which is also found in foods.

Objectives:
Zinc is an essential trace element for living organisms and their biological processes. Zinc plays a key role in more than 300 enzymes and it is involved in cell communication, proliferation, differentiation and survival. Zinc also plays a role in regulating the immune system with implications in pathologies where zinc deficiency and inflammation are observed. Therefore, this meta-analysis (systematic review) has been conducted.

Do zinc deficiency increase risk of autoimmune disorders?

Study design:
This review article included 62 case-control studies.

The manner of collecting and investigating zinc samples was very heterogeneous.

Results and conclusions:
The investigators found in fixed model that serum zinc concentration of autoimmune disease patients was significantly lower than in controls [mean effect = -1.19, 95% CI = -1.26 to -1.11].

The investigators found in fixed model that plasma zinc concentration of autoimmune disease patients was significantly lower than in controls [mean effect = -3.97, 95% CI = -4.08 to -3.87].

The investigators concluded that a deficiency of zinc in serum and plasma increases risk of autoimmune disorders in humans.

Original title:
Zinc Status and Autoimmunity: A Systematic Review and Meta-Analysis by Sanna A, Firinu D, […], Valera P.

Link:
http://www.mdpi.com/2072-6643/10/1/68/htm

Additional information of El Mondo:
Find here more information/studies about zinc and chronic diseases.

An autoimmune disease is a condition in which your immune system mistakenly attacks your body. These are the most common autoimmune diseases:  

1. Addison’s disease: Caused by an adrenal hormone insufficiency. Addison’s disease can lead to muscle weakness and fatigue, nausea, weight loss, irritability, low blood pressure, low blood sugar and depression.
2. Celiac disease (gluten allergy): Celiac disease is a reaction to gluten (found in barley, rye and wheat) that causes damage to the lining of the small intestine.
3. Graves’ disease: Caused by extremely overactive thyroid gland. People who have Graves’ disease may have difficulty sleeping, bulging of the eyes, irritability, brittle hair, unexplained weight loss, sensitivity to heat, muscle weakness, light menstrual periods and shakiness of the hands. On the other hand, some people with Graves’ disease may experience no symptoms at all.
4. Hashimoto’s disease: Caused by inflammation of the thyroid gland. Although sometimes no symptoms occur, Hashimoto’s thyroiditis often results in a goiter (enlargement of the thyroid gland, which may be visible as a bulge in the neck), weight gain, fatigue, muscle weakness, depression, cold sensitivity, dry hair and skin, and constipation.
5. Inflammatory bowel disease: This disease refers to a group of inflammatory diseases of the colon and small intestine.
6. Multiple Sclerosis or MS: This disease affects the brain and spinal cord. People who have MS may experience weakness, trouble with balance and coordination, problems speaking and walking, tremors, paralysis and numbness in the extremities.
7. Psoriasis: This is a skin condition that causes redness and irritation as well as thick, flaky, silver-white patches.
8. Pernicious anemia: Caused by the inability to absorb vitamin B12 leading to a decrease in red blood cells.
9. Reactive arthritis: Caused by inflammation of joints, the urethra and eyes.
10. Raynaud’s phenomenon: People with Raynaud’s have a problem with blood flow, resulting in numbness, tingling of the fingers, discoloration, toes and tip of the nose with exposure to cold temperatures.
11. Rheumatoid arthritis: In rheumatoid arthritis, autoimmunity causes the immune system to attack tissues in the joints. It typically affects the small joints in your hands and feet causing painful swelling, stiffness and loss of movement in the joints that can eventually result in bone erosion and joint deformity.
12. Scleroderma: Scleroderma is a connective tissue disease that causes changes in skin, muscles, blood vessels and internal organs.
13. Sjögren’s syndrome: Caused by destruction of the glands that produce tears and saliva causing dry eyes and mouth.
14. Systemic lupus erythematosus: In lupus, antibodies made by the immune system attack the body. Systemic lupus erythematosus can affect skin, kidneys, joints and brain.
15. Type 1 diabetes: In type 1 diabetes, the immune system attacks cells in the pancreas that produce insulin. When your insulin levels are insufficient, your body cannot control your blood glucose level, which can lead to a number of problems, including kidney failure, stroke, vision loss, circulation problems and heart disease.

Objectives:
Fish oil supplementation has been shown to be associated with a lower risk of metabolic syndrome and benefit a wide range of chronic diseases, such as cardiovascular disease, type 2 diabetes and several types of cancers. However, the evidence of fish oil supplementation on glucose metabolism and insulin sensitivity is still controversial. Therefore, this review article (meta-analysis) has been conducted.

Does fish oil supplementation improve insulin sensitivity in humans?

Study design:
This review article included a total of 17 RCTs with 672 participants. One of the 17 studies was crossover design and others were parallel design.
The doses of active ingredients of fish oil (n-3 fatty acids) ranged from 1 g/d to 4 g/d. Duration of the interventions was ranged from 4 weeks to 24 weeks.
There was no suggestion of small study effect based on visual inspection of the funnel plot. Results of the Egger’s (p = 0.78) and Begg’s (p = 0.43) tests showed that there was no potential publication bias.

Results and conclusions:
The investigators found pooled analysis showed that fish oil supplementation had no effects on insulin sensitivity overall [SMD = 0.17, 95% CI = -0.15 to 0.48, p = 0.292, I2 = 58.1%, p = 0.001].

The investigators found subgroup analysis showed that fish oil supplementation significantly improved insulin sensitivity among people who were experiencing at least one symptom of metabolic disorders [SMD = 0.53, 95% CI = 0.17 to 0.88, p 0.001].

The investigators found subgroup analysis showed a positive effect of fish oil on insulin sensitivity among the short-term intervention group (12 weeks) rather than the long-term intervention group [SMD = 0.31, 95% CI = 0.01-0.61, p = 0.04].

The investigators found subgroup analysis showed that fish oil had no effects on insulin sensitivity among the healthy people or people with T2DM.

The investigators found there were no significant differences between subgroups of methods of insulin sensitivity and doses of omega-3 polyunsaturated fatty acids (n-3 PUFA) of fish oil supplementation.

The investigators found in sensitivity analysis that summary results did not differ significantly when omitting studies one at a time.

The investigators concluded that fish oil supplementation during 12 weeks improves insulin sensitivity among people who were experiencing at least one symptom of metabolic disorders.

Original title:
Fish oil supplementation and insulin sensitivity: a systematic review and meta-analysis by Gao H, Geng T, [...], Zhao Q.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5496233/

Additional information of El Mondo:
Find more information/studies on fish oil supplements and diabetes right here.

 

Objectives:
Women have a 50% risk of urinary tract infection (UTI) over their lifetime and 20-30% experience a subsequent urinary tract infection recurrence. Cranberry (Vaccinium spp.) has been advocated for treatment of urinary tract infection; however, its efficacy is controversial. Therefore, this review article (meta-analysis) has been conducted.

Does cranberry reduce the risk of urinary tract infection recurrence in healthy women?

Study design:
This review article included 7 RCTs conducted in healthy nonpregnant women aged ≥18 years with a history of urinary tract infection (n = 1498 participants).
Risk of bias indicated that 2 studies had high loss to follow-up or selective outcome reporting. Overall, the studies were relatively small, with only 2 having >300 participants.

Results and conclusions:
The investigators found that cranberry significantly reduced the risk of urinary tract infection by 26% [pooled risk ratio = 0.74, 95% CI = 0.55-0.98, I2 = 54%].

The investigators concluded that cranberry may be effective in preventing urinary tract infection recurrence in generally healthy women. May be effective because the studies were relatively small, with only 2 having >300 participants. Therefore, larger high-quality studies are needed to confirm these findings.

Original title:
Cranberry Reduces the Risk of Urinary Tract Infection Recurrence in Otherwise Healthy Women: A Systematic Review and Meta-Analysis by Zhuxuan Fu, DeAnn Liska, […], Mei Chung.

Link:
http://jn.nutrition.org/content/147/12/2282.abstract

Additional information of El Mondo:
Find more information/studies on chronic disease and fruit right here.
 

Objectives:
Epidemiological studies have provided controversial evidence between beverage consumption and the risk of ulcerative colitis (UC). Therefore, this review article (meta-analysis) has been conducted.

Is there a relationship between beverage consumption and risk of ulcerative colitis?

Study design:
This review article included 13 case-control studies and 3 prospective cohort studies, with a total of 3,689 cases (subjects with ulcerative colitis) and 335,339 controls (subjects without ulcerative colitis).

Egger test detected no significant publication bias.

Results and conclusions:
The investigators found high intake of soft drinks versus low intake, significantly increased risk of ulcerative colitis with 69% [pooled RR = 1.69, 95% CI = 1.24-2.30, I2  =  12.9%, p  = 0 .332].
In subgroup analysis, no substantial changes of the primary result were found between subgroups.

The investigators found high tea consumption versus low consumption, significantly decreased risk of ulcerative colitis with 31% [pooled RR = 0.69, 95% CI = 0.58-0.83, I2  =  0.0%, p  = 0 .697].
In subgroup analysis, no substantial changes of the primary result were found between subgroups.

The investigators found no significant association between alcohol [pooled RR = 1.08, 95% CI = 0.66-1.51] or coffee consumption [pooled RR = 0.58, 95% CI = 0.33-1.05, I2  =  87.5%, p    0.001] and risk of ulcerative colitis. No significant association because RR of 1 was found in the 95% CI of 0.66 to 1.51. RR of 1 means no risk/association.

The investigators concluded high consumption of soft drinks increases the risk of ulcerative colitis, while high tea consumption decreases the risk.

Original title:
Beverage consumption and risk of ulcerative colitis. Systematic review and meta-analysis of epidemiological studies by Nie JY and Zhao Q.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5728934/

Additional information of El Mondo:
Find more information/studies on chronic disease, alcohol and tea consumption right here.
 

Objectives:
The role of omega-3 polyunsaturated fatty acids (omega-3 or n-3 PUFAs) in the pathogenesis and treatment of children and adolescents with attention deficit hyperactivity disorder (ADHD) is unclear. Therefore, this review article (meta-analysis) has been conducted.

Do children and adolescents with attention deficit hyperactivity disorder (ADHD) benefit from n-3 PUFA supplementation?

Study design:
This review article included 7 RCTs and 7 case-control studies.

Results and conclusions:
The investigators found in 7 RCTs (n = 534 randomised youth with ADHD) n-3 PUFAs supplementation significantly improved ADHD clinical symptom scores [g = 0.38, p 0.0001].

The investigators found in 3 RCTs (n = 214 randomised youth with ADHD) n-3 PUFAs supplementation significantly improved cognitive measures associated with attention [g = 1.09, p = 0.001].

The investigators found children and adolescents with ADHD had lower levels of DHA [7 case-control studies, n = 412, g = -0.76, p = 0.0002], EPA (7 case-control studies, n = 468, g = -0.38, p = 0.0008] and total n-3 PUFAs [6 case-control studies, n = 396, g = -0.58, p = 0.0001].

The investigators concluded there is evidence that n-3 PUFAs supplementation monotherapy improves clinical symptoms and cognitive performances in children and adolescents with ADHD and that these youth have a deficiency in n-3 PUFAs levels. These findings provide further support to the rationale for using n-3 PUFAs as a treatment option for ADHD.

Original title:
Omega-3 Polyunsaturated Fatty Acids in Youths with Attention Deficit Hyperactivity Disorder (ADHD): A Systematic Review and Meta-Analysis of Clinical Trials and Biological Studies by Chang JC, Su KP, [...], Pariante CM.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28741625

Additional information of El Mondo:
Find more information/studies on chronic disease, n-3 PUFA right here.
EPA and DHA are n-3 PUFA.

Objectives:
Recent data pose the question whether conservative management of chronic kidney disease (CKD) by means of a low-protein diet can be a safe and effective means to avoid or defer transition to dialysis therapy without causing protein-energy wasting or cachexia. Therefore, this review article (meta-analysis) has been conducted.

Do subjects with chronic kidney disease benefit from a low-protein diet?

Study design:
This review article included 16 controlled trials of low-protein diet in chronic kidney disease that met the stringent qualification criteria including having 30 or more participants.

Results and conclusions:
The investigators found compared with diets with protein intake of >0.8 g/kg/day, diets with restricted protein intake (0.8 g/kg/day) were associated with higher serum bicarbonate levels, lower phosphorus levels, lower azotemia, lower rates of progression to end-stage renal disease and a trend towards lower rates of all-cause death.

The investigators found compared with diets with protein intake of >0.8 g/kg/day, very-low-protein diets (protein intake 0.4 g/kg/day) were associated with greater preservation of kidney function and reduction in the rate of progression to end-stage renal disease.

The investigators found safety and adherence to a low-protein diet was not inferior to a normal protein diet and there was no difference in the rate of malnutrition or protein-energy wasting.

The investigators concluded a low-protein diet, particularly protein intake 0.4 g/kg/day, appears to enhance the conservative management of non-dialysis-dependent chronic kidney disease and may be considered as a potential option for chronic kidney disease patients who wish to avoid or defer dialysis initiation and to slow down the progression of chronic kidney disease, while the risk of protein-energy wasting and cachexia remains minimal.
 
Original title:
Low-protein diet for conservative management of chronic kidney disease: a systematic review and meta-analysis of controlled trials by Rhee CM, Ahmadi SF, [...], Kalantar-Zadeh K.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29094800

Additional information of El Mondo:
Find more information/studies on chronic disease and protein right here.
A protein intake of 0.8 g/kg/day usually corresponds to a diet with 11 En% protein.
A protein intake of 0.4 g/kg/day usually corresponds to a diet with 5.5 En% protein.
A diet with 5.5 En% protein is a diet with a lot of products with 5.5 En% protein. Check here which products contain 5.5 En% protein.
 

Objectives:
The potential glucose-lowering effects of pomegranate have been reported in animal and observational studies, but intervention studies in humans have generated mixed results. Therefore, this review article (meta-analysis) has been conducted.

What are the effects of pomegranate supplementation on measures of glucose control, insulin levels and insulin sensitivity in humans?

Study design:
This review article included 16 RCTs with 538 subjects. 14 trials adopted parallel study designs and the 2 remaining trials used crossover designs.
The total number of subjects included in each study ranged from 14 to 74 subjects.
The mean age of participants in each trial ranged from 30 to 70 years, with differing age ranges in most studies.
11 studies used pomegranate juice as a supplement (the dosage ranged from 120 to 500 ml/day).
2 studies used pomegranate seed oil as treatments (the dosage ranged from 400 to 2000 mg/day).
3 studies utilized pomegranate extract as the intervention (the dosage ranged from 710 to 1420 mg/day).  
The duration of the pomegranate intervention varied from 1 to 12 weeks (median: 5.5 weeks).

Overall, significant heterogeneity was detected for FBI and HOMA-IR, but subgroup analysis could not identify factors significantly influencing these parameters.
No significant publication bias was found.

Results and conclusions:
The investigators found that pomegranate did not significantly affect the measures of:
-FBG (fasting blood glucose) [WMD = -0.6 mg/dL, 95% CI = -2.79 to 1.58, p = 0.59, I2 = 0%];
-FBI (fasting blood insulin) [WMD = 0.29 μIU/mL, 95% CI = -1.16 to 1.75, p = 0.70, I2 = 60.4%];
-HOMA-IR (homeostatic model assessment of insulin resistance) [WMD = -0.04, 95% CI = -0.53 to 0.46, p = 0.88, I2 = 59.8%] or;
-HbA1c (glycated haemoglobin) [WMD = -0.11%, 95% CI = -0.39 to 0.18, p = 0.46, I2 = 0%].
These results were robust in sensitivity analysis.

The investigators found meta-regression analysis showed that the factor (dose of pomegranate juice supplementation) was not associated with the treatment effects on FBG level [coefficient = -0.006, 95% CI = -0.023 to 0.011, p = 0.46].

The investigators found no significant difference in the FBG-lowering effect between trials that were conducted in subjects with cardiovascular disease risk [WMD = 0.30 mg/dL, 95% CI = -2.36 to 2.97, p = 0.82] and those that were conducted in healthy individuals [WMD = -2.53 mg/dL, 95% CI = -6.36 to 1.30, p = 0.19].

The investigators found no statistically significant differences in the pooled effects of pomegranate on FBG in the subgroups stratified by study designs, intervention durations, types of intervention, baseline BMI and baseline FBG levels (FBG levels at the beginning of the studie).

The investigators concluded pomegranate supplements have no favourable effect on improvements in glucose and insulin metabolism. The current evidence suggests that daily pomegranate supplementation is not recommended as a potential therapeutic strategy in glycemic management. Further large-scale RCTs with longer duration are required to confirm these results.

Original title:
Lack of efficacy of pomegranate supplementation for glucose management, insulin levels and sensitivity: evidence from a systematic review and meta-analysis by Huang H, Liao D, […], Zhu Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5629805/

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

Objectives:
Over 200 clinical trials have examined the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplements on risk factors associated with cardiovascular disease. However, an updated analysis of the evidence is lacking. Therefore, this review article (meta-analysis) has been conducted.

Do EPA and DHA supplements reduce risk of cardiovascular diseases?

Study design:
This review article included 171 RCTs with acceptable quality (Jadad score ≥3).

Results and conclusions:
The investigators found compared to placebo-control, EPA and DHA supplements produced significant reductions of triglycerides of 0.368 mmol/L [95% CI = -0.427 to -0.309].
The triglyceride-lowering effect was dose-dependent.

The investigators found compared to placebo-control, EPA and DHA supplements produced significant reductions of systolic blood pressure of 2.195 mmHg [95% CI = -3.172 to -1.217].

The investigators found compared to placebo-control, EPA and DHA supplements produced significant reductions of diastolic blood pressure of 1.08 mmHg [95% CI = -1.716 to -0.444].

The investigators found compared to placebo-control, EPA and DHA supplements produced significant reductions of heart rate of 1.37 bpm [95% CI = -2.41 to -0.325].

The investigators found compared to placebo-control, EPA and DHA supplements produced significant reductions of C-reactive protein of 0.343 mg/L [95% CI = -0.454 to -0.232].

The investigators found compared to placebo-control, EPA and DHA supplements produced a significant increase of LDL cholesterol (bad cholesterol) [mean difference = 0.150 mmol/L, 95% CI = 0.058 to 0.243].

The investigators found compared to placebo-control, EPA and DHA supplements produced a significant increase of HDL cholesterol (good cholesterol) [mean difference = 0.039 mmol/L, 95% CI = 0.024-0.054].

The investigators concluded EPA and DHA supplements have lipid-lowering, hypotensive, anti-arrhythmic and anti-inflammatory effects.

Original title:
Eicosapentaenoic acid and docosahexaenoic acid containing supplements modulate risk factors for cardiovascular disease: a meta-analysis of randomised placebo-control human clinical trials by AbuMweis S, Jew S, […], Agraib L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28675488

Additional information of El Mondo:
Find more information/studies on EPA and DHA, cholesterol and cardiovascular diseases right here. 

Objectives:
The results of randomized controlled trials (RCTs) investigating resveratrol supplementation on risk factors of non-communicable diseases (NCDs) have been inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does resveratrol supplementation reduce risk of non-communicable diseases?

Study design:
This review article included 29 RCTs (30 treatment arms) with 1069 participants.

Results and conclusions:
The investigators found that resveratrol supplementation significantly reduced the concentrations of:
-fasting glucose [-4.77 mg/dL, 95% CI = -9.33 to -0.21 mg/dL, p = 0.040];
-total cholesterol (TC) [-9.75 mg/dL, 95% CI = -17.04 to -2.46 mg/dL, p = 0.009] and;
-C-reactive protein (CRP) [-0.81 mg/L, 95% CI = -1.42 to -0.21 mg/L, p = 0.009].

The investigators found that resveratrol intervention exerted significant reductions in systolic blood pressure (SBP) and diastolic blood pressure (DBP) in subjects with type 2 diabetes mellitus (T2DM).

The investigators found subgroup analysis also showed that the trials with resveratrol intervention ≥3 months significantly reduced the low-density lipoprotein (LDL) cholesterol (bad cholesterol), diastolic blood pressure and glycated hemoglobin (HbA1c) values.

The investigators found that resveratrol intervention had no favourable effects in altering high-density lipoprotein (HDL) cholesterol (good cholesterol), triglyceride (TAG) and homeostasis model assessment of insulin resistance (HOMA-IR).

The investigators concluded resveratrol supplementation ≥3 months has favourable effects on several risk factors of non-communicable diseases.

Original title:
Effects of resveratrol supplementation on risk factors of non-communicable diseases: A meta-analysis of randomized controlled trials by Guo XF, Li JM, [...], Li D.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28933578

Additional information of El Mondo:
Find more information/studies on flavonoids, cholesterol, blood pressure, diabetes and chronic diseases right here.

Non-communicable or chronic diseases are diseases of long duration and generally slow progression. The four main types of non-communicable diseases are cardiovascular diseases (like heart attacks and stroke), cancer, chronic respiratory diseases (such as chronic obstructed pulmonary disease and asthma) and diabetes.

Non-communicable diseases are by far the leading cause of death in the world.
 

Objectives:
Do patients with type 2 diabetes benefit from a low carbohydrate diet?

Study design:
This review article included a total of 9 RCTs with 734 patients with type 2 diabetes.

Results and conclusions:
The investigators found that low carbohydrate diet significantly reduced HbA1c level [WMD = -0.44, 95% CI = -0.61 to -0.26, p= 0.00] of patients with type 2 diabetes.

The investigators found that low carbohydrate diet significantly reduced triglycerides concentration [WMD = -0.33, 95% CI = -0.45 to -0.21, p = 0.00] of patients with type 2 diabetes.

The investigators found that low carbohydrate diet significantly increased HDL cholesterol concentration (WMD = 0.07, 95% CI = 0.03 to 0.11, p = 0.00] of patients with type 2 diabetes.

The investigators found that low carbohydrate diet was not associated with decreased level of total cholesterol and LDL cholesterol.

The investigators found subgroup analyses showed that short term intervention of low carbohydrate diet was effective for weight loss [WMD = -1.18, 95% CI = -2.32 to -0.04, p = 0.04] in patients with type 2 diabetes.

The investigators concluded there is a beneficial effect of low carbohydrate diet intervention on glucose control in patients with type 2 diabetes. The low carbohydrate diet intervention also has a positive effect on triglycerides and HDL cholesterol concentrations, but without significant effect on long term weight loss.

Original title:
Efficacy of low carbohydrate diet for type 2 diabetes mellitus management: A systematic review and meta-analysis of randomized controlled trials by Meng Y, Bai H, […], Chen L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28750216

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

A low carbohydrate diet is a diet that is largely made up of meals/products with 20-40 En% carbohydrate. Practically, this means that all meals/products that you eat on a daily basis should on average contain 20-40 En% carbohydrate.
20-40 En% carbohydrate means that the total amounts of carbohydrate make up for a 20-40% of the total kcal of the diet. Check here which products contain 20-40 En% carbohydrate.

Objectives:
Polyunsaturated fats (PUFAs) have been shown to reduce type 2 diabetes (T2DM) risk and improve insulin responsiveness in T2DM subjects, but whether the plant sources of omega-3 PUFA (alpha-linolenic acid [ALA]) have an effect on glycemic control requires further investigation. Therefore, this review article (meta-analysis) has been conducted.

Does alpha-linolenic acid dietary intake reduce diabetes risk?

Study design:
This review article included a total of 8 RCTs involving 212 participants with type 2 diabetes.
5 trials (62.5%) were parallel designs and 3 (37.5%) were crossover designs.
Participants were generally middle-aged (median age  =  54 years, range  =  47-64 years) and overweight or obese (median BMI  =  30.7, range  =  28.0-33.2).
Overall, participants had controlled diabetes (median HbA1c = 6.8%, median FBG = 7.95 mmol/L) and the majority of studies indicated the use of hypoglycemic drugs or other medications, although all studies excluded the use of insulin therapy.
The dose of ALA ranged from 1.5 to 7.4 g/day with a median assigned dose of 4.4, 5.4 and 5.4 g/day of ALA for trials that reported HbA1c, FBG and FBI, respectively.
The median duration of the treatment was 3 months, ranging from 2 to 12 months.
7 studies (87.5%) were considered high quality (MQS ≥8).

Results and conclusions:
The investigators found compared to a control diet, a median dose of 4.4 g/day of alpha-linolenic acid intake for a median duration of 3 months did not affect HbA1c (%) of patients with type 2 diabetes [MD =  -0.01, 95% = -0.32 to 0.31, p  =  0.96].

The investigators found compared to a control diet, a median alpha-linolenic acid dose of 5.4 g/day did not lower fasting blood glucose (FBG) of patients with type 2 diabetes [MD  = 0 .07, 95% CI = -0.61 to 0.76, p  = 0 .84] or fasting blood insulin (FBI) of patients with type 2 diabetes [MD  =  7.03, 95% CI = -5.84 to 19.89, p  = 0 .28].

The investigators found summary effect estimates were generally compromised by considerable and unexplained heterogeneity [I2 ≥ 75%].

The investigators found in the subgroup analysis of continuous predictors, a reduction in HbA1c (%) and FBG (mmol/L) was significantly associated with an increased intake of ALA.

The investigators found further adjustment for publication bias using Duval and Tweedie's trim-and-fill analysis provided an adjusted, significant MD of 0.25 [95% CI = -0.38 to -0.12, 0.001) for HbA1c (%).

The investigators concluded alpha-linolenic acid-enriched diet with a median alpha-linolenic acid dose of 4.4 g/day during 3 months has no effects on HbA1c, FBG or FBI in patients with type 2 diabetes. The scarce number of existing RCTs and the presence of heterogeneity in the meta-analysis limit the ability to make firm conclusions about alpha-linolenic acid in type 2 diabetes management. The potential for alpha-linolenic acid to have dose-dependent effects warrants further research in this area.

Original title:
The effect of alpha-linolenic acid on glycemic control in individuals with type 2 diabetes: A systematic review and meta-analysis of randomized controlled clinical trials by Jovanovski E1, Li D, […], Vuksan V.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5457843/

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

4.4 g/day alpha-linolenic acid can be achieved by taking 1 to 2 tablespoons of flax or salba-chia seeds or about 12 whole walnuts per day.

 

Objectives:
Promising experimental studies suggest that quercetin has potential anti-inflammatory effects. However, the results of current clinical trials on quercetin's effects on the C-reactive protein (CRP), a sensitive inflammatory biomarker, are ambiguous. Therefore, this review article (meta-analysis) has been conducted.

Does quercetin supplementation reduce CRP levels?

Study design:
This review article included 7 RCTs with 10 treatment arms.

Results and conclusions:
The investigators found a significant reduction of circulating CRP levels [WMD = -0.33 mg/L, 95% CI = -0.50 to -0.15, p 0.001] following quercetin supplementation.

The investigators found in subgroup analysis, a significant reducing effect in trials with ≥500 mg/day dosage [WMD = -0.34 mg/L, 95% CI = -0.52 to -0.16, p ≤ 0.001] and in those with CRP 3 mg/L [WMD = -0.34 mg/L, 95% CI = -0.51 to -0.18, p ≤ 0.001].

The investigators found in meta-regression, no association between changes in CRP concentrations, dose of supplementation and CRP baseline values.

The investigators concluded quercetin supplementation reduces circulating C-reactive protein levels; especially at doses above 500 mg/day and in patients with CRP 3 mg/L.
 
Original title:
Effects of supplementation with quercetin on plasma C-reactive protein concentrations: a systematic review and meta-analysis of randomized controlled trials by Mohammadi-Sartang M, Mazloom Z, […], Firoozi D.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28537580

Additional information of El Mondo:
Find more information/studies on chronic disease and flavonoids right here. Quercetin is a flavonoid.

Objectives:
Previous studies have demonstrated that asthma might be associated with an increase in cardiovascular disease (CVD) and death. However, this relationship differs by gender. Therefore, this review article (meta-analysis) has been conducted.

Is asthma associate with an increase risk in cardiovascular disease and death among men and women?

Study design:
This review article included 4 retrospective cohort studies and 6 prospective cohort studies. The length of follow-up ranged from 4.5 to 27 years. The sample sizes of the cohorts ranged from 1,233 to 151,620 (a total of 406,426).

There was no evidence of publication bias [Begg’s, p = 1.000 and Egger’s linear regression, p = 0.150].

Results and conclusions:
The investigators found overall, subjects with asthma experienced a significant increased risk of 33% for cardiovascular disease events [RR = 1.33, 95% CI = 1.15-1.53, p 0.0001, I2 = 88%, p 0.00001]. These findings remained consistent after sensitivity analysis by omitting one study each time.

The investigators found in subgroup analyses that women with asthma had a significantly higher risk of cardiovascular disease as compared to the reference group [RR = 1.55, 95% CI = 1.20-2.00, p = 0.0007, I2 = 84%], whereas no significant association was found in men [RR = 1.20, I2 = 83%, 95% CI = 0.92-1.56, p = 0.17]. However, the combined RR value was 1.36, 95% CI = 1.15-1.62, p = 0.0003]. These findings remained consistent after sensitivity analysis by omitting one study each time.
To further explore the interaction between gender and asthma on cardiovascular disease risk, the “test for subgroup differences” were examined and gave a p = 0.17, which suggested that the influence of gender on the association between asthma and cardiovascular disease risk was not statistically significant. Therefore, it cannot confirm or refute a significant difference in the incidence of cardiovascular disease between male and female asthmatic patients.

The investigators found asthma was associated with an increased risk of 36% of all-cause mortality in a random effects model as compared to reference subjects without asthma [RR = 1.36, 95% CI = 1.01-1.83, p = 0.05, I2 = 62%, p = 0.05]. These findings remained consistent after sensitivity analysis by omitting one study each time.

The investigators concluded there is an association between asthma and an increased risk of cardiovascular disease and all-cause mortality and women with asthma have a higher risk of cardiovascular disease than men with asthma. These findings indicate a need for early detection and intervention during general outpatient visits in asthmatics who may have potential cardiovascular disease complications or mortality.

Original title:
Asthma and risk of cardiovascular disease or all-cause mortality: a meta-analysis by Xu M, Xu J and Yang X.

Link:
http://www.annsaudimed.net/index.php/vol37/vol37iss2/1109.html

Additional information of El Mondo:
Find more information/studies on chronic disease right here.

Objectives:
Iron deficiency is a prevalent nutritional disease and fatigue is a common complaint in the general and patient population, however, the association between iron deficiency without anaemia (IDNA) and fatigue is unclear. Therefore, this review article (meta-analysis) has been conducted.

Does improving iron status decrease fatigue in patients with iron deficiency without anaemia?

Study design:
This review article included a total of 6 RCTs and 6 cross-sectional studies.

Results and conclusions:
The investigators found in the meta-analysis of 6 RCTs, a significant therapeutic effect of iron supplements in fatigue patients with iron deficiency without anaemia [pooled effect size = 0.33, 95% CI = 0.17 to 0.48, I2 = 0.0%, p 0.0001]. A sensitivity analysis found that the overall results (i.e. significant association) were robust.

The investigators found in the meta-analysis of 6 cross-sectional studies, a non-significant therapeutic effect of iron supplements in fatigue patients with iron deficiency without anaemia [pooled effect size = 0.10, 95% CI = -0.11 to 0.31, I2 = 57.4%, p = 0.362]. A sensitivity analysis found that the overall results (i.e. no significant association) were not robust, however, removal of one study made the outcomes significant.

The investigators concluded improving iron status decreases fatigue in patients with iron deficiency without anaemia. However, further research is necessary to identify diagnostic criteria for selecting fatigue patients who might benefit from iron therapy and to assess the prevalence of patients with iron deficiency without anaemia in the general population.

Original title:
Iron deficiency without anaemia is a potential cause of fatigue: meta-analyses of randomised controlled trials and cross-sectional studies by Yokoi K and Konomi A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28625177

Additional information of El Mondo:
Find more information/studies on iron right here.

Objectives:
It has been unclear whether supplemental probiotics therapy improves clinical outcomes in type 2 diabetic patients. Therefore, this meta-analysis (systematic review) has been conducted.

Do probiotics supplements improve clinical outcomes in type 2 diabetic patients?

Study design:
This review article included 12 RCTs involving 684 type 2 diabetic patients.

Results and conclusions:
The investigators found a significant decreased glucose level in the probiotics group [pooled standardized mean difference = -0.18 mg/dL, 95% CI = -0.35 to -0.01, p = 0.04, I2 = 64%, p = 0.004] compared to the control group.

The investigators found a significant reduction in HbA1c in the probiotics group [pooled standardized mean difference = -0.38%, 95% CI = -0.62 to -0.14, p = 0.002, I2 = 0%, p = 0.72] compared to the control group.

The investigators found a significant reduction in fasting insulin level in the probiotics group [pooled standardized mean difference = -0.38, 95% CI = -0.59 to -0.18, p = 0.003, I2 = 0%, p = 0.81] compared to the control group.

The investigators found a significant reduced HOMA-IR level in the probiotics group [pooled standardized mean difference = -0.99, 95% CI = -1.52 to -0.4, p = 0.0002, I2 = 86%, p 0.00001] compared to the control group.

The investigators found a significant reduced CRP level in the probiotics group [pooled standardized mean difference = -1.34 mg/L, 95% CI = -1.76 to -0.92, p 0.00001, I2 = 90%, p 0.00001] compared to the control group.

The investigators found a non-significant reduction in both triglyceride levels [SMD = -0.23, 95% CI = -0.48 to 0.02, p = 0.07, I2 = 52%, p = 0.03] and cholesterol levels [total cholesterol: SMD = -0.18, 95% CI = -0.42 to 0.06, p = 0.14, I2 = 47%, p = 0.05 and LDL-cholesterol: SMD = -0.03, 95% CI = -0.20 to 0.14, p = 0.73, I2 = 3%, p = 0.41] in the probiotics group compared to the control group.

The investigators concluded that probiotics supplementation is associated with significant improvement in HbA1c and fasting insulin in type 2 diabetes patients. These results may provide evidence for encouraging use of probiotics in patients with type 2 diabetes mellitus. However, more randomized placebo-controlled trials with larger sample sizes are warranted to confirm these findings.

Original title:
Effect of Probiotics on Glucose and Lipid Metabolism in Type 2 Diabetes Mellitus: A Meta-Analysis of 12 Randomized Controlled Trials by Yao K, Zeng L, [...], Zou X.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5491138/

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

Objectives:
Dietary intake is potentially associated with the onset of Crohn’s disease (CD), but evidence from epidemiological studies has remained unclear. Therefore, this review article (meta-analysis) has been conducted.

Is there a positive association between fat, carbohydrate or protein intake and the risk of Crohn’s disease?

Study design:
This review article included 4 case-control studies with a total of 311 Crohn’s disease cases and 660 controls and 5 prospective cohort studies with a total of 238,887 participants and 482 Crohn’s disease cases.

The Egger’s test detected no obvious publication bias in fiber (p = 0.708), while there were not enough studies to conduct the analyses for carbohydrate, fat and protein.

Results and conclusions:
The investigators found no evidence of a non-linear relationship between total carbohydrate intake and Crohn’s disease risk [p for non-linearity = 0.376].

The investigators found no association between 10 g increment/day of total carbohydrate intake and Crohn’s disease risk [RR = 0.991, 95% CI = 0.978-1.004, I2 = 0.0%, p = 0.439]. No association because RR of 1 was found in the 95% CI of 0.978 to 1.004. RR of 1 means no risk/association.

The investigators found no evidence of a non-linear relationship between total fat intake and Crohn’s disease risk [p for non-linearity = 0.281].

The investigators found no association between 10 g increment/day of total fat intake and Crohn’s disease risk [RR = 1.018, 95% CI = 0.969-1.069, I2 = 44.6%, p = 0.125].

The investigators found no evidence of a non-linear relationship between total protein intake and Crohn’s disease risk [p for non-linearity = 0.163].

The investigators found no association between 10 g increment/day of total protein intake and Crohn’s disease risk [RR = 1.029, 95% CI = 0.955-1.109, I2 = 54.7%, p = 0.085].

The investigators found a non-linear relationship between fiber dietary intake and Crohn’s disease risk [p for non-linearity = 0.019].

The investigators found a significant reduced risk of 14.7% for Crohn’s disease for per 10 g increment/day of fiber [RR = 0.853, 95% CI = 0.762-0.955]. However, the protective role of fiber dietary intake in the development of Crohn’s disease was gone after adjustment for the risk factor smoking [RR for per 10 g increment/day = 0.890, 95% CI = 0.776-1.020].

The investigators found a non-linear relationship between sucrose intake and Crohn’s disease risk [p for non-linearity = 0.023].

The investigators found a significant increased risk of 8.8% for Crohn’s disease for per 10 g increment/day of sucrose [RR = 1.088, 95% CI = 1.020-1.160, I2 = 0.0%, p = 0.39]. Significant means it can be said with a 95% confidence that each 10 g increment/day of sucrose really increased the risk of Crohn’s disease. 

The investigators concluded there is a lack of association between total carbohydrate, fat or protein intake and the risk of Crohn’s disease, while high fiber dietary intake might decrease the risk but the association was influenced by study design and smoking adjustment. High sucrose intake might increase the risk of Crohn’s disease. However, large-scale prospective designed studies are needed to confirm these findings.

Original title:
Macronutrient Intake and Risk of Crohn’s Disease: Systematic Review and Dose–Response Meta-Analysis of Epidemiological Studies by Zeng L, Hu S, [...], Tan Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5452230/

Additional information of El Mondo:
Find more information/studies on fat, protein, carbohydrate and fiber right here.