Nutrition and health

Objectives:
Isoflavones have a structure similar to 17β-estradiol, so they may be useful to postmenopausal women in preventing bone loss related to estrogen deficiency. Therefore, this review article has been conducted.

Do isoflavone supplements increase bone mineral density (BMD) in postmenopausal women?

Study design:
This review article included 63 RCTs, involving 6,427 postmenopausal women.

Isoflavone interventions were generally safe and well tolerated.

Results and conclusions:
The investigators found statistically significant differences in bone mineral density at the last follow-up visit between the two groups (isoflavones vs. control) at the lumbar spine [MD = 21.34 mg/cm², 95% CI = 8.21 to 34.47 mg/cm², p = 0.001], the femoral neck [MD = 28.88 mg/cm², 95% CI = 15.05 to 42.71 mg/cm², p 0.0001] and the distal radius [MD = 19.27 mg/cm², 95% CI = 5.65 to 32.89 mg/cm², p = 0.006].
This improved bone mineral density was found for genistein 54 mg/day and ipriflavone (a synthetic isoflavone) 600 mg/day.

The investigators concluded isoflavone interventions, genistein (54 mg/day) and ipriflavone (600 mg/day) in particular, have beneficial effects on bone mineral density outcomes and are safe in postmenopausal women. They may be considered as a complementary or alternative option in the prevention and treatment of menopause-related osteoporosis.

Original title:
Effects of Isoflavone Interventions on Bone Mineral Density in Postmenopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials by Sansai K, Takuathung MN, [...], Koonrungsesomboon N.

Link:
https://pubmed.ncbi.nlm.nih.gov/32524173/

Additional information of El Mondo:
Find more information/studies on isoflavones and elderly right here.

Objectives:
Is there a causal relationship between black or green tea consumption and lowering blood pressure in subjects with elevated blood pressure (BP) or hypertension?
 
Study design:
This review article included 5 RCTs with 408 individuals.

None of the studies reported any side effects.

Results and conclusions:
The investigators found regular tea consumption significantly reduced systolic blood pressure [WMD = -4.81 mmHg, 95% CI = -8.40 to -1.58, p = 0.004] in subjects with elevated blood pressure (BP) or hypertension.

The investigators found regular tea consumption significantly reduced diastolic blood pressure [WMD = -1.98 mmHg, 95% CI = -3.77 to -0.20, p = 0.029] in subjects with elevated blood pressure (BP) or hypertension.

The investigators found, however, excluding the most heterogeneous trials showed that regular tea intake significantly reduced systolic blood pressure and diastolic blood pressure by about -3.53 and -0.99 mmHg, respectively.

The investigators found based on meta-regression findings, the longer the duration of tea intake (≥3 months), the higher the decrease in both systolic blood pressure and diastolic blood pressure.

The investigators found categorized studies, according to the tea type, revealed that the hypotensive effects of green tea were more pronounced compared to black tea.

The investigators concluded regular tea consumption, particularly green tea during ≥3 months reduces systolic blood pressure and diastolic blood pressure in subjects with elevated blood pressure (BP) or hypertension. Hence, it may be applicable to physicians, health care providers and particularly hypertension patients.

Original title:
The Effects of Regular Consumption of Green or Black Tea Beverage on Blood Pressure in Those With Elevated Blood Pressure or Hypertension: A Systematic Review and Meta-Analysis by Mahdavi-Roshan M, Salari A, […], Ashouri A.

Link:
https://www.sciencedirect.com/science/article/abs/pii/S0965229919316899?via%3Dihub

Additional information of El Mondo:
Find more information/studies on green tea consumption and lowering of blood pressure right here.

Objectives:
Has oral supplementation of vitamin B (vitamins B1, B6, B12 and folic acid alone or combined) preventive effect on cognitive decline in cognitively unimpaired individuals?

Study design:
This review article included 20 RCTs, ranging from 23 to 2,919 participants per study, with a total of 12,697 participants.
8 of these 20 RCTs were deemed appropriate for the meta-analysis.

Results and conclusions:
The investigators found meta-analysis did not yield a significant overall effect of supplementation with vitamin B on cognitive function [SMD = 0.02, 95% CI = -0.034 to 0.08]. A sensitivity analysis focusing on specific risk factors did not alter this result.
Some studies reported isolated significant effects of the intervention on secondary outcomes. However, these findings were outnumbered by the number of cognitive tests that did not yield significant effects.

The investigators concluded there is no overall evidence that oral vitamin B supplementation prevent cognitive decline in cognitively unimpaired individuals. The results of this review do not provide evidence that population groups with certain risk factors would profit more from the intervention than others.

Original title:
Vitamin B-Can It Prevent Cognitive Decline? A Systematic Review and Meta-Analysis by Behrens A, Graessel E, [...], Donath C.

Link:
https://systematicreviewsjournal.biomedcentral.com/articles/10.1186/s13643-020-01378-7

Additional information of El Mondo:
Find more information/studies on vitamins B1, B6, B12 and folic acid and dementia right here.

Objectives:
Epidemiologic studies, including trials, suggest an association between potassium intake and blood pressure (BP). However, the strength and shape of this relationship is uncertain. Therefore, this review article has been conducted.

What is the strength and shape of the relationship between potassium intake and blood pressure (BP)?
 
Study design:
This review article included 32 RCTs with a duration ≥4 weeks using the recently developed 1‐stage cubic spline regression model. This model allows use of trials with at least 2 exposure categories.
Most trials were conducted in adults with hypertension using a crossover design and potassium supplementation doses that ranged from 30 to 140 mmol (1173 and 5474 mg) per day.

Results and conclusions:
The investigators found a U‐shaped relationship between 24‐hour active and control arm differences in potassium excretion and blood pressure (BP) levels, with weakening of the blood pressure reduction effect above differences of 30 mmol/d and a blood pressure increase above differences ≈80 mmol/d.

The investigators found achieved potassium excretion analysis also identified a U‐shaped relationship. The blood pressure lowering effects of potassium supplementation were stronger in participants with hypertension and at higher levels of sodium intake.

The investigators found blood pressure increased with high potassium excretion in participants with antihypertensive drug‐treated hypertension but not in their untreated counterparts.

The investigators concluded that an adequate intake of potassium (≤30 mmol (1173 mg) per day) is desirable to achieve a lower blood pressure level but excessive potassium supplementation (>80 mmol (3128 mg) per day) should be avoided, particularly in specific subgroups.

Original title:
Potassium Intake and Blood Pressure: A Dose‐Response Meta‐Analysis of Randomized Controlled Trials by Filippini T, Naska A, […], Whelton PK.

Link:
https://www.ahajournals.org/doi/full/10.1161/JAHA.119.015719?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub++0pubmed&

Additional information of El Mondo:
Find more information/studies on potassium consumption and lowering of blood pressure right here.

Objectives:
Is there a causal relationship between tomato consumption and lowering effects on cholesterol, triglycerides or fasting blood sugar levels?
 
Study design:
This review article included 6 RCTs.

Results and conclusions:
The investigators found tomato consumption significantly reduced total plasma cholesterol levels [WMD = -4.39 mg/dL, 95% CI = -7.09 to -1.68, I2 = 48%, p = 0.05].

The investigators found tomato consumption significantly reduced plasma triglyceride (TG) levels [WMD = -3.94 mg/dL, 95% CI = -7.67 to -0.21, I2 = 90%, p = 0.001].
A higher reduction effect was found on younger participants.

The investigators found tomato consumption significantly reduced plasma LDL cholesterol (bad cholesterol) levels [WMD = -2.09 mg/dL, 95% CI = -3.73 to -0.81, I2 = 78%, p = 0.001].
A higher reduction effect was found on younger participants.

The investigators found tomato consumption significantly increased plasma HDL cholesterol (good cholesterol) levels [WMD = 2.25 mg/dL, 95% CI = 0.41 to 4.10, I2 = 97%, p = 0.001].

The investigators found tomato consumption had no significant effect on plasma fasting blood sugar levels [WMD = 0.59 mg/dL, 95% CI = -0.28 to 1.46, I2 = 95%, p = 0.001].

The investigators concluded that tomato consumption increases plasma HDL cholesterol (good cholesterol) levels and decreases plasma total cholesterol, LDL cholesterol (bad cholesterol) and triglyceride levels.

Original title:
Effect of Tomato Consumption on Fasting Blood Glucose and Lipid Profiles: A Systematic Review and Meta-Analysis of Randomized Controlled Trials by Li H, Chen, A, [...],Yin X.

Link:
https://pubmed.ncbi.nlm.nih.gov/32243013/

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Find more information/studies on tomato consumption and lowering of cholesterol levels right here.

Patients with heart disease often have high LDL cholesterol, low HDL cholesterol and high triglycerides levels.

Objectives:
Do dietary calcium intakes or calcium supplements increase risk of cardiovascular disease?
 
Study design:
This review article included 26 prospective cohort studies and 16 RCTs.

Results and conclusions:
The investigators found in cohort studies that dietary calcium intakes ranging from 200 to 1500 mg/d did not affect the risk of cardiovascular disease [relative risk = 0.96, 95% CI = 0.87 to 1.05].

The investigators found in cohort studies that dietary calcium intakes ranging from 200 to 1500 mg/d did not affect the risk of coronary heart disease [relative risk = 0.98, 95% CI = 0.88 to 1.08].

The investigators found in cohort studies that dietary calcium intakes ranging from 200 to 1500 mg/d did not affect the risk of stroke [relative risk = 0.94, 95% CI = 0.85 to 1.04].

The investigators found in RCTs that calcium supplements significantly increased risk of coronary heart disease with 20% [relative risk = 1.20, 95% CI = 1.08 to 1.33, I2 = 0.0%].

The investigators found in RCTs that calcium supplements significantly increased risk of myocardial infarction with 21% [relative risk = 1.21, 95% CI = 1.08 to 1.35, I2 = 0.0%].

The investigators concluded that 200-1500 mg/d calcium intake from dietary sources do not increase the risk of cardiovascular disease, including coronary heart disease and stroke, while calcium supplements increase coronary heart disease risk, especially myocardial infarction.

Original title:
The Evidence and Controversy Between Dietary Calcium Intake and Calcium Supplementation and the Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Cohort Studies and Randomized Controlled Trials by Yang C, Shi X, […], Sun G.

Link:
https://pubmed.ncbi.nlm.nih.gov/31625814/

Additional information of El Mondo:
Find more information/studies on calcium and lowering of blood pressure right here.

Objectives:
Is there a causal relationship between daily egg consumption and positive effects on blood pressure?
 
Study design:
This review article included 15 RCTs with a total of 748 participants and mean age range from 23.3 to 67.1 years old.

All included studies used whole egg as an intervention which varied from one egg/day to three eggs/day and duration of supplementation ranged from 3 to 12 weeks.

No evidence of publication bias was seen in the meta-analyse (review article) of systolic blood pressure [Begg’s p = 0.235, Eggers’s p = 0.433] and diastolic blood pressure [Begg’s p = 0.254, Eggers’s p = 0.267].

No heterogeneity was found among included studies.

Results and conclusions:
The investigators found, overall, egg consumption had no significant effect on systolic blood pressure [WMD = 0.046 mmHg, 95% CI = - 0.792 to 0.884, p = 0.914, I2 = 0.0%, p = 0.453] and diastolic blood pressure [WMD = -0.603 mmHg, 95% CI = -1.521 to 0.315, p = 0.198, I2 = 38.1%, p = 0.067].
Subgroup analyses had no effect on pooled results.
Sensitivity analysis indicated that excluding each trial did not significantly change the overall observed effects of egg consumption.

The investigators found nonlinear dose-response meta-analysis did not reveal a significant effect of egg consumption [p-nonlinearity = 0.76] and study duration on diastolic blood pressure [p-nonlinearity = 0.63].

The investigators found subgroup analyses based on study design, sex, population health status, obesity and hypertension status, diet adherence, study duration and amount of egg consumption did not affect the overall effects of egg consumption on systolic blood pressure and diastolic blood pressure values.

The investigators concluded that 1-3 eggs/day during 3 to 12 weeks have no effect on blood pressure. However, high-quality RCTs with longer durations are needed to further confirm the effects of egg consumption on blood pressure.

Original title:
Effect of Egg Consumption on Blood Pressure: a Systematic Review and Meta-analysis of Randomized Clinical Trials by Kolahdouz-Mohammadi R, Malekahmadi M, […], Soltani S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7189334/

Additional information of El Mondo:
Find more information/studies on causal relationship/significantly, egg consumption and lowering of blood pressure right here.

Objectives:
Does Alzheimer disease increase risk of stroke?

Study design:
This review article included 8 studies, representing 121,719 individuals (Alzheimer disease = 73,044 and non-Alzheimer disease = 48,675).

Results and conclusions:
The investigators found patients with Alzheimer disease had a significantly increased risk of 42% [relative risk = 1.42, 95% CI = 1.23 to 1.64] for hemorrhagic stroke.

The investigators concluded Alzheimer disease increases risk of hemorrhagic stroke.

Original title:
Risk of hemorrhagic and ischemic stroke in patients with Alzheimer disease: A synthesis of the literature by Waziry R, Chibnik LB, […], Hofman A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31949087

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

Objectives:
Is there a causal relationship between strawberry consumption and positive effects on cardiovascular risk factors?
 
Study design:
This review article included 11 RCTs (6 for blood pressure, 7 for lipid profile, 7 for fasting blood glucose and 6 for C-reactive protein).

There was little evidence of heterogeneity in the analysis and no evidence of publication bias.

Results and conclusions:
The investigators found overall, strawberry consumption significantly reduced C-reactive protein (CRP) levels by 0.63 mg/L [95% CI = -1.04 to -0.22] but did not affect blood pressure, lipid profile or fasting blood glucose in the main analyses.

The investigators found stratified by baseline endpoint levels, that strawberry consumption significantly reduced total cholesterol levels among people with baseline levels >5 mmol/L [-0.52 mmol/L, 95% CI = -088 to -0.15] and reduced LDL-cholesterol levels among people with baseline levels >3 mmol/L [-0.31 mmol/L, 95% CI = -0.60 to -0.02].

The investigators concluded strawberry consumption reduces C-reactive protein (CRP) levels and improves total cholesterol and LDL-cholesterol (bad cholesterol) in individuals with high baseline levels (level at the beginning of the study).

Original title:
Effects of strawberry intervention on cardiovascular risk factors: a meta-analysis of randomized controlled trials by Gao Q, Qin LQ, […], Dong JY.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32238201

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

Objectives:
Previous studies did not draw a consistent conclusion about the effects of vitamin K combined with vitamin D on human skeletal quality. Therefore, this review article has been conducted.

Does vitamin K combined with vitamin D supplementation increase bone mineral density (BMD)?

Study design:
This review article included 8 RCTs with a total of 971 participants.

Results and conclusions:
The investigators found vitamin K combined with vitamin D supplementation significantly increased total bone mineral density (BMD) [pooled effect size = 0.316, 95% CI = 0.031 to 0.601].

The investigators found vitamin K combined with vitamin D supplementation significantly decreased levels of undercarboxylated osteocalcin [effect size = -0.945, 95% CI = -1.113 to -0.778].

The investigators found simultaneously, subgroup analysis showed that K2 or vitamin K (not specified) supplement less than 500 μg/d, when combined with vitamin D significantly increased total bone mineral density compared with the control group fed a normal diet or the group with no treatment [effect size = 0.479, 95% CI = 0.101 to 0.858 and effect size = 0.570, 95% CI = 0.196 to 0.945, respectively).

The investigators concluded the combination of vitamin K and D supplement increases the total bone mineral density (BMD) and decreases levels of undercarboxylated osteocalcin and a more favorable effect is expected when less than 500 μg/d vitamin K2 is used.

Original title:
The combination effect of vitamin K and vitamin D on human bone quality: a meta-analysis of randomized controlled trials by Kuang X, Liu C, […], Li D.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32219282

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

Undercarboxylated osteocalcin represents inadequately carboxylated osteocalcin and this fraction increases with vitamin K insufficiency.

Objectives:
Does fish consumption decrease risk of cardiovascular disease, depression, mortality and cancer?
 
Study design:
This review article included a total of 34 meta-analyses of prospective observational studies, reporting summary relative risks (SRR) for 40 different outcomes obtained from 298 primary prospective cohort studies.

The summary relative risk (SRR) for each meta-analysis was recalculated by using a random-effects model.

Results and conclusions:
The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 8% lower risk of all-cause mortality [SRR = 0.92, 95% CI = 0.87 to 0.97].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 25% lower risk of cardiovascular mortality [SRR = 0.75, 95% CI = 0.65 to 0.87].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 12% lower risk of coronary heart disease [SRR = 0.88, 95% CI = 0.79 to 0.99].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 25% lower risk of myocardial infarction [SRR = 0.75, 95% CI = 0.65 to 0.93].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 14% lower risk of stroke [SRR = 0.86, 95% CI = 0.75 to 0.99].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 20% lower risk of heart failure [SRR = 0.80, 95% CI = 0.67 to 0.95].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 12% lower risk of depression [SRR = 0.88, 95% CI = 0.79 to 0.98].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 35% lower risk of liver cancer [SRR = 0.65, 95% CI = 0.48 to 0.87].

The investigators concluded evidence of moderate quality shows that 100-g/d fish consumption is associated with a lower risk of cardiovascular disease, depression, mortality and liver cancer and therefore, can be considered as a healthy animal-based dietary source of protein. Further research is needed for outcomes for which the quality of the evidence was rated low and very low, considering types of fish consumed, different methods of cooking fish and all potential confounding variables.

Original title:
Fish Consumption and the Risk of Chronic Disease: An Umbrella Review of Meta-Analyses of Prospective Cohort Studies by Jayedi A and Shab-Bidar S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32207773

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

Objectives:
Is there a causal relationship between dietary intake of dairy products and a positive effect on bone mineral density (BMD) in healthy postmenopausal women?

Study design:
This review article included 6 RCTs with a total of 618 participants. Milk was the main dairy product used in the trials.

Results and conclusions:
The investigators found there was a significant association between dairy product consumption and bone mineral density of the lumbar spine [SMD = 0.21, 95% CI = 0.05 to 0.37, p = 0.009], femoral neck [SMD = 0.36, 95% CI = 0.19 to 0.53, p  0.001], total hip [SMD = 0.37, 95% CI = 0.20 to 0.55, p  0.001] and total body [SMD = 0.58, 95% CI = 0.39 to 0.77, p  0.001].

The investigators found subgroup analysis showed a positive effect of dairy product consumption on the bone mineral density of the total hip starting from 12 months and the femoral neck starting from 18 months. There was also a positive association with the bone mineral density in the 4 sites in people living in low-calcium intake countries.

The investigators concluded that there is a causal relationship between dietary intake of dairy products, particularly milk during at least 12 months and a positive effect on bone mineral density (BMD) in healthy postmenopausal women. Therefore, dairy product consumption should be considered an effective public health measure to prevent osteoporosis in postmenopausal women.

Original title:
Effects of dairy products on bone mineral density in healthy postmenopausal women: a systematic review and meta-analysis of randomized controlled trials by Shi Y, Zhan Y, [...], Jiang Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32185512

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Find more information/studies on dairy products and elderly right here.

Menopause is the point when a woman no longer has menstrual periods for at least 12 months. Postmenopause is the stage after menopause.

Objectives:
Do fermented dairy foods and probiotics supplementation improve risk factors (such as metabolic syndrome, type 2 diabetes, cholesterol) of cardiovascular diseases?

Study design:
This review article included 20 prospective cohort studies and 52 RCTs.

Results and conclusions:
The investigators found in prospective cohort studies, that fermented milk was associated with a 4% reduction in risk of stroke, ischemic heart disease and cardiovascular mortality [RR = 0.96, 95% CI = 0.94 to 0.98].

The investigators found in prospective cohort studies, that yogurt intake was associated with a risk reduction of 27% [RR = 0.73, 95% CI = 0.70 to 0.76] for type 2 diabetes.

The investigators found in prospective cohort studies, that yogurt intake was associated with a risk reduction of 20% [RR = 0.80, 95% CI = 0.74 to 0.87] for metabolic syndrome development.

The investigators found in RCTs, that probiotic supplementation added into dairy matrices produced a greater reduction in lipid biomarkers than when added into capsules/powder in hypercholesterolemic subjects.

The investigators found in RCTs, that probiotic supplementation by capsules/powder produced a greater reduction in type 2 diabetes biomarkers than when added into dairy matrices in diabetic subjects.

The investigators found in RCTs, that probiotic supplementation by both treatments (dairy matrix and capsules/powder) resulted in a significant reduction in anthropometric parameters in obese subjects.

The investigators concluded fermented milk consumption is associated with reduced cardiovascular risk, while yogurt intake is associated with a reduced risk of type 2 diabetes and metabolic syndrome development in the general population. Furthermore, probiotic supplementation added into dairy matrices is beneficial for lowering lipid concentrations and reduce anthropometric parameters. Additionally, probiotic capsule/powder supplementation contributes to type 2 diabetes management and reduces anthropometric parameters. However, these results should be interpreted with caution due to the heterogeneity of the studies and the different probiotic strains used in the studies.

Original title:
Fermented Dairy Products, Probiotic Supplementation, and Cardiometabolic Diseases: A Systematic Review and Meta-analysis by Companys J, Pla-Pagà L, […], Valls RM.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32277831

Additional information of El Mondo:
Find more information/studies on probiotic, diabetes, overweight and cardiovascular disease right here.

Objectives:
Does a high LDL cholesterol level (bad cholesterol) increase risk of Alzheimer's disease (AD)?

Study design:
This review article included 26 case-control studies involving 7,033 participants (2,266 Alzheimer's disease patients and 4,767 non-dementia controls).

There was no significant evidence of publication bias according to the results of Egger's test [p = 0.084].

Results and conclusions:
The investigators found results from the meta-analysis of 26 studies revealed higher levels of LDL cholesterol (>121 mg/dL) in Alzheimer's disease than that of non-dementia controls [SMD = 0.35, 95% CI = 0.12 to 0.58, p 0.01], which was consistent with the results of the fixed-effect model [SMD = 0.16, 95% CI = 0.10 to 0.22, p 0.01].
Sensitivity analyses showed that no single study exerted substantial influence on the pooled effect size after sequentially omitting a study.

The investigators found subgroup analysis of age showed LDL cholesterol levels in Alzheimer's disease patients aged 60-70 were higher than that of non-dementia [60 ≤ age 70: SMD = 0.80, 95% CI = 0.23 to 1.37, p 0.01].  

The investigators concluded that elevated concentration of LDL cholesterol (>121 mg/dL) is a risk factor for Alzheimer's disease. This strong association is significant in patients with Alzheimer's disease aged 60-70 years, but vanishes with increasing age. This review article provides a promising strategy for reducing the risk of Alzheimer's disease in patients with hyperlipidemia, which may be achieved by regulating LDL cholesterol concentration between 103.9 and 121 mg/dL with statins. Prospective studies that exclude potential confounders, more scientific design and adequate long-term follow-up are needed to validate this hypothesis.

Original title:
Low-Density Lipoprotein Cholesterol and Alzheimer's Disease: A Systematic Review and Meta-Analysis by Zhou Z, Liang Y, […], Zhao M.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7002548/

Additional information of El Mondo:
Find more information/studies on cholesterol and Alzheimer's disease right here.
 

Objectives:
Does tea consumption decrease risk of cardiovascular disease and all-cause mortality among adults?
 
Study design:
This review article included 39 prospective cohort studies.

Strength of evidence was rated as low and moderate (depending on study population age group) for cardiovascular disease-specific mortality outcome and was rated as low for cardiovascular disease events, stroke and all-cause mortality outcomes.

Results and conclusions:
The investigators found linear meta-regression showed that each cup (236.6 mL) increase in daily tea consumption (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) was associated with an average 4% lower risk of cardiovascular disease mortality, a 2% lower risk of cardiovascular disease events, a 4% lower risk of stroke and a 1.5% lower risk of all-cause mortality.

The investigators found subgroup meta-analysis showed that each cup (236.6 mL) increase in daily tea consumption (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) was associated with a 11% [pooled adjusted RR = 0.89, 95% CI = 0.83 to 0.96, p = 0.001, I2 = 72.4%, n = 4] lower risk of cardiovascular disease mortality in elderly individuals.

The investigators found subgroup meta-analysis showed that each cup (236.6 mL) increase in daily tea consumption (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) was associated with a 8% [pooled adjusted RR = 0.92, 95% CI = 0.90 to 0.94, p 0.0001, I2 = 0.3%, n = 3] lower risk of all-cause mortality in elderly individuals.

The investigators found, generally, studies with higher risk of bias appeared to show larger magnitudes of associations than studies with lower risk of bias.

The investigators concluded that daily a cup (236.6 mL) of tea (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) is associated with a lower risk of cardiovascular disease and all-cause mortality among elderly individuals.

Original title:
Dose-Response Relation between Tea Consumption and Risk of Cardiovascular Disease and All-Cause Mortality: A Systematic Review and Meta-Analysis of Population-Based Studies by Chung M, Zhao N, […], Wallace TC.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32073596

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Objectives:
Does flaxseed supplementation decrease plasma lipoprotein(a) levels?

Study design:
This review article included 7 RCTs with 629 individuals.

Results and conclusions:
The investigators found flaxseed supplementation significantly reduced plasma lipoprotein(a) levels [MD = -2.06 mg/dL, 95% CI = -3.846 to -0.274, p = 0.024, I2 = 0%, p = 0.986].

The investigators found subgroup analysis also revealed that longer duration only showed significant lowering effect of flaxseed supplementation on plasma lipoprotein(a) levels.

The investigators concluded that long duration of flaxseed supplementation decreases plasma lipoprotein(a) levels. However, future well-designed and long-term clinical trials are required to confirm these results.

Original title:
Impact of flaxseed supplementation on plasma lipoprotein(a) concentrations: A systematic review and meta-analysis of randomized controlled trials by Hadi A, Askarpour M, […], Ghavami A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32073724

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Lipoprotein(a) is a risk factor for atherosclerosis and related diseases, such as coronary heart disease and stroke.

 

Objectives:
Several epidemiological studies have been performed to evaluate the association of dietary intake of vitamin C-oriented foods (DIVCF) with risk of fracture and bone mineral density (BMD) loss, but the results remain controversial. Therefore, this review article has been conducted.

Does dietary intake of vitamin C-oriented foods decrease risk of fracture and bone mineral density loss?

Study design:
This review article included 4 cohort studies, 11 case-control studies and 2 cross-sectional studies with a total of 19,484 subjects.

The studies received a quality score of ≥5, indicating that the methodological quality of the studies was generally good.

No evidence of publication bias was found in the evaluation of dietary intake of vitamin C-oriented foods and the risk of hip fracture.

Results and conclusions:
The investigators found that the people with a higher dietary intake of vitamin C-oriented foods had a significantly 34% [RR = 0.66, 95% CI = 0.47 to 0.94, I2 = 79.5%, p = 0.000] lower risk of hip fracture.

The investigators found that the people with a higher dietary intake of vitamin C-oriented foods had a significantly 42% [RR = 0.58, 95% CI = 0.38 to 0.89] lower risk of hip fracture in case-control studies.
However, this reduced risk was not significant in cohort studies [RR = 0.92, 95% CI = 0.59 to 1.44]. 

The investigators found that the people with a higher dietary intake of vitamin C-oriented foods had a significantly 34% [RR = 0.66, 95% CI = 0.48 to 0.92] lower risk of osteoporosis.

The investigators found higher dietary intake of vitamin C-oriented foods was negatively associated with the risk of bone mineral density loss at the lumbar spine [pooled r = 0.15, 95% CI = 0.09 to 0.23] and at the femoral neck [pooled r = 0.20, 95% CI = 0.11 to 0.34].

The investigators concluded that higher dietary intake of vitamin C-oriented foods reduces the risk of hip fracture, osteoporosis and bone mineral density loss, suggesting that people should consume more vitamin C to decrease the risk of hip fracture, osteoporosis and bone mineral density loss, particularly lumbar spine and femoral neck.

Original title:
Can Dietary Intake of Vitamin C-Oriented Foods Reduce the Risk of Osteoporosis, Fracture, and BMD Loss? Systematic Review With Meta-Analyses of Recent Studies by Zeng LF, Luo MH, […], Liu J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7008177/

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

Objectives:
Current evidence on associations between intakes of linoleic acid (LA), the predominant n-6 (ω-6) fatty acid and mortality is inconsistent and has not been summarized by a systematic review and meta-analysis. Therefore, this review article has been conducted.

Does higher linoleic acid intake, assessed by dietary surveys or biomarkers decrease mortality from all causes, cardiovascular disease (CVD) and cancer?

Study design:
This review article included 44 prospective cohort studies with 811,069 participants with dietary intake assessment (170,076 all-cause, 50,786 cardiovascular disease and 59,684 cancer deaths) and 65,411 participants with biomarker measurements (9,758 all-cause, 6,492 cardiovascular disease and 1,719 cancer deaths).

Meta-regressions suggested baseline age and dietary assessment methods as potential sources of heterogeneity for the association between linoleic acid and total mortality.

Results and conclusions:
The investigators found when compared with the lowest categories of dietary linoleic acid intake, that the highest categories of dietary linoleic acid intake significantly reduced total mortality risk with 13% [pooled RR = 0.87, 95% CI = 0.81 to 0.94, I2 = 67.9%].

The investigators found when compared with the lowest categories of dietary linoleic acid intake, that the highest categories of dietary linoleic acid intake significantly reduced cardiovascular disease mortality risk with 13% [pooled RR = 0.87, 95% CI = 0.82 to 0.92, I2 = 3.7%].

The investigators found when compared with the lowest categories of dietary linoleic acid intake, that the highest categories of dietary linoleic acid intake significantly reduced cancer mortality risk with 11% [pooled RR = 0.89, 95% CI = 0.85 to 0.93, I2 = 0%].

The investigators found for each standard deviation increment in linoleic acid concentrations in adipose tissue/blood compartments a significantly reduced total mortality risk of 9% [pooled RR = 0.91, 95% CI = 0.87 to 0.95, I2 = 64.1%].

The investigators found for each standard deviation increment in linoleic acid concentrations in adipose tissue/blood compartments a significantly reduced cardiovascular disease mortality risk of 11% [pooled RR = 0.89, 95% CI = 0.85 to 0.94, I2 = 28.9%].

The investigators found for each standard deviation increment in linoleic acid concentrations in adipose tissue/blood compartments a significantly reduced cancer mortality risk of 9% [pooled RR = 0.91, 95% CI = 0.84 to 0.98, I2 = 26.3%].

The investigators concluded higher linoleic acid intake, assessed by dietary surveys or biomarkers, reduces risk of mortality from all causes, cardiovascular disease and cancer. These data support the potential long-term benefits of PUFA intake in lowering the risk of cardiovascular disease and premature death.

Original title:
Dietary intake and biomarkers of linoleic acid and mortality: systematic review and meta-analysis of prospective cohort studies by Li J, Guasch-Ferré M, […], Hu FB.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32020162

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Linoleic acid is a PUFA.
 

Objectives:
Vitamin C as a supplement to treat hypertension has been proposed. However, it remains controversial whether vitamin C can improve blood pressure in patients with primary hypertension. Therefore, this review article has been conducted.

Do vitamin C supplements reduce blood pressure in patients with primary hypertension?

Study design:
This review article included 8 RCTs involving 614 participants.
There was no publication bias.

Results and conclusions:
The investigators found vitamin C supplements significantly reduced systolic blood pressure in patients with essential hypertension [WMD  = -4.09, 95% CI = -5.56 to -2.62, p 0 .001, I2  =  35%, p = 0.15].

The investigators found vitamin C supplements significantly reduced diastolic blood pressure in patients with essential hypertension [WMD  = -2.30, 95% CI = -4.27 to -0.331, p  = 0 .02, I2 = 75%, p = 0 .0002].

The investigators found vitamin C supplements significantly reduced systolic blood pressure for the subgroup with an age ≥60 years and that with ≥35 participants [WMD = -3.75, 95% CI = -6.24 to -1.26, p  = 0 .003].

The investigators found vitamin C supplements significantly reduced diastolic blood pressure for the subgroup with an age ≥60 years and that with ≥35 participants [WMD = -3.29, 95% CI = -5.98 to -0.60, p  = 0 .02].

The investigators found in the subgroup analysis that vitamin C supplements during ≥6 weeks significantly reduced systolic blood pressure in patients with essential hypertension [WMD = -4.77, 95% CI = -6.46 to -3.08, p   0 .001].

The investigators found in the subgroup analysis that ≥500 mg/d vitamin C supplements significantly reduced systolic blood pressure in patients with essential hypertension [WMD  =  -5.01, 95% CI = -8.55 to -1.48, p  = 0.005, I2  =  44%, p =  0.13].

The investigators concluded ≥500 mg/d vitamin C supplements during ≥6 weeks reduce blood pressure in patients with primary hypertension. However, in view of the current level of evidence, large-scale trials should be conducted and attention should be paid to the evaluation of blood pressure variability.

Original title:
Effects of vitamin C supplementation on essential hypertension: A systematic review and meta-analysis by Guan Y, Dai P and Wang H.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7034722/

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Objectives:
Clinical trials examining the cardiovascular protective effects of quercetin in humans have reported conflicting results. Therefore, this review article has been conducted.

Do quercetin supplements reduce plasma lipid levels and blood pressure?

Study design:
This review article included 17 RCTs with a total of 896 participants.

Results and conclusions:
The investigators found pooled results showed that quercetin supplements significantly lowered both systolic blood pressure [WMD = -3.09 mmHg, 95% CI = -4.59 to -1.59, p = 0.0001] and diastolic blood pressure [WMD = -2.86 mmHg, 95% CI = -5.09 to -0.63, p = 0.01].
Neither lipid profiles nor glucose concentrations changed significantly.

The investigators found in subgroup analyses, significant changes in high-density lipoprotein (HDL or good) cholesterol and triglycerides were observed in trials with a parallel design and in which participants consumed quercetin for 8 weeks or more.

The investigators concluded quercetin supplements decrease blood pressure in humans. Moreover, participants who consume quercetin for 8 weeks or more show significantly changed levels of high-density lipoprotein cholesterol (good cholesterol) and triglycerides in trials with a parallel design.  

Original title:
Effect of quercetin supplementation on plasma lipid profiles, blood pressure, and glucose levels: a systematic review and meta-analysis by Huang H, Liao D, [...], Pu R.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31940027

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Objectives:
Data from in vitro and animal studies support the preventive effect of tea (Camellia sinensis) against colorectal cancer. Further, many epidemiologic studies evaluated the association between tea consumption and colorectal cancer risk, but the results were inconsistent. Therefore, this review article has been conducted.

Does tea consumption reduce colorectal cancer risk?

Study design:
This review article included 20 cohort studies with 2,068,137 participants and 21,437 colorectal cancer cases.

Results and conclusions:
The investigators found that tea consumption had no significant association with colorectal cancer risk for the highest vs. lowest categories [combined RR = 0.97, 95% CI = 0.94-1.01, I2 = 24.0%, p = 0.093] among all studies.

The investigators found stratified analysis showed no significant differences in all subgroups.

The investigators found no significant association between tea consumption and colorectal cancer risk in male [combined RR = 0.97, 95% CI = 0.90-1.04].

The investigators found, however, tea consumption had a marginal significant inverse impact on colorectal cancer risk in female [combined RR = 0.93, 95% CI = 0.86-1.00].

The investigators found a significantly reduced risk of 10% for colorectal cancer for tea consumption among the female studies with no adjustment of coffee intake [RR = 0.90, 95% CI = 0.82-1.00, p  0.05].
However, this reduced risk was not significant among the female studies that adjusted for coffee intake [RR = 0.97, 95% CI = 0.87-1.09, p > 0.05].

The investigators concluded that tea consumption may reduce colorectal cancer risk in female. May reduced because this reduced risk was not significant among the female studies that adjusted for coffee intake.

Original title:
Tea consumption and colorectal cancer risk: a meta-analysis of prospective cohort studies by Zhu MZ, Lu DM, […], Liu ZH.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32078065

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Objectives:
There are differences among the outcomes regarding cognitive impairment in heart failure (HF) because the evidence is fragmented and sample size is small. Therefore, this review article has been conducted.

Does heart failure increase risk of dementia?

Study design:
This review article included 12 studies with 2,406,680 heart failure patients.

Begg test, Egger tests and funnel plots showed no significant risks of publication bias.

Results and conclusions:
The investigators found heart failure significantly increased risk of all-cause dementia with 28% [OR/RR  =  1.28, 95% CI = 1.15 to 1.43, I2 = 70.0%, p    0.001].
Sensitivity analysis showed no changes in the direction of effect when any one study was excluded for the studies on associations between heart failure and all-cause dementia.

The investigators found no significant association between heart failure and risk of Alzheimer's disease [OR/RR  =  1.38, 95% CI = 0.90 to 2.13, I 2 =  74.8%, p =  0.008].
Sensitivity analysis showed no changes in the direction of effect when any one study was excluded for the studies on associations between heart failure and Alzheimer's disease.

The investigators concluded heart failure increases risk of all-cause dementia. In addition, large scale prospective studies are essential to explore the associations between heart failure and risk of Alzheimer's disease.

Original title:
Associations between heart failure and risk of dementia: A PRISMA-compliant meta-analysis by Li J, Wu Y, [...], Nie J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7004760/

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Objectives:
The benefits of LDL cholesterol-lowering treatment for the prevention of atherosclerotic cardiovascular disease are well established. However, the extent to which these effects differ by baseline LDL cholesterol, atherosclerotic cardiovascular disease risk and the presence of comorbidities remains uncertain. Therefore, this review article has been conducted.

Does LDL cholesterol-lowering treatment reduce risk of major vascular events (a composite of cardiovascular mortality, non-fatal myocardial infarction, non-fatal ischaemic stroke or coronary revascularisation)?

Study design:
This review article included 52 RCTs with a total of 327,037 patients.

Results and conclusions:
The investigators found each 1 mmol/L reduction in LDL cholesterol (bad cholesterol) was associated with a 19% relative risk (RR) reduction for major vascular events [RR = 0.81, 95% CI = 0.78 to 0.84,  p 0.0001].

The investigators found similar reductions (per 1 mmol/L reduction in LDL cholesterol) in trials with participants with LDL cholesterol level of 2.60 mmol/L or lower, 2.61-3.40 mmol/L, 3.41-4.10 mmol/L and more than 4.1 mmol/L [p = 0.232 for interaction] and in a subgroup of patients who all had a baseline LDL cholesterol level less than 2.07 mmol/L [80 mg/dL: RR = 0.83, 95% CI = 0.75-0.92, p = 0.001].

The investigators found greater RR reductions in patients at lower 10-year atherosclerotic cardiovascular disease risk [change in RR per 10% lower 10-year atherosclerotic cardiovascular disease = 0.97, 95% CI = 0.95 to 0.98, p 0.0001] and in patients at younger age across a mean age of 50-75 years [change in RR per 10 years younger age = 0.92, 95% CI = 0.83 to 0.97, p = 0.015].

The investigators found no difference in RR reduction for participants with or without diabetes [p = 0.878 for interaction] and chronic kidney disease [p = 0.934 for interaction].

The investigators concluded for each 1 mmol/L LDL cholesterol lowering, the risk reduction of major vascular events is independent of the starting LDL cholesterol or the presence of diabetes or chronic kidney disease. Patients at lower cardiovascular risk and younger age might have a similar relative reduction in risk with LDL-cholesterol lowering therapies and future studies should investigate the potential benefits of earlier intervention.

Original title:
Intensive LDL cholesterol-lowering treatment beyond current recommendations for the prevention of major vascular events: a systematic review and meta-analysis of randomised trials including 327 037 participants by Wang N, Fulcher J, […], Lal S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31862150

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Objectives:
Alzheimer's disease (AD) is a common type of dementia, which has caused heavy global economic and health burden and the using of statins to treat Alzheimer disease has caused widely debated. Therefore, this review article has been conducted.

Does statin use decrease Alzheimer disease?

Study design:
This review article included a total of 9 RCTs containing 1,489 patients. Of them, 742 patients in the statins group, 747 patients in the control group (group without statins).

There were 9 studies used the MMSE scale, 5 studies used the ADAS-Cog scale, 4 studies used the NPI scale and 6 studies used the ADL scale.

Sensitivity analysis and publication bias test were both negative and the results were relatively reliable and stable.

Results and conclusions:
The investigators found meta-analysis of the 9 studies that reported the MMSE scale scores indicated that there was no significant effect of statins as compared with control group [pooled WMD = 1.09, 95% CI = -0.00 to 2.18, p = 0.05, I2 = 87.9%].

The investigators found meta-analysis of the 5 studies that reported the ADAS-Cog scale scores also indicated that there was no significant effect of statins as compared with control group [pooled WMD = -0.16, 95% CI = -2.67 to 2.36, p = 0.90, I2 = 80.1%].

The investigators found meta-analysis of the 4 studies that reported the NPI scale scores indicated that treatment with statins significantly slowed the rise in the NPI scale scores as compared with control group [pooled WMD = -1.16, 95% CI = -1.88 to -0.44, p = 0.002, I2 = 45.4%].

The investigators found meta-analysis of the 6 studies that reported the ADL scale scores indicated that treatment with statins significantly improve patients' daily living ability [pooled WMD = -4.06, 95% CI = -6.88 to -1.24, p = 0.005, I2 = 86.7%].

The investigators found results of subgroup analysis indicated that the use of statins in the short term (≤ 12 months) associated with the change of the MMSE scale scores [pooled WMD = 1.78, 95% CI = 0.53 to 3.04, p = 0.005, I2 = 79.6%].

The investigators concluded statins used in Alzheimer disease patients have beneficial effects on the scores of MMSE scale in the short term (≤ 12 months) and statins slow the deterioration of neuropsychiatric status and improve activities of daily living ability in Alzheimer disease patients.

Original title:
The efficacy of statins in the treatment of Alzheimer's disease: a meta-analysis of randomized controlled trial by Xuan K, Zhao T, […], Sun Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31930449

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Objectives:
Despite growing evidence for the association between other dietary macronutrients and bone health, limited and inconsistent knowledge is available regarding carbohydrate intake. Therefore, this review article has been conducted.

Does a high carbohydrate intake increase risk of fracture?

Study design:
This review article included observational studies.

Results and conclusions:
The investigators found no association between carbohydrate intake and the risk of fracture in high versus low intake meta-analysis [overall relative risk = 1.24, 95% CI = 0.84 to 1.84, p = 0.27, I2 = 57.7%, p = 0.05].

The investigators found, moreover, there was no relationship between carbohydrate intake and the risk of fracture in both linear [overall RR = 1.00, 95% CI = 0.94 to 1.05, p = 0.88, I2 = 68.1%, p = 0.48] and nonlinear [p non-linearity = 0.14] models.

The investigators concluded high carbohydrate intake does not increase risk of fracture.

Original title:
Dietary carbohydrate intake and risk of bone fracture: a systematic review and meta-analysis of observational studies by Mozaffari H, Daneshzad E and Azadbakht L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31982636

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