Nutrition and health

Objectives:
The results of human studies are inconsistent regarding selenium and depressive disorders. Therefore, this review article has been conducted.

Does high selenium intake (through diet or supplements) reduce risk of depression?

Study design:
This review article included 20 studies (4 RCTs, 9 cross-sectional studies, 4 case-control studies and 3 prospective cohort studies) with a total of 47,164 participants.
The age of participants ranged from 18.0 ± 1.2 to 82 years old.
12 studies included both men and women.
Confounding variables were adjusted in half of included studies.
All included randomized controlled trials (RCTs) had high quality.
There was no publication bias.

Results and conclusions:
The investigators found no significant differences in serum selenium levels between patients with depression and healthy subjects [WMD = 2.12 mg/L, 95% CI = -0.11 to 4.36, I2 = 98.0%, p 0.001].

The investigators found no significant differences between serum levels of selenium and depression scores [r = -0.12, 95% CI = -0.33 to 0.08, I2 = 73.5%, p = 0.010].

The investigators found high selenium supplementation significantly reduced the risk of postpartum depression with 3% [OR = 0.97, 95% CI = 0.95 to 0.99, I2 = 0.0%, p = 0.507].

The investigators found selenium supplementation significantly reduced depressive symptoms [WMD = -0.37, 95% CI = -0.56 to -0.18, I2 = 0.0%, p = 0.959].

The investigators concluded that high selenium supplementation has a protective role against postpartum depression. In addition, supplementation with selenium reduces depressive symptoms. Nevertheless, further studies are needed to draw definitive conclusions.

Original title:
The role of selenium in depression: a systematic review and meta-analysis of human observational and interventional studies by Sajjadi SS, Foshati S, […], Rouhani H.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8776795/

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Objectives:
Inflammation is a major cause of chronic diseases. Several studies have investigated the effects of tomato intake on inflammatory biomarkers; however, the results are equivocal. Therefore, this review article has been conducted.

Does tomato intake have positive impact on inflammatory biomarkers in adults?

Study design:
This review article included 7 RCTs (8 treatment arms) with a total of 465 subjects.

Results and conclusions:
The investigators found that pooled effect size of articles indicated that tomato intake was not significantly effective on CRP [WMD = 0.13 mg/dL, 95% CI = -0.09 to 0.36, p = 0.23, I2 = 83.9%] and IL-6 [Hedges' g = -0.12, 95% CI = -0.36 to 0.13, p = 0.34, I2 = 0.0%] levels compared to the control group.

The investigators found that pooled effect size of articles indicated that tomato intake significantly reduced TNF-α [Hedges' g = -0.45, 95% CI = -0.76 to -0.13, p = 0.005, I2 = 0.0%] levels in adults.

The investigators concluded that tomato intake causally reduces TNF-α levels in adults. However, additional well-designed studies that include more diverse populations and longer duration are warranted.

Original title:
Effect of tomato consumption on inflammatory markers in health and disease status: A systematic review and meta-analysis of clinical trials by Widjaja G, Doewes RI, […], Aravindhan S.

Link:
https://pubmed.ncbi.nlm.nih.gov/35871957/

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Tumor necrosis factor alpha (TNF-α) is an inflammatory cytokine that is elevated in heart failure.

Objectives:
Do COPD patients benefit from vitamin C supplementation?

Study design:
This review article included 10 RCTs with a total of 487 patients.

Results and conclusions:
The investigators found that vitamin C supplementation (≥400 mg/day) significantly improved the forced expiratory volume in one second as a percentage (FEV1%) of COPD patients [SMD = 1.08, 95% CI = 0.03 to 2.12, p = 0.04].

The investigators found, moreover, vitamin C supplementation (≥400 mg/day) significantly improved the ratio of forced expiratory volume in 1 second and forced vital capacity (FEV1/FVC) [WMD = 0.66, 95% CI = 0.26 to 1.06, p = 0.001], vitamin C level in serum [SMD = 0.63, 95% CI = 0.02 to 1.24, p = 0.04] and glutathione (GSH) level in serum [SMD = 2.47, 95% CI = 1.06 to 3.89, p = 0.0006] of COPD patients.

The investigators found no statistically significant difference was observed in body mass index (BMI), fat-free mass index (FFMI), vitamin E level and superoxide dismutase (SOD) level in serum.

The investigators concluded vitamin C supplementation increases the levels of antioxidation in serum (vitamin C and GSH) and improves lung function (FEV1% and FEV1/FVC) of COPD patients, especially when treated with vitamin C supplementation greater than 400 mg/day. However, further prospective studies are needed to explore the role of vitamin C in improving nutritional status.

Original title:
Efficacy of Vitamin C Supplementation on Chronic Obstructive Pulmonary Disease (COPD): A Systematic Review and Meta-Analysis by Lei T, Lu T, […], Liu J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9473551/

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Objectives:
Do rheumatoid arthritis patients benefit from vitamin E supplements?

Study design:
This review article included 9 RCTs with a total of 39,845 patients.

Results and conclusions:
The investigators found that vitamin E supplements were shown to be more effective in individuals with rheumatoid arthritis for sensitive joints [MD = -1.66, 95% CI = -6.32 to -2.99, I2 = 93%, p 0.00001] and swollen joints [MD = -0.46, 95% CI = -1.98 to 1.07, I2 = 56%, p = 0.08].

The investigators concluded vitamin E's ability to restore the intestinal barrier and improve the gastrointestinal tract may be linked to the prevention and treatment of rheumatoid arthritis. Vitamin E supplements used on a regular basis can help individuals with rheumatoid arthritis reduce joint discomfort, edema and stiffness, as well as enhance their overall quality of life.

Original title:
Effect of vitamin E supplementation in rheumatoid arthritis: a systematic review and meta-analysis by Kou H, Qing Z, […], Ma J.

Link:
https://pubmed.ncbi.nlm.nih.gov/35468933/

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Objectives:
Vitamin D levels have been shown to be associated with diabetic retinopathy, however to date, no review has examined the relationship between vitamin D and sight threatening diabetic retinopathy (STDR) and non-sight threatening diabetic retinopathy (NSTDR). Therefore, this review article has been conducted. 

Does vitamin D deficiency (defined as 25(OH)D levels of 20 ng/mL) increase risk of diabetic retinopathy in patients with diabetes?

Study design:
This review article included 11 cross-sectional studies and 1 case-control study with a total of  9,057 participants.
There was no publication bias.

Results and conclusions:
The investigators found vitamin D deficiency significantly increased risk of sight threatening diabetic retinopathy with 80% [OR = 1.80, 95% CI = 1.40 to 2.30, p ≤ 0.001, I2 = 39.39%].
However, this increased risk was not found for non-sight threatening diabetic retinopathy [OR = 1.10, 95% CI = 0.90 to 1.27, p = 0.48, I2 = 30.21%].

The investigators concluded that vitamin D deficiency (defined as 25(OH)D levels of 20 ng/mL)  increases risk of sight threatening diabetic retinopathy but not non-sight threatening diabetic retinopathy. Given the well-reported associations between vitamin D deficiency and other unfavourable outcomes, it is important that vitamin D deficiency is managed appropriately and in a timely manner to reduce the risk of blindness in people with diabetes.

Original title:
Associations between vitamin D status and sight threatening and non-sight threatening diabetic retinopathy: a systematic review and meta-analysis by Trott M, Driscoll R, […], Pardhan S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9167360/

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Diabetic retinopathy, also known as diabetic eye disease (DED), is a complication of diabetes, caused by high blood sugar levels damaging the back of the eye (retina). It can cause blindness if left undiagnosed and untreated.

Objectives:
What is the association of total protein, animal protein and animal protein sources with risk of kidney stones in the general population?

Study design:
This review article included 14 prospective cohort studies.
According to NutriGrade scoring system, the credibility of evidence for most of the exposures was rated as low.
Some kind of publication bias was found in the association of animal protein intake and risk of kidney stones, according to Egger's and Begg's tests.
Sensitivity analysis of processed meat as well as dairy consumption with risk of kidney stones showed one study changed the overall estimate.

Results and conclusions:
The investigators found that higher dietary intake of non-dairy animal protein significantly increased risk of kidney stones with 11% [RR = 1.11, 95% CI = 1.03 to 1.20, I2 = 0%, n = 4].
Significant means that there is an association with a 95% confidence.

The investigators found that higher dietary intake of total meat and meat products significantly increased risk of kidney stones with 22% [RR = 1.22, 95% CI = 1.09 to 1.38, I2 = 13%, n = 3].
Significant because RR of 1 was not found in the 95% CI of 1.09 to 1.38. RR of 1 means no risk/association.

The investigators found that higher dietary intake of processed meat significantly increased risk of kidney stones with 22% [RR = 1.22, 95% CI = 1.10 to 1.51, I2 = 0%, n = 2]. 

The investigators found that higher intake of dairy protein significantly decreased risk of kidney stones with 9% [RR = 0.91, 95% CI = 0.84 to 0.99, I2 = 0%, n = 4].

The investigators found, moreover, each 100 gram increment of red meat dietary intake was significantly associated with an increased risk of 39% for kidney stones [RR = 1.39, 95% CI = 1.13 to 1.71].

The investigators concluded that higher dietary intake of meat and meat products may increase the risk of kidney stones in the general population, while higher dietary intake of dairy proteins may decrease the risk of kidney stones in the general population. May because the credibility of evidence for most of the exposures was rated as low and there was publication bias. Therefore, further observational studies are needed to confirm present results.

Original title:
Associations of Total Protein or Animal Protein Intake and Animal Protein Sources with Risk of Kidney Stones: A Systematic Review and Dose-Response Meta-Analysis by Asoudeh F, Talebi S, […], Mohammadi H.

Link:
https://pubmed.ncbi.nlm.nih.gov/35179185/

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When the credibility of evidence of the studies in the review article is low and there is publication bias, the results will not be very reliable.
 

Objectives:
An enhanced risk for cardiovascular disease (CVD) still exists even when patients with type 2 diabetes have tight control on blood sugar. Thus, identification of treatment approaches that address CVD risk factors may be useful for patients beyond the blood sugar management. Although emerging evidence suggests that nuts consumption have beneficial effects on cardiometabolic health, the effects of almond intake in patients with type 2 diabetes are still controversial. Therefore, this review article has been conducted. 

Does almond consumption improve risk factors (cholesterol, triglycerides, fasting plasma glucose, insulin, hemoglobin A1c (HbA1c), body mass index, weight, body fat, systolic and diastolic blood pressure and CRP) of cardiovascular disease in patients with type 2 diabetes?

Study design:
This review article included 9 RCTs.

Results and conclusions:
The investigators found there was a causal relationship between almond dietary intake and a  significant reduction in low-density lipoprotein cholesterol (LDL cholesterol or bad cholesterol) [WMD = -5.28 mg/dL, 95% CI = -9.92 to -0.64, p = 0.026] in patients with type 2 diabetes compared with the control group.
This lowering effect of LDL cholesterol was robust in subgroups with almond consumption >50 g/day and baseline LDL cholesterol level 130 mg/dL.

The investigators found, however, the effect of almond on total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL cholesterol or good cholesterol), fasting plasma glucose, insulin, HbA1c, body mass index, weight, body fat, systolic and diastolic blood pressure and CRP was not significant compared with the control group.

The investigators concluded that a dietary intake of at least 50 g/d almond decreases causally LDL cholesterol (bad cholesterol) but has no favourable effect on other cardiometabolic outcomes in patients with type 2 diabetes. Further high-quality studies are needed to firmly establish the clinical efficacy of the almond.

Original title:
Effects of almond on cardiometabolic outcomes in patients with type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials by Moosavian SP, Rahimlou M, […], Jalili C.

Link:
https://pubmed.ncbi.nlm.nih.gov/35443097/

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Objectives:
There is currently a lack of high-quality research on the best dietary recommendations for patients with early glaucoma or at high risk for glaucoma. Therefore, this review article has been conducted.

Does a high dietary vitamin intake reduce risk of glaucoma?

Study design:
This review article included 8 cohort studies, with a total of 262,189 patients.

There was no publication bias.

Results and conclusions:
The investigators found that high-dose dietary intake of vitamins A was significantly associated with a 27% low risk of glaucoma [OR = 0.63, 95% CI = 0.53 to 0.76 , p 001, I2 = 49%].

The investigators found that high-dose dietary intake of vitamins B (a combination of B1, B2, B3, B6 and B12) was significantly associated with a 29% low risk of glaucoma [OR = 0.71, 95% CI = 0.64 to 0.80, p 0.001, I2 = 29%].

The investigators found no association between high-dose dietary intake of vitamins C, D or E and lower risk of glaucoma.

The investigators concluded that high-dose dietary intake of vitamins A and B, but not vitamins C, D or E, is associated with a low prevalence of glaucoma. Overall, middle-aged and elderly people or patients with early glaucoma should consume vitamin-rich foods rich or take additional vitamin supplements.

Original title:
Vitamin intake and glaucoma risk: A systematic review and meta-analysis by Han FF and Fu XX.             

Link:
https://www.sciencedirect.com/science/article/pii/S0181551222000419?via%3Dihub

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Objectives:
There is some evidence regarding the positive effects of ginger supplementation on metabolic profile in patients with type 2 diabetes (T2DM). However, they are conflicting and therefore, this review article has been conducted. 

Does ginger supplementation improve metabolic profile (FBS, HbA1c, TC, TG, LDL, HDL, SBP and DBP) in patients with type 2 diabetes?

Study design:
This review article included 10 RCTs.

Results and conclusions:
The investigators found pooled meta-analysis showed a significant reduction in fasting blood sugar (FBS) level following ginger supplementation by polling 8 effect sizes [WMD = -18.81, 95% CI = -28.70 to -8.92, I2 = 77.4%].

The investigators found pooled meta-analysis showed a significant reduction in HbA1c level following ginger supplementation by polling 7 effect sizes [WMD = -0.57, 95% CI = -0.93 to -0.20, I2 = 88.6%].

The investigators found pooled meta-analysis showed a significant reduction in systolic blood pressure (SBP) following ginger supplementation by polling 5 effect sizes [WMD = -4.20, 95% CI = -7.64 to -0.77, I2 = 97%].

The investigators found pooled meta-analysis showed a significant reduction in diastolic blood pressure (DBP) following ginger supplementation by polling 5 effect sizes [WMD = -1.61, 95% CI = -3.04 to -0.18, I2 = 93.2%].

The investigators found pooled meta-analysis showed ginger supplementation had no significant influence on lipid profile involving triglyceride (TG), total cholesterol (TC), LDL cholesterol and HDL cholesterol.

The investigators concluded supplementation with ginger reduces fasting blood sugar, HbA1c, systolic blood pressure and diastolic blood pressure in patients with type 2 diabetes. Further large RCTs are required to shed light on this issue.

Original title:
The effect of ginger supplementation on metabolic profiles in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials by Ebrahimzadeh A, Ebrahimzadeh A, […], Milajerdi A.

Link:
https://pubmed.ncbi.nlm.nih.gov/35031435/

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Objectives:
Does a higher intake of dietary antioxidants (like vitamin C and E, β-carotene, zinc, anthocyanins, lutein) reduce risk of Parkinson's disease (PD)?

Study design:
This review article included 6 prospective cohort studies and 2 nested case-control studies (448,737 participants with 4,654 persons with Parkinson's disease) and 6 case-control studies (1,948 persons without Parkinson's disease and 1, 273 persons with Parkinson's disease).

Results and conclusions:
The investigators found comparded to the lowest dietary vitamine E intake, that the highest dietary vitamine E intake significantly reduced risk of Parkinson's disease with 16% [pooled RR = 0.84, 95% CI = 0.71 to 0.99, n = 7 cohort studies].
Significantly means that there is an association with a 95% confidence.

The investigators found compared to the lowest dietary anthocyanins intake, that the highest dietary anthocyanins intake significantly reduced risk of Parkinson's disease with 24% [pooled RR = 0.76, 95% CI = 0.61 to 0.96, n = 2 cohort studies].
Significantly because pooled RR of 1 was not found in the 95% CI of 0.61 to 0.96. RR of 1 means no risk/association.

The investigators found compared to the lowest dietary lutein intake, that the highest dietary lutein intake significantly increased risk of Parkinson's disease with 86% [pooled RR = 1.86, 95% CI = 1.20 to 2.88, n = 3 case-control studies].

The investigators found in dose-response meta-analyses that every increment of dietary vitamin C intake with 50 mg/d significantly reduced risk of Parkinson's disease with 6% [RR = 0.94, 95% CI = 0.88 to 0.99, n = 6].

The investigators found in dose-response meta-analyses that every increment of dietary vitamin E intake with 5 mg/d significantly reduced risk of Parkinson's disease with 16% [RR = 0.84, 95% CI = 0.70 to 0.99, n = 7].

The investigators found in dose-response meta-analyses that every increment of dietary β-carotene intake with 2 mg/d significantly reduced risk of Parkinson's disease with 6% [RR = 0.94, 95% CI = 0.89 to 0.99, n = 6].

The investigators found in dose-response meta-analyses that every increment of dietary zinc intake with 1 mg/d significantly reduced risk of Parkinson's disease with 35% [RR = 0.65, 95% CI = 0.49 to 0.86, n = 1].

The investigators concluded that higher intake of antioxidant-rich foods reduces risk of Parkinson's disease. Future, well-designed prospective studies are needed to validate the present findings.

Original title:
Dietary Antioxidants and Risk of Parkinson's Disease: A Systematic Review and Dose-response Meta-analysis of Observational Studies by Talebi S, Ghoreishy SM, […], Mohammadi H.

Link:
https://pubmed.ncbi.nlm.nih.gov/35030236/

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