Nutrition and health

Objectives:
Dementia is a chronic progressive neurodegenerative disease that can lead to disability and death in humans, but there is still no effective prevention and treatment. Due to the neuroprotective effects of vitamin E, a large number of researchers have explored whether vitamin E can reduce the risk of dementia. Some researchers believe that vitamin E can reduce the risk of dementia, while others hold the opposite conclusion. Therefore, this review article has been conducted.

Do high intakes of diet or vitamin E supplements reduce the risk of dementia?

Study design:
This review article included 13 cohort studies (46,968 participants and 6,046 dementia patients after 4-23 years of follow-up) and 2 case-control studies with (3,157 controls and 3,459 patients).
The studies included in this meta-analysis (review article) were published between 1983 and 2022.
The literary NOS quality score ranged from 6 to 8.
There was no publication bias.

Results and conclusions:
The investigators found a high intake of diet or vitamin E supplements significantly decreased the risk of dementia by 21% [OR = 0.79, 95% CI = 0.70 to 0.88, I2 = 35.0%, p = 0.071].
This decreased risk was also significant in cohort studies [OR = 0.79, 95% CI = 0.69 to 0.89], dietary intake of vitamin E [OR = 0.78, 95% CI = 0.65 to 0.95], vitamin E supplement [OR = 0.83, 95% CI = 0.73 to 0.94] and studies with NOS scores >7 [OR = 0.85, 95% CI = 0.75 to 0.97].

The investigators found a high intake of diet or vitamin E supplements significantly decreased the risk of Alzheimer's disease by 22% [OR = 0.78, 95% CI = 0.64 to 0.94, I2 = 36.9%, p = 0.123].
This decreased risk was also significant in cohort studies [OR = 0.77, 95% CI = 0.63 to 0.94].

The investigators found in sensitivity analysis the pooled ORs fluctuated within a certain range after deleting each study, indicating that the results of this meta-analysis were stable.

The investigators concluded high intakes of diet or vitamin E supplements reduce the risk of dementia. Therefore, the elderly can reduce the risk of dementia by appropriately increasing foods rich in vitamin E, but also pay attention to the toxic side effects of vitamin E. Although the results are reliable, they should be further validated by large RCTs.

Original title:
Association of vitamin E intake in diet and supplements with risk of dementia: A meta-analysis by Zhao R, Han X, [...], You H.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9376618/

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

Objectives:
Do plant-based diets improve age-related ocular outcomes among adults?

Study design:
This review article included 15 studies (n = 51,695 participants) assessed the impact of fish consumption, 8 studies (n = 28,753 participants) analyzed the effect of red meat intake and 3 studies (n = 7,723 participants) assessed the impact of omission of skim milk, poultry and non-meat animal products and the presence of disease incidence as indicated by age-related macular degeneration or cataract development.

Results and conclusions:
The investigators found in 15 studies (n = 51,695 participants) that regular consumption of fish significantly reduced the risk of age-related eye disease development among adults with 30% [odds ratio = 0.70, 95% CI = 0.62 to 0.79].
Significant means that there is an association with a 95% confidence.

The investigators found in 3 studies (n = 7,723 participants) that regular consumption of skim milk, poultry and non-meat animal products significantly reduced the risk of age-related eye disease development among adults with 30% [odds ratio = 0.70, 95% CI = 0.61 to 0.79].
Significant because odds ratio of 1 was not found in the 95% CI of 1.07 to 1.72. Odds ratio of 1 means no risk/association.

The investigators found in 8 studies (n = 28,753 participants) that regular consumption of red meat significantly increased the risk of age-related eye disease development among adults with 41% [odds ratio = 1.41, 95% CI = 1.07 to 1.86].

The investigators concluded that regular consumption of both fish and skim milk, poultry and non-meat animal products reduce the risk of age-related eye disease development among adults, while regular consumption of red meat increases the risk of age-related eye disease development among adults. Results suggest a need for more initiatives promoting a healthy and balanced diet.

Original title:
Linkage between a plant-based diet and age-related eye diseases: a systematic review and meta-analysis by Cirone C, Cirone KD and Malvankar-Mehta MS.

Link:
https://pubmed.ncbi.nlm.nih.gov/36102832/

Additional information of El Mondo:
Find more information/studies on fish, milk, meat and elderly right here.

In practice, regular fish consumption corresponds to at least twice (100-150g per time) a week.
 

Objectives:
Although recent studies comparing various dosages and intervals of vitamin D supplementation have been published, it is yet to be elucidated whether there is an appropriate dose or interval to provide benefit regarding fracture risk. Therefore, this review article has been conducted.

What are the putative beneficial effects of vitamin D supplements on fractures and falls according to various dosages and intervals?

Study design:
This review article included 32 RCTs with a total of 104,363 patients, with a median of 3,162 patients per study (range 46 to 36,282).
The median daily dose of cholecalciferol (D3) was 800 IU/day and 8 studies reported 800 IU/day, 15 studies reported 800 to 1,000 IU/day and 9 studies reported >1,000 IU/day.
The median follow-up duration was 24 months (range 9 to 120) and the median age was 72 years (range 53 to 85).

Results and conclusions:
The investigators found vitamin D3 supplementation with daily dose of 800 to 1,000 IU was significantly associated with a lower risk of 13% for osteoporotic fracture [pooled relative risk = 0.87, 95% CI = 0.78 to 0.97, I2 = 23.5%] while studies with 800 or >1,000 IU/day did not.

The investigators found vitamin D3 supplementation with daily dose of 800 to 1,000 IU was significantly associated with a lower risk of 9% for fall [pooled relative risk = 0.91, 95% CI = 0.85 to 0.98, I2 = 70.9%] while studies with 800 or >1,000 IU/day did not.

The investigators found daily administration of vitamin D3 was associated with the reduced risk of falls, while intermittent dose was not.
Also, patients with vitamin D deficiency showed a significant risk reduction of falls after vitamin D3 supplementation.

The investigators concluded that daily vitamin D3 dose of 800 to 1,000 IU (20-25 mcg) during 24 months is the most probable way to reduce the fracture and fall risk among elderly. Further studies designed with various regimens and targeted vitamin D levels are required to elucidate the benefits of vitamin D supplements.

Original title:
Effect of Vitamin D Supplementation on Risk of Fractures and Falls According to Dosage and Interval: A Meta-Analysis by Kong SH, Jang HN, […], Shin CS.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9081312/

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

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/

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

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:
In postmenopausal women, vitamin D deficiency (as defined by the circulating level of 25(OH)D being below 20 ng/mL (50 nmol/L)) is a regular occurrence. The effect of vitamin D supplementation on the muscle function of postmenopausal women has been controversial. Therefore, this review article has been conducted.

Does vitamin D supplementation enhance the muscular strength and mobility of postmenopausal women?

Study design:
This review article included 19 RCTs between 2003 and 2021, with 5,398 participants.
The sample size of the RCTs included in multiple countries ranges from 20 to 2,347. Furthermore, the duration of vitamin D supplementation ranged from 3 to 60 months.
Vitamin D3 was applied in 12 of the 19 retrieved trials, whose dosages ranged from 400 IU/day to 300,000 IU (10 tot 7500 mcg vitamin D3) in a single oral dose.
Visual inspection of the funnel plot and Egger’s linear regression test revealed no indication of publication bias in the meta-analysis of vitamin D supplementation on handgrip strength.

Results and conclusions:
The investigators found meta-analysis of 9 RCTs (1,997 participants supplemented with vitamin D and 2,232 participants as the control group (vitamin D in low dosage or placebo)), showed that vitamin D supplementation significantly improved handgrip strength in postmenopausal women [WMD = 0.876 kg, 95% CI = 0.180 to 1.571, p = 0.014, I2 = 68.5%, p = 0.001].
Moreover, according to subgroup analysis, vitamin D supplementation substantially raised handgrip strength when compared to baseline blood vitamin D levels >75 nmol/L (30 ng/ml) [WMD = 0.478 kg, 95% CI = 0.963 to 1.918, p = 0.003], without calcium [WMD = 1.931 kg, 95% CI = 0.166 to 3.697, p = 0.032] and subject to an age of more than 60 [WMD = 1.116 kg, 95% CI = 0.433 to 1.799, p = 0.001].

The investigators concluded that 400 IU/day to 300,000 IU vitamin D supplementation during 3 to 60 months improves handgrip strength in postmenopausal women over 60 years of age who are without calcium supplementation or whose baseline vitamin D is >75 nmol/L (30 ng/mL). These findings show that future trials should focus on determining the ideal dosage and duration and taking into account the several factors that may impair muscle performance, such as exercise, calcium consumption, frailty, a history of falls or fractures and baseline vitamin D status and the relationship between muscle function and/or strength with muscle composition.

Original title:
Vitamin D Supplementation Improves Handgrip Strength in Postmenopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials by Zhang JL, Poon CCW, […], Zhang Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9199366/

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

Objectives:
Data from studies support a beneficial effect of carotenoids and vitamins on an age-related macular degeneration (AMD) risk. However, studies on the relations between blood levels of these nutrients and AMD are limited and provided conflicting results. Therefore, this review article has been conducted.

Does a higher concentration of carotenoids (lutein/zeaxanthin, β-carotene, β-cryptoxanthin, lycopene) and vitamins in blood reduce age-related macular degeneration risk?

Study design:
This review article included 9 studies (1 cohort, 4 case-control and 4 cross-sectional studies) involving 15,674 participants and 2,077 AMD cases (persons with age-related macular degeneration).  
There was no evidence of publication bias.

Results and conclusions:
The investigators found in the meta-analysis that high blood lutein/zeaxanthin level significantly reduced risk of age-related macular degeneration with 47% [OR = 0.53, 95% CI = 0.40 to 0.72, p 0.001, I2 = 43.3%, p = 0.079], compared to those with low level.
Results stratified by factors yielded similar results to the main analysis.

The investigators found in the meta-analysis that high blood β-carotene level significantly reduced risk of age-related macular degeneration with 52% [OR = 0.48, 95% CI = 0.28 to 0.84, p = 0.01, I2 = 71.7%, p = 0.003], compared to those with low level.
A subgroup analysis by geographic region showed that the significant inverse association between blood β-carotene levels and risk of age-related macular degeneration was only found among the Asians.

The investigators found in the meta-analysis that high blood β-cryptoxanthin level significantly reduced risk of age-related macular degeneration with 52% [OR = 0.48, 95% CI = 0.23 to 1.00, p = 0.04, I2 = 83.5%, p 0.001], compared to those with low level.
In stratified analyses, no significant difference was observed for any subgroups.

The investigators found in the meta-analysis that high blood lycopene level significantly reduced risk of age-related macular degeneration with 30% [OR = 0.70, 95% CI = 0.54 to 0.90, p = 0.006, I2 = 0.0%, p = 0.67], compared to those with low level.

The investigators found in the meta-analysis that high blood α-tocopherol (vitamin E) level significantly reduced risk of age-related macular degeneration with 50% [OR = 0.50, 95% CI = 0.31 to 0.81, p = 0.005, I2 = 34.4%, p = 0.19], compared to those with low level.

The investigators found sensitivity analyses, that excluded one study at a time, did not change the statistical significance or the direction of the present findings, corroborating the robustness of the results.

The investigators concluded that there is a protective effect of higher concentration of carotenoids (lutein/zeaxanthin, β-carotene, β-cryptoxanthin, lycopene) and vitamin E in blood against age-related macular degeneration risk, which provides further evidence of the associations between carotenoid and vitamin status and the risk of age-related eye problems. Further randomized clinical trials are necessary for Asians to confirm such associations and to provide the most reliable direct information to base public health recommendations for age-related eye disease prevention by nutritional supplementation with carotenoids and vitamins.

Original title:
The Associations of Plasma Carotenoids and Vitamins With Risk of Age-Related Macular Degeneration: Results From a Matched Case-Control Study in China and Meta-Analysis by Jiang H, Fan  Y, […], Ma L.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8873933/

Additional information of El Mondo:
Find more information/studies on meta-analysis/cohort, carotenoids, vitamin E and elderly right here.

High blood levels of beta-carotene can be obtained by consuming beta-carotene-rich foods and/or taking beta-carotene supplements.
 

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/

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

Objectives:
While there is growing research interest in the effects of nutrition and exercise on delaying sarcopenia, the results are inconclusive and there is scarce information on regional patterns. Therefore, this review article has been conducted.

Do protein supplements combined with exercise improve extremity strength in healthy older adults with sarcopenia?

Study design:
This review article included 14 RCTs, involving a total of 888 healthy older adults (>60 years).

4 studies in Asian countries provided data on lower-extremity strength, involving 280 participants (138 in protein supplements + exercise group and 142 in exercise group).
Lower-extremity strength was assessed using knee extension (n = 3) or leg extension (n = 1).
The intervention period of all studies was 12 weeks.
The dosage of protein ranged from 3 g/d to 40 g/d.

Results and conclusions:
The investigators found in 4 studies in Asian countries a significant increase in the lower-extremity strength in the protein supplementation + exercise group compared to the exercise group, with a SMD of 0.24 [95% CI = 0.00 to 0.47, p = 0.048, I2 = 0.0%, p = 0.513].

The investigators concluded that protein supplements (3 g/d to 40 g/d during 12 weeks) combined with exercise (knee extension and leg extension) exerts superior benefit on lower-extremity strength in healthy older adults with sarcopenia in Asian countries, when compared to exercise alone or with a placebo. However, no additional benefits from protein supplementation are observed on upper-extremity strength, muscle mass and physical performance regardless of the regions. More well-designed RCTs with information on baseline and total protein intake for longer follow-up periods are warranted to evaluate the effectiveness of protein supplementation and exercise on the prevention and management of sarcopenia in healthy older adults.

Original title:
Effects of protein supplementation and exercise on delaying sarcopenia in healthy older individuals in Asian and non-Asian countries: A systematic review and meta-analysis by Li L, He Y, […], Liu X.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8808080/

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Upper extremity is part of the body that includes the arm, wrist and hand.

Lower extremity refers to the part of the body from the hip to the toes.

Sarcopenia is a type of muscle loss (muscle atrophy) that occurs with aging and/or immobility. Sarcopenia can affect people in their 30s and beyond.
 

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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