Nutritional advice

Objectives:
Can the biomarker miRNAs predict Alzheimer's disease?

Study design:
This review article included 10 studies containing 770 Alzheimer's disease and 664 normal controls (persons without Alzheimer's disease).

Results and conclusions:
The investigators found miRNAs presented excellent diagnostic performance and the overall sensitivity was 0.80 [95% CI = 0.75-0.83], specificity was 0.83 [95% CI = 0.78-0.87] and diagnostic odds ratio was 14 [95% CI = 11-19].

The investigators found subgroup analysis suggested that the Caucasian group and blood group showed a better performance in Alzheimer's disease diagnosis and the diagnostic odds ratio was 42 and 34, respectively.

The investigators concluded that miRNAs may be a promising biomarker for Alzheimer's disease.

Original title:
Blood circulating miRNAs as biomarkers of Alzheimer's disease: a systematic review and meta-analysis by Zhang YH, Bai SF and Yan JQ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31385521

Additional information of El Mondo:
Find more information/studies on dementia and elderly.

Objectives:
Does alcohol consumption increase of risk of osteoporosis?

Study design:
This review article included  3 case control studies, 2 cohort studies and 1 cross-sectional study.

Results and conclusions:
The investigators found no association between consuming 0.5-1 drinks per day and the risk of developing osteoporosis [adjusted RR = 1.38, 95% CI = 0.90-2.12].
No association because RR of 1 was found in the 95% CI of 0.90 to 2.12. RR of 1 means no risk/association.

The investigators found compared with abstainers of alcohol, persons consuming 1-2 drinks per day had 1.34 times the risk of developing osteoporosis [adjusted RR = 1.34, 95% CI = 1.11-1.62].

The investigators found compared with abstainers of alcohol, persons consuming 2 drinks or more per day had 1.63 times the risk of developing osteoporosis [adjusted RR = 1.63, 95% CI = 1.01-2.65].

The investigators found a positive association between alcohol consumption and osteoporosis in the case-control studies [adjusted OR = 2.95, 95% CI = 1.78-4.90].

The investigators concluded there is a positive relationship between alcohol consumption, particularly 1 drink or more per day and osteoporosis.

Original title:
The effect of alcohol on osteoporosis: A systematic review and meta-analysis by Cheraghi Z, Doosti-Irani A, Almasi-Hashiani A, […], Mansournia MA.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30844616

Additional information of El Mondo:
Find more information/studies on alcohol consumption and elderly.

Objectives:
The role of zinc in the etiology of type 2 diabetes has been widely reported in recent decades. However, much remains uncertain concerning the effect of zinc on the risk of developing type 2 diabetes. Therefore, this review article has been conducted.

Does zinc reduce risk of type 2 diabetes?

Study design:
This review article included 16 studies.
There was no publication bias.

Results and conclusions:
The investigators found in 7 prospective cohort studies and 1 cross-sectional study (146,027 participants aged between 18 and 84 years and of both genders, belonging to different ethnic groups. Of which, 11,511 type 2 diabetes cases) when comparing the highest versus lowest dietary zinc intakes, a significantly reduced risk of 13% [OR = 0.87, 95% CI = 0.78-0.98, I2 = 64.5%, p = 0.003] for type 2 diabetes.
This relationship was stronger and more evident in rural compared to urban areas [rural areas: OR = 0.59, 95% CI = 0.48-0.73, I2 = 0.0%, p = 0.843 versus urban areas: OR = 0.94, 95% CI = 0.86-1.02, I2 = 43.9%, p = 0.113].

The investigators found no association between supplementary [OR = 0.94, 95% CI = 0.75-1.19, I2 = 85.4%, p = 0.009] or total zinc intake from both diet and supplementation [OR = 0.95, 95% CI = 0.82-1.11, I2 = 56.5%, p = 0.129] and type 2 diabetes risk.

The investigators found in population-based studies that high serum/plasma zinc levels significantly increased risk of type 2 diabetes with 64% [OR = 1.64, 95% CI = 1.25-2.14, I2 > 22.5%, p = 0.275].

The investigators concluded high dietary zinc intake reduces risk of type 2 diabetes. This relationship is stronger and more evident in rural compared to urban areas. However, an elevated serum/plasma zinc concentration is associated with an increased risk of type 2 diabetes in the general population.

Link:
Zinc Intake and Status and Risk of Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis by Fernández-Cao JC, Warthon-Medina M, […], Lowe NM.

Link:
https://www.mdpi.com/2072-6643/11/5/1027/htm

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

Serum/plasma zinc levels can be increased by eating products that contain a lot of zinc and/or taking zinc supplements.
 

Objectives:
Do older adults benefit from high protein intake (>0.8 g/kg body weight/day)?

Study design:
This review article included 12 cohort studies and 1 RCT.
Studies had an intervention duration of at least 6 months.

Results and conclusions:
The investigators found meta-analysis of the cohort studies showed that high vs low protein intake resulted in a statistically significant decrease of 11% for hip fractures [pooled HR = 0.89, 95% CI = 0.84 to 0.94, p 0.001, I2 = 0.0%, p = 0.614].
Sensitivity analyses showed that there was no single study affecting the overall estimate considerably.

The investigators concluded there is an association between a dietary protein intake above the current RDA of 0.8 g/kg body weight/day and a reduced hip fracture risk in older adults. In comparison with younger adults, the body of evidence from the included studies is not strong enough to increase the protein recommendation for older adults with respect to bone health.

Original title:
High Versus low Dietary Protein Intake and Bone Health in Older Adults: a Systematic Review and Meta-Analysis by Groenendijk I, den Boeft L , [...], de Groot LCPGM.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6704341/

Additional information of El Mondo:
Find more information/studies on protein and elderly.

A protein intake higher than 0.8 g/kg body weight/day corresponds to a diet with a minimum of 11 En% protein. The easiest way to follow a diet with at least 11 En% protein is to choose only products that contain at least 11 En% protein. These products from the supermarket contain at least 11% En% protein.
 

Objectives:
Does magnesium reduce risk of type 2 diabetes?

Study design:
This review article included 35 cohort studies and 26 RCTs (1,168 participants).

Results and conclusions:
The investigators found compared to the lowest magnesium dietary intake, the highest level was associated with a 22% lower risk for type 2 diabetes.

The investigators found the risk for type 2 diabetes was reduced by 6% for each 100mg increment in daily magnesium dietary intake.

The investigators found in 26 RCTs (1,168 participants) that magnesium supplementation significantly reduced:
-the fasting plasma glucose (FPG) level [SMD = -0.32, 95% CI = -0.59 to -0.05];
-2-h oral glucose tolerance test (2-h OGTT) result [SMD = -0.30, 95% CI = -0.58 to -0.02];
-fasting insulin level [SMD = -0.17, 95% CI = -0.30 to -0.04];
-homeostatic model assessment-insulin resistance (HOMA-IR) score [SMD = -0.41, 95% CI = -0.71 to -0.11];
-triglyceride (TG) level;
-systolic blood pressure (SBP) and;
-diastolic blood pressure (DBP).

The investigators found trial sequential analysis (TSA) showed an inverse association, with most benefits of magnesium supplementation on glucose metabolism being stable.

The investigators concluded magnesium dietary intake has an inverse dose-response association with type 2 diabetes incidence and supplementation appears to be advisable in terms of glucose parameters in type 2 diabetes/high-risk individuals.

Original title:
Association of Magnesium Consumption with Type 2 Diabetes and Glucose Metabolism: a Systematic Literature Review and Pooled Study with Trial Sequential Analysis by Zhao B, Deng H, [...], Zhang W.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31758631

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

Objectives:
Do low folate levels and vitamin B12 levels increase risk of depression among the aged people?

Study design:
This review article included both gender data of 11 folate-related (7,949 individuals) and 9 B12-related studies (6,308 individuals) and gender-specific data of 4 folate-related (3,409 individuals) and 3 B12-related studies (1,934 individuals).

Results and conclusions:
The investigators found low folate levels significantly increased risk of depression among the aged people with 23% [OR =1.23, 95% CI =1.07-1.43]. 

The investigators found low vitamin B12 levels significantly increased risk of depression among the aged people with 20% [OR =1.20, 95% CI =1.02-1.42]. 

The investigators found in subgroup analysis low vitamin B12 levels significantly increased risk of depression among the aged women with 33% [OR =1.33, 95% CI =1.02-1.74]. 

The investigators concluded both low folate levels and low vitamin B12 levels increase risk of depression among the aged people.

Original title:
Folate and B12 serum levels in association with depression in the aged: a systematic review and meta-analysis by Petridou ET, Kousoulis AA, [...], Stefanadis C.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/26055921

Additional information of El Mondo:
Find more information/studies on vitamin B12, folate and elderly.
 

Objectives:
Observational evidence suggests higher nut consumption is associated with better glycemic control. However, it is unclear if this association is causal. Therefore, this review article has been conducted.

Is there a causal relationship between consumption of tree nuts or peanuts and reduced risk of type 2 diabetes?

Study design:
This review article included a total of 40 RCTs with 2,832 unique participants, with a median duration of 3 months (range: 1-12 months).

Results and conclusions:
The investigators found overall consumption of tree nuts or peanuts had a favourable effect on HOMA-IR values [WMD = -0.23, 95% CI = -0.40 to -0.06, I2 = 51.7%] and fasting insulin levels [WMD = -0.40 μIU/mL, 95% CI = -0.73 to -0.07 μIU/mL, I2 = 49.4%].

The investigators found, however, there was no significant effect of nut consumption on fasting blood glucose levels [WMD = -0.52 mg/dL, 95% CI = -1.43 to 0.38 mg/dL, I2 = 53.4%] or HbA1c [WMD = 0.02%, 95% CI = -0.01% to 0.04%, I2 = 51.0%].

The investigators concluded consumption of peanuts or tree nuts decreases HOMA-IR and fasting insulin levels. These findings suggest that nut consumption may improve insulin sensitivity. In the future, well-designed clinical trials are required to elucidate the mechanisms that account for these observed effects.

Original title:
The effect of nuts on markers of glycemic control: a systematic review and meta-analysis of randomized controlled trials by Tindall AM, Johnston EA, […], Petersen KS.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30722007

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

Objectives:
Findings from observational studies and clinical trials on the associations between vitamin E and dementia remain controversial. Therefore, this review article has been conducted.

Do low vitamin E levels increase risk of Alzheimer's disease (AD) or age-related cognitive deficits and mild cognitive impairment (MCI)?

Study design:
This review article included 31 studies.

Results and conclusions:
The investigators found individuals with Alzheimer's disease had lower circulatory concentrations of α-tocopherol (vitamin E) compared with healthy controls [SMD = -0.97, 95% CI = -1.27 to -0.68, p  0.00001].

The investigators found individuals with age-related cognitive deficits had lower circulatory concentrations of α-tocopherol (vitamin E) compared with healthy controls [SMD = -0.72, 95% CI = -1.12 to -0.32, p  0.0005].

The investigators found individuals with mild cognitive impairment had lower circulatory concentrations of α-tocopherol (vitamin E) compared with healthy controls [SMD = -0.72, 95% CI = -1.12 to -0.32, p  0.0005].

The investigators found levels of β-, γ- and δ-tocopherols did not significantly differ between groups of Alzheimer's disease and age-related cognitive deficits compared to controls.

The investigators concluded that lower α-tocopherol (vitamin E) levels have a strong association with Alzheimer's disease and mild cognitive impairment supporting evidence for the role of diet and vitamin E in Alzheimer's disease risk and age-related cognitive decline.

Original title:
A meta-analysis of peripheral tocopherol levels in age-related cognitive decline and Alzheimer's disease by Ashley S, Bradburn S and Murgatroyd C.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31661399

Additional information of El Mondo:
Find more information/studies on vitamin E and elderly.
 

Objectives:
The incidence of type 2 diabetes mellitus (DM) has increased in the US over the last several years. The consumption of low-fat dairy foods has been linked with decreasing the risk of diabetes mellitus but studies have yet to show a clear correlation. Therefore, this review article has been conducted.

Is there a causal relationship between consumption of low-fat dairy foods and reduced risk of type 2 diabetes?

Study design:
This review article included 30 RCTs.
The total sample size was 2,900 with >50% female participants, but the distribution varied greatly across different studies.
The mean age of subjects ranged from 18-63 years.
The funnel plots for all 3 outcomes (HOMA-IR, waist circumference and body weight) did not suggest significant publication bias.

Results and conclusions:
The investigators found (794 individuals) comparing high intake to the control group, consumption of low-fat dairy foods significantly reduced the HOMA-IR values [MD = -1.21, 95% CI = -1.74 to -0.67, p 0.00001, I2 = 92%].

The investigators found (1,348 individuals) comparing high intake to the control group, consumption of low-fat dairy foods significantly reduced waist circumference [MD = -1.09 cm, 95% CI = -1.68 to -0.58, p 0.00001, I2 = 94%].

The investigators found for body weight (2,362 individuals), the low-fat dairy foods intervention group weighed 0.42 kg less than the control group [p 0.00001, I2 = 92%].

The investigators found limiting to studies that were assessed to have low risk of bias did not significantly change the point estimates or heterogeneity statistics (Q or I2) for all 3 outcomes.
Similarly excluding studies with a physical activity component did not significantly alter point estimates or heterogeneity statistics for all 3 outcomes.

The investigators concluded low-fat dairy products have a beneficial effect on HOMA-IR, waist circumference and body weight. This could impact dietary recommendations to reduce type 2 diabetes risk.

Original title:
The Effects of Dairy Intake on Insulin Resistance: A Systematic Review and Meta-Analysis of Randomized Clinical Trials by Sochol KM, Johns TS, […], Melamed ML.

Link:
https://www.mdpi.com/2072-6643/11/9/2237/htm

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

Objectives:
Serum uric acid (SUA) accounts for about 50% of extracellular antioxidant activity, suggesting that hyperuricemia (an abnormally high level of uric acid in the blood) may have a protective role in diseases characterized by high levels of oxidative stress, such as osteoporosis. Therefore, this review article has been conducted.

Does a high serum uric acid level (also called hyperuricemia) increase bone mineral density (BMD)?

Study design:
This review article included 19 cross-sectional studies with a total of 55,859 participants.

Results and conclusions:
The investigators found in 6 studies that subjects with higher serum uric acid levels had significantly higher bone mineral density values for the spine [SMD = 0.29, 95% CI = 0.22-0.35, I2 = 47%].
Simple correlation analyses substantially confirmed this finding.

The investigators found in 7 studies that subjects with higher serum uric acid levels had significantly higher bone mineral density values for total hip [SMD = 0.29, 95% CI = 0.24-0.34, I2 = 33%].
Simple correlation analyses substantially confirmed this finding.

The investigators found in 6 studies that subjects with higher serum uric acid levels had significantly higher bone mineral density values for femoral neck [SMD = 0.25, 95% CI = 0.16-0.34, I2 = 71%].
Simple correlation analyses substantially confirmed this finding.

The investigators found in 3 studies that an increase of one standard deviation in serum uric acid levels significantly reduced risk of new fractures with 17% [HR = 0.83, 95% CI = 0.74-0.92, I2 = 0%].

The investigators found no significant differences between men and women, although data about women were limited.

The investigators concluded a high serum uric acid level is independently associated with higher bone mineral density values and a lower risk of fractures, supporting a protective role for uric acid in bone metabolism disorders.

Original title:
Hyperuricemia protects against low bone mineral density, osteoporosis and fractures: a systematic review and meta-analysis by Veronese N, Carraro S, […], Cereda E.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/27636234

Additional information of El Mondo:
Find more information/studies on elderly.
 

Objectives:
In recent years, cardiovascular diseases (CVDs) have become a focus topic and global concern. There have been mixed reports on the relationship between whole grain or cereal fiber intake and the risk of type 2 diabetes. Therefore, this review article has been conducted.

Does grain or cereal fiber dietary intake reduce risk of type 2 diabetes?

Study design:
This review article included 7 cohort studies and 1 case-control study with a total of 434,903 participants and 14,728 cases of type 2 diabetes.
The average follow-up was 12.6 years.
There was no publication bias.

Results and conclusions:
The investigators found whole grain or cereal fiber dietary intake was associated with a reduced risk of 26% [combined RR = 0.74, 95% CI = 0.67 to 0.82, I2 = 56.8%, p = 0.06] for type 2 diabetes.
This reduced risk was 38% [pooled RR = 0.68, 95% CI = 0.64-0.73, I2 = 0.0%, p = 0.452] in sensitivity analysis.

The investigators found whole grain or cereal fiber dietary intake was associated with a reduced risk of 32% [combined RR = 0.68, 95% CI = 0.49 to 0.88] for type 2 diabetes among males.

The investigators found whole grain or cereal fiber dietary intake was associated with a reduced risk of 26% [combined RR = 0.74, 95% CI = 0.64 to 0.77] for type 2 diabetes among females.

The investigators concluded that increased whole grain and cereal fiber dietary intake reduce risk of type 2 diabetes.

Original title:
Whole grain and cereal fiber intake and the risk of type 2 diabetes: a meta-analysis by Wang Y, Duan Y, […], Jin Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6627783/

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

Objectives:
Do dietary intakes of soy, soy isoflavones and soy protein reduce risk of mortality from all causes, cancers and cardiovascular diseases?

Study design:
This review article included 23 prospective cohort studies with an overall sample size of 330,826 participants.

Results and conclusions:
The investigators found soy/soy products consumption significantly reduced risk of mortality from cancers with 12% [pooled relative risk = 0.88, 95% CI = 0.79 to 0.99, p = 0.03, I2 = 47.1%].

The investigators found soy/soy products consumption significantly reduced risk of mortality from cardiovascular diseases with 15% [pooled effect size = 0.85, 95% CI = 0.72 to 0.99, p = 0.04, I2 = 50.0%].

The investigators found such significant associations were also observed for all-cause mortality in some subgroups of the included studies, particularly those with higher quality.

The investigators found in addition, higher dietary intake of soy was associated with decreased risk of mortality from gastric, colorectal and lung cancers as well as ischemic cardiovascular diseases.

The investigators found participants in the highest category of dietary soy isoflavones intake had a 10% lower risk of all-cause mortality compared with those in the lowest category.

The investigators found that a 10-mg/day increase in dietary intake of soy isoflavones was associated with 7% and 9% decreased risk of mortality from all cancers and breast cancer, respectively.

The investigators found for each 5-g/day increase in consumption of soy protein a 12% reduction in breast cancer death.

The investigators found, however, dietary intake of soy protein was not significantly associated with all-cause and cardiovascular diseases mortality.

The investigators concluded that soy and its isoflavones consumption favorably influence risk of mortality. In addition, soy protein dietary intake is associated with a decreased risk in the mortality of breast cancer. These findings support the current recommendations to increase intake of soy for greater longevity.

Original title:
Soy, Soy Isoflavones, and Protein Intake in Relation to Mortality from All Causes, Cancers, and Cardiovascular Diseases: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies by Nachvak SM, Moradi S, […], Sadeghi O.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31278047

Additional information of El Mondo:
Find more information/studies on soy consumption, cardiovascular diseases and breast cancer right here.

 

Objectives:
Does a high blood homocysteine level increase risk of cognitive impairment, like Alzheimer's disease and vascular dementia?

Study design:
This review article included 28 prospective cohort studies with 2,557 cases (1,035 all-cause dementia, 530 Alzheimer's disease, 92 vascular dementia and >900 cognitive impairment without dementia (CIND)) among 28,257 participants.
 
The average follow-up period ranged from 2.7 to 35 years.

There was no clear evidence of publication bias with Begg's and Egger's tests for Alzheimer dementia [p = 0.806, 0.084, respectively].

Results and conclusions:
The investigators found there was a clear linear dose-response relationship between blood homocysteine concentration and risk of Alzheimer-type dementia [p > 0.05 for non-linearity].

The investigators found for every 5 μmol/L increase in blood homocysteine a significantly increased risk of 15% [pooled RR = 1.15, 95% CI = 1.04 to 1.26, I2 = 56.6%, n = 5] for Alzheimer-type dementia.
Sensitivity analysis showed similar results.

The investigators found due to the presence of publication bias and low statistical power, elevated levels of blood homocysteine were not appreciably associated with risk of all-cause, vascular dementia and cognitive impairment without dementia.

The investigators concluded every 5 μmol/L increase in blood homocysteine is linearly associated with a 15% increase in relative risk of Alzheimer-type dementia.

Original title:
Hyperhomocysteinemia and risk of incident cognitive outcomes: An updated dose-response meta-analysis of prospective cohort studies by Zhou F and Chen S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30826501

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

Objectives:
Although intake of fruits and vegetables seemed to have a protective effect on bone metabolism, its effect on fractures remains uncertain. Therefore, this review article has been conducted.

Does intake of fruits and vegetables reduce risk of fractures?

Study design:
This review article included 6 cohort studies and 4 RCTs.
6 cohort studies included 225,062 participants (134,365 women and 90,697 men) aged 50 years or older. The participants’ follow-up time ranged from 2.8 years to 20 years.

Validated food frequency questionnaires (FFQs), 24-hour food recall (24h-R) and 7-day food record were used to evaluate fruit and vegetable intake.

Results and conclusions:
The investigators found in 5 cohort studies that intake of at least one serving of fruits and vegetables per day significantly reduced risk of hip fractures with 8% [pooled HR = 0.92, 95% CI = 0.87 to 0.98, I2 = 55.7%, p = 0.060] among participants aged 50 years or older.

The investigators found in 2 cohort studies that intake of at least one serving of fruits and vegetables per day significantly reduced risk of any fractures with 10% [pooled HR = 0.90, 95% CI = 0.86 to 0.96, I2 = 24.9%, p = 0.249] among participants aged 50 years or older.

The investigators found no association between the bone resorption marker CTx and 3 months of fruit and vegetable intake evaluated by 4 RCTs.

The investigators concluded that at least one serving of fruits and vegetables per day is associated with a lower risk of fractures among participants aged 50 years or older.

Original title:
Fruit and vegetable intake and bones: A systematic review and meta-analysis by Brondani JE, Comim FV, […], Premaor MO.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6544223/

Additional information of El Mondo:
Find more information/studies on fruits and vegetables consumption and elderly.
 

Objectives:
Does a dietary low-ratio n-6/n-3 PUFA supplementation improve risk factors (such as fasting blood glucose, HbA1c) of diabetes?

Study design:
This review article included 11 RCTs.

No significant publication bias was observed for all blood glucose and other related indicators as suggested by Begg's test and Egger's test.

Results and conclusions:
The investigators found no significant effect of dietary low-ratio n-6/n-3 PUFA supplementation on:
-fasting blood glucose [WMD = 0.057 mmol/L, 95% CI = -0.090 to 0.204 mmol/L];
-insulin [WMD = -0.757 mIU/L, 95% CI = -2.419 to 0.904 mIU/L];
-insulin resistance index [WMD = -0.201, 95% CI = -0.566 to 0.165] and;
-glycosylated hemoglobin [WMD = -0.063%, 95% CI = -0.061 to 0.186%].

The investigators found subgroup analysis showed that the effect of dietary low-ratio n-6/n-3 PUFA on the reduction of the plasma insulin level in North America [WMD = -3.473 mIU/L, 95% CI = -5.760 to -1.185 mIU/L] was more obvious than that in Asian countries [WMD = -0.797 mIU/L, 95% CI = -2.497 to 0.902 mIU/L] and European countries [WMD = -0.063 mIU/L, 95% CI = -0.061 to 0.186 mIU/L].

The investigators found in the subgroup of diabetic subjects, dietary low-ratio n-6/n-3 PUFA supplementation significantly decreased plasma insulin level [WMD = -3.010 mIU/L, 95% CI = -5.371 to -0.648 mIU/L] and insulin resistance index [WMD = -0.460, 95% CI = -0.908 to -0.012].

The investigators found when the intervention period was longer than 8 weeks, dietary low-ratio n-6/n-3 PUFA supplementation significantly decreased the plasma insulin level [WMD = -2.782 mIU/L, 95% CI = -4.946 to -0.618 mIU/L].

The investigators concluded dietary low-ratio n-6/n-3 PUFA supplementation improves the glucose metabolism by reducing the insulin and insulin resistance in the diabetic patients. Dietary low-ratio n-6/n-3 PUFA supplementation also reduces the plasma insulin level when the supplementation duration is longer than 8 weeks.

Original title:
Effect of low-ratio n-6/n-3 PUFA on blood glucose: a meta-analysis by Li N, Yue H, […], Xu T.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31292599

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

Objectives:
The associations between dietary fat intake and cognitive function are inconsistent and inconclusive. Therefore, this review article has been conducted.

Is there a relationship between different types of fat intake and cognitive impairment?

Study design:
This review article included 9 prospective cohort studies covering a total of 23,402 participants.

Results and conclusions:
The investigators found compared with the lowest category of consumption, the highest category of saturated fat consumption significantly increased risk of cognitive impairment with 40% [RR = 1.40, 95% CI = 1.02-1.91].

The investigators found compared with the lowest category of consumption, the highest category of saturated fat consumption significantly increased risk of Alzheimer disease with 87% [RR = 1.87, 95% CI = 1.09-3.20].

The investigators found total and unsaturated fat dietary intakes were not statistically associated with cognitive outcomes with significant between-study heterogeneity.

The investigators concluded there is an increased risk between saturated fat consumption and both cognitive impairment and Alzheimer disease. Given the substantial heterogeneity in the sample size and methodology used across studies, the evidence presented here should be interpreted with caution.

Original title:
Dietary Fat Intake and Cognitive Function among Older Populations: A Systematic Review and Meta-Analysis by Cao GY, Li M, […], Xu B.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31062836

Additional information of El Mondo:
Find more information/studies on saturated fat intake, dementia and elderly right here.

A diet with a high saturated fat intake is a diet with >10 En% saturated fat.
>10 En% saturated fat means that the total amounts of saturated fat make up for >10% of the total kcal of the diet.
The easiest way to follow this diet is to choose only meals/products that also contain 10 En% saturated fat.
Check here which products contain >10 En% saturated fat.

A diet with a low saturated fat intake is a diet with 7 En% saturated fat.

Objectives:
Although many studies have shown that low zinc status is associated with diabetes, the putative effects of zinc supplementation on glycemic control are inconclusive. Therefore, this review article (meta-analysis) has been conducted.

Does zinc supplementation reduce risk of diabetes mellitus?

Study design:
This review article included 32 RCTs, involving a total of 1,700 participants in 14 countries.

Results and conclusions:
The investigators found overall, compared with their respective control groups, the subjects in the zinc supplementation group had a statistically significant reduction in concentrations of :
-fasting glucose [WMD = -14.15 mg/dL, 95% CI = -17.36 to -10.93 mg/dL];
-2-h postprandial glucose [WMD = -36.85 mg/dL, 95% CI = -62.05 to -11.65 mg/dL];
-fasting insulin [WMD = -1.82 mU/L, 95% CI = -3.10 to -0.54 mU/L];
-homeostasis model assessment for insulin resistance [WMD = -0.73, 95% CI = -1.22 to -0.24]:
-glycated hemoglobin [WMD = -0.55%, 95% CI = -0.84 to -0.27%] and;
-high-sensitivity C-reactive protein [WMD = -1.31 mg/L, 95% CI = -2.05 to -0.56 mg/L].

The investigators found, moreover, subgroup analyses revealed that the effects of zinc supplementation on fasting glucose were significantly influenced by diabetic status and the formulation of the zinc supplement.

The investigators concluded several key glycemic indicators are significantly reduced by zinc supplementation, particularly the fasting glucose in subjects with diabetes and in subjects who received an inorganic zinc supplement. Together, these findings support the notion that zinc supplementation may have clinical potential as an adjunct therapy for preventing or managing diabetes.

Original title:
Zinc supplementation improves glycemic control for diabetes prevention and management: a systematic review and meta-analysis of randomized controlled trials by Wang X, Wu W, [...], Wang F.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31161192

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

Objectives:
Dietary proteins, including those obtained from animal and plant sources, have inconsistently been correlated with type 2 diabetes mellitus (T2DM) risk. Therefore, this review article (meta-analysis) has been conducted.

Does dietary protein intake increase risk of type 2 diabetes mellitus?

Study design:
This review article included 21 cohort studies with a total of 487,956 individuals and 38,350 T2DM cases (persons with type 2 diabetes mellitus).

Results and conclusions:
The investigators found high total dietary protein intake was associated with an increased risk of 10% for type 2 diabetes mellitus [RR = 1.10, p = 0.006] whereas moderate total dietary protein intake was not significantly associated with type 2 diabetes mellitus risk [RR = 1.00,  p = 0.917].  
Not significantly because the calculated p-value of 0.917 was larger than the p-value of 0.05.

The investigators found, moreover, an increased risk of 13% [RR = 1.13, p = 0.013] for type 2 diabetes mellitus was observed with high  dietary animal protein intake whereas moderate animal protein intake had little or no effect on type 2 diabetes mellitus risk [RR = 1.06, p = 0.058].

The investigators found, high dietary intake of plant protein did not affect type 2 diabetes mellitus risk [RR = 0.93, p = 0.074], whereas moderate intake was associated with a reduced risk of 6% for type 2 diabetes mellitus [RR = 0.94, p  0.001].

The investigators concluded high dietary total protein and dietary animal protein intakes are associated with an increased risk of type 2 diabetes mellitus, whereas moderate plant protein intake is associated with a decreased risk of type 2 diabetes mellitus.

Original title:
Dietary protein intake and subsequent risk of type 2 diabetes: a dose-response meta-analysis of prospective cohort studies by Ye J, Yu Q, [...], Wang Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30929078

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Find more information/studies on diabetes and protein right here.

A diet with high protein intake is a diet with a minimum of 35 En% protein (En% = energy percentage). These products from the supermarket contain at least 35 En% protein.
35 En% protein means that the amounts of protein contribute 35% to the total calories (kcal) of the diet.
If the diet contains 2000 kcal, 175 grams of protein contribute 35% to this 2000 kcal.
1 gram of protein gives 4 kcal. Thus, 175 grams of protein provide 700 kcal and 700 kcal is 35% of 2000 kcal.

A diet with moderate protein consumption is a diet with 20-25 En% protein. The easiest way to follow a diet with moderate protein consumption is to choose only products/meals that also contain 20-25 En% protein. These products from the supermarket contain 20-25 En% protein.

 

Objectives:
The role of gut microbiota in the management of diabetes has been shown. Several current trials are investigating the effect of probiotics and prebiotics, which are widely used to modulate intestinal microbiota, on inflammatory factors and biomarkers of oxidative stress in diabetic patient. However, their findings are controversial. Therefore, this review article (meta-analysis) has been conducted.

Do probiotic and synbiotic supplementation improve biomarkers of inflammation and oxidative stress in diabetic patients?

Study design:
This review article included 16 RCTs (n = 1,060).

Randomized controlled trials (RCTs) reported the effect of probiotics or synbiotics on circulating (serum and plasma) inflammatory marker (hs-CRP) and oxidative stress indicators (malondialdehyde [MDA], glutathione [GSH], nitric oxide [NO] and total antioxidant capacity [TAC]) among patients with diabetes.

The methodological quality varied across these trials.

Results and conclusions:
The investigators found probiotic and synbiotic supplementation significantly decreased hs-CRP level [SMD = -0.38, 95% CI = -0.51 to -0.24, p = 0.000] and the oxidative stress indicator malondialdehyde [SMD = -0.61, 95% CI = -0.89 to -0.32, p = 0.000] in diabetic patients compared to those in subjects receiving placebos.

The investigators found, in addition, probiotic and synbiotic supplementation significantly increased total antioxidant capacity [SMD = 0.31, 95% CI = 0.09 to 0.52, p = 0.006], nitric oxide [SMD = 0.62, 95% CI = 0.25 to 0.99, p = 0.001] and glutathione [SMD = 0.41, 95% CI = 0.26, 0.55, p = 0.000] levels.

The investigators concluded that probiotic and synbiotic supplementation improve biomarkers of inflammation and oxidative stress in diabetic patients. Further studies are needed to develop clinical practice guidelines for the management of inflammation and oxidative stress in these patients.

Original title:
The effect of probiotic and synbiotic supplementation on biomarkers of inflammation and oxidative stress in diabetic patients: A systematic review and meta-analysis of randomized controlled trials by Zheng HJ, Guo J, [...], Wang Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30794924

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Oxidative stress is an imbalance between free radicals and antioxidants in your body. Antioxidants can reduce oxidative stress.
 

Objectives:
Various mechanisms link higher total homocysteine to higher insulin resistance and risk of type 2 diabetes (T2D). Folate supplementation is recognized as a way to lower homocysteine. However, randomized controlled trials (RCTs) show inconsistent results on insulin resistance and type 2 diabetes outcomes. Therefore, this review article (meta-analysis) has been conducted.

Does folate supplementation improve insulin resistance and type 2 diabetes outcomes?

Study design:
This review article included 29 RCTs (22,250 participants) that assessed the effect of placebo-controlled folate supplementation alone or in combination with other B vitamins on fasting glucose, insulin, homeostasis model assessment for insulin resistance (HOMA-IR), glycated hemoglobin (HbA1c) or risk of type 2 diabetes.

The meta-analysis was conducted using both random- and fixed-effects models to calculate weighted mean differences (WMDs) or risk ratios with 95% CIs.
Heterogeneity was low in all meta-analyses.

Results and conclusions:
The investigators found when compared with placebo, folate supplementation significantly lowered fasting insulin [WMD = -13.47 pmol/L, 95% CI = -21.41 to -5.53 pmol/L, p 0.001] and HOMA-IR [WMD = -0.57 units, 95% CI = -0.76 to -0.37 units, p 0.0001], but no overall effects were observed for fasting glucose or HbA1c.

The investigators found subgroup analysis showed no signs of effect modification except for change in homocysteine, with the most pronounced effects in trials with a change of >2.5 µmol/L.
Changes in homocysteine after folate supplementation correlated with changes in fasting glucose [β = 0.07, 95% CI = 0.01 to 0.14, p = 0.025] and HbA1c [β = 0.46, 95% CI = 0.06 to 0.85, p = 0.02].

The investigators found only 2 studies examined folate supplementation on risk of type 2 diabetes and they found no change in RR [pooled RR = 0.91, 95% CI = 0.80 to 1.04, p = 0.16].

The investigators concluded that folate supplementation lowers fasting insulin and HOMA-IR. However, folate supplementation does not reduce risk of type 2 diabetes.

Original title:
Effect of folate supplementation on insulin sensitivity and type 2 diabetes: a meta-analysis of randomized controlled trials by Lind MV, Lauritzen L, [...], Eriksen JN.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30615110

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Objectives:
No conclusive information is available about the association between dietary total antioxidant capacity (DTAC) and risk of mortality. Therefore, this review article has been conducted.

Does dietary total antioxidant capacity (DTAC) reduce risk of death from all-cause (all-cause mortality), cancer (cancer mortality) and cardiovascular diseases (CVDs mortality)?

Study design:
This review article included 5 prospective cohort studies with a follow-up period of 4.3-16.5 years. There were 38,449 deaths from all-cause, 4,470 from cancer and 2,841 from cardiovascular diseases among 226,297 individuals.

Results and conclusions:
The investigators found dietary total antioxidant capacity significantly reduced all-cause mortality with 38% [combined effect size = 0.62, 95% CI = 0.60-0.64].
Significant because combined effect size of 1 was not found in the 95% CI of 0.60 to 0.64. Combined effect size of 1 means no risk/association.

The investigators found dietary total antioxidant capacity significantly reduced cancer mortality with 19% [combined effect size = 0.81, 95% CI = 0.75-0.88].
Significant means that there is an association with a 95% confidence.

The investigators found dietary total antioxidant capacity significantly reduced cardiovascular diseases mortality with 29% [combined effect size = 0.71, 95% CI = 0.63-0.82].

The investigators found findings from linear dose-response meta-analysis revealed that a 5 mmol/day increment in dietary total antioxidant capacity based on ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) was associated with 7% and 15% lower risk of all-cause mortality, respectively.

The investigators found findings from non-linear dose-response meta-analysis showed a significant reduction in risk of all-cause mortality when increasing ferric reducing antioxidant power (FRAP) from 2 to 12 mmol/day [p-nonlinearity = 0.002] and oxygen radical absorbance capacity (ORAC) from 5 to 11 mmol/day [p-nonlinearity  0.001].

The investigators concluded a diet with high total antioxidant capacity decreases risk of death from all-cause, cancer and cardiovascular diseases.

Original title:
Dietary total antioxidant capacity and mortality from all causes, cardiovascular disease and cancer: a systematic review and dose-response meta-analysis of prospective cohort studies by Parohan M, Anjom-Shoae J, […], Sadeghi O

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30756144

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Find more information/studies on significantly/review article, antioxidant and cancer and cardiovascular diseases mortality right here.

The easiest way to get enough antioxidants from food is to eat at least 200 grams of vegetables and at least 200 grams of fruit per day.

There exist different methods to measure the antioxidant capacity of foods: Oxygen Radical Absorbance Capacity (ORAC), Ferric Ion Reducing Power (FRAP) and Trolox Equivalence Antioxidant Capacity (TEAC). The most popular method is the ORAC determination, which was developed by the National Institutes of Health in Baltimore.

The USDA recommends an ORAC unit ingestion of about 3000 to 5000 units daily.

Objectives:
Is there an association between potato consumption and risk of all-cause, cancer and cardiovascular mortality in adults?

Study design:
This review article included 20  prospective cohort studies with 25,208 cases of all-cause mortality, 4,877 of cancer mortality and 2,366 of cardiovascular mortality.

There was no evidence for publication bias.

Results and conclusions:
The investigators found no significant association between potato consumption and risk of all-cause [RR = 0.90, 95% CI = 0.8 to 1.02, p = 0.096] and cancer [RR = 1.09, 95% CI = 0.96 to 1.24, p = 0.204] mortality.

The investigators found, in addition, no significant linear association between each 100 g/d increments in potato consumption and risk of all-cause [p = 0.7] and cancer [p = 0.09] mortality.
Moreover, nonlinear association between potato consumption and risk of cancer mortality was non-significant [p-nonlinearity = 0.99].

The investigators found, in addition, 2 of 3 studies which examined the association of potato consumption with cardiovascular mortality did not find any significant relationship.

The investigators concluded there is no association between potato consumption and risk of all-cause, cancer and cardiovascular mortality in adults.

Original title:
Potato consumption and risk of all cause, cancer and cardiovascular mortality: a systematic review and dose-response meta-analysis of prospective cohort studies by Darooghegi Mofrad M, Milajerdi A, […], Azadbakht L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30638040

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Find more information/studies on of potato consumption and elderly right here.
 

Objectives:
Existing studies suggest that dietary vitamins and carotenoids might be associated with a reduced risk of age-related cataract (ARC), although a quantitative summary of these associations is lacking. Therefore, this review article has been conducted.

Do vitamins and carotenoids intake reduce risk of the eye disease age-related cataract? 

Study design:
This review article included 8 RCTs and 12 cohort studies.

Results and conclusions:
The investigators found in cohort studies a significantly reduced risk of 19% [RR = 0.81, 95% CI = 0.71 to 0.92, p = 0.001] of age-related cataract for dietary vitamin A intake.

The investigators found in cohort studies a significantly reduced risk of 20% [RR = 0.80, 95% CI = 0.72 to 0.88, p 0.001] of age-related cataract for dietary vitamin C intake.

The investigators found in cohort studies a significantly reduced risk of 10% [RR = 0.90, 95% CI = 0.80 to 1.00, p 0.049] of age-related cataract for dietary vitamin E intake.

The investigators found in cohort studies a significantly reduced risk of 10% [RR = 0.90, 95% CI = 0.83 to 0.99, p = 0.023] of age-related cataract for dietary β-carotene intake.

The investigators found in cohort studies a significantly reduced risk of 19% [RR = 0.81, 95% CI = 0.75 to 0.89, p 0.001] of age-related cataract for dietary β lutein or zeaxanthin intake.

The investigators found in RCTs compared with the placebo, a non-significantly reduced risk of 3% [RR = 0.97, 95% CI = 0.91 to 1.03, p 0.262] of age-related cataract for vitamin E supplementation.
Non-significantly because RR of 1 was found in the 95% CI of 0.91 to 1.03. RR of 1 means no risk/association.

The investigators found in RCTs compared with the placebo, a non-significantly reduced risk of 1% [RR = 0.99, 95% CI = 0.92 to 1.07, p 0.820] of age-related cataract for β-carotene supplementation.

The investigators found in dose-response analysis of cohort studies a significantly reduced risk of 26% [RR = 0.74, 95% CI = 0.67 to 0.80, p 0.001] of age-related cataract for every 10-mg/d increase in dietary lutein or zeaxanthin intake.

The investigators found in dose-response analysis of cohort studies a significantly reduced risk of 18% [RR = 0.82, 95% CI = 0.74 to 0.91, p 0.001] of age-related cataract for every 500-mg/d increase in dietary vitamin C intake.

The investigators found in dose-response analysis of cohort studies a significantly reduced risk of 8% [RR = 0.92, 95% CI = 0.88 to 0.96, p 0.001] of age-related cataract for every 5-mg/d increase in dietary β-carotene intake.

The investigators found in dose-response analysis of cohort studies a significantly reduced risk of 6% [RR = 0.94, 95% CI = 0.90 to 0.98, p 0.001] of age-related cataract for every 5 mg/d increase in dietary vitamin A intake.

The investigators concluded dietary intake of vitamin A (at least 5 mg per day), vitamin C (at least 500 mg per day), vitamin E, β-carotene (at least 5 mg per day) and lutein or zeaxanthin intake (at least 10 mg per day) reduce risk of age-related cataract.

Original title:
Dietary vitamin and carotenoid intake and risk of age-related cataract by Jiang H, Yin Y, […], Ma L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30624584

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Objectives:
Evidence from randomized controlled trials (RCTs) suggests that viscous dietary fiber may offer beneficial effects on glycemic control and, thus, an improved cardiovascular disease risk profile. Therefore, this review article (meta-analysis) has been conducted.

Does viscous dietary fiber supplementation improve glycemic control in type 2 diabetes?

Study design:
This review article included 28 RCTs of ≥3 weeks in duration that assessed the effects of viscous fiber on markers of glycemic control in type 2 diabetes with a total of 1,394 participants.

Results and conclusions:
The investigators found that viscous fiber at a median dose of ∼13.1 g/day significantly reduced HbA1c in type 2 diabetes [MD = -0.58%, 95% CI = -0.88 to -0.28, p = 0.0002] compared with control and in addition to standard of care.

The investigators found that viscous fiber at a median dose of ∼13.1 g/day significantly reduced fasting blood glucose in type 2 diabetes [MD = -0.82 mmol/L, 95% CI = -1.32 to -0.31, p = 0.001] compared with control and in addition to standard of care. 

The investigators found that viscous fiber at a median dose of ∼13.1 g/day significantly reduced HOMA-insulin resistance in type 2 diabetes [MD = -1.89, 95% CI = -3.45 to -0.33, p = 0.02] compared with control and in addition to standard of care.

The investigators found the certainty of evidence was graded moderate for HbA1c, fasting glucose, fasting insulin and HOMA-IR and low for fructosamine.

The investigators concluded that 13.1 g/day viscous fiber supplements improve conventional markers of glycemic control beyond usual care and should be considered in the management of type 2 diabetes.

Original title:
Should Viscous Fiber Supplements Be Considered in Diabetes Control? Results From a Systematic Review and Meta-analysis of Randomized Controlled Trials by Jovanovski E, Khayyat R, […], Vuksan V.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30617143

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Find more information/studies on diabetes and dietary fiber right here.