Nutrition and health

Objectives:
Probiotic supplementation in early life may be effective in preventing atopic dermatitis (AD); however, results regarding efficacy have been controversial. Therefore, this meta-analysis (systematic review) has been conducted.

Does probiotic supplementation in early life prevent atopic dermatitis in infants and children?

Study design:
This review article included 28 RCTs.

Results and conclusions:
The investigators found compared with controls, probiotic supplementation of mother was associated with a significantly reduced risk of 31% for atopic dermatitis in infants and children [OR = 0.69, 95% CI = 0.58-0.82, p  0.0001].

The investigators found compared with controls, the use of probiotics of mother during both the prenatal and the postnatal period significantly reduced the incidence of atopic dermatitis in infants and children with 33% [OR = 0.67, 95% CI = 0.54-0.82].
However, analysis of studies of probiotics given prenatally only or postnatally only did not reach statistical significance.

The investigators concluded that probiotic supplementation of mother during both the prenatal and the postnatal period reduces the incidence of atopic dermatitis in infants and children. These findings suggest that starting probiotic treatment during gestation and continuing through the first 6 months of the infant's life may be of benefit in the prevention of atopic dermatitis.

Original title:
Probiotic Supplementation for Prevention of Atopic Dermatitis in Infants and Children: A Systematic Review and Meta-analysis by Li L, Han Z, […], He C.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30465329

Additional information of El Mondo:
Find more information/studies on protbiotics and pregnancy right here.
 

Objectives:
Inositol (ISL) embraces a family of simple carbohydrates with insulin-sensitizing properties, whose most common isoforms are Myo-inositol (MYO) and D-chiro inositol (DCI). Therefore, this meta-analysis (systematic review) has been conducted.

Does inositol supplementation reduce gestational diabetes (GDM)?

Study design:
This review article included 5 RCTs with a total of  965 participants.
The primary outcome was the preventive effect on gestational diabetes, defined as the rate of gestational diabetes in women without a prior diagnosis of gestational diabetes.
Pooled results were expressed as odds ratio (OR) with a 95% confidence interval (95% CI).
No adverse effects were reported for inositol supplementation.

Results and conclusions:
The investigators found inositol supplementation significantly reduced risk of gestational diabetes with 51% [OR = 0.49, p = 0.01]. However, this reduced risk was only significant in patients receiving 2g inositol twice daily.

The investigators found inositol supplementation significantly reduced risk of preterm delivery with 65% [OR = 0.35, 95% CI = 0.17-0.74, p = 0.006]. However, this reduced risk was only significant in patients receiving 2g inositol twice daily.

The investigators concluded double administration of inositol 2g per day reduces gestational diabetes rate and preterm delivery rate. Therefore, inositol supplementation may represent a novel strategy for gestational diabetes prevention.

Original title:
Inositol for the prevention of gestational diabetes: a systematic review and meta-analysis of randomized controlled trials by Vitagliano A, Saccone G, […], Berghella V.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30564926

Additional information of El Mondo:
Find more information/studies on inositol and pregnancy right here.
 

Objectives:
Diabetes prevention is a public health priority. Vitamin D supplementation may help prevent the development of diabetes in persons at increased risk. Therefore, this review article has been conducted.

Does vitamin D supplementation reduce risk of type 2 diabetes?

Study design:
This review article included 28 RCTs with 3,848 participants.

The sample size varied from 23 to 511.
The mean age of participants ranged from 26 years to 71 years.
The duration of follow-up across studies ranged from 2 months to 5 years, with a median follow-up of 22 weeks [interquartile range (IQR): 14 to 48 weeks], a duration long enough to detect changes in measured outcomes.

The average vitamin D supplementation dose of 88 µg/d (3500 IU/d).
All included trials measured the effect of vitamin D supplementation on serum 25(OH)D concentrations.

Results and conclusions:
The investigators found overall, serum 25(OH)D concentrations in the treated arms (vitamin D-supplemented groups) significantly improved by 45.1 nmol/L [95% CI = 41.3 to 48.9, p 0.001, I2 = 97.4%].

The investigators found compared with the control group, vitamin D supplementation significantly reduced HbA1c level by -0.48% [95% CI = -0.79 to -0.18, p = 0.002, I2 = 92.1%].
However, after adjusting the effect size for potential publication bias using the “trim and fill” method, 4 potentially missing studies were imputed in the funnel plot and the effect size increased from -0.48% [95% CI = -0.79 to -0.18] to -0.71% [95% CI = -1.02 to -0.39].

The investigators found compared with the control group, vitamin D supplementation significantly reduced fasting plasma glucose level by -0.46 mmol/L [95% CI = -0.74 to -0.19, p = 0.001, I2 = 92.4%].  
However, after adjusting the effect size for potential publication bias using the “trim and fill” method, 6 potentially missing studies were imputed in the funnel plot and the effect size increased -0.46 mmol/L [95% CI = -0.74 to ­0.19] to -0.72 mmol/L [95% CI =-1.02 to -0.42].

The investigators found compared with the control group, vitamin D supplementation significantly reduced HOMA-IR level by -0.39 [95% CI = -0.68 to -0.11, p = 0.007, I2 = 91.3%].
However, after adjusting the effect size for potential publication bias using the “trim and fill” method, 5 potentially missing studies were imputed in the funnel plot and the effect size increased from -0.39 [95% CI = -0.68 to -0.11] to -0.62 [95% CI = -0.92 to -0.32].

The investigators found in subgroup analysis both HbA1c and HOMA-IR showed a greater reduction over time among overweight/obese individuals compared with prediabetics [HbA1c = -0.98 ± 0.45 vs -0.29 ± 0.14, p = 0.1 and HOMA-IR = -0.62 ± 0.23 vs -0.07 ± 0.16, p = 0.05].

The investigators found in subgroup analysis vitamin D supplementation significantly decreased HbA1c [p = 0.05], fasting plasma glucose level [p = 0.05] and HOMA-IR [p = 0.1] to a greater extent when serum 25(OH)D concentration achieved was above 86 nmol/L.

The investigators found in subgroup analysis vitamin D supplementation for less than 6 months provided a larger effect size on HbA1c in comparison with long durations [-0.75 ± 0.33 vs -0.25 ± 0.11, p = 0.1].

The investigators found in subgroup analysis HbA1c showed greater improvement in populations with a mean age younger than 45 years in comparison with older populations [-1.15 ± 0.6 vs -0.30 ± 0.1, p = 0.05].

The investigators found in subgroup analysis greater reductions were found within HbA1c and fasting plasma glucose levels when baseline (at the beginning of the study) mean serum 25(OH)D concentration was ≥50 nmol/L, whereas the lowering effect was significantly less in the subgroup with baseline mean 25(OH)D 50 nmol/L [HbA1c = -0.79 ± 0.25 vs -0.14 ± 0.13, p = 0.04 and fasting plasma glucose level = -0.69 ± 0.21 vs -0.11 ± 0.10, p = 0.05].

The investigators concluded 88 µg/d vitamin D supplementation during 22 weeks improves glycemic measures and insulin sensitivity and may be useful as part of a preventive strategy for type 2 diabetes, particularly among overweight/obese individuals younger than 45 years.

Original title:
Vitamin D Supplementation, Glycemic Control, and Insulin Resistance in Prediabetics: A Meta-Analysis by Mirhosseini N, Vatanparast H, [...], Kimball SM.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6016617/

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

HbA1c, FPG, HOMA-IR and plasma glucose after 2-hour oral glucose tolerance test (2HPG) are different parameters associated with (pre)diabetes.

 

Objectives:
Infertility, which affects ∼15% of the world's population, is a global public health issue recognized by the WHO. Therefore, it is of major clinical and public health importance to investigate whether modifiable lifestyle factors,such as stress, drug use, smoking, alcohol intake and diet may influence human fertility. Therefore, this meta-analysis (systematic review) has been conducted.

What is the effect of supplementation of nutrients on sperm quality parameters?

Study design:
This review article included 28 articles (RCTs) for qualitative analysis and 15 for quantitative meta-analysis.

Results and conclusions:
The investigators found total sperm concentrations were significantly increased by:
-selenium [MD = 3.91 × 106 spz/mL, 95% CI = 3.08 to 4.73 spz/mL];
-zinc [MD = 1.48 × 106 spz/mL, 95% CI = 0.69 to 2.27 spz/mL];
-omega 3 fatty acids [MD = 10.98 × 106 spz/mL, 95% CI = 10.25 to 11.72 spz/mL] and
-coenzyme Q10 [MD = 5.93 × 106 spz/mL, 95% CI = 5.36 to 6.51 spz/mL].

The investigators found sperm counts were significantly increased by:
-omega 3 fatty acids [MD = 18.70 × 106 spz/mL, 95% CI = 16.89 to 20.51 spz/mL] and
-coenzyme Q10 [MD = 10.15 × 106 spz/mL, 95% CI = 8.34 to 11.97 spz/mL].

The investigators found sperm total motility was significantly increased by:
-selenium [MD = 3.30%, 95% CI = 2.95% to 3.65%];
-zinc [MD = 7.03%, 95% CI = 6.03% to 8.03%];
-omega 3 fatty acids [MD = 7.55%, 95% CI = 7.09% to 8.01%];
-coenzyme Q10 [MD = 5.30%, 95% CI = 4.98% to 5.62%] and
-carnitines [MD = 7.84%, 95% CI = 6.54% to 9.13%].

The investigators found sperm progressive motility significantly increased by supplementation with carnitines [MD = 7.45%, 95% CI = 6.24% to 8.67%].

The investigators found sperm morphology was significantly enhanced by:
-selenium [MD = 1.87%, 95% CI = 1.50% to 2.24%];
-omega 3 fatty acid [MD = 0.91%, 95% CI = 0.69% to 1.13%];
-coenzyme Q10 [MD = 1.06%, 95% CI = 0.72% to 1.41%] and
-carnitine [MD = 4.91%, 95% CI = 3.68% to 6.15%].

The investigators concluded evidence from RCTs shows that some dietary supplements beneficially modulate sperm quality parameters and affect male fertility. However, results must be cautiously interpreted due to the limited sample size of the meta-analyzed studies and the considerable observed interstudy heterogeneity.

Original title:
The Effect of Nutrients and Dietary Supplements on Sperm Quality Parameters: A Systematic Review and Meta-Analysis of Randomized Clinical Trials by Salas-Huetos A, Rosique-Esteban N, […], Salas-Salvadó J.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30462179

Additional information of El Mondo:
Find more information/studies on mineral, antioxidants and pregnancy right here.

 

Objectives:
The timing of the introduction of egg to an infant's diet is of current interest, as new evidence raises questions regarding the benefit of delaying egg introduction. Therefore, this meta-analysis (systematic review) has been conducted.

Does early introduction of egg into an infant’s diet reduce risk of egg allergy?

Study design:
This review article included 6 RCTs with a total of 3,032 participants.
The RCTs compared early (between 3 and 6 months of age) egg introduction to no early introduction. The primary outcome was the development of egg allergy.

Results and conclusions:
The investigators found compared early (between 3 and 6 months of age) egg introduction to no early introduction, early introduction of egg significantly reduced risk of egg allergy with 40% [RR = 0.60, 95% CI = 0.44-0.82, p = 0.002, I2 = 23%, low to moderate level of evidence].

The investigators found the absolute risk reduction for a population with an incidence of egg allergy was 9.3% or 37 fewer cases [95% CI = 17-52] per 1,000 people.

The investigators found consumption of 4,000 mg/week of egg protein had a greater preventive effect than a higher dose.

The investigators concluded that introduction of egg into an infant’s diet between 3 and 6 months of age reduces risk of egg allergy, particularly for 4,000 mg/week of egg protein. Furthermore, the nature and dose of egg protein exposure may play a role. These findings should be addressed in the context of primary studies.

Original title:
Early Introduction of Egg and the Development of Egg Allergy in Children: A Systematic Review and Meta-Analysis by Al-Saud B and Sigurdardóttir ST.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30184525

Additional information of El Mondo:
Find more information/studies on protein and pregnancy right here.
 

Objectives:
High potato intake has been suggested as a risk factor for the development of type 2 diabetes. Therefore, this review article has been conducted.

Does potato intake increase risk of type 2 diabetes?

Study design:
This review article included 6 prospective cohort studies with a total of 4,545,230 person-year of follow-up and 17,758 diabetes cases.

Results and conclusions:
The investigators found for every increment of 1 serving/day of total potato consumption a significantly increased risk of 20% [HR = 1.20, 95% CI = 1.13 to 1.127, p 0.001, I2 = 27.1%, p for heterogeneity = 0.23] for type 2 diabetes both in men en women.

The investigators found for 2 servings/day of total potato consumption a significantly increased risk of 44% [HR = 1.44, 95% CI = 1.28 to 1.63] for type 2 diabetes both in men en women.

The investigators found for 3 servings/day of total potato consumption a significantly increased risk of 74% [HR = 1.74, 95% CI = 1.45 to 2.09] for type 2 diabetes both in men en women.

The investigators found significant evidence of a non-linear association between total potato consumption and risk of type 2 diabetes [X2 = 17.5, p for linearity 0.001].

The investigators concluded that long-term high consumption of potato (each serving a day increase) is strongly associated with increased risk of type 2 diabetes. These findings suggest that diet-health policy may be of importance in the prevention of diabetes.

Original title:
Potato consumption and risk of type 2 diabetes: A dose-response meta-analysis of cohort studies by Bidel Z, Teymoori F, […], Nazarzadeh M.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30144898

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

According to the USDA Dietary Guidelines a serving of potato is 1 cup diced, mashed or baked or 1 medium boiled potato.

 

Objectives:
Low birth weight infant (LBWIs) are prone to mental and behavioural problems. As an important constituent of the brain and retina, long chain polyunsaturated fatty acids are essential for foetal infant mental and visual development. The effect of lactation supplemented with long chain polyunsaturated fatty acids (LCPUFA) on the improvement of intelligence in low birth weight children requires further validation. Therefore, this meta-analysis (systematic review) has been conducted.

Do long chain polyunsaturated fatty acids (LCPUFA or PUFA) supplements improve intelligence in low birth weight children?

Study design:
This review article included 10 studies with a total of 1,793 individuals, of which 908 cases in the intervention group (group with LCPUFA supplements) and 885 controls (group without LCPUFA supplements).

The mean birth weights in 8 studies were less than 1500g and those in 2 studies were more than 1500g. None of the included studies had infants with birth weight less than 750g.

LCPUFA supplements were DHA+AA, DHA+EPA+DPA or DHA+AA+EPA.

There was no evidence of publication bias.

Results and conclusions:
The investigators found that the long chain polyunsaturated fatty acids supplemented group did not have significantly higher mental development index (MDI) scores than the group without supplementation [SMD = 0.07, 95% CI = -0.05 to 0.19, I2 = 23.8%, p = 0.222].
Subgroup analysis showed that the long chain polyunsaturated fatty acids supplementation groups did not have significantly higher mental development index scores than the control groups.

The investigators found that the long chain polyunsaturated fatty acids supplemented group did not have significantly higher psychomotor development index (PDI) scores than the group without supplementation [SMD = -0.01, 95% CI = -0.23 to 0.21, I2 = 60.5%, p = 0.906].
Subgroup analysis showed that the long chain polyunsaturated fatty acids supplementation groups did not have significantly higher psychomotor development index scores than the control groups.

The investigators found that the long chain polyunsaturated fatty acids supplemented group did not have significantly higher full scale intelligence quotient (FSIQ) scores than the group without supplementation [SMD = 0.00, 95% CI = -0.14 to 0.14, I2 = 0.00%, p = 0.991].

The investigators found that the long chain polyunsaturated fatty acids supplemented group did not have significantly higher verbal intelligence quotient (VIQ) scores than the group without supplementation [SMD = 0.01, 95% CI = -0.15 to 0.12, I2 = 42.2%, p = 0.844].

The investigators found that the long chain polyunsaturated fatty acids supplemented group did not have significantly higher performance intelligence quotient (PIQ) scores than the group without supplementation [SMD = -0.01, 95% CI = -0.15 to 0.13, I2 = 0.00, p = 0.877].

The investigators concluded that long chain polyunsaturated fatty acids (LCPUFA or PUFA) supplements do not improve intelligence in low birth weight children. Therefore, whether long-chain polyunsaturated fatty acids supplements are beneficial for LBWIs has not been shown conclusively.

Original title:
The effect of long chain polyunsaturated fatty acid supplementation on intelligence in low birth weight infant during lactation: A meta-analysis by Song Y, Liu Y, […], Li D.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5892917/

Additional information of El Mondo:
Find more information/studies on long chain polyunsaturated fatty acids and pregnancy right here.

 

Objectives:
Several studies have been published about the effect of garlic on lipid profile and blood glucose in diabetic patients. Which, the results mostly contradict with each other. Therefore, this review article has been conducted.

Does garlic improve lipid profile and blood glucose in diabetic patients?

Study design:
This review article included 33 articles with a total of 1,273 individuals, with a mean of 39 samples per study.

Results and conclusions:
The investigators found the concentration of serum total cholesterol significantly decreased wih 16.87 mg/dL [95% CI = -21.01 to -12.73, p = 0.001] in the garlic group when compared with the placebo group.

The investigators found the concentration of serum LDL cholesterol (bad cholesterol) significantly decreased with 9.65 mg/dL [95% CI = -15.07 to -4.23, p = 0.001] in the garlic group when compared with the placebo group.

The investigators found the concentration of serum triglycerides significantly decreased with 12.44 mg/dL [95% CI = -18.19 to -6.69, p = 0.001] in the garlic group when compared with the placebo group.

The investigators found the concentration of serum HDL cholesterol (good cholesterol) significantly increased with 3.19 mg/dL [95% CI = 1.85 to 4.53, p = 0.001] in the garlic group when compared with the placebo group.

The investigators found the concentration of serum fasting blood sugar significantly decreased with 10.90 mg/dL [95% CI = -16.40 to -5.40, p = 0.001] in the garlic group when compared with the placebo group.

The investigators found the concentration of serum HbA1c significantly decreased with 0.60 mg/dL [95% CI = -0.98 to -0.22, p = 0.001] in the garlic group when compared with the placebo group.

The investigators concluded that garlic improves lipid profile as well as glucose parameters and can be therapeutically effective in patients suffering from cardiovascular diseases and diabetes.

Original title:
The effect of garlic on lipid profile and glucose parameters in diabetic patients: A systematic review and meta-analysis by Shabani E, Sayemiri K and Mohammadpour M.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30049636

Additional information of El Mondo:
Find more information/studies on diabetes, cholesterol, meta-analyses/heterogeneity and garlic right here.

 

Objectives:
Despite the World Health Organization recommendation of exclusive breastfeeding (EBF) for the first six months of life, the rate remains low both in developed and developing countries. In Ethiopia, findings regarding the prevalence of exclusive breastfeeding have been highly variable. Antenatal care and institutional delivery are the most important factors contributing to the practice of exclusive breastfeeding. However, their effect has not been investigated in Ethiopia. Therefore, this review article has been conducted.

Do antenatal care and institutional delivery increase exclusive breastfeeding?

Study design:
This review article included 32 studies (published between 2007 to 2017) with a total of 23,543 breastfeeding women. 29 (71.8%) of the studies are cross-sectional study design. The sample size of the studies ranged from 119 to 5, 227.

Results and conclusions:
The investigators found the result of 32 included studies indicated that the pooled prevalence of exclusive breastfeeding in Ethiopia was 59.3% [95% CI = 53.8 to 64.8%].

The investigators found subgroup analysis indicated that the highest prevalence was observed in Afar region (65.6%), followed by SNNP (63.8%) and then by Oromia (61.8%).

The investigators found mothers who attended antenatal visits were 2.1 times more likely to practice exclusive breastfeeding compared to their counterparts [OR = 2.1, 95% CI = 1.5 to 2.8).

The investigators found, moreover, mothers who gave birth at a health institution were 2.2 times more likely to practice exclusive breastfeeding compared to mothers who gave birth at home [OR = 2.2, 95% CI = 1.3 to 3.5].

The investigators concluded exclusive breastfeeding in Ethiopia is significantly lower than the global recommendations. Mothers who attended antenatal visits and who gave birth at health institutions have better exclusive breastfeeding practices. Based on these findings, it is strongly recommended that the utilization of antenatal care and institutional delivery should be improved through health extension workers.

Original title:
Exclusive breastfeeding practice in Ethiopia and its association with antenatal care and institutional delivery: a systematic review and meta-analysis by Alebel A, Tesma C, […], Kibret GD.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6048887/

Additional information of El Mondo:
Find more information/studies on food fortification/malnutrition and breastfeeding right here.

Objectives:
Whether a vegetarian diet is appropriate for pregnancy remains unclear. Therefore, this review article has been conducted.

What is the association between vegetarian diet during pregnancy and various maternal-fetal outcomes?

Study design:
This review article included 19 observational studies.

Results and conclusions:
The investigators found in pooled analysis no association between vegetarian pregnancy and low birth weight (LBW) [RR = 1.27, 95% CI = 0.98-1.65, p = 0.07, I2 = 0%].

The investigators found, however, in subgroup analysis that Asian (India/Nepal) vegetarian mothers exhibited a significantly increased risk of 33% to deliver a baby with low birth weight [RR = 1.33, 95% CI = 1.01-1.76, p = 0.04, I2 = 0%]. But, the WMD of neonatal birth weight in 5 studies suggested no difference between vegetarians and omnivores.

Given the high heterogeneity of the included studies, lack of high-quality evidence and limited studies included for each category, the investigators failed to reach conclusive results regarding the risks of hypospadias, intrauterine growth retardation, maternal anemia and gestational diabetes mellitus.

The investigators concluded that Asian vegetarian mothers have an increased risk to deliver babies with low birth weight than those of omnivores. Large-scale prospective studies focusing on pre- and/or early gestational nutrition will help clarify the correlation between vegetarian diet and various pregnancy outcomes.

Original title:
Is a vegetarian diet safe to follow during pregnancy? A systematic review and meta-analysis of observational studies by Tan C, Zhao Y and Wang S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29621406

Additional information of El Mondo:
Find more information/studies on veganism and pregnancy right here.

 

Objectives:
The purpose of this review article is to review previously published meta-analyses on the effectiveness of dietary fiber on type 2 diabetes.

Study design:
This umbrella review article included 16 meta-analyses.

Results and conclusions:
The investigators found in the meta-analyses when comparing highest versus lowest dietary fiber intake, a statistically significant reduced risk of 15 to 19% [RR = 0.81-0.85] for type 2 diabetes. However, statistically significant heterogeneity was observed in all of these meta-analyses.

The investigators found in the meta-analyses when comparing highest versus lowest dietary cereal fibers, a statistically significant reduced risk of 13 to 33% [RR = 0.67-0.87] for type 2 diabetes. However, statistically significant heterogeneity was observed in all of these meta-analyses.

The investigators found in the meta-analyses of supplementation studies using β-glucan or psyllium fibers on type 2 diabetic participants, statistically significant reductions were identified in both fasting blood glucose concentrations and glycosylated hemoglobin percentages.

The investigators concluded that those consuming the highest amounts of dietary fiber, especially cereal fiber, may benefit from a reduction in the incidence of developing type 2 diabetes. May benefit because statistically significant heterogeneity was observed in all of these meta-analyses.
There also appears to be a small reduction in fasting blood glucose concentration, as well as a small reduction in glycosylated hemoglobin percentage for individuals with type 2 diabetes who add β-glucan or psyllium to their daily dietary intake.

Original title:
Dietary Fiber Intake and Type 2 Diabetes Mellitus: An Umbrella Review of Meta-analyses by McRae MP.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29628808

Additional information of El Mondo:
Find more information/studies on diabetes, meta-analyses/heterogeneity and dietary fiber right here.

 

Objectives:
The association between dietary protein intake and type 2 diabetes risk has been inconsistent in the previous epidemiological studies. Therefore, this review article (meta-analysis) has been conducted.

Is there an association between dietary protein intake and type 2 diabetes risk?

Study design:
This review article included 10 prospective cohort studies with a total of 34,221 type 2 diabetes cases.
No publication bias was detected.

Results and conclusions:
The investigators found after adjustment of potential confounders, a 5% of energy (5 En%) increment from dietary total protein intake was related to a significantly 9% [95 CI = 1.04-1.13, I2 = 42.0%] higher risk of type 2 diabetes. The results were robust in sensitivity analysis.

The investigators found after adjustment of potential confounders, a 5% of energy (5 En%) increment from dietary animal protein intake was related to a significantly 12% [95 CI = 1.08-1.17, I2 = 14.0%] higher risk of type 2 diabetes. The results were robust in sensitivity analysis.

The investigators found after adjustment of potential confounders, a significant U-shaped curve was observed for plant protein intake with the most risk reduction at about 6% of energy from plant protein intake [p nonlinearity = 0.001]. The results were robust in sensitivity analysis.

The investigators concluded that the consumption of protein, particularly animal protein increases risk of type 2 diabetes.

Original title:
Dietary protein intake and risk of type 2 diabetes: a dose-response meta-analysis of prospective studies by Zhao LG, Zhang QL, [...], Xiang YB.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29858629

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

 

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

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

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

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

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

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

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

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

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

 

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

Does flavonoids intake decrease risk of developing type 2 diabetes?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Objectives:
The efficacy of myo-inositol supplementation to prevent gestational diabetes onset remains controversial. Therefore, this meta-analysis (systematic review) has been conducted.

Does myo-inositol supplementation reduce risk of gestational diabetes in pregnant women?

Study design:
This review article included 5 RCTs.

Results and conclusions:
The investigators found compared with control group in pregnant women, myo-inositol supplementation significantly reduced risk of gestational diabetes with 57% [risk ratio = 0.43, 95% CI = 0.21-0.89, p = 0.02].

The investigators found compared with control group in pregnant women, myo-inositol supplementation significantly reduced risk of preterm delivery with 64% [risk ratio = 0.36, 95% CI = 0.17-0.73, p = 0.005].

The investigators found compared with control group in pregnant women, no association between myo-inositol supplementation and 2-h glucose oral glucose tolerance test (OGTT) [mean difference = -6.90, 95% CI = -15.07 to 1.27, p = 0.10].

The investigators found compared with control group in pregnant women, no association between myo-inositol supplementation and gestational age at birth [MD = 0.74, 95% CI = -1.06 to 2.54, p = 0.42].

The investigators found compared with control group in pregnant women, no association between myo-inositol supplementation and birth weight [MD = -5.50, 95% CI = -116.99 to 105.99, p = 0.92].

The investigators found compared with control group in pregnant women, no association between myo-inositol supplementation and macrosomia (a newborn with an excessive birth weight (≥4 kg)) [RR = 0.65, 95% CI = 0.20-2.11, p = 0.47].

The investigators concluded that myo-inositol supplementation reduces the incidence of gestational diabetes and preterm delivery in pregnant women.

Original title:
The efficacy of myo-inositol supplementation to prevent gestational diabetes onset: a meta-analysis of randomized controlled trials by Zhang H, Lv Y, […], Guo W.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29343138

Additional information of El Mondo:
Find more information/studies on inositol and pregnancy right here.

A review article (a collection of scientific studies on a specific topic) of randomized, placebo-controlled double blind clinical trials (RCTs) will answer the following question:
"Do taking dietary supplements make sense?" Yes for a positive conclusion and no for a negative conclusion.

Objectives:
Anemia is a major public health and nutritional problem in the world. Studies have reported the relationship between anemia during pregnancy and small for gestational age (SGA). Therefore, this meta-analysis (systematic review) has been conducted.

Does maternal anemia during pregnancy increase risk of SGA?

Study design:
This review article included 10 studies with a total of 620,080 pregnant women.

Results and conclusions:
The investigators found the overall relationship between maternal anemia during pregnancy and SGA was not significant [RR = 1.11, 95% CI = 0.99-1.24, p = 0.074].
Not significant means that there is no association with a 95% confidence.

The investigators found, however, a significantly increased risk of 11% [RR = 1.11, 95% CI = 1.00-1.22, p = 0.044] of SGA for materal anemia during first trimester. But this relationship was not significant in the second trimester [RR = 1.11, 95% CI = 0.85-1.18, p = 0.91].

The investigators concluded maternal anemia in the first trimester of pregnancy increases risk of small for gestational age (SGA).

Original title:
Maternal anemia during pregnancy and small for gestational age: a systematic review and meta-analysis by Badfar G, Shohani M, […], Azami M.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29183181

Additional information of El Mondo:
Find more information/studies on anemia and pregnancy right here.
 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Study design:
This review article included 6 RCTs.

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

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

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

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

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

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

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

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

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

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

There was no evidence of publication bias.

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

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

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

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

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

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

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

Does L-carnitine supplementation reduce leptin serum level?

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

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

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

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

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

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

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

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

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

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

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