Nutrition and health

Objectives:
Have flaxseed supplementation positive effects on body composition?

Study design:
This review article included a total of 45 RCTs.

Results and conclusions:
The investigators found a significant reduction in body weight [WMD = -0.99 kg, 95% CI = -1.67 to -0.31, p = 0.004], BMI [WMD = -0.30 kg m², 95% CI = -0.53 to -0.08, p = 0.008] and waist circumference [WMD = -0.80 cm, 95% CI = -1.40 to -0.20, p = 0.008] following flaxseed supplementation.

The investigators found subgroup analyses showed that using whole flaxseed in doses ≥30 g/d, longer-term interventions (≥12 weeks) and studies including participants with higher BMI (≥ 27 kg/m²) had positive effects on body composition.

The investigators concluded whole flaxseed supplementation in doses ≥30 g/d during ≥12 weeks has positive effects on body composition in overweight and obese participants (=participants with BMI ≥ 25 kg/m²).

Original title:
The effect of flaxseed supplementation on body weight and body composition: a systematic review and meta-analysis of 45 randomized placebo-controlled trials by Mohammadi-Sartang M, Mazloom Z, […], Totosy de Zepetnek JO.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28635182

Additional information of El Mondo:
Find more information/studies on nuts&seeds and overweight right here. 

Find out whether you are overweight or not right here.

Objectives:
Epidemiological studies evaluating the associations between serum copper and ratios of copper/zinc (Cu/Zn) and the preeclampsia (PE) risk in Asian population have produced inconsistent results. Therefore, this review article (meta-analysis) has been conducted.

Do a higher serum copper and ratios of Cu/Zn increase the preeclampsia risk in Asian population?

Study design:
This review article included relevant studies up to November 2016.
Pooled standardized mean difference (SMD) was calculated with random effects model.

Results and conclusions:
The investigators found that preeclampsia patients significantly had a higher serum copper level [SMD = 1.05, 95% CI = 0.34 to 1.77, I2 = 96.9%, p 0.0001] compared with healthy pregnancy controls.

The investigators found in subgroup analyses, a higher serum copper level in preeclampsia patients was observed in case-control studies [SMD = 1.39, 95% CI = 0.44 to 2.34]. However, no significant difference was found between preeclampsia patients and healthy pregnancy controls for ratios of Cu/Zn [SMD = 0.26, 95% CI = -0.77 to 1.29, I2 = 95.8%, p 0.0001].

The investigators concluded that a higher serum copper level is associated with an increased risk of preeclampsia in Asian population. However, further studies are needed to confirm these results.

Original title:
High serum copper level is associated with an increased risk of preeclampsia in Asians: A meta-analysis by Song X, Li B, [...], Zhang D.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28385285

Additional information of El Mondo:
Find more information/studies on copper, zinc, pregnancy and review article/significant/95% CI right here.

Objectives:
Do overweight and obese adults benefit from n-3 PUFA supplements?

Study design:
This review article included a total of 11 RCTs involving 617 participants.

Results and conclusions:
The investigators found a statistically non-significant difference in weight loss between n-3 PUFA supplements and placebo [WMD = 0.00, 95% CI = -0.42 to 0.43, p = 0.99].

The investigators found n-3 PUFA supplements was superior to placebo in reducing serum triglyceride levels [Std MD = -0.59, 95% CI = -0.93 to -0.25, p = 0.0007].

The investigators found a significant reduction in waist circumference for n-3 PUFA group [WMD = -0.53, 95% CI = -0.90 to -0.16, p = 0.005].

The investigators found no significant differences in body mass index, total serum levels of cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol and fasting glucose levels between n-3 PUFA supplements and placebo.

The investigators concluded that n-3 PUFA supplements reduce waist circumference and triglyceride levels in overweight and obese adults. However, large-scale, well-designed RCTs are needed to further address this issue.

Original title:
Efficacy of Omega-3 Polyunsaturated Fatty Acids Supplementation in Managing Overweight and Obesity: A Meta-Analysis of Randomized Clinical Trials by Zhang YY, Liu W, […], Tian HM.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28112774

Additional information of El Mondo:
Find more information/studies on overweight, n-3 PUFA and cholesterol right here.  

Click here to find out whether you are overweight or not?

Objectives:
The effects of green tea on lipid metabolism were inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Have tea consumption beneficial effects on lipid metabolism?

Study design:
This review article included 21 RCTs studying 1,704 overweight or obese subjects.

Results and conclusions:
The investigators found that green tea consumption significantly decreased plasma total cholesterol with 3.38 mg/dL [WMD = -3.38 mg/dL, 95% CI = -6.42 to -0.33 mg/dL] in overweight or obese people.

The investigators found that green tea consumption significantly decreased plasma LDL cholesterol (bad cholesterol) with 5.29 mg/dL [WMD = -5.29 mg/dL,95% CI = -7.92 to -2.66 mg/dL] in overweight or obese people.

The investigators found that green tea consumption, however, showed no effect on plasma triglyceride and HDL cholesterol levels (good cholesterol) in overweight or obese people with a relatively high heterogeneity.

The investigators concluded that drinking green tea lowers plasma total cholesterol and LDL cholesterol levels in overweight or obese people. Nevertheless, green tea's effect on plasma triglyceride and HDL cholesterol levels must be further evaluated by additional high-quality and large-scale RCTs.

Original title:
Effects of green tea on lipid metabolism in overweight or obese people: A meta-analysis of randomized controlled trials by Fen Y, Hui D, [...], Fu Er L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28636182

Additional information of El Mondo:
Find more information/studies on overweight, cholesterol and tea consumption right here. 

Objectives:
Zinc sulfate may be a promising approach to treat neonatal jaundice. However, the results remain controversial. Therefore, this review article (meta-analysis) has been conducted.

Does zinc sulfate supplementation reduce neonatal jaundice?

Study design:
This review article included 5 RCTs involving 645 patients.

Results and conclusions:
The investigators found overall, compared with placebo, zinc sulfate supplementation failed to significantly reduce total serum bilirubin on 3 days [mean difference = 0.09 mg/dL, 95% CI = -0.49 to 0.67, p = 0.77]. Non-significant because p-value of 0.77 was greater than p-value of 0.05.

The investigators found overall, compared with placebo, zinc sulfate supplementation failed to significantly reduce total serum bilirubin on 7 days [mean difference= -0.37 mg/dL, 95% CI= -98 to 0.25, p  = 0.25].

The investigators found overall, compared with placebo, zinc sulfate supplementation failed to significantly reduce the incidence of hyperbilirubinemia [OR = 1.14, 95% CI = 0.74 to 1.76, p = 0.56].

The investigators found overall, compared with placebo, zinc sulfate supplementation showed no influence on phototherapy requirement [OR = 0.90, 95% CI = 0.41 to 1.98, p = 0.79]. Non-significant because OR of 1 was found in the OR of 0.41 to 1.98. OR of 1 means no risk/association.

The investigators found overall, compared with placebo, zinc sulfate supplementation significantly decreased duration of phototherapy [mean difference = -16.69 h, 95% CI = -25.09 to -8.3 h, p 0.000].

The investigators concluded zinc sulphate supplementation does not reduce the total serum bilirubin on 3 days and 7 days, the incidence of hyperbilirubinemia and phototherapy requirement, but significantly decreases duration of phototherapy.

Original title:
The influence of zinc sulfate on neonatal jaundice: a systematic review and meta-analysis by Yang L, Wu, [...], Tang J.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28372469

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

Neonatal jaundice occurs when a baby has a high level of bilirubin in the blood. Bilirubin is a yellow substance that the body creates when it replaces old red blood cells. The liver helps break down the substance so it can be removed from the body in the stool.

A high level of bilirubin makes a baby's skin and whites of the eyes look yellow. This is called neonatal jaundice.

Jaundice is a common and usually harmless condition in newborn babies.
The symptoms of neonatal jaundice usually develop 2 to 3 days after the birth and tend to get better without treatment by the time the baby is about 2 weeks old.

Objectives:
Emerging randomized controlled trials (RCTs) investigating the effect of green tea or green tea extract (GTE) supplementation on blood pressure (BP) among overweight and obese adults reported inconsistent findings. Therefore, this review article has been conducted.

Does tea consumption decrease blood pressure among overweight and obese adults?

Study design:
This review article included 14 RCTs with 971 participants (47% women).

Results and conclusions:
The investigators found green tea or green tea extract supplementation compared with placebo, significantly reduced systolic blood pressure with 1.42 mmHg [95% CI = -2.47 to -0.36, p  =  0.008, I2  =  52%, p for heterogeneity =  0.01 ] among overweight and obese adults.

The investigators found green tea or green tea extract supplementation compared with placebo, significantly reduced diastolic blood pressure with 1.25 mmHg [95% CI = -2.32 to -0.19, p = 0.02, I2 = 74%, p for heterogeneity   0.001] among overweight and obese adults.

The investigators found the quality of evidence across studies was low. Similar results were found in subgroup and sensitivity analyses.

The investigators concluded among overweight and obese adults, green tea or green tea extract supplementation is found to cause a small but significant reduction in blood pressure. However, more high-quality RCTs with large sample sizes are needed to further confirm the efficacy on blood pressure and make strong recommendations for green tea or green tea extract supplementation among the overweight and obese adults.

Original title:
Effect of green tea supplementation on blood pressure among overweight and obese adults: a systematic review and meta-analysis by Li G, Zhang Y, […], Holbrook A.

Link:
http://journals.lww.com/jhypertension/Abstract/2015/02000/Effect_of_green_tea_supplementation_on_blood.6.aspx

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

Objectives:
Epidemiological studies have presented inconsistent evidence of the correlation between a fish-oriented dietary intake (FDI) and the risk of cognitive decline. Therefore, this meta-analysis (review article) has been conducted.

Does a fish-oriented dietary intake reduce risk of cognitive decline?

Study design:
This review article included 9 cohort studies containing 28,754 subjects.
Limited evidence involving heterogeneity was found within subgroups or across studies.

Results and conclusions:
The investigators found when comparing the highest versus lowest categories of fish consumption a significant reduced risk of 20% [RR = 0.80, 95% CI = 0.65-0.97] for dementia of Alzheimer type (DAT).

The investigators found the dose-response synthesized data indicated that a 100-g/week increase in fish intake reduced the risk of dementia of Alzheimer type by an additional 12% [RR = 0.88, 95% CI = 0.79-0.99].

The investigators found that the reduced risk of dementia of all causes (DAC) and mild cognitive impairment (MCI) was non-significant.

The investigators concluded that a higher intake of fish, at least 100-g/week is correlated with a reduced risk of dementia of Alzheimer type.

Original title:
An exploration of the role of a fish-oriented diet in cognitive decline: a systematic review of the literature by Zeng LF, Cao Y, […], Wang NS.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28418899

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

Objectives:
Does iron supplementation during pregnancy improve maternal haematological status and birth weight?

Study design:
This review article included 48 RCTs (17,793 women) and 44 cohort studies (1,851,682 women).

The dose of iron in RCTs ranged from 10 mg to 240 mg daily. Duration of supplementation varied from 7 to 8 weeks up to 30 weeks during pregnancy.

Significant heterogeneity existed for several outcomes that could not be explained substantially by pre-specified subgroups.

Results and conclusions:
The investigators found iron supplementation during pregnancy increased maternal mean haemoglobin concentration by 4.59 g/L [95% CI = 3.72 to 5.46] compared with controls.

The investigators found iron with folic acid was associated with a significant increase in mean haemoglobin concentration of 10.41 g/L [95% CI = 5.36 to 15.46, I2 = 0%, 9 trials] and reduction in risk of anaemia in the third trimester or at delivery of 56% [95% CI = 0.37 to 0.53, I2 = 44%, 5 trials]. Significant means there is an association with a 95% confidence.

The investigators found iron supplementation during pregnancy significantly reduced the risk of anaemia with 50% [95% CI = 0.42 to 0.59] compared with controls.

The investigators found iron supplementation during pregnancy significantly reduced the risk of iron deficiency (of the mother) with 41% [95% CI = 0.46 to 0.79] compared with controls.

The investigators found iron supplementation during pregnancy significantly reduced the risk of iron deficiency anaemia with 60% [95% CI = 0.26 to 0.60] compared with controls.

The investigators found iron supplementation during pregnancy significantly reduced the risk of low birth weight (2500 g) with 19% [95% CI = 0.71 to 0.93] compared with controls.

However, the investigators found iron supplementation during pregnancy non-significantly reduced the risk of preterm birth with 16% [95% CI = 0.68 to 1.03] compared with controls. Non-significant means there is no association with a 95% confidence.

The investigators found in cohort studies that anaemia in the first or second trimester was significantly associated with a higher risk for low birth weight of 29% [adjusted odds ratio 1.29, 95% CI = 1.09 to 1.53] and preterm birth with 21% [adjusted odds ratio = 1.21, 95% CI = 1.13 to 1.30].

The investigators found in exposure-response analysis that for every 10 mg increase in iron dose/day, up to 66 mg/day, the relative risk of maternal anaemia was significantly 0.88 [95% CI = 0.84 to 0.92, p for linear trend 0.001].

The investigators found in exposure-response analysis that birth weight increased by 15.1 g [95% CI = 6.0 to 24.2, p for linear trend = 0.005] and risk of low birth weight significantly decreased by 3% [relative risk = 0.97, 95% CI = 0.95 to 0.98, p for linear trend 0.001] every 10 mg increase in dose/day.

Furthermore, the investigators found for each 1 g/L increase in mean haemoglobin, birth weight increased by 14.0 g [95% CI = 6.8 to 21.8, p for linear trend = 0.002]. However, mean haemoglobin was not associated with the risk of low birth weight and preterm birth.

The investigators found no evidence of a significant effect on duration of gestation, small for gestational age births and birth length and duration of iron use was not significantly associated with the outcomes after adjustment for dose.

The investigators concluded daily prenatal use of iron substantially improved birth weight in a linear dose-response fashion, probably leading to a reduction in risk of low birth weight. An improvement in prenatal mean haemoglobin concentration linearly increased birth weight and a linear decrease in maternal anaemia with higher doses of iron, up to 66 mg/day.

Original title:
Anaemia, prenatal iron use, and risk of adverse pregnancy outcomes: systematic review and meta-analysis by Haider BA, Olofin I, […], Fawzi WW.

Link:
http://www.bmj.com/content/346/bmj.f3443

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

Iron deficiency anaemia occurs when there isn't enough iron in the body. Anaemia is a condition where the amount of haemoglobin in the blood is below the normal level.
Iron deficiency anaemia has been defined as haemoglobin 110 g/L and serum ferritin 12 µg/L.

Objectives:
Controversy persists regarding the effect of mixtures of conjugated linoleic acids (c9,t11- and t12,c10-CLA) in fasting blood glucose (FBG) and waist circumference (WC) in humans. Therefore, this review article (meta-analysis) has been conducted.

Does CLA reduce fasting blood glucose (FBG) and waist circumference (WC) in humans?

Study design:
This review article included 32 randomized clinical trials.

Results and conclusions:
The investigators found subgroup analysis showed that taking CLA supplement did not significantly influence fasting blood glucose [SMD = 0.075 mg/dL, 95% CI = -0.099 to 0.249, p = 0.399].

The investigators found subgroup analysis showed that taking CLA supplement reduced non-significantly waist circumference with 0.149cm [SMD = -0.149cm, 95% CI = -0.522 to 0.225, p = 0.435].

The investigators found foods enriched in CLA also showed no significant effect on fasting blood glucose [SMD = 0.126 mg/dL, 95% CI = -0.100 to 0.352, p = 0.274].

The investigators found foods enriched in CLA also showed no significant effect on waist circumference [SMD = -0.233cm, 95% CI = -0.625 to 0.159, p = 0.244].

The investigators concluded that c9,t11- and t12,c10-CLA administered as a supplement or used to enrich foods does not reduce fasting blood glucose (FBG) and waist circumference (WC) in humans.

Original title:
Effect of conjugated linoleic acid as a supplement or enrichment in foods on blood glucose and waist circumference in humans: A meta-analysis by Rahbar AR, Ostvar A, […], Rahbar A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28176632

Additional information of El Mondo:
Find more information/studies on overweight and fat consumption right here.
Overweight people often have higher fasting blood glucose (FBG) and greater waist circumference (WC).

Find here whether you are overweight or not?

Conjugated linoleic acids (CLA) are a family of isomers of linoleic acid found mostly in meat and dairy products derived from ruminants. An average daily diet supplies 15-174mg of conjugated linoleic acid.

Chemical structures of CLA.

Objectives:
Is supplementation of formula milk with LCPUFA (long-chain polyunsaturated fatty acids) both safe and beneficial for full-term infants, while focusing on effects on visual function, neurodevelopment and physical growth?

Study design:
This review article included 15 RCTs (n = 1889).
9 studies assessed visual acuity, 6 of which used visual evoked potentials (VEP), 2 Teller cards and 1 both. 4 studies reported beneficial effects and the remaining 5 did not.
GRADE analysis of the outcomes indicated that the overall quality of evidence was low.

Results and conclusions:
The investigators found a meta-analysis of 3 RCTs (n = 244) showed significant benefit for sweep VEP acuity at 12 months (log of the minimum angle of resolution) [MD = -0.15, 95% CI = -0.17 to -0.13, I2 = 0%, low-quality of evidence].
However, the meta-analysis of 3 other RCTs (n = 256) showed no benefit for visual acuity measured with Teller cards at 12 months (cycles/degree) [MD = -0.01, 95% CI = -0.12 to 0.11, I2 = 0%, low-quality of evidence].

The investigators found meta-analysis of 4 RCTs (n = 661) revealed no significant differences between LCPUFA and placebo groups in BSID Mental Developmental Index scores at 18 months [MD = 0.06, 95% CI = -2.01 to 2.14, I2 = 75%, low-quality of evidence] and no significant differences in BSID Psychomotor Development Index scores at 18 months [MD = 0.69, 95% CI = -0.78 to 2.16, I2 = 61%, low-quality of evidence].

There were also no significant differences between the two groups in BSID-II scores at one year and two years of age.

The investigators found meta-analysis of 5 RCTs (n = 521) showed that the supplemented group had lower weight (z scores) at one year of age [MD = -0.23, 95% CI = -0.40 to -0.06, I2 = 83%, low-quality of evidence] and that the two groups showed no significant differences with respect to length and head circumference (z scores).

The investigators found meta-analysis at 18 months and at two years revealed no significant differences between the two groups with respect to weight (kg), length (cm) and head circumference (cm).

The investigators concluded there are no beneficial effects or harms of LCPUFA supplementation on neurodevelopmental outcomes of formula-fed full-term infants and no consistent beneficial effects on visual acuity. Therefore, routine supplementation of full-term infant milk formula with LCPUFA cannot be recommended at this time.

Original title:
Long chain polyunsaturated fatty acid supplementation in infants born at term by Jasani B, Simmer K, […], Rao SC.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28281303

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

Objectives:
Is a low maternal circulating 25 hydroxyvitamin D (25-OHD) associated with an increased risk of preterm birth or spontaneous preterm birth and can vitamin D supplementation alone during pregnancy reduce risk of preterm birth?

Study design:
This review article included 6 RCTs and 18 observational studies.

Results and conclusions:
The investigators found maternal circulating 25-OHD deficiency significantly increased risk of preterm birth with 25% [pooled OR = 1.25, 95% CI = 1.13-1.38]. However, maternal circulating 25-OHD insufficiency was not associated with an increased risk of preterm birth [pooled OR = 1.09, 95% CI = 0.89-1.35]. Not associated because OR of 1 was found in 95% CI of 0.89 to 1.35. OR of 1 means no risk/association.

The investigators found vitamin D supplementation alone during pregnancy significantly reduced risk of preterm birth with 43% [pooled RR = 0.57, 95% CI = 0.36-0.91]. Significantly because RR of 1 was not found in 95% CI of 0.36 to 0.91. RR of 1 means no risk/association.

The investigators found maternal circulating 25-OHD 50 nmol/L significantly increased risk of spontaneous preterm birth with 45% [pooled OR = 1.45, 95% CI = 1.20-1.75]. 

The investigators concluded a maternal circulating 25-OHD 50 nmol/L increases risk of spontaneous preterm birth and vitamin D supplementation alone during pregnancy reduces risk of preterm birth. However, extrapolation of the results must be done with caution and there is urgent need for larger, better-designed RCT to confirm this effect.

Original title:
Vitamin D and risk of preterm birth: Up-to-date meta-analysis of randomized controlled trials and observational studies by Zhou SS, Tao YH, […], Tao FB.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28150405

Additional information of El Mondo:
Find more information/studies about vitamin D, pregnancy, review article, significant and 95% CI right here.