Nutritional advice

Objectives:
Is there a causal relationship between sugar-sweetened beverages consumption and higher BMI and body weight in both children and adults?
 
Study design:
This review article included 85 studies with 48 in children (40 cohort studies with 91,713 participants and 8 RCTs with 2,783 participants) and 37 in adults (21 cohort studies with 448,661 participants and 16 RCTs with 1,343 participants).

Results and conclusions:
The investigators found among cohort studies, each serving/day increase in sugar-sweetened beverages intake was significantly associated with a 0.07 kg/m² [95% CI = 0.04 to 0.10 kg/m²] higher BMI in children and a 0.42 kg [95% CI = 0.26 to 0.58 kg] higher body weight in adults.

The investigators found RCTs in children indicated less BMI gain with sugar-sweetened beverages reduction interventions compared with control [MD = -0.21 kg/m², 95% CI = -0.40 to -0.01 kg/m²].

The investigators found RCTs in adults showed randomization to addition of sugar-sweetened beverages to the diet led to greater body weight gain [MD = 0.83 kg, 95% CI = 0.47 to 1.19 kg] and subtraction of sugar-sweetened beverages led to weight loss [MD = -0.49 kg, 95% CI = -0.66 to -0.32 kg] compared with the control groups.

The investigators found a positive linear dose-response association between sugar-sweetened beverages consumption and weight gain for all outcomes assessed.

The investigators concluded there is a causal relationship between sugar-sweetened beverages consumption and higher BMI and higher body weight in both children and adults.

Original title:
Sugar-sweetened beverage consumption and weight gain in children and adults: a systematic review and meta-analysis of prospective cohort studies and randomized controlled trials by Nguyen M, Jarvis SE, [...], Malik VS.

Link:
https://pubmed.ncbi.nlm.nih.gov/36789935/

Additional information of El Mondo:
Find more information/studies on sugar-sweetened beverages consumption and obesity/overweight right here.

Objectives:
Does high-dose dietary intake of vitamin E, β-carotene or vitamin C reduce risk of Parkinson's disease?

Study design:
This review article included 13 observational studies.

Results and conclusions:
The investigators found no significant association between high-dose vitamin C dietary intake and the risk of Parkinson's disease compared with low-dose vitamin C dietary intake [RR = 0.98, 95% CI = 0.89 to 1.08].

The investigators found compared with low-dose dietary intake, high-dose dietary intake of vitamin E significantly reduced risk of Parkinson's disease with 13% [RR = 0.87, 95% CI = 0.77 to 0.99].

The investigators found compared with low-dose dietary intake, high-dose dietary intake of β-carotene significantly reduced risk of Parkinson's disease among women with 22% [RR = 0.78, 95% CI = 0.64 to 0.96].

The investigators concluded both high-dose dietary intake of vitamin E and β-carotene (beta-carotene) reduce risk of Parkinson's disease.

Original title:
Vitamin C, vitamin E, β-carotene and risk of Parkinson's disease: a systematic review and dose-response meta-analysis of observational studies by Niu F, Xie W, […], Yu X.

Link:
https://pubmed.ncbi.nlm.nih.gov/36961747/

Additional information of El Mondo:
Find here more information/studies about RCTs/significant, vitamin C, E, beta-carotene and Parkinson’s disease.
 

Objectives:
Epidemiological studies that focus on the relationship between dietary isoflavone intake and the risk of breast cancer still lead to inconsistent conclusions. Therefore, this review article has been conducted.

Does a high isoflavone dietary intake reduce risk of breast cancer among women?

Study design:
This review article included 7 cohort studies and 17 case-control studies with a total of 902,438 females.
The verification of breast cancer in these studies was based on either a cancer registry record or a histological diagnosis.
The exposure assessment of all included studies was based on a food frequency questionnaire (FFQ) via either face-to-face interviews or self-administrative questionnaires.

The publication biases were evaluated using Begg’s test and Egger’s test. The shape of the funnel plots showed asymmetry [p = 0.001] and the Egger’s test found virtual publication bias [p 0.001]. However, the trim-and-fill method failed to identify any potentially missing studies, indicating the publication bias did not affect the results.

Results and conclusions:
The investigators found in the meta-analysis a significantly reduced risk of 29% for breast cancer [summary OR = 0.71, 95% CI = 0.72 to 0.81, I2 = 82.6%] when comparing the highest to the lowest isoflavone dietary intake.
The result remained the same in sensitivity analysis.

The investigators found in subgroup analysis a statistically significant protective effect of 38% for isoflavone dietary intake on breast cancer in the case-control studies [OR = 0.62, 95% CI = 0.50 to 0.76], while no such effect was observed in the cohort studies [OR = 0.94, 95% CI = 0.86 to 1.02].

The investigators found in subgroup analysis a statistically significant protective effect of 38% for isoflavone dietary intake on breast cancer in Asian women [OR = 0.62, 95% CI = 0.52 to 0.74], while no such effect was observed in non-Asian women [OR = 0.97, 95% CI = 0.88 to 1.06].

The investigators found when the highest isoflavone dietary intake was lower than 10 mg/d, the negative relationship between isoflavone dietary intake and breast cancer disappeared [OR = 1.01, 95% CI = 0.94 to 1.08], whereas a statistically significant protective effect of 37% [OR = 0.63, 95% CI = 0.53 to 0.75] was found, when the highest isoflavone dietary intake was above 10 mg/d.
However, a statistically significant difference in the protective effect of isoflavone dietary intake on breast cancer was observed regardless of whether the women were pre- or postmenopausal and regardless of whether they were ER positive or negative.

The investigators concluded at least 10 mg/d isoflavone dietary intake is helpful in reducing breast cancer risk, particularly among Asian women.

Original title:
Isoflavone Consumption and Risk of Breast Cancer: An Updated Systematic Review with Meta-Analysis of Observational Studies by Yang J, Shen H,  […], Qin Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10224089/

Additional information of El Mondo:
Find more information/studies on isoflavone and breast cancer right here.

Objectives:
The effect of probiotic/synbiotic supplementation on gestational diabetes mellitus (GDM) is controversial. Therefore, this review article has been conducted.

Do probiotic/synbiotic supplements improve glucose and lipid metabolism in pregnant women with gestational diabetes mellitus?

Study design:
This review article included 11 RCTs with a total of 390 women with gestational diabetes mellitus in probiotics/synbiotics group and 389 women with gestational diabetes mellitus in placebo group.

The mean age of those participants ranged from 26.4 years to 33.5 years.
The duration of intervention ranged from 4 weeks to 8 weeks.

Results and conclusions:
The investigators found compared with the placebo, probiotics/synbiotics supplements were associated with a statistically significant improvement in fasting plasma glucose (FPG) [MD = -2.33, 95% CI = -4.27 to -0.40, p = 0.02, I2 = 74%].  

The investigators found compared with the placebo, probiotics/synbiotics supplements were associated with a statistically significant improvement in the homoeostatic model assessment for insulin resistance (HOMA-IR) [MD = -0.40, 95% CI = -0.74 to -0.06, p = 0.02, I2 = 76%].  

The investigators found compared with the placebo, probiotics/synbiotics supplements were associated with a statistically significant improvement in fasting serum insulin (FSI) [MD = -2.47, 95% CI = -3.82 to -1.12, p = 0.0003, I2 =73%].  

The investigators found compared with the placebo, probiotics/synbiotics supplements were associated with a statistically significant improvement in total cholesterol (TC) [MD = -6.59, 95% CI = -12.23 to -0.95, p = 0.02].  

The investigators found subgroup analysis revealed that the kind of supplement led to heterogeneity for FPG and FSI, while heterogeneity was not found for others.

The investigators concluded probiotic/synbiotic supplements improve glucose and lipid metabolism in pregnant women with gestational diabetes mellitus. The use of specific probiotic supplementations containing Lactobacillus acidophilus and Bifidobacterium bifidum (>1 × 106 CFU/g) may be a promising prevention and therapeutic strategy for gestational diabetes mellitus, as they could directly act on the intestinal mucosal barrier and restore the gut flora balance. However, due to the heterogeneity among existing studies, further studies are warranted to address the limitations of existing evidence and better inform the management of gestational diabetes mellitus.

Original title:
The Effects of Probiotics/Synbiotics on Glucose and Lipid Metabolism in Women with Gestational Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials by Mu J, Xian Guo X, […], Cao G.

Link:
https://www.mdpi.com/2072-6643/15/6/1375

Additional information of El Mondo:
Find more information/studies on probiotic, diabetes mellitus and pregnancy right here.

 

Objectives:
Previous studies have suggested that selenium as a trace element is involved in bone health, but findings related to the specific effect of selenium on bone health remain inconclusive. Therefore, this review article has been conducted.

Do both high dietary selenium intake and high serum selenium levels increase bone density?

Study design:
This review article included 8 cross-sectional studies, 7 case-control studies and 3 prospective cohort studies and 1 RCT with a total of 69,672 subjects.

The number of participants ranged from 60 to 21,939, while the mean age varied from 39.4 to 75.8 years, with mean selenium intake ranging from 41.2 to 154.4 μg/d or mean serum selenium level ranging from 66.7 to 131.1 μg/L.
All the observational studies had a NOS score ≥ 4, namely moderate- to high-quality scores.
There was no publication bias.

Results and conclusions:
The investigators found a significantly positive association between dietary selenium intake [β = 0.04, 95% CI = 0.00 to 0.07, p = 0.029, I2 = 95.91%] as well as serum selenium [β = 0.13, 95% CI = 0.00 to 0.26, p = 0.046, I2 = 86.60%] and bone mineral density.

The investigators found high dietary selenium intake significantly reduced risk of hip fracture with 56% [OR = 0.44, 95% CI = 0.37 to 0.52, p 0.001, I2 = 65.2%].

The investigators found osteoporosis patients had lower serum selenium level than healthy controls [WMD = -2.01, 95% CI = -3.91 to -0.12, p = 0.037, I2 = 0%].

The investigators concluded persons with higher dietary selenium intake and higher serum selenium have higher bone mineral density. Furthermore, high selenium dietary intake reduces hip fracture.

Original title:
The association between selenium and bone health: a meta-analysis by Xie H, Wang N, […], Wang Y.

Link:
https://boneandjoint.org.uk/article/10.1302/2046-3758.127.BJR-2022-0420.R1

Additional information of El Mondo:
Find more information/studies on selenium and preventing fractures right here.

Circulating concentration of selenium in blood (serum selenium level) can be increased by eating foods that are high in selenium and/or taking selenium supplements.

Objectives:
Findings on the association of dietary intake and tissue biomarkers of linoleic acid (LA) with the risk of prostate cancer are conflicting. Also, no meta-analysis summarized available findings in this regard. Therefore, this review article has been conducted.

Do higher tissue levels or higher dietary intakes of linoleic acid reduce prostate cancer risk in men?

Study design:
This review article included 15 prospective cohort studies with 511,622 participants with an age range of ≥18 years.

During the follow-up periods ranging from 5 to 21 years, 39,993 cases of prostate cancer, 5,929 cases of advanced prostate cancer and 1,661 cases of fatal prostate cancer were detected.

Results and conclusions:
The investigators found higher tissue levels of linoleic acid were significantly associated with a reduced risk of 14% for prostate cancer [RR = 0.86, 95% CI = 0.77 to 0.96].   
However, a significant association was not seen for advanced prostate cancer [RR = 0.86, 95% CI = 0.65 to 1.13].

The investigators found in dose-response analysis, each 5% increase in tissue levels of linoleic acid was significantly associated with a 14% lower risk of prostate cancer.

The investigators found no significant association between dietary intake of linoleic acid and risk of total [RR = 1.00, 95% CI = 0.97 to 1.04], advanced [RR = 0.98, 95% CI = 0.90 to 1.07] and fatal prostate cancer [RR = 0.97, 95% CI = 0.83 to 1.13].
Not significant because RR of 1 was found in the 95% CI of 0.83 to 1.13. RR of 1 means no risk/association.

The investigators concluded higher tissue levels of linoleic acid reduce prostate cancer in men.

Original title:
Dietary intake and biomarkers of linoleic acid and risk of prostate cancer in men: A systematic review and dose-response meta-analysis of prospective cohort studies by Yousefi M, Eshaghian N, […], Sadeghi O.

Link:
https://pubmed.ncbi.nlm.nih.gov/37077161/

Additional information of El Mondo:
Find more information/studies on linoleic acid and prostate cancer right here.

Tissue levels of linoleic acid can be increased by eating foods that are high in linoleic acid and/or taking linoleic acid supplements.
 

Sunflower oil, corn oil, soybean oil, rice bran oil, canola (rapeseed) oil are high in linoleic acid.

Objectives:
Does orange juice consumption causally improve lipid profile?

Study design:
This review article included 9 RCTs with a total of 386 participants.
The mean age of the participants ranged from 36 to 56 years.
All the RCTs used a parallel study design.
The dosage of orange juice ranged from 250 to 1000 mL/d.
The duration of interventions ranged from 3 to 12 weeks.

Results and conclusions:
The investigators found orange juice consumption significantly reduced LDL cholesterol (bad cholesterol) levels [WMD  = -8.35 mg/dL, 95% CI = -15.43 to 1.26, p = 0.021, I2 = 45.8%, p = 0.055].

The investigators found in subgroup analysis based on the administered dosage, LDL cholesterol levels significantly decreased following the consumption of >500 mL/d orange juice [WMD = -9.85 mg/dL, 95% CI = -18.18 to -1.52, p = 0.02].
Moreover, the subgroup analyses based on the duration of intervention revealed that the effect of orange juice supplementation on LDL cholesterol levels was significantly greater in trials lasting ≤8 weeks [WMD = -7.91 mg/dL, 95% CI = -15.91 to -36, p = 0·04].
Also, studies conducted on both genders were observed to be significantly more likely to reduce blood LDL-C levels [WMD = -12.61 mg/dL, 95% CI = -21.19 to -4.04, p = 0.004].

The investigators concluded that  at least 500 mL/d orange juice consumption causally reduce LDL cholesterol (bad cholesterol) levels.

Original title:
Orange juice intake and lipid profile: a systematic review and meta-analysis of randomised controlled trials by Amini MR, Sheikhhossein F, […], Askarpour M.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10052563/

Additional information of El Mondo:
Find more information/studies on orange juice consumption, cholesterol and cardiovasculair disease right here.
 

Objectives:
There is an equivocal and inconsistent association between legume consumption and health outcomes and longevity. Therefore, this review article has been conducted.

Does a higher legume dietary intake reduce mortality and stroke risk?

Study design:
This review article included 32 cohort studies (31 publications) involving 1,141,793 participants and 93,373 deaths from all causes (all-cause mortality).

The certainty of evidence was judged from low to moderate.

Results and conclusions:
The investigators found higher dietary intakes of legumes, compared with lower dietary intakes, were significantly associated with a reduced risk of 6% for mortality from all causes [HR = 0.94, 95% CI = 0.91 to 0.98, n = 27].

The investigators found higher dietary intakes of legumes, compared with lower dietary intakes, were significantly associated with a reduced risk of 9% for stroke [HR = 0.91, 95% CI = 0.84 to 0.99, n = 5].

The investigators found no significant association for cardiovascular diseases mortality [HR = 0.99, 95% CI = 0.91 to 1.09, n =11], coronary heart disease mortality [HR = 0.93, 95% CI = 0.78 to 1.09, n = 5] or cancer mortality [HR = 0.85, 95% CI = 0.72 to 1.01, n = 5].

The investigators found in the linear dose-response analysis, a 50 g/d increase in legume dietary intake was significantly associated with a 6% reduction in the risk of all-cause mortality [HR = 0.94, 95% CI = 0.89 to 0.99, n = 19], but no significant association was observed for the remaining outcomes.

The investigators concluded a higher legume dietary intake may reduce mortality from all causes and stroke risk. May reduce because the certainty of evidence is low to moderate.

Original title:
Legume Consumption and Risk of All-Cause and Cause-Specific Mortality: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies by Zargarzadeh N, Mousavi SM, […], Esmaillzadeh A.

Link:
https://pubmed.ncbi.nlm.nih.gov/36811595/

Additional information of El Mondo:
Find here more information/studies about RCTs/significant, vegetable intake and stroke prevention.
 

Objectives:
Does a high dietary intake of vitamin B6 or a high blood PLP levels (vitamin B6 level in blood) reduce the risk of colorectal cancer?

Study design:
This review article included 20 cohort studies and 8 case-control studies.

Results and conclusions:
The investigators found higher dietary intake of vitamin B6 significantly reduced the risk of colorectal cancer with 20% [combined OR = 0.80, 95% CI = 0.68 to 0.94].

The investigators found higher blood PLP level significantly reduced the risk of colorectal cancer with 46% [combined OR = 0.54, 95% CI = 0.35 to 0.84].

The investigators found subgroup analysis revealed that higher dietary intake of vitamin B6 significantly reduced the risk of colorectal cancer in women with 21% [combined OR = 0.79, 95% CI = 0.65 to 0.96].

The investigators found subgroup analysis revealed that higher blood PLP level significantly reduced the risk of colorectal cancer in women with 59% [combined OR = 0.41, 95% CI = 0.30 to 0.57].

The investigators found subgroup analysis revealed that higher dietary intake of vitamin B6 significantly reduced the risk of colon cancer in men and women with 24% [combined OR = 0.76, 95% CI = 0.64 to 0.91].

The investigators found subgroup analysis revealed that higher blood PLP level significantly reduced the risk of colon cancer in men and women with 44% [combined OR = 0.56, 95% CI = 0.42 to 0.73].

The investigators concluded that higher dietary intake of vitamin B6 and higher blood PLP level (vitamin B6 level in blood) reduce colorectal cancer risk, particularly colon cancer.

Original title:
Association Between Vitamin B6 and the Risk of Colorectal Cancer: A Meta-analysis of Observational Studies by Lai J, Guo M, […], Li J.

Link:
https://pubmed.ncbi.nlm.nih.gov/36961108/

Additional information of El Mondo:
Find more information/studies on vitamin B6 and colorectal cancer right here.

Circulating concentration of vitamin B6 in blood can be increased by eating foods that are high in vitamin B6 and/or taking vitamin B6 supplements.
 

Objectives:
Although relationships between the intake of whole grains and refined grains and the incidence of cardiovascular disease (CVD) events and all-cause mortality have been investigated, the conclusions have been inconclusive. Therefore, this review article has been conducted.

Does consumption of whole grains reduce risk of stroke, coronary heart disease, heart  failure, cardiovascular disease and all-cause mortality?

Study design:
This review article included 68 prospective cohort studies (46 for whole grains and 22 for refined grains) with 1,624,407 participants.

The included studies had follow-up periods between 5.4 y and 26 y, with sample sizes varying from 535 to 461,047 participants.

Based on NOS, the mean score of the included studies was 7.74 for whole grains and 7.45 for refined grains.

Egger’s test and funnel plot did not indicate any publication bias for the relationships between 30g/d increases in whole grain consumption and the risk of stroke [p = 0.481], cardiovascular disease [p= 0.144] or all-cause mortality [p = 0.409].

The quality of meta-evidence for the association between whole grain consumption and risks of stroke, coronary heart disease, heart failure, cardiovascular disease and all-cause mortality was moderate, moderate, low, high and high, respectively.
The quality of evidence for refined grain was low.

Results and conclusions:
The investigators found a significantly reduced risk of 3% for stroke per 30-g increase in daily whole grain consumption [RR = 0.97, 95% CI = 0.96 to 0.99, I2 = 0%].

The investigators found a significantly reduced risk of 6% for coronary heart disease (CHD) per 30-g increase in daily whole grain consumption [RR = 0.94, 95% CI = 0.92 to 0.97, I2 = 54.4%].
Sensitivity analyses indicated that the result was stable.

The investigators found a significantly reduced risk of 8% for cardiovascular disease (CVD) per 30-g increase in daily whole grain consumption [RR = 0.92, 95% CI = 0.88 to 0.96, I2 = 82.9%].
Sensitivity analyses indicated that the result was stable.

The investigators found a significantly reduced risk of 6% for all-cause mortality per 30-g increase in daily whole grain consumption [RR = 0.94, 95% CI = 0.92 to 0.97, I2 = 89.8%].
Sensitivity analyses indicated that the result was stable.

The investigators found whole grain consumption was linearly associated with coronary heart disease [p nonlinearity = 0.231] and nonlinearly associated with cardiovascular disease [p nonlinearity = 0.002] and all-cause mortality [p nonlinearity = 0.001].

The investigators concluded that consumption of at least 30g/d whole grains reduce stroke, coronary heart disease, cardiovascular disease and all-cause mortality.

Original title:
Consumption of whole grains and refined grains and associated risk of cardiovascular disease events and all-cause mortality: a systematic review and dose-response meta-analysis of prospective cohort studies by Hu H, Zhao Y, […], Hu D.

Link:
https://www.sciencedirect.com/science/article/pii/S0002916522105186?via%3Dihub

Additional information of El Mondo:
Find more information/studies on whole grain consumption, cardiovasculair disease and stroke right here.

Objectives:
Prospective cohorts are inconsistent regarding the association between dietary calcium intake and the risk of stroke. Therefore, this review article has been conducted.

Does dietary intake of calcium reduce risk of stroke?

Study design:
This review article included 18 prospective cohort studies witth19,557 stroke cases (persons) among 882,181 participants.

Results and conclusions:
The investigators found a nonlinear association between calcium intake and risk of stroke [p nonlinearity 0.003].

The investigators found compared with the lowest value of zero assumed as the reference, dietary intake of 200 mg/day calcium significantly reduced stroke risk with 5% [95% CI = 0.92 to 0.98].
This protective effect was only found in Asian countries.

The investigators found compared with the lowest value of zero assumed as the reference, dietary intake of 300 mg/day calcium significantly reduced stroke risk with 6% [95% CI = 0.90 to 0.98].
This protective effect was only found in Asian countries.

The investigators found compared with the lowest value of zero assumed as the reference, dietary intake of 500 mg/day calcium significantly reduced stroke risk with 5% [95% CI = 0.90 to 0.99].
This protective effect was only found in Asian countries.

The investigators found no protective effect for stroke at dietary intake of 700 mg/day calcium or higher.

The investigators concluded dietary intake of 200-700 mg/day calcium reduces stroke risk among Asians.

Original title:
Dietary calcium intake and the risk of stroke: Meta-analysis of cohort studies by Wang ZM, Bu XX, […], Nie ZL.

Link:
https://pubmed.ncbi.nlm.nih.gov/36958976/

Additional information of El Mondo:
Find more information/studies on calcium and stroke right here.

Objectives:
Magnesium, an essential cation for numerous cellular processes, is a major component of bone. However, its relationship with the risk of fractures is still uncertain. Therefore, this review article has been conducted.

Do lower serum magnesium concentrations increase risk of incident fractures?

Study design:
This review article included 3 prospective cohort studies and 1 retrospective cohort study with a total of 119,755 participants and a mean follow-up duration of 79 months.
The mean age was 62 years, with a mean percentage of 33% women.
The analyses were adjusted for a mean of 15 potential confounders.
All 4 studies included in the meta-analysis were of high quality (Newcastle-Ottawa Scale of 9 for all).

Results and conclusions:
The investigators found lower serum magnesium concentrations were associated with a significantly higher risk of 58% for incident fractures [RR = 1.579, 95% CI = 1.216 to 2.051, p = 0.001, I2 = 46.9%].
The results were not affected by any heterogeneity [I2 = 31.2%, p = 0.201] nor publication bias [Egger’s test = 0.94 ± 0.43, p = 0.10]. After trimming, the recalculated effect size was only slightly reduced [RR = 1.25, 95% CI = 1.09 to 1.43].
Significant because RR of 1 was not found in the 95% CI of 1.09 to 1.43. RR of 1 means no risk/association.

The investigators concluded lower serum magnesium concentrations increase risk of incident fractures.

Original title:
Association between Serum Magnesium and Fractures: A Systematic Review and Meta-Analysis of Observational Studies by Dominguez LJ, Rodas-Regalado S, […], Barbagallo M.

Link:
https://www.mdpi.com/2072-6643/15/6/1304

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

Circulating concentration of magnesium in blood can be increased by eating foods that are high in magnesium and/or taking magnesium supplements.

Objectives:
Given their potent antioxidation properties, carotenoids play a role in delaying and preventing dementia and mild cognitive impairment (MCI). However, observational studies have found inconsistent results regarding the associations between blood carotenoid levels and the risk of dementia and MCI. Therefore, this review article has been conducted.

Is a lower blood carotenoid level (like lycopene, zeaxanthin, lutein) a risk factor for dementia or mild cognitive impairment?

Study design:
This review article included 23 studies with 1,422 patients with dementia, 435 patients with mild cognitive impairment and 4,753 controls (persons without dementia or mild cognitive impairment).

Results and conclusions:
The investigators found meta-analysis showed that patients with dementia had lower blood lycopene [SMD = -0.521, 95% CI = -0.74 to -0.301], α-carotene [SMD = -0.489, 95% CI = -0.697 to -0.281] β-carotene [SMD = -0.476, 95% CI = -0.784 to -0.168], lutein [SMD = -0.516, 95% CI = -0.753 to -0.279], zeaxanthin [SMD = -0.571, 95% CI = -0.910 to -0.232] and β-cryptoxanthin [SMD = -0.617, 95% CI = -0.953 to -0.281] than the controls.

The investigators found owing to insufficient data, no similar and stable relationship between blood carotenoid levels and mild cognitive impairment was observed.

The investigators concluded lower blood carotenoid level is a risk factor for dementia.

Original title:
Low blood carotenoid status in dementia and mild cognitive impairment: A systematic review and meta-analysis by Wang L, Zhao T, […], Jiang Q.

Link:
https://pubmed.ncbi.nlm.nih.gov/36997905/

Additional information of El Mondo:
Find more information/studies on carotenoids and Alzheimer 's disease right here.

Circulating concentration of lycopene in blood can be increased by eating foods that are high in lycopene and/or taking lycopene supplements.

Objectives:
Nausea and vomiting during pregnancy (NVP) are common symptoms in pregnancy. Although no definitive treatment option for NVP, pyridoxine (vitamin B6) supplementation has been used widely. Therefore, this review article has been conducted.

Does supplementation of pyridoxine alone as well as combined treatment of pyridoxine with an active ingredient as the intervention reduce nausea and vomiting during pregnancy?

Study design:
This review article included 8 RCTs.

Results and conclusions:
The investigators found 8 studies showed beneficial effects with pyridoxine alone as the supplementation, while 6 others found that the supplementation of pyridoxine in combination with another active substance had favourable effects.

The investigators found supplementation of pyridoxine alone as well as combined treatment of pyridoxine with an active ingredient as the intervention significantly improved the symptoms of nausea according to Rhode's score [0.78, 95% CI= 0.26 to 1.31, p = 0.003, I2 = 57%, p = 0.10] and PUQE score [0.75, 95% CI = 0.28 to 1.22, p = 0.002, I2 = 0%, p = 0.51], respectively.

The investigators concluded supplementation of pyridoxine (vitamin B6) alone as well as combined treatment of pyridoxine with an active ingredient as the intervention reduces nausea and vomiting during pregnancy.

Original title:
The effects of pyridoxine (vitamin B6) supplementation in nausea and vomiting during pregnancy: a systematic review and meta-analysis by Jayawardena R, Majeed S, […], Ranaweera P.

Link:
https://pubmed.ncbi.nlm.nih.gov/36719452/

Additional information of El Mondo:
Find more information/studies on vitamin B6 and pregnancy right here.
 

Objectives:
Does a high antioxidant dietary intake reduce risk of Alzheimer's disease and dementia?

Study design:
This review article included 17 cohort studies with 98,264 participants, of which 7,425 had dementia after 3-23 years of follow-up.

Results and conclusions:
The investigators found a high antioxidant dietary intake significantly reduced the incidence of Alzheimer's disease with 15% [RR = 0.85, 95% CI= 0.79 to 0.92, I2 = 45.5%].
However, this reduced risk was not significant for dementia [RR = 0.84, 95% CI = 0.77 to 1.19, I2 = 54.6%].
Significant because RR of 1 was not found in the 95% CI of 0.79 to 0.92. RR of 1 means no risk/association.

The investigators concluded that a high antioxidant dietary intake reduces Alzheimer's disease.

Original title:
Association of Dietary and Supplement Intake of Antioxidants with Risk of Dementia: A Meta-Analysis of Cohort Studies by Zhao R, Han X, […], You H.

Link:
https://pubmed.ncbi.nlm.nih.gov/36846999/

Additional information of El Mondo:
Find more information/studies on antioxidant and Alzheimer 's disease right here.

Objectives:
The associations between dietary intakes and circulating blood levels of methionine, choline or betaine and breast cancer risk remain currently unclear. Therefore, this review article has been conducted.

Do higher dietary intakes and circulating blood levels of methionine, choline or betaine reduce breast cancer risk?

Study design:
This review article included 8 prospective cohort studies and 10 case-control studies.

Results and conclusions:
The investigators found in case-control studies that higher dietary choline intake significantly reduced breast cancer risk with 62% [OR = 0.38, 95% CI = 0.16 to 0.86].
However, this reduced risk was not significant in prospective cohort studies [HR = 1.01, 95% CI = 0.92 to 1.12].

The investigators concluded that higher choline dietary intake may reduce breast cancer risk. May reduce because this reduced risk is not found in cohort studies.

Original title:
The association between dietary intakes of methionine, choline and betaine and breast cancer risk: A systematic review and meta-analysis by Van Puyvelde H, Dimou N, […], De Bacquer D.

Link:
https://pubmed.ncbi.nlm.nih.gov/36701983/

Additional information of El Mondo:
Find more information/studies on cohort studies/significantly, choline and breast cancer right here.

Objectives:
The roles of anti-inflammatory cytokines in the pathogenesis of severe malaria have been widely studied and the role of IL-10 in the pathogenesis of severe malaria remains unclear. Therefore, this review article has been conducted.

Is there a difference in IL-10 levels between patients with severe malaria and those with non-severe malaria?

Study design:
This review article included 19 studies, published between 1994 and 2021.
11 studies (57.9%) were prospective studies, 6 (31.6%) were retrospective studies and 2 (10.5%) were cross-sectional studies.
Of the included studies, 10 (52.6%) were conducted in Africa, 5 (26.3%) were conducted in Asia, 3 (15.8%) were conducted in the United States and 1 (5.26%) was conducted in Europe.
13 studies (68.4%) enrolled patients infected with P. falciparum, 4 (21.1%) enrolled patients with P. vivax, and 2 (10.5%) enrolled patients with both P. falciparum and P. knowlesi.
10 studies (52.6%) enrolled children, 6 (31.6%) enrolled adults and 3 (15.8%) enrolled all age groups.

18 studies (94.7%) were high-quality studies, whereas 1 study (5.26%) was of moderate quality.

Results and conclusions:
The investigators found, overall, the meta-analysis results showed that patients with severe malaria had a higher SMD of the IL-10 levels than those with non-severe malaria [pooled SMD = 0.74, 95% CI = 0.08 to 1.40, p = 0.03, I2 = 97.22%].

The investigators found meta-regression analysis using the study designs, geographic location (continents), Plasmodium spp., age, mean parasitemia and methods for the IL-10’s quantification showed that these covariates did not confound the pooled SMD [p > 0.05].

The investigators found subgroup analysis based on the study design revealed no difference in the SMD of the IL-10 levels between patients with severe and non-severe malaria in cross-sectional studies, prospective studies and retrospective studies.

The investigators found subgroup analysis, based on Plasmodium spp. showed a higher SMD of the IL-10 level in patients with severe P. falciparum malaria than in those with non-severe P. falciparum malaria and a higher SMD of the IL-10 level in patients with severe P. knowlesi malaria than in those with non-severe P. knowlesi malaria.
However, a lower SMD of the IL-10 level was observed in patients with severe P. vivax malaria than in those with non-severe P. vivax malaria.

The investigators found subgroup analysis based on the age groups showed no difference in the SMD of the IL-10 level between patients with severe malaria and those with non-severe malaria among studies that enrolled adults, children and participants of all age groups.   

The investigators found sensitivity analysis showed that when each study was omitted from the analysis, the meta-analysis results of the IL-10 levels showed outliers [p 0.05 or p > 0.05 in re-run analyses].

The investigators found after the publication bias was adjusted by the trim and fill method, the pooled SMD in the IL-10 levels between severe and non-severe malaria was 0.743 [95% CI = 0.085 to 1.401].

The investigators concluded that patients with severe malaria have a higher mean IL-10 level than those with non-severe malaria. This finding suggests the possibility of using IL-10 as a severity marker for malaria. However, with the heterogeneity of the meta-analysis results, further studies are required to confirm the changes in the IL-10 levels according to the severity of malaria and to investigate whether a combination of other severity parameters with IL-10 levels could be an alternative marker for severe malaria.

Original title:
Relation between Increased IL-10 Levels and Malaria Severity: A Systematic Review and Meta-Analysis by Sornsenee P, Wilairatana P, […], Kotepui M.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9865813/

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Objectives:
Current findings about the differential effects of various sources of dietary animal protein on the risk of neurodegenerative diseases are contradictory. Therefore, this review article has been conducted.

Is there an association between various sources of dietary animal protein and the risk of Parkinson's disease, Alzheimer's disease, dementia and cognitive impairment?

Study design:
This review article included 33 prospective cohort studies.

Results and conclusions:
The investigators found dietary fish consumption was significantly associated with a reduced risk of 25% for Alzheimer's disease [RR = 0.75, 95% CI = 0.57 to 0.97].

The investigators found dietary fish consumption was significantly associated with a reduced risk of 16% for dementia [RR = 0.84, 95% CI = 0.75 to 0.93].

The investigators found dietary fish consumption was significantly associated with a reduced risk of 15% for cognitive impairment [RR = 0.85, 95% CI = 0.81 to 0.95].

The investigators found compared to the lowest consumption, the highest total dairy products consumption was significantly associated with an increased risk of 49% for Parkinson's disease [RR = 1.49, 95% CI = 1.06 to 2.10].

The investigators found compared to the lowest consumption, the highest milk consumption was significantly associated with an increased risk of 40% for Parkinson's disease [RR = 1.40, 95% CI = 1.13 to 1.73].

The investigators found total dairy products consumption was significantly associated with a reduced risk of 11% for cognitive impairment [RR = 0.89, 95% CI = 0.80 to 0.99].

The investigators found total meat consumption was significantly associated with a reduced risk of 28% for cognitive impairment [RR = 0.72, 95% CI = 0.57 to 0.90].

The investigators found poultry consumption was significantly associated with a reduced risk of 18% for cognitive impairment [RR = 0.82, 95% CI = 0.68 to 0.99].

The investigators found linear dose-response meta-analysis revealed that each 200g/d increase in total dairy dietary intake was significantly associated with an 11% higher risk of Parkinson's disease and a 12% lower risk of cognitive impairment.

The investigators found a strong linear association between fish consumption and reduced risk of dementia.

The investigators concluded dairy consumption, particularly milk is associated with an increased risk of Parkinson's disease, while a higher intake of fish reduces Alzheimer's disease, dementia and cognitive impairment. Future well-controlled, randomized clinical trials are essential to validate the present findings.

Original title:
Association between animal protein sources and risk of neurodegenerative diseases: a systematic review and dose-response meta-analysis by Talebi S, Asoudeh F, […], Mohammadi H.

Link:
https://pubmed.ncbi.nlm.nih.gov/36647769/

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Objectives:
Is there a causal relationship between drinking green tea and improving risk factors of cardiovascular disease, like cholesterol, fasting blood sugar, blood pressure, HbA1c, HOMA-IR?

Study design:
This review article included 55 RCTs with 63 effect sizes with 2,487 participants in the green tea group and 2,387 in the placebo group (group without green tea).

The participants’ mean age ranged between 18 and 68.7 years and the period of intervention ranged between 2 to 48 weeks.
Some of the studies enrolled only males or females and some of them included both genders.

TC, LDL, HDL, FBS, HbA1c and DBP-related evidence had moderate quality due to the serious inconsistency reasons. Additionally, it was shown that evidence regarding TG, fasting insulin, SBP and CRP had low quality due to serious imprecision and inconsistency reasons. The evidence relating to HOMA-IR was also downgraded to very low quality because of the serious inconsistency, imprecision and publication bias.

Results and conclusions:
The investigators found green tea supplementation significantly reduced total cholesterol levels (TC) [WMD = -7.62, 95% CI = -10.51 to -4.73, p ≤ 0.001, I2 = 90.9%].
This significantly reduced effect was also found if females or both males and females were included, the dosage of supplementation was less than 1,000 mg/d, the baseline BMI was between 25-29.9 kg/m² and the baseline value of TC was more than 200 mg/dL.

The investigators found green tea supplementation significantly reduced LDL cholesterol levels (LDL-C) [WMD = -5.80, 95% CI = -8.30 to -3.30, p ≤ 0.001, I2 = 90.5%].
This significantly reduced effect was also found if males or both males and females were included, the baseline BMI was between 25-29.9 kg/m² and participants were not affected by T2DM.

The investigators found green tea supplementation significantly reduced fasting blood sugar levels (FBS) [WMD = -1.67, 95% CI = -2.58 to -0.75, p ≤ 0.001, I2 = 72.2%].

This significantly reduced effect was also found when the baseline BMI of participants was between 25-29.9 kg/m², female or both male and female were included, the duration of intervention was more than 12 weeks, the dosage of supplementation was less than 1,000 mg/d and baseline values of FBS were less than 100 mg/dL.

The investigators found green tea supplementation significantly reduced HbA1c levels [WMD = -0.15, 95% CI = -0.26 to -0.04, p = 0.008, I2 = 71.3%].
This significantly reduced effect was also found if the duration of intervention was ≤ 12 weeks, the dosage of supplementation was ≥ 1,000 mg/d, baseline values of HbA1c were less than 6.5%, male or both genders were involved and the baseline value of BMI was ≥ 30 kg/m².

The investigators found green tea supplementation significantly reduced diastolic blood pressure (DBP) [WMD = -0.87, 95% CI = -1.45 to -0.29, p = 0.003, I2 = 92.4%].
This significantly reduced effect was also found if the duration of intervention was ≤ 12 weeks, the dosage of supplementation was less than 1,000 mg/d, baseline values of DBP were more than 80 mmHg and the baseline value of BMI was ≥ 30 kg/m².

The investigators found green tea supplementation significantly increased HDL cholesterol levels (HDL-C) [WMD = 1.85, 95% CI = 0.87 to 2.84, p = 0.010, I2 = 94.4%].
This significantly increased effect was also found if females were included, the baseline BMI was lower more than 30 kg/m², there was no past medical history of T2DM, the duration of intervention was more than 12 weeks, the dosage of supplementation was less than 1,000 mg/d and baseline values of HDL were more than 50 mg/dL.

The investigators found sensitivity analysis showed no significant difference in results with removing one single study for all considered cardiovascular risk factors including lipid profiles, glycemic indices, SBP and DBP and CRP.

The investigators concluded drinking ≤1,000 mg/d green tea may causally improve risk factors of cardiovascular disease. May improve because the RCTs are of low quality.

Original title:
The effects of green tea supplementation on cardiovascular risk factors: A systematic review and meta-analysis by Zamani M, Kelishadi MR, […], Asbaghi O.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9871939/

Additional information of El Mondo:
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Objectives:
Is there a causal relationship between drinking green tea and lowering blood pressure in healthy individuals?

Study design:
This review article included 9 RCTs with 345 healty individuals in the intervention group (group with green tea) and 335 healthy individuals in the control group (group without green tea).

The mean age of the individuals in the intervention group was 35.89 ± 8.52, while the mean age of the control group was 36.48 ± 7.68.
All studies clearly described allocation randomization, none had incomplete outcome data, and all used appropriate statistical analysis.
The completion rate of the consumption of green tea ranged from 85-100%.
No publication bias was observed in the studies.

Results and conclusions:
The investigators found combined results of the studies showed that green tea was effective in lowering systolic blood pressure in healthy individuals [MD = -2.99, 95% CI = -3.77 to -2.22, p 0.00001, I2 = 0%].

The investigators found combined results of the studies showed that green tea was effective in lowering diastolic blood pressure in healthy individuals [MD= -0.95, 95% CI = -1.62 to -0.27, p = 0.006, I2 = 0%]. 

The investigators concluded in healthy individuals, green tea supplementation reduces systolic blood pressure by 2.99 mmHg and diastolic blood pressure by 0.95 mmHg.

Original title:
Effect of Green Tea on Blood Pressure in Healthy Individuals: A Meta-Analysis by Ayaz EY, Dincer B and Mesci B.

Link:
https://pubmed.ncbi.nlm.nih.gov/36689359/

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Objectives:
Lutein and zeaxanthin are thought to have beneficial effects on protecting the lens against cataract formation, but findings from epidemiologic studies have been inconsistent. Therefore, this review article has been conducted.

Does dietary lutein and zeaxanthin intake reduce age-related cataract risk?

Study design:
This review article included 6 prospective cohort studies, involving 4416 cases and 41999 participants.

Results and conclusions:
The investigators found for comparing the highest with the lowest categories of dietary lutein and zeaxanthin intake, a significant reduced risk for nuclear cataract of 25% [RR = 0.75, 95% CI = 0.65-0.85], but the reduced risk was not significant for cortical cataract [RR = 0.85, 95% CI = 0.53-1.17] and for posterior subcapsular cataract [RR = 0.77, 95% CI = 0.40-1.13]. Significant means, there is an association with a 95% confidence.

The investigators found in dose-response analysis that every 300 μg/d increment in dietary lutein and zeaxanthin intake was significantly associated with a 3% [RR = 0.97, 95% CI = 0.94-0.99] reduction in the risk of nuclear cataract.

The investigators found in dose-response analysis that every 300 μg/d increment in dietary lutein and zeaxanthin intake was non-significantly associated with a 1% [RR = 0.99, 95% CI = 0.95-1.02] reduction in the risk of cortical cataract. Non-significantly means, there is no association with a 95% confidence.

The investigators found in dose-response analysis that every 300 μg/d increment in dietary lutein and zeaxanthin intake was non-significantly associated with a 3% [RR = 0.97, 95% CI = 0.93-1.01] reduction in the risk of posterior subcapsular cataract. Non-significantly because RR of 1 was found in 95% CI of 0.93 to 1.01. RR of 1 means no risk.

The investigators concluded dietary lutein and zeaxanthin intake (at least 300 μg/d) is associated with a reduced risk of age-related cataract, especially nuclear cataract in a dose-response manner, indicating a beneficial effect of lutein and zeaxanthin in age-related cataract prevention.

Original title:
A dose–response meta-analysis of dietary lutein and zeaxanthin intake in relation to risk of age-related cataract by Ma L, Hao ZX, [...], Pan JP.

Link:
http://link.springer.com/article/10.1007/s00417-013-2492-3

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Objectives:
Does a low salt intake reduce blood pressure?

Study design:
This review article included 34 randomized trials with 3230 participants (the median age was 50 (range 22-73)), of which 22 were in hypertensive individuals and 12 in normotensive individuals. Of the 34 trials, 23 used crossover design and 11 used paralleled comparisons. 22 of the 34 trials were double blind, in 11 the observer was blind to blood pressure and one did not report any blinding procedure.

The study duration varied from 4 weeks to 3 years (median 4 weeks). With the usual salt intake the median 24 hour urinary sodium was 160 mmol (range 125-200 mmol), equivalent to a salt intake of 9.4 g/day (range 7.3-11.7 g/day) and the median blood pressure was 141/86 mmHg.

Despite the fact that only 7 out of 34 trials performed intention to treat analysis, the percentage of participants lost to follow-up after randomization was small (6.7% on average).

Results and conclusions:
The investigators found meta-analysis showed that the mean change in urinary sodium (reduced salt v usual salt) was -75 mmol/24 h (equivalent to a reduction of 4.4 g/day salt), and with this reduction in salt intake, the mean change in blood pressure was -4.18 mmHg [95% CI = -5.18 to -3.18, I2 = 75%] for systolic blood pressure and -2.06 mmHg [95% CI = -2.67 to -1.45, I2 = 68%] for diastolic blood pressure.

The investigators found meta-regression showed that age, ethnic group, blood pressure status (hypertensive or normotensive) and the change in 24 hour urinary sodium were all significantly associated with the fall in systolic blood pressure, explaining 68% of the variance between studies.

The investigators found a 100 mmol reduction in 24 hour urinary sodium (equivalent to a reduction 6 g/day salt) was associated with a fall in systolic blood pressure of 5.8 mmHg [95% CI = -2.5 to -9.2,  p = 0.001] after adjustment for age, ethnic group and blood pressure status.
For diastolic blood pressure, age, ethnic group, blood pressure status and the change in 24 hour urinary sodium explained 41% of the variance between studies.

The investigators found meta-analysis by subgroup showed that in people with hypertension the mean effect was -5.39 mmHg [95% CI = -6.62 to -4.15, I2 = 61%] for systolic blood pressure and -2.82 mmHg [95% CI = -3.54 to -2.11, I2 = 52%] for diastolic blood pressure.
In normotensive people, the figures were -2.42 mmHg [95% CI = -3.56 to -1.29, I2 = 66%] and -1.00 mmHg [95% CI = -1.85 to -0.15, I2 = 66%], respectively.

The investigators found further subgroup analysis showed that the decrease in systolic blood pressure was significant in both white and black people and in men and women.

The investigators found meta-analysis of data on hormones and lipids showed that the mean change was:
0.26 ng/mL/h [95% CI = 0.17 to 0.36, I2 = 70%] for plasma renin activity;
73.20 pmol/L [95% CI = 44.92 to 101.48, I2 = 62%] for aldosterone;
187 pmol/L [95% CI = 39 to 336, I2 = 5%] for noradrenaline (norepinephrine);
37 pmol/L [95% CI = -1 to 74, I2 = 12%] for adrenaline (epinephrine);
0.05 mmol/L [95% CI = -0.02 to 0.11, I2 = 0%] for total cholesterol;
0.05 mmol/L [95% CI = -0.01 to 0.12, I2 = 0%] for low density lipoprotein cholesterol (LDL-cholesterol or bad cholesterol);
-0.02 mmol/L [95% CI = -0.06 to 0.01, I2 = 16%] high density lipoprotein cholesterol (HDL-cholesterol or good cholesterol) and:
0.04 mmol/L [95% CI = -0.02 to 0.09, I2 = 0%] for triglycerides.

The investigators concluded a modest reduction in salt intake of 4.4 g/day for 4 or more weeks causes, from a population viewpoint, important falls in blood pressure in people with both raised and normal blood pressure.
Salt reduction is associated with a small physiological increase in plasma renin activity, aldosterone and noradrenaline and no significant change in lipid concentrations.
The current recommendations to reduce salt intake from 9-12 to 5-6 g/day will have a major effect on blood pressure, but a further reduction to 3 g/day will have a greater effect and should become the long term target for population salt intake.

Original title:
Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials by He FJ, Li J and MacGregor GA.

Link:
http://www.bmj.com/content/346/bmj.f1325

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A daily diet with a maximum of 3 grams salt per day is a diet with a maximum of 0.15 gram salt per 100 kcal.
A daily diet with a maximum of 0.15 gram salt per 100 kcal is a diet with mainly products/meals with a maximum of 0.15 gram salt per 100 kcal.

Objectives:
Previous trials have shown that zinc supplementation can decrease the risk of diarrhea, pneumonia and malaria in children; however, the effects of zinc supplementation on mortality remain unclear. Therefore, this review article has been conducted.

Does zinc supplementation reduce total mortality and cause-specific mortality in preschool children?

Study design:
This review article included 8 RCTs which included 87,854 children and reported 1,558 events of mortality. The population of the trials ranged from 96 to 42,546 and the follow-up for subjects ranged from 6 to 17.6 months.

Egger and Begg tests showed no evidence of publication bias for total mortality [p value for Egger = 0.207, p value for Begg = 0.902].

Results and conclusions:
The investigators found overall, zinc supplementation had no effect on:
total mortality [RR = 0.76, 95% CI = 0.56-1.04, p = 0.084];
diarrhea-related mortality [RR = 0.80, 95% CI = 0.53-1.20, p = 0.276];
pneumonia-related mortality [RR = 0.52, 95% CI = 0.11-2.39, p = 0.399];
malaria-related mortality [RR = 0.90, 95% CI = 0.77-1.06, p = 0.196] or;  

other causes of mortality [RR = 0.98, 95% CI = 0.67-1.44, p = 0.917]. No effect because RR of 1 was found in the 95% CI of 0.67 to 1.44. RR of 1 means no risk/effect/association.

The investigators found subgroup analysis indicated that zinc supplementation was significantly associated with a reduction in total mortality risk if the participants were boys, aged greater than 12 months and the duration of the follow-up period was less than 12 months. Significant means, there is an association with a 95% confidence

The investigators concluded zinc supplementation reduces total mortality risk if the participants are boys, aged greater than 12 months and the duration of the follow-up period is less than 12 months.

Original title:
Effects of zinc supplementation on the incidence of mortality in preschool children: a meta-analysis of randomized controlled trials by Fu W, Ding LR, [...], Zhou YH.

Link:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3823854/

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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

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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:
Several reviews and meta-analyses have examined the effects of iodine on mental development. However, none focused on young children, so they were incomplete in summarizing the effects on this important age group. Therefore, this review article has been conducted.

Is there a relationship between iodine and mental development of children 5 years old and under?

Study design:
This review article included 24 studies (14 cohort en 10 intervention studies).
Studies providing supplementation to women before or during pregnancy tended to give injections of iodized oil of 950 mg; only the studies conducted in China and DR Congo gave lower doses (400 and 475 mg, respectively).
The median sample size per group across the 10 intervention studies was 50 with a range of 7 to 624.

Results and conclusions:
The investigators found that the best estimate to date of the effect size of iodine supplementation on mental development in children 5 years old and under was 0.49, which translated into 7.4 IQ points lost due to iodine deficiency.

The investigators found 6.9 to 10.2 IQ points lower in iodine deficient children compared with iodine replete children.

The investigators concluded, regardless of study design, iodine deficiency has a substantial impact on mental development in children 5 years old and under. To further quantify the importance of iodine for mental development in young children, this review points to the need for well-designed randomized controlled trials with adequate sample sizes as well as studies that assess the effectiveness of iodized salt.

Original title:
Iodine and Mental Development of Children 5 Years Old and Under: A Systematic Review and Meta-Analysis by Bougma K, Aboud FE, […], Marquis GS.

Link:
http://www.mdpi.com/2072-6643/5/4/1384/htm

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