Nutrition and health

Objectives:
Iron deficiency is a prevalent nutritional disease and fatigue is a common complaint in the general and patient population, however, the association between iron deficiency without anaemia (IDNA) and fatigue is unclear. Therefore, this review article (meta-analysis) has been conducted.

Does improving iron status decrease fatigue in patients with iron deficiency without anaemia?

Study design:
This review article included a total of 6 RCTs and 6 cross-sectional studies.

Results and conclusions:
The investigators found in the meta-analysis of 6 RCTs, a significant therapeutic effect of iron supplements in fatigue patients with iron deficiency without anaemia [pooled effect size = 0.33, 95% CI = 0.17 to 0.48, I2 = 0.0%, p 0.0001]. A sensitivity analysis found that the overall results (i.e. significant association) were robust.

The investigators found in the meta-analysis of 6 cross-sectional studies, a non-significant therapeutic effect of iron supplements in fatigue patients with iron deficiency without anaemia [pooled effect size = 0.10, 95% CI = -0.11 to 0.31, I2 = 57.4%, p = 0.362]. A sensitivity analysis found that the overall results (i.e. no significant association) were not robust, however, removal of one study made the outcomes significant.

The investigators concluded improving iron status decreases fatigue in patients with iron deficiency without anaemia. However, further research is necessary to identify diagnostic criteria for selecting fatigue patients who might benefit from iron therapy and to assess the prevalence of patients with iron deficiency without anaemia in the general population.

Original title:
Iron deficiency without anaemia is a potential cause of fatigue: meta-analyses of randomised controlled trials and cross-sectional studies by Yokoi K and Konomi A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28625177

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

Objectives:
Dietary intake is potentially associated with the onset of Crohn’s disease (CD), but evidence from epidemiological studies has remained unclear. Therefore, this review article (meta-analysis) has been conducted.

Is there a positive association between fat, carbohydrate or protein intake and the risk of Crohn’s disease?

Study design:
This review article included 4 case-control studies with a total of 311 Crohn’s disease cases and 660 controls and 5 prospective cohort studies with a total of 238,887 participants and 482 Crohn’s disease cases.

The Egger’s test detected no obvious publication bias in fiber (p = 0.708), while there were not enough studies to conduct the analyses for carbohydrate, fat and protein.

Results and conclusions:
The investigators found no evidence of a non-linear relationship between total carbohydrate intake and Crohn’s disease risk [p for non-linearity = 0.376].

The investigators found no association between 10 g increment/day of total carbohydrate intake and Crohn’s disease risk [RR = 0.991, 95% CI = 0.978-1.004, I2 = 0.0%, p = 0.439]. No association because RR of 1 was found in the 95% CI of 0.978 to 1.004. RR of 1 means no risk/association.

The investigators found no evidence of a non-linear relationship between total fat intake and Crohn’s disease risk [p for non-linearity = 0.281].

The investigators found no association between 10 g increment/day of total fat intake and Crohn’s disease risk [RR = 1.018, 95% CI = 0.969-1.069, I2 = 44.6%, p = 0.125].

The investigators found no evidence of a non-linear relationship between total protein intake and Crohn’s disease risk [p for non-linearity = 0.163].

The investigators found no association between 10 g increment/day of total protein intake and Crohn’s disease risk [RR = 1.029, 95% CI = 0.955-1.109, I2 = 54.7%, p = 0.085].

The investigators found a non-linear relationship between fiber dietary intake and Crohn’s disease risk [p for non-linearity = 0.019].

The investigators found a significant reduced risk of 14.7% for Crohn’s disease for per 10 g increment/day of fiber [RR = 0.853, 95% CI = 0.762-0.955]. However, the protective role of fiber dietary intake in the development of Crohn’s disease was gone after adjustment for the risk factor smoking [RR for per 10 g increment/day = 0.890, 95% CI = 0.776-1.020].

The investigators found a non-linear relationship between sucrose intake and Crohn’s disease risk [p for non-linearity = 0.023].

The investigators found a significant increased risk of 8.8% for Crohn’s disease for per 10 g increment/day of sucrose [RR = 1.088, 95% CI = 1.020-1.160, I2 = 0.0%, p = 0.39]. Significant means it can be said with a 95% confidence that each 10 g increment/day of sucrose really increased the risk of Crohn’s disease. 

The investigators concluded there is a lack of association between total carbohydrate, fat or protein intake and the risk of Crohn’s disease, while high fiber dietary intake might decrease the risk but the association was influenced by study design and smoking adjustment. High sucrose intake might increase the risk of Crohn’s disease. However, large-scale prospective designed studies are needed to confirm these findings.

Original title:
Macronutrient Intake and Risk of Crohn’s Disease: Systematic Review and Dose–Response Meta-Analysis of Epidemiological Studies by Zeng L, Hu S, [...], Tan Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5452230/

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Find more information/studies on fat, protein, carbohydrate and fiber 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

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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

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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:
C-reactive protein (CRP) has been proposed as a risk marker and risk factor of cardiovascular disease. There have been a number of clinical reports suggesting that supplementation with L-carnitine can modulate systemic inflammation and lower circulating CRP concentrations, but the results have not been consistent. Therefore, this review article (meta-analysis) has been conducted.

Does supplementation with L-carnitine reduce circulating CRP concentrations?

Study design:
This review article included 6 RCTs comprising 541 cases and 546 controls.
3 studies were conducted in diabetic or prediabetic patients, 2 studies in hemodialysis patients and 1 study in patients with non-alcoholic steatohepatitis.
Duration of L-carnitine supplementation ranged between 8 to 48 weeks.
Dosage of L-carnitine ranged between 1-2 g/day in all the included trials.

Results and conclusions:
The investigators found in random effect analysis a statistically significant pooled effect size [net change = -0.39 mg/L, 95% CI = -0.62 to -0.16, p = 0.001, I2 = 44%, p = 0.11] for the impact of L-carnitine supplementation among 541 cases and 546 controls. This effect size estimate was found to be robust and remained unaffected by the removal of each single study.

The investigators concluded the present meta-analysis support the clinically relevant benefit of L-carnitine supplementation (1-2 g/day) in lowering the circulating levels of CRP. Conducting future, large-scale, randomized clinical trials is warranted in homogenous populations to verify the findings of this meta-analysis.

Original title:
Effect of L-carnitine Supplementation on Circulating C-reactive Protein Levels: A Systematic Review and Meta-Analysis by Sahebkar A.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4922328/

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Higher circulating levels of CRP increase inflammation.
 

Objectives:
The aim of this review article (meta-analysis) was to assess the clinical efficacy and safety of oral ginger for symptomatic treatment of osteoarthritis (OA).

Study design:
This review article included 5 RCTs with in total 593 patients.

The average age of the patients ranged from 47 years to 66 years and the percentage of women included in the studies ranged from 26% to 80%.
The dose of oral administration of ginger ranged from 500 mg/day to 1000 mg/day.
Trial duration ranged from 3 to 12 weeks.

Results and conclusions:
The investigators found compared to placebo, ginger intake significantly reduced pain [SMD = -0.30, 95% CI = -0.50 to -0.09, p = 0.005, I2 = 27%].

The investigators found compared to placebo, ginger intake showed a statistically significant reduction in disability [SMD = -0.22, 95% CI = -0.39 to -0.04, p = 0.01, I2 = 0%].

The investigators found patients given ginger were more than twice as likely to discontinue (due to adverse events) treatment compared to placebo [RR = 2.33, 95% CI = 1.04 to 5.22, p = 0.04, I2 = 0%].

The investigators concluded that 500-1000 mg/day oral ginger intake is able to reduce pain and disability in osteoarthritis patients.

Original title:
Efficacy and safety of ginger in osteoarthritis patients: a meta-analysis of randomized placebo-controlled trials by Bartels EM, Folmer VN, […], Christensen R.

Link:
http://www.oarsijournal.com/article/S1063-4584(14)01276-X/pdf

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Objectives:
The aim of this review article was to evaluate the diagnostic accuracy of ultrasound in assessing active Crohn’s disease (CD) in adults.

Study design:
This meta-analysis included 15 studies involving 1558 adults with active Crohn’s disease.

Results and conclusions:
The investigators found overall, the pooled sensitivity (0.88) and LR- (0.14) were not heterogeneous, whereas the pooled specificity [0.97, I2 = 72.9%] and LR + [15.10, I2 = 71.8 %] were.

The investigators found the DOR of ultrasound for assessing active CD was 121.70, with significant heterogeneity (I2 = 63.3%).
A symmetrical summary ROC curve was plotted showing that the area under the curve was 0.94, indicating good diagnostic accuracy.

The investigators found meta-regression and subgroup analysis showed that the disease location may be a major cause of heterogeneity.

The investigators concluded ultrasound has high diagnostic accuracy in detecting active Crohn’s disease in adults, especially for small bowel Crohn’s disease.

Original title:
Ultrasound as a diagnostic tool in detecting active Crohn’s disease: a meta-analysis of prospective studies by Dong J, Wang H, [...], Li J.

Link:
http://link.springer.com/article/10.1007/s00330-013-2973-0

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Objectives:
Is there a causal association between low serum vitamin D concentrations, increased body mass index (BMI) and pediatric-onset multiple sclerosis (MS) using genetic risk scores (GRS)?

Study design:
This review article included participants of non-Hispanic white individuals recruited from over 15 sites across the United States (n = 394 cases, 10,875 controls) and Sweden (n = 175 cases, 5,376 controls; total n = 16,820).

Results and conclusions:
The investigators found meta-analysis findings demonstrated that a vitamin D GRS associated with increasing levels of 25(OH)D in serum significantly decreased risk of pediatric-onset MS with 28% [OR =  0.72, 95% CI = 0.55-0.94, p = 0.02] after controlling for sex, genetic ancestry, HLA-DRB1*15:01 and over 100 non-human leukocyte antigen MS risk variants.

The investigators also found that a higher BMI GRS significant increased risk of pediatric-onset MS with 17% [OR = 1.17, 95% CI = 1.05-1.30, p = 0.01] after adjusting for covariates.

The investigators found estimates for each GRS were unchanged when considered together in a multivariable model.

The investigators concluded evidence supporting independent and causal effects of decreased vitamin D levels and increased BMI on susceptibility to pediatric-onset MS.

Original title:
Evidence for a causal relationship between low vitamin D, high BMI, and pediatric-onset MS by Gianfrancesco MA, Stridh P, […], Waubant E.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28356466

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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:
Recent studies have found that the serum zinc levels were associated with the risk of Parkinson's disease (PD), but the results were inconsistent. Therefore, this meta-analysis (review article) has been conducted.

Is there an association between serum zinc levels and Parkinson's disease risk?

Study design:
This review article included 11 articles involving 822 Parkinson's disease patients and 777 healthy controls (subjects without Parkinson's disease).

No publication bias was found.

Results and conclusions:
The investigators found that the serum zinc levels in Parkinson's disease patients were significantly lower than those in health controls [SMD = -0.779, 95% CI = -1.323 to -0.234, p 0.001].

This association was also significant in oriental studies [SMD = -1.601, 95% CI = -2.398 to -0.805, p 0.001].

The investigators concluded that serum zinc levels in Parkinson's disease patients are significantly lower than those in healthy controls.

Original title:
Association Between Serum Zinc Levels and the Risk of Parkinson's Disease: a Meta-Analysis by Sun H, Liu X, […], Li W.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28160244

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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

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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

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Objectives:
Is there an association between folate level and the risk of schizophrenia?

Study design:
This review article included 16 high quality studies with a total of 1,183 (52.1%) cases and 1,089 (47.9%) controls.

There was no publication bias based on Egger’s and Begg’s tests [p = 0.48 and 0.30, respectively].

Results and conclusions:
The investigators found folate level in schizophrenia patients was significantly lower than that in healthy controls [SMD = -0.65, 95% CI = -0.86 to -0.45, p 0.00001].

The investigators found in subgroup analysis a decreased folate level in both Asian and European patients (SMD = -0.86, p 0.00001 and SMD = -0.44, p 0.00001, respectively], while there were no significant differences in patients from other areas [p > 0.05].

The investigators found sensitivity analysis confirmed that these results were stable and reliable.

The investigators concluded decreased folate level is a risk factor for schizophrenia, especially in Asian and European patients. More epidemiological and biochemistry studies are required to describe how folate or folate supplementation play roles in the progress of schizophrenia.

Original title:
Folate Deficiency Increased the Risk of Schizophrenia: a Meta-Analysis by Ding Y, Ju M, […], He L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28124599

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The folate level of the human body can be increased by dietary folate intake and/or taking folate supplements.

Objectives:
Has coenzyme Q10 supplementation lowering effects on inflammatory mediator C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α)?

Study design:
This review article included 17 RCTs.

Results and conclusions:
The investigators found coenzyme Q10 supplementation significantly reduced the levels of circulating CRP with 0.35 mg/L [95% CI = -0.64 to -0.05, p = 0.022].
The results of meta-regression showed that the changes of CRP were independent of baseline CRP, treatment duration, dosage and patients characteristics.

The investigators found coenzyme Q10 supplementation significantly reduced the levels of circulating IL-6 with 1.61 pg/mL [95% CI = -2.64 to -0.58, p = 0.002].
In the meta-regression analyses, a higher baseline IL-6 level was significantly associated with greater effects of coenzyme Q10 on IL-6 levels [p for interaction = 0.006].

The investigators found coenzyme Q10 supplementation significantly reduced the levels of circulating TNF-α with 0.49 pg/mL [95% CI = -0.93 to -0.06, p = 0.027].

The investigators concluded coenzyme Q10 supplementation has lowering effects on CRP, IL-6 and TNF-α. However, these results should be interpreted with caution because of evidence of heterogeneity between studies and limited number of studies.

Original title:
Effects of coenzyme Q10 supplementation on inflammatory markers: A systematic review and meta-analysis of randomized controlled trials by Fan L, Feng Y, […], Chen LH.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28179205

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Objectives:
The associations between dietary zinc and iron intake and risk of depression remain controversial. Therefore, this meta-analysis (systematic review) has been conducted.

Do dietary zink and iron intake decrease risk of depression?

Study design:
This review article included a total of 9 studies for dietary zinc intake and 3 studies for dietary iron intake. 

Results and conclusions:
The investigators found for the highest versus lowest dietary zinc a significant reduced risk of 33% [pooled RR = 0.67, 95% CI = 0.58-0.76] for depression.

The investigators found for the highest versus lowest dietary iron a significant reduced risk of 43% [pooled RR = 0.57, 95% CI = 0.34-0.95] for depression.

The investigators found in subgroup analysis by study design, the inverse association between dietary zinc intake and risk of depression remained significant in cohort studies and cross-sectional studies.

The investigators found the pooled RRs (95% CIs) for depression did not substantially change in the influence analysis and subgroup analysis by adjustment for body mass index (BMI).

The investigators concluded dietary zinc intake reduces risk of depression.

Original title:
Dietary zinc and iron intake and risk of depression: A meta-analysis by Li Z, Li B, [...], Zhang D.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28189077

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Objectives:
Arthritis patients often take fish oil supplements to alleviate symptoms, but limited evidence exists regarding their efficacy. Therefore, this meta-analysis (systematic review) has been conducted.

Do taking marine oil supplements alleviate pain in arthritis patients?

Study design:
This review article included 42 randomized trials; 30 trials reported complete data on pain.

The trials used treatment durations from 2 weeks to 18 months, with doses of EPA from 0.013 to 4.050 g/day and doses of DHA from 0.010 to 2.700 g/day.
Most trials used marine oil from whole fish, but some used cod liver oil, mussel extracts, seal oil and krill oil.

The trials included 2751 patients with a mean age of 53.8 years (range of mean age of 10-68 years) and the mean disease duration was 9.7 years (range 2.3-19.0 years).

Results and conclusions:
The investigators found a favorable effect [SMD = -0.24, 95% CI = -0.42 to -0.07, I2 = 63%] for using marine oil supplements.

The investigators found in 22 trials a significant effect in patients with rheumatoid arthritis [SMD = -0.21, 95% CI = -0.42 to -0.004] for using marine oil supplements.

The investigators also found in 3 trials a significant effect for other or mixed diagnoses [SMD = -0.63, 95% CI = -1.20 to -0.06] for using marine oil supplements, but no significant effect was found in osteoarthritis patients [5 trials: SMD = -0.17, 95% CI = -0.57 to 0.24].

The investigators found a significant, beneficial effect on pain for marine oil with an EPA/DHA ratio >1.5.

The investigators found a significant positive association between SMD and total dose of EPA and DHA [slope β, 0.13 (g/day), 95% CI = 0.04 to 0.22, p = 0.006], indicating less effect at higher dose, but there was no duration-response relationship [p = 0.568].

The investigators concluded using marine oil supplements (with an EPA/DHA ratio >1.5) alleviates pain in rheumatoid arthritis patients.

Original title:
Marine Oil Supplements for Arthritis Pain: A Systematic Review and Meta-Analysis of Randomized Trials by Senftleber NK, Nielsen SM, […], Christensen R.

Link:
http://www.mdpi.com/2072-6643/9/1/42/htm

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Find here more information/studies about EPA&DHA and chronic diseases.

Objectives:
The role of vitamin D status in the etiology of allergic diseases is uncertain. Therefore, this meta-analysis (systematic review) has been conducted.

Study design:
This review article included a total of 21 observational studies.

Results and conclusions:
The investigators found children with serum 25(OH)D ≥75 nmol/L had significantly reduced odds of aeroallergen sensitization, but neither vitamin D intake during pregnancy nor vitamin D supplementation in infancy were associated with risk of allergic rhinitis.

The investigators found compared to those with serum 25(OH)D 50 nmol/L, individuals with serum 25(OH)D ≥75 nmol/L had a significant decreased risk of 29% [OR = 0.71, 95% CI = 0.56-0.89, p = 0.04] for allergic rhinitis.
However, this association was mainly observed in adult men; prevalence of allergic rhinitis (AR) was lower in men with serum 25(OH)D ≥75 nmol/L compared to men with serum 25(OH)D 50 nmol/L, while this association was not observed in women.

The investigators concluded serum 25(OH)D ≥75 nmol/L reduced odds of aeroallergen sensitization in children and risk of allergic rhinitis in men.

Original title:
Vitamin D status, aeroallergen sensitization, and allergic rhinitis: A systematic review and meta-analysis by Aryan Z, Rezaei N and Camargo CA Jr.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28102718

Additional information of El Mondo:
Find here more information/studies about vitamin D and chronic diseases.