The effect of calcium supplement intake on lipid profile: a systematic review and meta-analysis of randomized controlled clinical trials.

Despite the potential role of dietary calcium in fat excretion, the favorable effects of calcium supplements on lipid profile remains inconclusive. The current study aimed to review the effect of calcium supplement intake on lipid profile in randomized controlled clinical trials (RCTs). This systematic review and meta-analysis was conducted in PubMed, Scopus, Embase, and Central. RCTs which assessed the effects of calcium supplementation on lipid profile were included. All outcomes were recorded as continuous variables, and the effect size was measured. We classified studies according to dose of supplement, study duration, and dyslipidemia. Calcium supplement intake was associated with a significant reduction in low density lipoprotein cholesterol (LDL-C) level (WMD:-0.08; 95%CI:-0.16,-0.01)(mmol/l), especially with intakes of at least 1000 mg/day (WMD:-0.13; 95%CI:-0.23,-0.03)(mmol/l), with intakes of at least 12 weeks (WMD:-0.08; 95%CI: -0.16,-0.00)(mmol/l), and in individuals without dyslipidemia (WMD:-0.15; 95%CI:-0.26,-0.04)(mmol/l). Also, in another subgroup analysis, consumption of less than 1000 mg/day calcium supplement caused a significant increase in Total Cholesterol (TC) level (WMD: 0.24; 95%CI: 0.05,0.42) (mmol/l). In other blood lipids or study subgroups we observed no significant effect. We concluded that calcium supplements had a favorable effect on LDL-C level, especially in individuals without dyslipidemia, higher calcium intakes, and longer period of consumption.

No adverse effects of dairy products on lipid profile: A systematic review and meta-analysis of randomized controlled clinical trials.

BACKGROUND AND AIMS: The current study aimed to review the effects of dairy foods on lipid profile in randomized controlled clinical trials (RCTs). METHODS: We searched PubMed, Scopus, Embase, and Central. RCTs that assess the effects of dairy foods on lipid profile were included. RESULTS: The overall effects of dairy foods on lipid profile were non-significant. Dairy foods were associated with a non-significant reduction in triacylglycerol level, and a non-significant increase in total cholesterol, low density lipoprotein cholesterol, and high-density lipoprotein cholesterol level. CONCLUSION: We conclude that dairy foods doesn't have any unfavorable effects on lipids.

Effects of Conjugated Linoleic Acid Intake in the Form of Dietary Supplement or Enriched Food on C-Reactive Protein and Lipoprotein (a) Levels in Humans: A Literature Review and Meta-Analysis.

BACKGROUND: C-reactive protein (CRP) and lipoprotein (a) (Lp[a]) play essential roles in cardiovascular disease incidence. This study aimed to review the association between the intake of conjugated linoleic acid (CLA) in the form of dietary supplement or enriched food with different treatment durations and the levels of Lp(a) and CRP in human studies. METHODS: All the articles published in Cochrane Library, ProQuest, Scopus, and Google Scholar from November 2014 to October 2015 were searched and the clinical trials on the effects of CLA on Lp(a) and CRP levels were assessed. Of the 2249 articles initially retrieved, 21 eligible randomized clinical trials were enrolled in this systematic review. The publication dates of the eligible articles ranged from 2005 to 2013. The mean difference and the standard deviation of changes in CRP and Lp(a) levels in intervention and control groups were used as effect-size measures for meta-analysis. The obtained data from the eligible randomized controlled trials were meta-analyzed using Stata, version 13. RESULTS: The intake of CLA as a dietary supplement led to a significant increase in CRP levels (standardized mean difference [SMD]=0.41, 95% CI: 0.28 to 0.54; P=0.001). Subgroup analysis based on the duration of CLA consumption showed that CLA consumption more than 24 weeks resulted in a significant increase in the levels of CRP (SMD=0.52, 95% CI: 0.36 to 0.68; P=0.001) and Lp(a) (SMD=0.24, 95% CI: 0.01 to 0.47; P=0.04). CONCLUSION: The current systematic review and meta-analysis showed that the long-term consumption of CLA increases the levels of CRP and Lp(a).

Effect of Conjugated Linoleic Acid as a Supplement or Enrichment in Foods on Blood Glucose and Waist Circumference in Humans: A Metaanalysis.

BACKGROUND: Controversy persists regarding the effect of mixtures of conjugated linoleic acids (c9, t11- and t10, c12-CLA) in fasting blood glucose (FBG) and waist circumference (WC) in humans. OBJECTIVE: The aim of this meta-analysis is to explore the effect of CLA on FBG and WC. METHOD: PubMed, Google Scholar, Cochrane Library, Science Direct, Pro-Quest and Ovid were searched up to January 2015. Studies that examined the effect of CLA supplementation or foods enriched with CLA on FBG and WC in healthy adults were included. Studies in animals or unhealthy individuals and studies other than clinical trials were excluded. Of the 3,095 articles initially retrieved, 32 eligible randomized clinical trials were included in this systematic review. The mean difference and standard deviation of changes in FBG and WC in the intervention and control groups were used as effect size measures for the meta-analysis. RESULTS: Subgroup analysis showed that CLA supplement consumption did not significantly influence FBG (standardized mean differences [SMD] = 0.075 mg/dL; 95% confidence interval (CI) = -0.099 to 0.249; p = 0.399) or WC (SMD = -0.149 cm; 95% CI = -0.522 to 0.225; p = 0.435). Foods enriched in CLA also showed no significant effect on FBG (SMD = 0.126 mg/dL; 95% CI = -0.100 to 0.352; p = 0.274) or WC (SMD = -0.233 cm; 95% CI = -0.625 to 0.159; p = 0.244). CONCLUSION: We conclude that c9, t11- and t10, c12-CLA administered as a supplement or used to enrich foods does not affect FBG or WC in humans.

Association of conjugated linoleic acid consumption and liver enzymes in human studies: A systematic review and meta-analysis of randomized controlled clinical trials.

OBJECTIVE: The aim of this study was to systematically review the association of conjugated linoleic acid (CLA) consumption in two forms of foods enriched or supplemented with CLA on serum liver enzymes in human studies. METHODS: We searched PubMed, Google Scholar, Cochrane Library, ScienceDirect, ProQuest, and Ovid up to January 2015. Studies that examined the effect of CLA supplementation or foods enriched with CLA on liver enzymes concentrations among healthy adults were included. The mean difference and SD of changes in serum liver enzymes between the intervention and control groups were used as effect size for the meta-analysis. RESULTS: The analysis demonstrated that CLA supplementation led to slight and nonsignificant decreases in alkaline phosphatase (ALP) levels (mean difference [MD] -0.216; 95% confidence interval [CI], -0.60 to 0.17; P = 0.28). CLA intake can nonsignificantly increase alanine transaminase (ALT) levels (MD = 0.107 U/L; 95% CI, -0.29 to 0.244; P = 0.124) and can significantly increase aspartate aminotransferase (AST) levels (MD = 0.171 U/L; 95% CI, 0.034-0.307; P = 0.01). Subgroup analysis based on CLA source showed that CLA supplementation or foods enriched with CLA did not significantly alter ALT levels. Subgroup analysis showed that CLA supplementation led to significant increases in AST levels (MD = 0.224 U/L; 95% CI, 0.071-0.376; P = 0.004). However, foods enriched with CLA did not have any significant effects on AST levels. CONCLUSION: CLA supplementation was associated with a significantly increased circulating AST without any significant effect on ALP and ALT levels. Prospective studies are necessary to assess the clinical outcomes of the association between CLA and liver enzyme concentrations.