Effects of Ramadan intermittent fasting on lipid and lipoprotein parameters: An updated meta-analysis

Aims This systematic review and meta-analysis aimed to clarify several aspects of intermittent fasting during the month of Ramadan on lipid and lipoprotein levels in apparently healthy subjects. Data synthesis We searched PubMed, Scopus, and Embase databases and the reference lists of previous reviews, up to Feb 2019 for studies that investigated the effects of Ramadan fasting on fasting levels of triglycerides (TG), total cholesterol (TC), HDL-C, LDL-C, and VLDL-C among healthy subjects including pregnant women and athletic subjects. Studies were selected for quality assessment, meta-analyses, subgroup analyses, and meta-regressions; data of 33 eligible studies, conducted between 1978 and 2019, were included in the analysis. Results Intermittent fasting showed no significant effect on circulating TG (WMD = −0.38 mg/dl, 95% CI = −5.33, 4.57), TC (WMD = −1.58 mg/dl, 95% CI = −6.04, 2.88), and LDL-C levels (WMD = 1.85 mg/dl, 95% CI = 0.77, 2.92). Overall, HDL-C (WMD = −2.97 mg/dl; 95% CI = −6.43, 0.48 mg/dl) and VLDL-C (WMD = −1.41 mg/dl; 95% CI = −2.73, −0.10 mg/dl) significantly decreased after Ramadan fasting. A significant increase in LDL-C levels was observed in athletic subjects (WMD = 2.97 mg/dl; 95% CI = 0.80, 5.13) and apparently healthy subjects (WMD = 1.81 mg/dl; 95% CI = 0.55, 3.07). Change in TG levels was associated with age (β = −0.94, P = 0.043), its baseline values (β = −0.44, P = 0.001), and weight change during the fasting period (β = −0.57, P = 0.032). Conclusion Ramadan fasting may be accompanied by a moderate improvement of lipid and lipoprotein parameters, especially HDL-C levels; fasting appears to be more beneficial for men and athletic subjects.