Background
Low-density lipoprotein cholesterol (LDL-C) predicts heart disease onset and may be reduced by intermittent fasting. Some studies, though, reported that fasting increased LDL-C; however, no study evaluated LDL-C as the primary endpoint. This randomized controlled trial evaluated the effect of low-frequency intermittent fasting on LDL-C and other biomarkers.
Methods
Adults ages 21-70 years were enrolled who were not taking a statin, had modestly elevated LDL-C, had ≥1 metabolic syndrome feature or type 2 diabetes, and were not taking anti-diabetic medication (N = 103). Water-only 24-hour fasting was performed twice-weekly for 4 weeks, then once-weekly for 22 weeks; controls ate ad libitum. The primary outcome was 26-week LDL-C change score. Secondary outcomes (requiring p ≤ 0.01) were 26-week changes in homeostatic model assessment of insulin resistance (HOMA-IR), Metabolic Syndrome Score (MSS), brain-derived neurotrophic factor (BDNF), and MicroCog general cognitive proficiency index (GCPi).
Results
Intermittent fasting (n = 50) and control (n = 53) subjects were, respectively, aged 49.3±12.0 and 47.0±9.8 years, predominantly female (66.0% & 67.9%), overweight (103±24 & 100±21 kg), and had modest LDL-C elevation (124±19 & 128±20 mg/dL). Drop-outs (n = 12 fasting, n = 20 control) provided an evaluable sample of n = 71 (n = 38 fasting, n = 33 control). Intermittent fasting did not change LDL-C (0.2±16.7 mg/dL) versus control (2.5±19.4 mg/dL; p = 0.59), but it improved HOMA-IR (-0.75±0.79 vs. -0.10±1.06; p = 0.004) and MSS (-0.34±4.72 vs. 0.31±1.98, p = 0.006). BDNF (p = 0.58), GCPi (p = 0.17), and weight (-1.7±4.7 kg vs. 0.2±3.5 kg, p = 0.06) were unchanged.
Conclusions
A low-frequency intermittent fasting regimen did not reduce LDL-C or improve cognitive function, but significantly reduced both HOMA-IR and MSS.
Trial registration
clinicaltrials.gov, NCT02770313