Hypercholesterolaemia of prolonged fasting and cholesterol lowering of re-feeding in lean human subjects

Serum cholesterol and triglycerides were determined in 36 lean, healthy adults (mean body mass index = 24.3 +/- 0.4 kg m-2) during a period of fasting of 7-21 days. Fasting for 1 week resulted in significant elevation of serum cholesterol (mean increase 25%, range 0-68) and triglycerides (mean increase 24%). No correlation was observed between pre-fast cholesterol level and fasting-induced hypercholesterolaemia. Continued fasting for up to 21 days resulted in lowering of both cholesterol and triglycerides to pre-fast levels. One week of hypocaloric re-feeding resulted in significantly lower than pre-fast cholesterol (mean decrease 13%) and significantly higher than prefast triglycerides (mean increase 86%). The net change in serum cholesterol observed as a result of fasting and re-feeding correlated with prefast cholesterol (r = -0.6901, p = 0.0001). No significant change in the ratio of unesterified cholesterol to total cholesterol was observed during fasting. Fasting for 3 weeks followed by 1 week of hypocaloric re-feeding, however, resulted in a significant (p = 0.05) increase in this ratio from 0.27 +/- 0.0057 to 0.34 +/- 0.01. Fasting for 1 or 2 weeks followed by re-feeding also resulted in a similar increase in the ratio of unesterified cholesterol to total cholesterol. Cholesterol in the HDL fraction remained within normal range throughout the fasting and re-feeding period, with no significant changes between time points.