Effect of meal timing on the diurnal rhythm of human cholesterol
synthesis.
Cella, Lynn Kessler, Eve Van Cauter, Dale A. Schoeller.
Committee for Human Nutrition and Nutritional Biology and
Department of Medicine, University of Chicago, Chicago, Illinois
60637
APStracts 2:0125E, 1995.
To test whether the diurnal rhythm of cholesterol synthesis in humans
is entrained to meal timing, the effect of a 6.5-h delay of mealtimes
was investigated in four normolipemic male subjects. Cholesterol
fractional synthetic rate was measured by deuterium incorporation
from body water using blood sampling every 2h. The baseline was a 24
-hour control period in which 3 Western-style meals were consumed at
0700, 1150, and 1640 h, followed by three days in which meals were
delayed by 6.5 h, i.e. meals consumed at 1330, 1820, and 2310 h,
without changing the sleep-wake and light-dark cycles. Cholesterol
synthesis was maximal at 2200+/-0200 h and minimal at 1130+/-0050 h
on the baseline day. On Day 1 of the shifted meals, the maximum was
delayed 6.0+/-0.5 h, and the nadir was not changed. On Day 3, the
maximum was delayed 8.6+/-3.7 h and the minimum was delayed 6.5+/-2.4
h from baseline. The mean amplitude of the cholesterol rhythm was
significantly greater on Day 3, 233+/-35%, compared to baseline which
was 109+/-15%. A strong negative correlation (r = -0.66+/-0.10) was
found between the rhythms of cholesterol synthesis and cortisol
during the baseline day, but there was a phase delay in the rhythm of
cholesterol synthesis relative to cortisol on Day 1 and Day 3.
Findings indicate that the 24-hour variation in cholesterol synthesis
is strongly dependent on meal timing.
Received 4 January 1995; accepted in final form 26 May 1995.
APS Manuscript Number E001-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 June 1995.