EFFECT OF NIBBLING VERSUS GORGING ON CARDIOVASCULAR RISK-FACTORS - SERUM URIC-ACID AND BLOOD-LIPIDS

Nibbling has been reported to decrease serum cholesterol under fasting conditions, as well as the incidence of cardiovascular disease. It ha s been suggested that these effects are partly attributable to reduced concentrations of serum insulin, which are also observed. However, da ta on the effects of nibbling on serum lipids throughout the day are n ot available, nor is it known how nibbling affects serum uric acid as a further insulin-related risk factor for cardiovascular disease. We h ave attempted to address these issues. Seven healthy men consumed iden tical diets in a randomized crossover design either as three meals dai ly (control) or as 17 meals daily (nibbling) for 2 weeks. On day 13, s erum lipid levels were measured over the course of the day (12 hours) together with the 24-hour urinary excretion of mevalonic acid as an in dicator of hepatic cholesterol synthesis. Concentrations of uric acid in serum and 24-hour urinary excretion of uric acid were also determin ed. Mean (+/-SE) percent treatment differences in day-long total, low- density lipoprotein (LDL), and non-high-density lipoprotein (HDL) chol esterol, and apolipoprotein (ape) B were significant, with lower value s on the nibbling diet as compared with the control diet (8.1% +/- 1.6 %, P = .002; 12.2% +/- 2.6%, P = .005; 10.1% +/- 1.6%, P < .001; and 9 .9% +/- 2.6%, P = .008, respectively). No significant difference was s een in the total to HDL cholesterol ratio or in urinary mevalonic acid excretion. However, the percent difference between treatments in tota l cholesterol levels was directly related to the percent difference in urinary mevalonic acid excretion (r = .94, P = .005, n = 6). The mean fasting concentration of uric acid was significantly lower during the nibbling period as compared with the three-meal period (5.8% +/- 1.8% , P = .019). Urinary uric acid excretion was also increased on nibblin g (26.3% +/- 7.9%, P = .021), and the treatment difference related to the reduction in serum insulin over the day (r = -.83, P = .041). We c onclude that spreading the nutrient load over time reduces serum risk factors for cardiovascular disease. Our results suggest that these eff ects may be partly due to lower serum insulin concentrations. Lower in sulin concentrations may lead to increased urinary uric acid excretion and possibly reduced hepatic cholesterol synthesis, since the treatme nt difference in urinary mevalonic acid excretion, although nonsignifi cant, related significantly to the treatment difference in serum chole sterol. Copyright (c) 1995 by W.B. Saunders Company