DIURNAL CHANGES IN PLASMA-LIPOPROTEINS OF FREE-LIVING HEALTHY-MEN CONSUMING A STANDARD DIET

Although it is well established that plasma lipoproteins are involved in atherogenesis, most patients with coronary heart disease have norma l or nearly normal fasting plasma lipid and lipoprotein levels. As mos t of the human life is spent in the fed state we elected to investigat e the changes occurring in plasma lipids and lipoproteins during norma l daily activities. We studied 12 healthy, normolipidemic and non-obes e subjects on a standard diet divided into three meals and three snack s. This method was found to be accurate and reproducible in four subje cts who underwent repeated studies. The major diurnal changes were obs erved in plasma triglyceride level and in the composition of plasma li poproteins. The degree and pattern of these changes differed among sub jects but was specific and constant for each individual. The extent of these diurnal changes, which correlated positively with fasting plasm a triglyceride and inversely with plasma HDL(2) levels, may play an im portant role in the pathogenesis of atherosclerosis.