Coffee Intake and Serum Lipids in Men

Abstract

To the Editor.— Williams et al 1 report a significant elevation in plasma apolipoprotein B associated with coffee intake in excess of two cups per day. The authors also reported that low-density lipoprotein (LDL) cholesterol levels were somewhat elevated while total plasma cholesterol levels correlated poorly with coffee intake. It is unfortunate that other caffeinecontaining substances could not be fully evaluated, for caffeine would appear to be the causative agent involved. Methylxanthines, such as caffeine, are inhibitors of 3′,5′-phosphodiesterase. Caffeine administration, therefore, may result in elevated cyclic adenosine monophosphate levels within adipocytes, thereby prolonging lipolysis initiated under normal metabolic demands. Upon liberation from the adipocyte, fatty acids are transported to the liver, where they are reesterified and the resultant triglycerides packaged for release in very-low-density lipoprotein (VLDL), which also contains apolipoprotein B. Catabolism of VLDL triglycerides results in the production of an intermediate, which accepts cholesterol esters, ultimately becoming LDL.