Alcohol-induced changes in serum lipoproteins and in their metabolism.

The effects of alcohol intake on serum lipids and lipoproteins depend on the dose and mode of alcohol intake, individual susceptibility, genetic variables, and dietary factors. Therefore the changes of lipoprotein pattern are different among moderate and heavy drinkers. Moderate intake of alcohol increases the concentrations of apolipoproteins (apo) AI, apo AII, and high-density lipoprotein subfraction (HDL3) in plasma without any effects on other lipoproteins. If alcohol intake exceeds 60 to 80 gm per day, the synthesis of very low-density lipoprotein (VLDL) particles is stimulated. Even short-term use of alcohol stimulates lipoprotein lipase (LPL) activity in adipose tissue, and consequently the concentration of VLDL in plasma stays normal or is even subnormal. If alcohol intake continues in excessive amounts, the increased transport rate of VLDL particles as a result of high LPL activity results in the up regulation of HDL2. This is clearly evident in chronic alcoholics. Low or subnormal low-density lipoprotein (LDL) levels are another characteristic of the lipoprotein pattern in chronic alcoholics. The increase of HDL (HDL2) and reduction of LDL levels could well explain the reduced risk of coronary heart disease in chronic alcoholics, whereas the causal factors remain open among moderate drinkers.