Heart disease risk is directly associated with elevated total cholesterol, but more specifically with low levels of "good" cholesterol, or HDL, coupled with high levels of "bad" cholesterol, or LDL. High levels of "good" cholesterol, on the other hand, reduce the overall risk of heart disease, and according to some studies, alcohol consumption helps to raise HDL levels in the blood. The exact mechanism by which this happens is a point of debate, and the benefit of raising HDL via alcohol consumption comes with the negative impact of excessive alcohol use on overall health outcomes.
Types of Cholesterol
Cholesterol is a fat soluble molecule transported through the blood by lipoproteins. Low-density lipoproteins, or LDL, adhere to the inner walls of the arteries causing plaque buildup, which decreases blood flow and increases the risk for a cardiac event. High-density lipoproteins, or HDL, carry cholesterol to the liver, where it is processed and excreted from the body.
Drinking for Health
The American Heart Association cautions non-drinkers that the data confirming alcohol's positive impacts on health outcomes do not outweigh the negative effects of alcohol consumption, and there are many more positive ways to impact overall health than turning to alcohol. For those who already drink alcohol, the AHA recommends no more than one drink per day for women or two drinks per day for men. Despite the mounting data supporting a link between moderate alcohol consumption and increased levels of HDL cholesterol, the AHA maintains that physical activity and other antioxidants found in fruits and vegetables can have just as great an impact without the associated risk.
Observational Studies
Observational studies, which effectively demonstrate correlation but cannot make assumptions about causation, have consistently demonstrated the link between moderate alcohol use and higher levels of HDL. However, these studies have also had difficulty establishing the point at which alcohol consumption turns from a net positive to a net negative with respect to overall health outcomes.
Binging
In 2010, lead researcher Michael Roerecke of the Center for Addiction and Mental Health in Toronto, attempted to define this line by pooling the data from 14 previous observational studies on the link between HDL and alcohol consumption. Roerecke found that moderate drinkers who occasionally raised their alcohol intake to at least five drinks in a day, a dozen or so times per year, raised their risk of cardiac events by 45 percent compared to a control sample that maintained steady but moderate use. Consistently heavy drinkers, who are thought to be at increased risk of heart disease no matter what the effect on HDL, were screened out of the sample.
Mechanisms
While studies investigating the means by which alcohol increases HDL have been inconclusive or even contradictory, a survey conducted by Dr. Elizabeth R. De Oliveira e Silva and colleagues found a correlation between alcohol dosing and the transport rate of certain associated lipoproteins, apoA-1 and apoA-2. Two groups were fed identical diets comprised of 15 percent protein, 43 percent carbohydrate and 42 percent fat that are typical in Western society. The control group ate a food-based diet while the study group replaced varying percentages of carbohydrate calories with alcohol. As in previous studies, the alcohol group showed statistically significant increases in HDL levels. The survey, published in the journal, "Circulation," concluded that the benefit was due to the 10 percent increase in apoA-1 and 17 percent increase in apoA-2. The increases were dose dependent with the participants who consumed the least amount of alcohol realizing the least benefit.
