Excessive alcohol consumption is directly linked to liver disease, heart disease and addiction, according to decades of medical literature, but an increasing number of studies indicate that moderate use of alcohol may actually lower the risk in otherwise healthy individuals. At issue is the correlation between cholesterol levels and alcohol intake. Some studies show a potentially positive impact while others indicate that genetic factors may be at play.
Types of Cholesterol
Low-density lipoprotein, or LDL, is known as "bad" cholesterol because it can build up in the arterial walls, reducing their elasticity and narrowing the opening through which blood must flow. This raises the risk of a full or partial blockage that causes a heart attack.
High-density lipoprotein, or HDL, is "good" cholesterol. Studies show that HDL carries cholesterol away from the arteries to the liver, where it can be processed and passed out of the body.
Acceptable Levels
Total cholesterol is a combination of HDL, LDL and triglyceride levels. Optimal LDL concentrations are below 100 mg/dL. Dangerous levels begin at 130 mg/dL, which is termed "borderline high" by the American Heart Association, and they can rise as high as 500 mg/dL. Your target level depends on your other risk factors such as diabetes or a history of heart disease in your family.
Genetics
The connection between alcohol consumption and LDL remains unclear and could owe more to genetic factors already present in drinkers rather than the drinking of alcohol itself. The apolipoprotein E gene, or APOE, may be a more direct indicator of the effects of alcohol consumption on LDL cholesterol. According to researcher Dolores Corella and colleagues in a study of more than 2000 men and women published in the "American Journal of Clinical Nutrition," male drinkers with a certain APOE variant, or E2 allele, had lower LDL levels than those with the APOE variant E4 allele. The study cast doubt on the direct influence of alcohol on LDL levels and instead suggested that genetics exerted a powerful influence on levels that behavior couldn't overcome.
Contradictory Evidence
Alcohol raises triglycerides, which increases risk of liver disorders, heart disease and stroke, according to the National Heart, Lung and Blood institute, or NHLBI. It also raises HDL cholesterol levels, which lowers the risk of such outcomes. However, there is no indication that alcohol alone lowers LDL cholesterol while raising HDL cholesterol, so the use of alcohol as a means of preventing heart attack or stroke is not recommended, says the NHLBI. Alcohol consumption in those without other risk factors, such as already high levels of LDL, do tend to lower their risk of heart disease in general; but drinkers with high LDL cholesterol levels dramatically increase their risk. This suggests that alcohol has positive effects on risk generally but little correlation to the most dangerous risk factors individually.
Alcohol Withdrawal
Heavy drinkers who abstained from drinking during a four-week study conducted by Japanese researcher Makato Ayaori and colleagues and published in the journal, "Arteriosclerosis, Thrombosis, and Vascular Biology" lowered their risk of heart disease because of the effect of alcohol withdrawal on LDL particle size. Compared to a control group that continued heavy consumption of alcohol, the abstainers shifted the diameter of the LDL particles in their blood from smaller to larger, improving the overall LDL profile and reducing the oxidative properties associated with small, dense LDL particles. Oxidation occurs when electrons break free from the molecule, causing cell damage.
References
- American Heart Association: Good Cholesterol vs. Bad Cholesterol
- "American Journal of Clinical Nutrition"; Alcohol Drinking Determines the Effect of the APOE Locus on LDL ...; Dolores Corella, et al.; April 2001.
- Nutrition Research Newsletter: Alcohol, LDL and Heart Disease
- "Arteriosclerosis, Thrombosis and Vascular Biology"; Beneficial Effects of Alcohol Withdrawal on LDL Particle Size ...; Makoto Ayaori, et al.; 1997.
- National Heart, Lung and Blood Institute: What Makes Your Cholesterol High or Low
