It has been a general, long-held belief that alcohol consumption, in any form, in any quantity, raises blood pressure, and, therefore, many of those at risk have been advised simply not to drink at all. It is not so simple. Who drinks, and what they drink, and how much, and in what pattern all appear to demand accounting.

Cardiovascular disease in young adults, especially women, has not been as well studied as it has in older people, perhaps in large part because it mostly only becomes apparent among middle-aged and older men and older women. Some authorities have minimized the beneficial cardiovascular effects of moderate drinking on the young because the pay off does not become apparent until later in life, shortsighted in the face of evidence of the many years of insidious incubation required for these afflictions.

A recently published large, detailed project has helped illuminate and stimulate by studying the effects of alcohol consumption on the blood pressure of 70,891 women 25 to 42 years of age, part of the seminal Nurses’ Health Study (Thadhani, et al.: Archives of Internal Medicine, March 11, 2002).

The investigators found that "the association between alcohol intake and risk of hypertension followed a J-shaped curve," that is, modest drinkers were less bothered by blood pressure than abstainers, and heavier drinkers had the highest blood pressures–a most familiar relationship.

The specific results that follow are the relative risks (compared to abstainers), adjusted for other major risk factors namely: age, body mass index, race, smoking, cholesterol level, family history of hypertension, physical activity and oral contraceptive use. Women who averaged less than 0.25 drink per day have nearly the same risk of hypertension as abstainers. Those who consumed on average 0.26-0.50 drinks per day have a 14 percent lower risk; 0.51-1.00 drinks gives an 8 percent risk reduction as compared with abstainers. The risks equalize at 1.01-1.50 drinks per day, and climb to 20 and 30 percent higher at the ranges 1.51-2.00 and greater than 2.00 drinks per day, respectively. (One might suppose that it would take appreciably more alcohol to bring about similar effects in men, because men neutralize alcohol more effectively than do women.)

The type of beverage seems to matter little, though there was a suggestion that light drinking of beer may be particularly associated with reduced risk of hypertension, but note the influence of antioxidants commented on below.

The pattern of drinking does appear to matter. Episodic consumption of more than 1.5 drinks per day does not increase the risk of elevating blood pressure, whereas the risk does rise among women with this level of consumption for at least five days per week. This sort of effect has been noted by others, and is one of the factors making the drinking/blood pressure relationship difficult to study.

Stimulated by the Thadhani report, I surveyed and reviewed pertinent medical literature applying to both sexes. Excessive alcohol has been held responsible for ten percent of all cases of hypertension by some epidemiologists. Physicians discovering elevated blood pressure are obligated to inquire into drinking habits, and advise accordingly.

Reduction of alcohol consumption to moderate levels often leads to substantial reduction of the high blood pressure. The benefit derived from moderation may add to other therapeutic efforts, such as weight loss. Heavy drinking is associated with hypertension, although the mechanism or mechanisms still need elucidation. They are doubtlessly complex, and may act so differently under different conditions that they may appear contradictory.

Randin, et al., and Victor and Hansen have investigated and pondered on, respectively, aspects of how alcohol might influence blood pressure (New England Journal of Finkel: BP 3 Medicine, June 29, 1995). Alcohol is thought to stimulate the release of cortiotropin-releasing hormone from the brain. This hormone (and alcohol)excites the sympathetic nervous system, thus increasing heart rate and cardiac output. These are short-term effects, so should not at this time be used as the basis for broad conclusions. Alcohol may sensitize blood vessels to other factors that raise blood pressure under certain conditions.

The blood pressure rise from alcohol administration is delayed, occurring when blood levels of alcohol are decreasing. It was speculated that it was breakdown products of alcohol, such as acetaldehyde, that were working, or that time was required for the hormonal effects to develop.

Hypertensives are regularly advised to abstain, but evidence is strong that no harm comes to them, assuming reasonable control of blood pressure, from moderate drinking. Certainly a glass of wine daily for women and two for men have been repeatedly demonstrated as not only harmless, but providing the same cardiovascular benefits we all derive to a group that needs them even more than the rest of us.

The polyphenolic antioxidants of wine help relax blood vessels and hence lower blood pressure. The J-shaped curve rules.

In a rather severe test of wine’s effect upon blood pressure, Foppa, et al., (Journal of Studies on Alcohol , March, 2002) had obese hypertensive individuals drink red wine with their noon meal, and found a fall in blood pressure that lasted all day. Diebolt, et al., (Hypertension, August, 2001) fed red-wine polyphenols to normotensive rats, and demonstrated a decrease in blood pressure and more relaxed, healthier blood vessel walls. Fruit and vegetable antioxidants have been reported associated with reduction in blood pressure (John, et al.: Lancet, June 8, 2002). Red wine, even when emasculated by removal of its alcohol, leads to relaxation of blood vessel walls (Hashimoto, et al.: American Journal of Cardiology, December 15, 2001).

What is our take-home message?

First, I would urge perusal of the list of major cardiovascular risk factors in the fifth paragraph, to which add blood pressure and excessive drinking, and attempt to correct those that require and are susceptible to correction.

Second, obtain individualized advice from your individual physician. Have your blood pressure checked: it may be dangerously high without causing trouble...yet. If your blood pressure is elevated, you may need medicine, which is highly likely to work well.

Third, with very rare exception, you need not fear enjoying wine in moderation; it is likely to do you good.

Harvey E. Finkel, M.D. is clinical professor at Boston University Medical Center and writes and lectures internationally on the influences of alcohol upon health. He is member of the AIM Social , Scientific and Medical Counsel.