When people develop hypertension, they may cut back on salt, try to lose weight, stop smoking, start exercising, reduce stress, lower intake of cholesterol and fat, and, if they are really knowledgeable, restrict their intake of sugar. If none of this works, they then decide the problem must be hereditary and resort to drugs. But while making all these life style changes, it never occurs to them to eliminate or cut back on alcohol because it never occurs to them that alcohol could be the culprit.
The relationship between alcohol and hypertension was first recognized in 1915 when a French physician named Lian reported alcoholism as a cause of hypertension in French service men. More than 50 years would go by before there was sufficient scientific evidence to confirm Lian's observation. There is now no question that consumption of three or more drinks of alcohol per day is associated with a significant increase in blood pressure. There is controversy, however, about the effects on blood pressure of one or two drinks per day. Some studies show an increase in blood pressure; some show no increase; and some actually show a decrease. The controversy centers on the studies that show a decrease.
One criticism of these studies involves differences between non-drinkers and moderate drinkers other than their intake of alcohol. Many non-drinkers are ex-drinkers. In a British study of middle-aged men done in 1990, 70 percent of the non-drinkers were ex-drinkers. Often ex-drinkers have stopped drinking because of health problems, and indeed ex-drinkers have high rates of illnesses including heart disease, peptic ulcers, diabetes, bronchitis and gallstones. They are older than drinkers, and a high percentage is smokers. In contrast, moderate drinkers in almost all these studies include the large group of light drinkers who are likely to have characteristics that are advantageous to health. They have the lowest prevalence of smoking, the lowest body mass index (a measure of obesity) and the highest level of physical activity of all the groups in these studies. So it is possible that the lower blood pressure of moderate drinkers compared to non-drinkers might be due to the differing health and life style characteristics of the two groups rather than their differing consumption of alcohol.
The problem with epidemiology studies
This is the problem with epidemiology studies (studies which show a relationship between life style factors and diseases in populations): there are so many different factors involved that it is impossible to determine which of these factors is a cause in the prevention or promotion of a disease. For example, epidemiology studies on hormone replacement therapy consistently showed that women who took HRT were less likely to get heart disease than women who did not take HRT. On the basis of these studies, doctors believed for half a century that long-term use of this therapy would protect women from heart disease. When the theory was put to the test in July of 2002 in a large, randomized, placebo-controlled trial that is the gold standard of science, women who were on HRT had a higher rate of heart disease than women who were not. In the earlier epidemiology studies, the women on HRT had healthier life style characteristics than the women who were not on HRT. Their healthier life styles protected them from heart disease, not the hormone replacement therapy. The same might be true of the studies on alcohol, which are almost entirely epidemiological. Healthier life styles might be protecting the moderate drinkers from high blood pressure, not the alcohol.
One woman's story
I have a friend in her mid-fifties who recently developed high blood pressure. Neither of us could understand why. She had always been thin; at 5'3" she weighs 115 pounds. She is very health conscious and eats lots of fruits and vegetables. She watches her intake of salt, sugar and cholesterol. She exercises regularly. She doesn't smoke and never has. "And, of course, you don't drink," I said. "Oh, but I do," she replied. "I have a glass of red wine every night with my dinner. I've heard it's good for you." When I told her that alcohol can raise blood pressure, she was quite surprised. She had never heard that before. She decided to cut her alcohol consumption to half a glass of wine every other night with her dinner. When I called her a couple of months later, her blood pressure had dropped from 160/95 to 130/85.
Fortunately, the effect of alcohol on blood pressure can be reversed, as was the case with my friend. If you have high blood pressure and drink, try cutting back or eliminating alcohol for two or three weeks. This is a way to find out for yourself if your high blood pressure is alcohol related. Decrease in alcohol consumption is especially important in view of evidence that alcohol-related hypertension may contribute to the higher prevalence of strokes in drinkers.
Mary Lou Williams, M. Ed., is a lecturer and writer in the field of nutrition. She welcomes inquiries. She can be reached at 267-6480.