Science in Christian Perspective
Practical Preventive Medicine
Jay Holtman, MD
Clinical Fellow in Cardiology
Atlanta, Georgia 30309
From: JASA 33
The area of preventive medicine has been filled with charletons and quacks. But amidst the quagmire of soft thinking and pseudoscience, there emerges some fairly sound science that we as Christians might do well to incorporate into our lifestyle.
I am now in the middle of a cardiology training program and an increasing portion of my time and effort is devoted to preventive medicine. In spite of the drama of bypass surgery and coronary care units, preventive medicine is cheaper and can be more broadly applied. Indeed in an era of decreasing resources, it may be the only type of medicine that the world can afford. To practice preventive medicine requires significant lifestyle changes. In order to make these changes, character strength is required. I have found that unless the patient is spiritually healthy, he is often unwilling to make these changes.
Cigarette smoking not only increases the incidence of lung cancer but also cancer of the mouth, larynx, esophagus, bladder, pancreas, liver and stomach. For some of these organs cancer is greatly increased, i.e. buccal cavity and pharynx cancer is 9.9 times more likely in smokers of age 45-64 than non-smokers of the same age group. Bladder cancer is two to three times more common among smokers-a small but still greatly significant increased risk.1
Not only is this cancer risk more widespread than simply lung cancer, it is also proportional to the number of cigarettes taken, the degree of inhalation and the age at which smoking began. The risk of lung cancer is almost 19 times greater in a two pack per day or greater smoker than in a non-smoker. The risk in a light smoker (less than V2 pack per day) is increased 4.6 times that of a nonsmoker. Light smokers and non-inhalers are still at a much higher risk than non-smokers. A person beginning smoking before age 15 is four times more likely to develop lung cancer than one beginning after age 25. This statistic is particularly relevant with increasing tobacco smoking among teenagers.2
Less well recognized is the probable greater risk to the smoker of premature death from coronary artery disease. The Framingham study3 is probably the best known of the prospective epidemiologic studies of heart disease. Its data suggest that: (1) the consumption of twenty or more cigarettes daily is associated with up to three times the danger of myocardial infarction found in non-smokers; (2)The danger of heart disease is greater because there are more deaths from coronary artery than there are from all forms of cancer combined. Moreover, the smoker at greatest risk is the young smoker.
Chronic obstructive pulmonary disease with death from progressive shortness of breath and peripheral vascular disease with gangrene and amputation of extremities are diseases that are concentrated in smokers. In fact, it is unusual to encounter a patient with these diseases who has not been a smoker. Lower infant birth weight is seen in infants born to mothers who smoke during gestation.4 The full effects of smoking on the newborn are only now beginning to be characterized.
The evidence is clear that smoking is a danger to the health of every smoker. Elimination of this habit from our country would prolong life expectancy as well as the quality of life. Despite the fact that every cigarette package sold today contains warning of health dangers, tobacco use is common. Certainly this is in part due to ignorance of the extent of risk; yet many cannot quit because they do not have the character.
Salt-sodium chloride-is clearly involved in the pathogenesis of idiopathic hypertension. This form of hypertension accounts for 9507o of the hypertension in this country. Hypertension-high blood pressure-by itself can cause heart failure and brain hemorrhage if sustained. Even more important than hypertension's direct effect is its association with premature atherosclerosis-hardening of the arteries-predisposing to heart attacks and strokes.
There is now some exciting new data on salt and hypertension or high blood pressure. There are now a number of epidemiologic studies that show a linear correlation between the average sodium chloride content of the diet and the percentage of hypertension in a given population. The average 40 gram per day sodium diet of the northern Japanese contains much salted fish; here. high blood pressure affects 40% of the population. The Eskimo diet contains about 2 - 4 grams of sodium per day. The incidence of hypertension is virtually zero. Americans could approximate this content in their own diet by adding no salt at the table or while cooking and by avoiding salty foods such a potato chips, bacon, ham and processed foods preserved with salt.
An objection to epidemiologic studies has been that many people, even on a high sodium diet, have a normal blood pressure. These studies are based on American standards of 140/90 or less as being normal. This is too high. Actuarial tables have shown decreased life expectancy associated with blood pressures greater than 100/60. What we have accepted as normal probably is not.
It is also expected that blood pressure should rise with age. This effect observed in our country is probably the result of salt intake that is too high in the average American diet. Studies done in several populations where salt intake is very low show no significant rise in blood pressure with age.5 I believe that we can improve our life expectancy and quality of life by omitting salt from our diets.
Let me cautiously add, however, that salt is not all you need to know about hypertension. Five percent of hypertension is secondary to tumor or renal (kidney) disease. Some experts such as Harriet Dustan6 believe that-obesity may also be an important factor in addition to dietary sodium.
The next diet modification is that of switching from a low fiber diet to a high fiber diet. Principally Dr. Denis Burkitt7 is responsible for the diet fiber hypothesis which is gaining increasing evidence and popularity. The idea is simple but the results can be far reaching. Dietary fiber is primarily complex carbohydrate that we cannot digest with the enzymes available in our gastrointestinal tract. These pass through the bowel and are excreted in the stool. Dr. Burkitt, who worked many years in Africa, noticed that many disorders of the bowel were not seen in African populations who ingested diets low in animal fat and high in fiber. These disorders include carcinoma of the colon, diverticulitis, appendicitis, hiatal hernia and hemorrhoids. The proposed mechanism by which fiber prevents these various diseases is simple. Larger stools have shorter transient times, i.e. the time from the mouth to the anus is shortened from the average 4-5 days in the American eating low fiber diet to two days. The shorter transient times mean less exposure of the colon to the carcinogens present in our stools-namely bile salts and cholesterol esters. Moreover, these carcinogens are diluted in the large volume of fiber in the stool. Carcinoma of the colon is the most frequent cancer in men (cancer of the colon kills less than cancer of the lung since it kills only about half of its victims). Colon cancer's elimination by itself would be worth the trouble of eating more fiber.
The other diseases prevented by fiber ingestion are not as lethal but are frequent and disabling. All these diseases are postulated to be secondary to high intraluminal pressure in the colon and abdominal cavity required to eliminate small, compact stools. High pressure in the colon causes the impaction of the fecalith that obstructs the appendix and leads to appendicitis; high colon pressures cause the veins to dilate leading to hemorrhoids and the colon walls to weaken leading to diverticulitis. Increased intrabdominal pressure may well be responsible for hiatal hernia.
Practically, in order to get enough fiber in our diet, unprocessed food should be eaten instead of refined. Whole grain should be substituted for white, fruit for candies. Such a diet may not always be convenient. Dr. Burkitt suggest that two tablespoons of bran daily, by itself, is sufficient for colon protection. This simple regimen should prevent much chronic bowel disease.
No paper on preventive medicine would be complete without a discussion of cholesterol. Cholesterol is the number one alterable risk factor for coronary artery disease.8 I have little time for those who say that cholesterol does not matter-those pseudo-preventive medicine people are ignoring vast quantities of epidemiologic data and animal studies. The fact remains that people who live in countries with low cholesterol have a low incidence of coronary artery disease and death from heart attacks. If these same people move to another country and develop the eating habits of the high cholesterol country, they develop heart attacks at a rate equal to the high attack rate country.
The average cholesterol in this country is 220; coronary heart disease kills approximately one half of the males. The average cholesterol in rural Africa is 140; coronary artery disease is very rare. The message is clear-high cholesterol is not healthy. While we wait for the last skeptic to be satisfied, may I offer a simple suggestion: lower your serum cholesterol to 150 mg value. Coronary disease is chronic; it takes years to build up and years to regress. If one waits for more information than is already available, one may well wait too long. Several steps are necessary often to achieve this 150 value. First check your cholesterol, you may be fortunate enough to require no further modification. If your cholesterol is high, the first step is to lose to ideal body weight. At this weight you should have minimal abdominal fat. If this is not sufficient, then decrease the amount of animal fat and eggs in your diet. Change meat portion to fish and poultry and cut down the size of the meat portion. Further increase fiber in your diet, particularly rolled oats such as oatmeal. If this is unsuccessful, then a total vegetarian diet may be necessary. Very few vegetarians have cholesterols greater than 170. A regular exercise program may also help with cholesterol control.
Running has become a popular form of exercise in America today. There is some direct epiderniologic data to support the contention that physically active people are less likely to die of ischemic heart disease. There are some fairly good data now that regular exercise reduces several risks that are responsible for coronary artery disease; excess weight, blood pressure and serum cholesterol. It is my clinical impression that those who exercise live higher quality lives with greater confidence and increased tolerance for stress.
Recently there have been several documented deaths from myocardial infarction among long distance runners.9 These individuals often had warning symptoms. Other risk factors (such as high cholesterol or tobacco use) for coronary artery disease were present and apparently ignored by these runners. My real point is that running is good for our well being and probably helps us live longer, more productive lives but it is not a panacea; other preventive measures must also be considered.
Alcoholism must be avoided for its chronic effect on personality. Heavy alcoholism is associated with cirrhosis of the liver and tumors of the liver. It is synergic with tobacco in the cancers that tobacco causes. Chronic heavy drinking also results in early brain degeneration. Heavy doses are directly toxic to the heart and can result in heart failure. The effect on the fetus from a drinking mother is profound and has only recently been delineated. I can, however, find no evidence that small doses, such as one glass of wine a day, is harmful.
There is controversy on the consumption of refined sugar or sucrose. People currently argue the sugar high and sugar blues. Some are now writing on atherosclerosis, hyperinsulinemia and glucose loading. All of this information is interesting but preliminary.
Despite this controversy, there is essentially no controversy on the association between dietary sucrose and dental caries.10 I This is not a cause of death but it certainly causes much discomfort and expense. Because of the risk of dental caries, I think it wise to avoid much refined sugar foods.
Much of what I have said is widely known. These principles are basic and the data are firm. I have not mentioned megavitamins, vitamin C, trace metals, yoga or yogurt. Data on health protection from such measures is at least an order of magnitude less firm than the data I have presented. My difficulty with proponents of these other forms of preventive medicine is that they often use poor science to defend their points and offer a false security which allows their adherent to overlook real preventive medicine.
Large lifestyle changes may be required. Quitting smoking, avoiding animal fat and salt in our diet, losing weight and exercising regularly are major changes in lifestyle. Motivation to change must come from the spirit of a man. Many patients that I inform of these risks are unable to make the necessary changes. Short term pleasures must be sacrificed for long term benefit. This requires character. In the area of preventive medicine, cult groups such as the Mormons11 and Protestant groups such as the Seventh Day Adventists12 are far ahead of mainline Christian groups and epidentiologic data shows clear health benefit. As Christians we have the duty to honor God with our bodies. The more we know, the more we must do. To whom much is given, much shall be required.
1 E. Cuyle Hammond in Persons at High Risk of Cancer, Joseph F. Fraumeni, Jr., ed., (New York: Academic Press, 1975), p. 131.
2Ibid., p. 131
3W.B. Kannel, "Some Lessons in Cardiovascular Epidemiology from Framingham", American Journal of Cardiology, (1976), 37:269-82.
4Jonathan Fielding, "Smoking and Pregnancy", New England Journal ofMedicine, (1978) pp. 298, 337-339.
5Ed Freis, "Salt, Volume and the Prevention of Hypertension," Circulation, (1979), 53:589.
6Harriet Dustan, "Research Contributions Toward Prevention of Cardiovascular Disease", "Research Related to the Underlying Mechanisms in Hypertension", Circulation, (December 1979), 60:1566-9.7D. P. Burkitt, "Are Our Commonest Diseases Preventable?", Preventive Medicine, (December 1977), 6(4):556-9.
9T. D. Noakes, et. al., "Autopsy - Proved Coronary Atherosclerosis in Marathon Runners", New England Journal of Medicine, (1979), 301:86-89.
10E. Newburn, "Dietary Carbohydrates: Their Role in Cariogenicity", Medical Clinics of North America, (September 1979), 63:1069.
11 J. L. Lyon, et. al., "Cancer Incidence in Mormons and Non-Mormons", New England Journal of Medicine, (1976), 294:129-33.
12R. L. Phillips, "Summary of Adventist Mortality - 1958-65", Cancer Research, (1975), 35:3513-22.