By Hans R. Larsen, MSc ChE :
A healthy diet is the strongest protection against cardiovascular disease. A heart-healthy diet is rich in fruits and vegetables and low in saturated fat, cholesterol, meat, and sugar(2,3,24,25,47-49).
A recent study carried out in Germany showed that the death rate among male vegetarians due to cardiovascular disease was only 39% of that of the general population while the death rate of female vegetarians was only 46%(50). Other studies have shown that high fat diets significantly increase the risk of cardiovascular disease(3,47). Trans-fatty acids found in hydrogenated vegetable oils are particularly harmful(51,52). A recent study at the Harvard Medical School found that people who had a high intake of margarine had more than twice the risk of having a heart attack than did people with a low intake(53). Another study found that women who had changed from butter to margarine to lower their cholesterol and avoid heart disease actually had a 67% higher incidence of heart disease than did women who had not made this switch(54).
The fat content of the average American diet is 40-50% of calories consumed and is mostly saturated fats(24,25,55). The World Health Organization recommends that dietary fats should only supply between 15 and 35% of daily energy intake with 30% being the maximum for sedentary individuals. Less than 10% of the daily energy intake should be in the form of saturated fat and the daily cholesterol intake should not exceed 300 mg (one egg)(56).
Leading experts in the prevention and treatment of cardiovascular disease go even further in their dietary recommendations. Dr. Dean Ornish, MD recommends a diet containing no more than 20% of calories from fat with the fat source being mostly polyunsaturated or mono-unsaturated. Dr. Ornish also recommends no more than 10 mg of cholesterol per day(24). To put these recommendations in perspective consider that just one "Quarter Pounder" hamburger with a side order of french fries provides about 30% of total daily energy intake, contains 100 mg of cholesterol and is loaded with saturated fat and trans- fatty acids; definitely not a heart-healthy meal(24,55).
Other researchers recommed an increased intake of non-contaminated fish as an effective way of reducing the risk of cardiovascular disease(57-60).
Most medical experts agree that a high total cholesterol level is a critical risk factor for cardiovascular disease and that a reduction in overall cholesterol levels is an important measure in preventing and treating atherosclerosis(3,5,24,25,61). There are, however, dissenters who provide compelling evidence that reducing total cholesterol levels has little if any effect on the progression of atherosclerosis and does not lower overall mortality or even mortality from cardiovascular disease(62-64). It may well be that a high cholesterol level is relatively unimportant in comparison to the major risk factors of hypertension, smoking, obesity, diabetes, and physical inactivity(65). Whatever the truth, there is now a growing consensus that a concerted effort should be made to lower cholesterol levels by dietary changes before considering drug therapy(3,66,67).
A significant increase in the intake of fruit, vegetables, grains and legumes and a drastic reduction in the consumption of saturated fats, cholesterol, meat and sugar are the cornerstones in any cholesterol reduction program. There is extensive evidence that such dietary modifications on their own can bring about impressive reductions in overall cholesterol levels(24,25,55,61,62,67-70). Very effective cholesterol-lowering programs have been developed by Dr. Julian Whitaker MD, Dr. Dean Ornish MD, and Dr. Hans Diehl. These programs are based on low fat diets, exercise and stress reduction. They not only lower cholesterol but actually reverse blockages in the arteries(24,25,55).
There are many specific dietary components and supplements which are highly effective in lowering cholesterol levels. Among them are wheat germ, oat bran, soy protein, calcium, green tea, nuts, garlic, and omega-3 fatty acids specifically fish oils and flax oil(71-84).
Cholesterol levels can also be lowered by the use of pharmaceutical drugs(3,5). However, there is considerable controversy as to the overall benefits of this approach(85,86). Niacin (vitamin B3) is equal or superior to pharmaceutical drugs in its ability to lower the "bad" cholesterols and increase the "good" (HDL) cholesterol(87-90).
Some researchers believe that low levels of HDL (high-density lipoprotein) are even more detrimental to cardiovascular health than are high total cholesterol levels and high LDL levels. HDL cholesterol counteracts the effects of low density cholesterol by scavenging excess cholesterol from the walls of the arteries and taking it to the liver where it is broken down and excreted(5). Exercise, dietary modifications, weight control and niacin therapy are effective in raising the blood levels of HDL cholesterol(3,47,87-90).
Avoidance of smoking and secondhand smoke vie with dietary modifications as the single-most effective measure in avoiding cardiovascular disease. Smoking kills over 400,000 Americans every year and over 125,000 of them die from cardiovascular disease(3,91). Women smokers who also use oral contraceptives increase their risk of heart attack substantially(3). Smoking also aggravates angina(92). Secondhand (passive) smoking increases the risk of heart disease and may aggravate existing angina pectoris(93). The benefits of quitting smoking occur fairly quickly. Smokers who quit lower their risk of stroke by 27% two years after stopping. Their risk reaches the level of non-smokers after about four years(94).
Antioxidants are very effective in preventing atherosclerosis. They work by deactivating free radicals and peroxidized fats and thereby prevent them from adhering to existing deposits on the artery walls(15,23,95-100).
Vitamin C helps to strengthen the artery walls by building up their collagen content. Numerous studies have found that vitamin C or vitamin C- rich foods help prevent heart disease(2,25,101,102). A low vitamin C intake has also been linked to an increased risk of heart disease and stroke(103- 105). A recent study showed that vitamin C supplementation helps protect the blood against oxidation and another showed that antioxidants protect fats in the blood against harmful peroxidation(95,105). Vitamin C helps thin the blood, regenerates vitamin E and lowers blood pressure(2,7,25,98,107). Vitamin C is safe and free of side effects even at high concentrations(108).
Vitamin E prevents cardiovascular disease in several different ways: by protecting low density lipoproteins from oxidation, by inhibiting smooth muscle cell proliferation (a major cause of atherosclerosis), by reducing platelet adhesion (an important factor in the formation of blood clots), and by increasing the concentration of "good" cholesterol (HDL) in the blood(7,8,25,109-115). The evidence of the protective effect of vitamin E is impressive and growing daily. Two large studies carried out at the Harvard Medical School concluded that people who had taken 100 IU of vitamin E for two years or more had a 40% lower incidence of coronary heart disease and a 30% lower incidence of ischemic stroke. The studies involved over 125,000 nurses and other health professionals(8,22,116). Other studies have shown that men who took 100-250 IU per day of vitamin E had a 44% lower risk of coronary heart disease than did men who did not supplement. The decrease in risk was only observed in men who supplemented; a high intake of vitamin E-rich foods did not decrease the risk significantly(116). Vitamin E is also useful in preventing diabetes which often leads to heart disease(117).
Vitamin E is entirely safe in dosages up to 1000 mg/day (1000 IU/day) and no toxicity has been observed with dosages as high as 3200 IU/day(108,118,119). Medical advice should, however, be obtained before starting a supplementation program in the case of individuals who have a vitamin K deficiency, a tendency to prolonged bleeding or who are taking anticoagulants like warfarin(108).
Beta-carotene is another fat-soluble antioxidant which is highly effective in protecting against free radical damage. Beta-carotene is particularly effective in protecting smokers from lipid peroxidation and thereby lowering their risk of heart disease(22,120). Several studies have found that people with a low level of beta-carotene in their blood have an increased risk of developing coronary heart disease(16,17,23,102).
Beta-carotene is approved by the U.S. Food and Drug Administration as a dietary supplement and is considered safe even in large intakes. Yellowing of the skin may occur in people taking more than 30 mg/day for extended periods. This condition, however, is entirely benign and disappears when supplementation is discontinued(108).
The importance of selenium as a dietary antioxidant is becoming increasingly clear. Selenium is a component of the body’s natural antioxidant, glutathione peroxidase, and also plays an important role in combatting the toxic effects of mercury(121). A low content of selenium in the blood has been linked to an increased risk of cancer and heart disease(122,123). A daily intake of 50-200 micrograms is safe and adequate(123).
Some very recent research has shown that Ubiquinol-10, the reduced form of ubiquinone-10 (coenzyme Q10) is even more powerful than vitamin E and beta-carotene in protecting low-density lipoproteins (LDLs) against peroxidation(124-127). It is, unfortunately, only found in very low levels in LDLs, but its concentration can be significantly increased by supplementing with coenzyme Q10(109,127). Coenzyme Q10 is relatively free of adverse effects in daily intakes as high as 300 mg/day(128).
The B-vitamins are receiving increasing attention as important factors in the prevention of cardiovascular disease. Folic acid, vitamin B6 and vitamin B12 are all required for the metabolism of homocysteine and supplementation with 400 micrograms/day of folic acid is effective in normalizing homocysteine levels(41,42). Supplementation with niacin (vitamin B3) reduces the risk of developing diabetes(129). Larger amounts of niacin are also very effective in lowering cholesterol levels(87-90).
A magnesium deficiency is closely associated with cardiovascular disease. Lower magnesium concentrations have been found in heart attack patients and administration of magnesium has proven beneficial in treating ventricular arrhythmias(3,130-138). Fatal heart attacks are more common in areas where the water supply is deficient in magnesium and the average intake through the diet is often significantly less than the 200-400 milligrams required daily(130).
Omega-3 fatty acids found in flax oil and fish oil are all powerful preventers of heart disease(57,60,81-84). Recent research has shown that supplementation with 3 grams of fish oil per day lowers blood pressure substantially in people with borderline hypertension(139).
Garlic lowers cholesterol levels and blood pressure; it also prevents clotting and plays a significant role in the natural "digestion" of blood clots (fibrinolysis)(80,140). Flavonoids, found in onions, tea and red wine, also lower the risk of coronary heart disease significantly(78,141).
Potassium, calcium, and magnesium are all very effective in the treatment of hypertension, one of the major risk factors for cardiovascular disease(142-146). A high intake of dietary fiber (24 g/day or more) lowers high blood pressure(143).
Regular exercise is one of the most important measures in the prevention of heart disease, stroke, hypertension, obesity, and diabetes(3,24,25,147-154). It is also effective in increasing the blood level of good HDL cholesterol(3,47). British researchers conclude that frequent, regular walking plus participation in a recreational activity or sport once a week lowers the risk of heart attack and stroke by over 50% in middle-aged men(152). Another study shows that men who bicycle to work (6 km round trip) every day are half as likely to suffer a heart attack or a stroke as those who chose a less strenous way of getting to work(153). Recent research has shown that postmenopausal women can cut their risk of a heart attack in half by going for a 30-45 minute walk three times a week(154). Studies have also shown that men and women who exercise at least once a week lower their risk of developing diabetes by 30%(151).
Avoidance of excessive stress is another important weapon in the fight against cardiovascular disease. A recent study by the Harvard Medical School found that men with a high anxiety level had a two to three times higher risk of dying from coronary heart disease than did men with a low level of anxiety(27). Another study showed that men with a high anxiety level have twice the risk of developing hypertension than do men with a low anxiety level(155).
Exercise, tai-chi, qi gong, meditation, long walks, indulging in a hobby, listening to music or relaxation tapes, and making a conscious effort to reduce one’s exposure to stress all go a long way towards reducing the risk of cardiovascular disease.
It is clear that there are many, many things we can do to effectively prevent cardiovascular disease. However, these diseases take a long time to develop and for many people it is too late to consider prevention; treatment and in many cases, urgent treatment is required.