Conditions:
Atherosclerosis and Heart Disease Prevention

Principal Proposed Treatments
  • Vitamin B6, Folate, Garlic, Antioxidants, Vitamin E, Vitamin C, Selenium, OPCs from Grape Seed or Pine Bark, Lipoic Acid, Turmeric, Resveratrol, Coenzyme Q10 (CoQ10), Combined Antioxidants, Lifestyle Changes
Other Proposed Treatments
  • Omega-3 Fatty Acids, Fish Oil, Flaxseed Oil, Flaxseed, Mesoglycan, Magnesium, Chromium, Green Tea, Bilberry Fruit and Leaf, Ginger, Ginkgo, Hawthorn, Genistein, Astragalus, Copper, GLA (Gamma-Linolenic Acid), Grass Pollen, Lutein, TMG (Trimethylglycine)
Not Recommended Treatments
  • Beta-Carotene

Atherosclerosis, or hardening of the arteries, is the leading cause of death in men over age 35 and all people over 45. Most heart attacks and strokes are due to atherosclerosis. Although the origin of this condition is not completely understood, we know that it is accelerated by factors such as high blood pressure (hypertension), high cholesterol, diabetes, mildly impaired glucose tolerance, smoking, and physical inactivity.

Current theories suggest that atherosclerosis begins with injury to the lining of the arteries. High blood pressure physically stresses this lining, while circulating substances, such as low-density lipoprotein (LDL) cholesterol, homocysteine, free radicals, and nicotine, chemically damage it. White blood cells then attach to the damaged wall and take up residence. Then, for reasons that are not entirely clear, they begin to accumulate cholesterol and other fats. Platelets also latch on, releasing substances that cause the formation of fibrous tissue. The overall effect is a thickening of the artery wall called a fibrous plaque.

Over time, the thickening increases, narrowing the bore of the artery. When blockage reaches 75 to 90%, the person begins to notice angina symptoms, specifically heart pain. In the lower legs, blockage of the blood flow leads to leg pain with exercise, a condition called intermittent claudication.

Blood clots can develop on the irregular surfaces of the artery and may become detached and block downstream blood flow. Fragments of plaque can also detach. Heart attacks are generally caused by such blood clots, whereas strokes are more often caused by plaque fragments or gradual obstruction. Furthermore, atherosclerotic blood vessels are weak and can burst.

With a disease as serious and progressive as atherosclerosis, the best treatment is prevention. Conventional medical approaches focus on lifestyle changes, such as increasing aerobic exercise, reducing the consumption of saturated fats, and quitting smoking. The regular use of aspirin also appears to be quite helpful by preventing platelet attachment and blood clot formation. If necessary, drugs may be used to lower cholesterol levels or blood pressure.

Recently, conventional medicine has also begun to suggest keeping levels of homocysteine low by adding supplemental folate to the diet, and making sure to get enough vitamin B₆ and B₁₂. Consult with your physician for up-to-date information regarding the ideal dose of these supplements. At the time of this writing, recommendations suggest that 800 mcg of folate daily (a dose higher than the standard recommended intake) may be necessary to achieve full benefits.¹ However, a physician's supervision is essential before taking this much folate, due to the risk of covering up B₁₂ deficiency. For other dosage and safety issues, see the full folate, vitamin B₆, and vitamin B₁₂ articles.

Principal Proposed Treatments for Atherosclerosis and Heart Disease Prevention

In the field of preventing atherosclerosis, conventional and alternative approaches overlap. Natural medicine supports (indeed, it first championed) many of the lifestyle changes now encouraged by conventional medicine, and treatments such as vitamin B₆ and folate are now widely recommended by physicians. Many other "alternative" approaches for preventing atherosclerosis are on the verge of acceptance into conventional medicine.

Numerous studies have been performed to determine precisely which nutrients are most helpful in preventing atherosclerosis. However, it is tricky to interpret the results of this research.

The most common and potentially most confusing type of study is the observational study. This type of study follows large groups of people for years and keeps track of a great deal of information about them, including diet. Researchers then examine the data closely and try to identify which dietary factors are associated with better health and longer life.

However, the results can be misleading. For example, if an observational study finds that people who take vitamin supplements live longer, it is not necessarily the vitamins that deserve the credit. Vitamin users also tend to exercise more and to eat more healthful foods, habits that may play a more important role than the vitamins. It is hard to tell.

A more reliable kind of study is the intervention trial. In these studies, some people are given a certain vitamin and then compared to others who are given a placebo (or sometimes no treatment at all). The best intervention trials use a double-blind design. The results of intervention trials are far more conclusive than those of observational studies. Unfortunately, they are very expensive to perform, and relatively few have been completed.

This section details the evidence that is available to date. Because this is such a rapidly changing field, new evidence will likely have been found by the time you read this article. Consult a health-care professional for the latest information.

(For other natural treatments that may reduce two important risk factors for atherosclerosis, see the articles on cholesterol and hypertension.)

Garlic: May Prevent Atherosclerosis Through a Combination of Effects

Garlic produces several effects that together may reduce atherosclerosis risk.¹⁵⁵ It appears to mildly lower cholesterol and blood pressure levels, as well as protect against free radicals and reduce the tendency of the blood to coagulate.^2–29

Garlic preparations have been shown to slow the development of atherosclerosis in rats, rabbits, and human blood vessels, reducing the size of plaque deposits by nearly 50%.^30,31 Furthermore, in a double-blind, placebo-controlled study that followed 152 individuals for 4 years, standardized garlic powder at a dosage of 900 mg per day significantly slowed the development of atherosclerosis as measured by ultrasound.³² While this study suffered from some statistical problems, it nonetheless provides preliminary evidence that garlic can protect against hardening of the arteries.

In addition, an observational study of 200 individuals suggests that garlic protects the arteries in other ways as well.³³ The study measured the flexibility of the aorta, the main artery exiting the heart. Participants who took garlic showed less evidence of damage to their arteries.

Finally, in another study 432 individuals who had suffered a heart attack were given either garlic oil extract or no treatment over a period of 3 years.³⁴ The results showed a significant reduction of second heart attacks and an approximately 50% reduction in death rate among those taking garlic.

For more information, including dosage and safety issues, see the full garlic article.

Antioxidants: Widely Recommended, but Do They Really Work?

The body is engaged in a constant battle against damaging chemicals called free radicals, or pro-oxidants. These highly reactive substances are believed to play a major role in atherosclerosis, cancer, and aging in general.

To counter the harmful effects of free radicals, the body manufactures antioxidants to chemically neutralize them. However, the natural antioxidant system may not always be equal to the task. Sources of free radicals, such as cigarette smoke and smoked meat, may overwhelm this defense mechanism. In the not-too-distant future, tests of "antioxidant status" may join cholesterol and blood pressure as standard components of preventive medicine screening.

Certain dietary nutrients augment the body's natural antioxidants and may be able to help out when the primary system is under stress. Vitamins E and C and beta-carotene are the best known, but many other substances found in fruits and vegetables are also strong antioxidants. For years we've been thinking that individual antioxidant supplements might offer considerable protection against heart disease, especially vitamin E. However, current evidence appears to dampen these high expectations.

Vitamin E: Not the Magic Bullet We Thought

Most but not all observational studies have found associations between high intake of vitamin E and reduced risk of cardiovascular disease.^{48-51,162,163} However, as noted above, observational studies alone cannot be relied upon to identify useful treatments. Intervention trials, which provide much more convincing evidence of effectiveness, have generally failed to find vitamin E supplements effective.

The Heart Outcomes Prevention Evaluation (HOPE) trial found that natural vitamin E (d-alpha-tocopherol) at a dose of 400 IU daily did not reduce the number of heart attacks, strokes, or deaths from heart disease any more than placebo.³⁹ The details of this well-designed, double-blind trial were published in the January 20, 2000, issue of The New England Journal of Medicine. The trial followed over 9,000 men and women who had existing heart disease or were at high risk for it.

In addition, a large, open trial compared the effectiveness of aspirin and vitamin E for the prevention of heart attacks, strokes, and other diseases related to atherosclerosis.⁴¹ While aspirin treatment proved dramatically helpful, vitamin E produced little-to-no benefit.

Negative results have been seen in other large trials as well.^{42–45,164-166}

The Cambridge Heart Antioxidant Study (CHAOS) trial,⁴⁶ published in 1996, really raised researchers' hopes. In that trial, people with existing heart disease who took natural vitamin E (400 IU or 800 IU daily) had substantially fewer nonfatal heart attacks compared to the placebo group after about 1.5 years. Even so, heart-related deaths were not reduced in the vitamin E group. Furthermore, it has been suggested that possible flaws in the design of this trial might make its findings questionable.

It has been suggested that another form of vitamin E (gamma-tocopherol) might be more helpful than the vitamin E used in these trials (alpha-tocopherol).^159-161,167 Gamma-tocopherol is present in the diet much more abundantly than alpha-tocopherol, and it could be that the studies showing benefits with dietary vitamin E actually tracked the influence of gamma-tocopherol. However, an observational study specifically looking to see if gamma-tocopherol levels were associated with risk of heart attack found no relationship between the two.¹⁶¹ Nonetheless, intervention trials of gamma-tocopherol are currently underway.

For more information, including dosage and safety issues, see the full vitamin E article.

Beta-Carotene: Best in Food, Not As a Supplement

The study results involving beta-carotene are interesting. Beta-carotene is one member of a large category of substances in foods known as carotenes, which are found in high levels in yellow, orange, and dark green vegetables.

Many studies suggest that eating foods high in carotenes can prevent atherosclerosis.⁶⁰ However, isolated beta-carotene in supplement form may not help, and could actually increase your risk, especially if you consume too much alcohol.⁶¹

A huge, double-blind, intervention trial involving 29,133 Finnish male smokers found 11% more deaths from heart disease and 15 to 20% more strokes in those participants taking beta-carotene supplements.⁶² This certainly does not encourage one to take it.

Similar poor results with beta-carotene were seen in another large, double-blind study in smokers.⁶³ Furthermore, beta-carotene supplementation was also found to increase the incidence of angina in smokers.⁶⁴

What is happening here? Clearly, smoking presents a challenge to antioxidants. However, the question remains: Why should beta-carotene not only fail to help but actually worsen the situation?

One possible explanation is that beta-carotene in the diet always comes along with other naturally occurring carotenes. It is quite likely that other carotenoids in the diet are equally or more important than beta-carotene alone.⁶⁵ Taking beta-carotene supplements may actually promote deficiencies of other natural carotenes,⁶⁶ and overall that may hurt more than it helps.

The moral of the story is that you should eat your vegetables but maybe not take beta-carotene supplements.

Other Antioxidants: May Be Helpful, but Little Direct Evidence

A high intake of vitamin C from fruits and vegetables appears to reduce the risk of heart disease.⁶⁷ However, there is little evidence that vitamin C supplements provide the same benefits. Foods containing vitamin C also contain many other healthful ingredients (such as bioflavonoids and carotenes), so it's not clear that pills containing only vitamin C work just as well.

Many other antioxidant vitamins, supplements, and herbs have been suggested as preventive treatments for atherosclerosis. Selenium, OPCs from grape seed or pine bark, lipoic acid, turmeric, resveratrol from red wine and grape skins, and coenzyme Q₁₀ are commonly mentioned. However, although a number of interesting studies have suggested that these substances may be beneficial, the state of the evidence is still too preliminary to draw any conclusions.

Combined Antioxidants

It has been suggested that the best approach is to use a combination of antioxidants. This makes sense theoretically because, for example, vitamin E fights free radicals that dissolve in fats while vitamin C fights those that dissolve in water. However, evidence for benefit with such combinations comes only from observational studies.⁶⁸ A 3-year, double-blind, placebo-controlled study of 160 individuals found no benefit with combined antioxidant treatment, providing vitamin E (800 IU), vitamin C (1,000 mg), beta-carotene (25 mg), and selenium (100 mcg).⁶⁹

Lifestyle Approaches

This fact cannot be emphasized enough: The most important way to prevent atherosclerosis involves lifestyle changes such as quitting smoking, increasing exercise, and adopting a diet high in whole grains, fruits, and vegetables and low in animal products.⁷⁰ Olive oil and canola oil are probably among the most healthful of vegetable oils. Heating oils to high temperatures (as in fried foods) can oxidize them and make them less healthful.⁷¹

The moderate use of alcohol, and specifically red wine, appears to help prevent atherosclerosis, although this is controversial as well.^72–75 Contrary to some reports,⁷⁶ coffee drinking does not appear to increase risk of heart disease.^77,78,79 although unfiltered coffee may be harmful.⁸⁰ 

Other Proposed Treatments for Atherosclerosis and Heart Disease Prevention

Although the following treatments are widely recommended for atherosclerosis, they cannot be considered scientifically proven at this time.

Omega-3 Fatty Acids

Study results on fish or fish oil for cardiovascular disease have yielded contradictory results. ^{97-115,156,168} However, a review (technically a meta-analysis) of many studies on the subject suggests that when all the evidence is put together, it appears that fish or fish oil can reduce overall mortality, heart disease mortality, and sudden cardiac death (e.g., heart stoppage due to arrhythmia).¹⁵⁷

Fish oil is believed to exert its primary benefit in cardiovascular disease by reducing serum triglycerides, although not all studies have found this effect.^81-84,169 The most important omega-3 fatty acids found in fish oil are called EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). DHA and EPA may have different effects on triglycerides, but again study results are not consistent; some studies found EPA more effective, while others did not.^170-175 Like cholesterol, triglycerides are a type of fat in the blood that tends to damage the arteries, leading to heart disease. Reducing triglyceride levels should help prevent heart disease to some extent. However, the standard drug gemfibrozil appears to be more effective than fish oil for this purpose.⁸⁵ Fish oil has been specifically studied for reducing triglyceride levels in people with diabetes, and it appears to do so safely and effectively.⁸⁶

Similarly, some but not all studies also suggest that fish, fish oil, or EPA or DHA separately can modestly raise levels of HDL ("good") cholesterol.^{87,88,169,174,175}

Additionally, fish oil may help the heart by "thinning" the blood and by reducing blood levels of homocysteine.⁸⁹ Blood clots play a major role in heart attacks, and homocysteine is an amino acid that appears to raise the risk of heart disease. One study directly indicates that fish oil may be able to prevent blood clots from blocking the synthetic grafts inserted in people undergoing kidney dialysis.¹⁷⁶

Studies contradict one another on whether fish oil can lower blood pressure.^90–95 A 6-week, double-blind, placebo-controlled study of 59 overweight men suggests that the DHA in fish oil, but not the EPA, can reduce blood pressure.⁹⁶

For more information, including dosage and safety issues, see the full fish oil article.

Flaxseed oil has been suggested as an alternative to fish oil. While fish oil is much better studied, there is some evidence, including two double-blind studies, that flaxseed oil or whole flaxseed may reduce LDL ("bad") cholesterol, perhaps slightly reduce hypertension, and slow down atherosclerosis.^118–124

Mesoglycan

Mesoglycan is a substance obtained from the intestines of pigs.

In one study, 200 mg per day of mesoglycan significantly slowed the rate of thickening of arteries.¹²⁵ After 18 months of treatment, the additional layering of the inside vessel lining was 7.5 times less in the group receiving mesoglycan than in the group that did not receive any treatment. However, because this was not a double-blind, placebo-controlled trial, the results can't be taken as truly reliable. Preliminary evidence suggests that this supplement may work in several ways: supplying material for repair of arteries, "thinning" the blood, and improving cholesterol levels.^126,127

For more information, including dosage and safety issues, see the full mesoglycan article.

Magnesium

A double-blind, placebo-controlled trial of 50 individuals with coronary artery disease found that supplementation with magnesium at 730 mg daily significantly improved exercise tolerance.¹²⁸ There is also some evidence that magnesium may reduce the atherosclerosis risk caused by hydrogenated oils, margarine-like fats found in many "junk" foods.¹²⁹

In addition, a double-blind study of 42 individuals with heart disease found that magnesium supplements reduced the tendency of the body to form blood clots.¹³⁰

For more information, including dosage and safety issues, see the full magnesium article.

Chromium

Mildly impaired responsiveness to insulin (insulin resistance) is a fairly common condition that appears to increase the risk of heart disease.^131–138 Chromium supplementation might restore normal insulin responsiveness, as well as aid in weight loss and possibly improve cholesterol levels. The net result might be decreased risk of heart disease.

In support of this theory, an observational trial found associations between higher chromium intake and reduced risk of heart attack.¹³⁹  

Other Herbs and Supplements

Some but not all observational studies suggest that green tea might help prevent heart disease.^140–143

Many herbs appear to decrease platelet stickiness, including bilberry, feverfew, ginger, ginkgo, and hawthorn. Whether this translates into an actual benefit for preventing atherosclerosis remains unknown.

Indirect evidence suggests that DHEA might help prevent heart disease;^144–149 however, it seems likely to be more beneficial for men than for women.

Frequent consumption of nuts may reduce the risk of heart disease,^150,151 probably because the monounsaturated fats in nuts reduce cholesterol levels.

Weak evidence suggests genistein may be helpful for preventing heart disease by reducing cholesterol and keeping it from depositing on cell walls.^152,153,154

Other treatments sometimes mentioned for atherosclerosis include astragalus, copper, GLA, grass pollen, lutein, bilberry leaf, and TMG, although there is little evidence as yet that they are helpful.

Chelation therapy, a technique that involves intravenous administration of the substance EDTA, is widely promoted in some alternative medicine circles as a treatment for atherosclerosis. However, there no is meaningful evidence that it works, and growing evidence that it does not work.^177,178

For other natural substances that may help prevent atherosclerosis by lowering its major risk factors, see the articles on cholesterol and hypertension.

Finally, accumulating evidence hints that trans-fatty acids, a type of fatty acid found in margarine and other hydrogenated oils, increase risk of cardiovascular disease. In July 2002, the US Institute of Medicine concluded that there is no safe intake level of trans-fatty acids, and overall consumption should be kept as low as possible.

Last reviewed August 2002 by Medical Review Board

Back to Top