Atherosclerosis, often known as hardening of the arteries, leads to cardiovascular disease, and 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 hypertension (high blood pressure), high cholesterol, diabetes, and milder forms of impaired glucose tolerance,smoking, physical inactivity, andobesity. Chronic inflammation in the body (of various types) is also hypothesized to play a role.

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, the artery lining begins 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 of the coronary arteries (the arteries supplying the heart) reaches 75% to 90%, symptoms of angina develop. 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 arteries 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.

This section presents some promising and not-so-promising natural approaches for preventing cardiovascular disease by fighting atherosclerosis. Note that we have left out two classes of treatments: those that reduce elevated cholesterol or blood pressure. These are discussed in their own articles. It has also been suggested that reducing levels ofhomocysteine might reduce cardiovascular disease risk, a subject also discussed in a separate article. In addition, other sections of this database contain articles on several conditions caused by atherosclerosis, such as angina, heart attacks, intermittent claudication, and stroke.

Omega-3 Fatty Acids

Omega-3 fatty acids are healthy fats, found in certain foods such as cold-water fish. Some evidence suggests fish or fish oilmight help fight atherosclerosis. However, study results on fish or fish oil for cardiovascular disease have yielded contradictory results.97-115,156,168,225228,229A 2002 review of many studies on the subject concluded that when all the evidence is put together, it appears that fish or fish oil can slightly reduce overall mortality, heart disease mortality, and sudden cardiac death (heart stoppage due to arrhythmia).157However, a subsequent comprehensive review published in 2004 included additional studies and came to a more pessimistic conclusion.190According to the authors, working for the prestigious Cochrane Collaboration, "It is not clear that dietary or supplemental omega-3 fats alter total mortality, combined cardiovascular events or cancers in people with, or at high risk of, cardiovascular disease or in the general population." And a 2012 review of 14 randomized, controlled trials involving over 20,000 people further questions the supplement's value in patients with cardiovascular disease.228Researchers concluded that omega-3 fatty acids (ranging from 0.4-4.8 g/day) were no better than placebo at reducing rates of cardiovascular events or cardiovascular-related death. A gigantic study (over 18,000 participants) published in 2007 was widely described in the media as finally proving beyond a shadow of a doubt that fish oil helps prevent heart problems.211 Unfortunately, this study lacked a placebo group, and therefore failed to provide reliable evidence.

If it does provide benefit for atherosclerosis, fish oil is thought to do so primarily by reducing serum triglycerides. Like cholesterol, triglycerides are a type of fat in the blood that tends to damage the arteries, leading to heart disease. According to most, but not all studies, fish oil can modestly reduce triglyceride levels.81-84,86,169,200However, the standard drug, gemfibrozil, appears to be more effective than fish oil for this purpose.85The most important omega-3 fatty acids found in fish oil are called eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA may have different effects on triglycerides, but as typical for studies involving marginally effective treatments, study results are not consistent; some found EPA more effective than DHA, while others did not find a difference.170-175

A specially-processed, FDA-approved omega-3 product called Omacor (Lovaza) is widely advertised as being more effective than ordinary fish oil in reducing high triglyceride levels. A very large randomized trial, though, did not find evidence to support Omacor in people with diabetes and prediabetes.229 Over 12,000 people with type 2 diabetes or prediabetes were randomized to receive Omacor (1 g) or placebo. All of the study participants had cardiovascular disease or had risk factors for the disease. Six years later at the follow-up, researchers found that there were no differences between the two groups in regards to cardiovascular-related death, heart attacks, strokes, or heart-related hospitalizations and surgeries. The only bright spot was that Omacor did help to reduce high triglyceride levels.

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

Alpha-linolenic acid (ALA) is an omega-3 fatty acid derived from plants. There is some evidence that flaxseed oil, which contains ALA, or whole flaxseedmay reduce LDL ("bad") cholesterol, perhaps slightly reduce hypertension, and slow down atherosclerosis.118-124But, a 2010 review of ALA's potential effects on cardiovascular health did not report such promising results.227 For example, an analysis of short-term trials (lasting 6-12 weeks) involving healthy adults did not find that ALA improved cholesterol levels. There were also conflicting results pertaining to ALA’s effect on inflammation in the body and glucose metabolism (two possible risk factors for developing heart disease). ALA may, though, offer some protection against nonfatal heart attacks, but there’s no evidence that this type of omega-3 can protect against heart failure, atrial fibrillation, or sudden death.

Finally, while it is commonly stated that people require a certain optimum ratio of omega-3 to omega-6fatty acids in the diet, there is no real evidence that this is true, and some evidence that it is false.210

Lifestyle Approaches

There is no doubt that quitting smoking will significantly reduce heart disease risk. Increasing exercise and losing weight(if you are overweight) will most likely help as well. Although for years there has been an emphasis on reducing fat in the diet, the balance of current evidence indicates that it's more useful to substitute healthy fats (such as the monounsaturated fats in olive oil) for saturated fats than to try to reduce total fat intake.191-194,201,223Evidence suggests that any low-calorie diet, whether low-carb, low-fat, or in-between, will result in weight loss and reduced cardiac risk—provided you stick to it.195Nuts, a food known to be high in healthy fats, have been associated with improved heart health. A large cohort analyzed data of 118,962 patients from Nurse's Health Study and the Health Professionals Follow-up study. Participants that consumed two servings of any nut per week (56 grams) had lower overall mortality and mortality due to heart disease and cancer than those who consumed no nuts.232

While it may not be important to cut down on total fat, 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 recommended that overall consumption should be kept as low as possible.

The moderate use of alcohol is thought to help reduce cardiovascular risk, but the evidence regarding this subject is both inherently unreliable (because it is based on observational studies) and self-contradictory.72-75,186,222According to the best current evidence available, it appears to be the alcohol in alcoholic drinks that provides benefits rather than, as previously thought, particular substances found in wine.222 The optimal intake appears to be about one drink per day for women, and 1-2 drinks per day for men. However, all of these statements are subject to revision, because, as discussed above, they are based on problematic evidence.

A randomized trial of 246 postal workers showed a decrease in 10-year risk assessment of heart disease when naturopathic care was added to usual care for 1 year compared to usual care alone. Naturopathic care included individualized health promotion, diet and lifestyle counseling, nutritional medicine, or dietary supplements. Keep in mind that this trial assessed the risk of heart disease it did not follow participants to see who actually developed heart disease. The trial also had some technical and statistical challenges that may have affected the outcome.231

An evaluation of 23 randomized trials with 1,461 people with coronary artery disease compared the addition of music therapy to standard care and standard care alone on stress and anxiety levels. Music listening was associated with a moderate reduction of both stress and anxiety in people who had a heart attack, were facing heart surgery, or were in cardiac rehabilitation. Music also appeared to have a beneficial effect on blood pressure, heart and breathing rates, and pain.233

Physical activity is a must for reducing risk of cardiovascular disease. There are countless ways to get exercise, but finding the right one can be tricky. Some people prefer a more nontraditional route to increasing their physical activity level. Yoga is believed by its practitioners to provide benefits above and beyond simple exercise. However, there is only minimal scientific evidence that the practice of yoga actually provides any well-defined medical benefits.

This was highlighted in a recent review of 11 randomized trials of 800 people with moderate to high risk of cardiovascular disease. At least three months of yoga showed some improvement in lowering diastolic blood pressure, triglycerides, and raising high density lipoproteins (the good cholesterol) when compared to little or no intervention. However, the trials were small and of low quality, making it difficult to draw absolute conclusions about yoga's effects on blood pressure and cholesterol.234