Monday, March 24, 2008

Cardiovascular Disease and Nutrition: An Overview

Cardiovascular disease, you have heard the term before. It is one of the most well-known and well-publicized conditions today, and with good reason. Cardiovascular disease (CVD) remains the No. 1 killer in the U.S. Deaths from this disease in 1997 were more than 720,000, and according to the Center For Disease Control 21 million cases are reported annually.

However, did you know that CVD is actually a term used to indicate a collection of conditions or risk factors that have a detrimental effect on the heart and vascular system? These risk factors or conditions associated with CVD include; elevated blood pressure, cholesterol, blood homocysteine levels, blood lipoproteins levels, diabetes and free radical damage. Sounds a little more complicated now than just cholesterol levels, doesn't it?

The two most common dietary factors associated with cardiovascular disease are fat and cholesterol. However, recent data suggests arterial plaque development has several other contributing factors, which highlights the point that focusing primarily on dietary intake of fat and cholesterol alone may not be sufficient to prevent CVD in some people.

While medical science has identified some genetic causes of this condition, the majority of risk factors for cardiovascular disease are associated with diet, nutrition and lifestyle. Some of these factors include consumption of salt, saturated fats, polyunsaturated fats, and hydrogenated or partially hydrogenated oils.

To understand the role diet has in the development of CVD, let's first outline the process of arterial plaque development (the process of developing clogged arteries). Essentially, the process of arterial plaque development is related to Low-Density lipoproteins (LDL). These fat-protein molecules attach to the endothelial arterial walls and become oxidized or glycosylated. This process of oxidizing LDL is capable of damaging the arteries and initiating the process called atherosclerosis. Once the arterial walls are damaged, plaque builds up and eventually obstructs the artery. In the case of a coronary or heart-supplying artery, you have a heart attack. So, controlling this plaque formation process is seen as the key to prevention and treatment of CVD.

Further complicating the issue is the fact that polyunsaturated vegetable oils, which were thought to be "heart-healthy," are actually very damaging to the vascular system. These are the oils and fats commonly found in "cholesterol-free" foods. It turns out these fats may be even more damaging for you than the cholesterol containing fats you are trying to avoid. An article in Natural Health Resources says high intake of polyunsaturated fats and oils, without adequate antioxidant protection, appears to actually increase the risk of cardiovascular disease. According to the latest research, polyunsaturated oils are easily oxidized, which results in the creation of free radicals that can lead to vascular damage.

A related issue is the process of hydrogenation. Hydrogenation turns polyunsaturated fats into products such as margarine, shortening and other types of processed foods. This process of partial hydrogenation alters the structure of fats, creating trans-fatty acids. As with the polyunsaturated fat itself, trans-fatty acids appear to be as, or even more, damaging than just plain saturated fats. In fact, according to that same Natural Health Resources article, trans-fatty acids have been shown to be positively associated with an increased risk of cardiovascular disease.

The issue with trans-fatty acids is they actually block an enzyme that would normally help metabolize cholesterol and remove it from the body. Which means, eating modified polyunsaturated fats actually increases your serum cholesterol, not the other way around. In fact, in a study cited in Nutrition Reviews , individuals who consumed the most trans-fatty acids (an average of 5.7 gm/day) were found to be 50 percent more likely to develop cardiovascular disease than individuals who consumed the least (2.4 gm/day).

The moral of this story is that margarine and other trans-fatty acid-containing foods may be cholesterol-free, but they inhibit the body's ability to eliminate cholesterol, which may actually increase your serum (blood) cholesterol instead of lowering it. So is there any fat okay to eat? Most research on the subject indicates that monounsaturated olive oil appears to be the healthiest dietary fat/oil and is part of the much-publicized Mediterranean diet.

Salt is another dietary factor that impacts cardiovascular disease. Approximately 60 percent of hypertensives (those with high blood pressure) are "salt sensitive" according to an article in the Journal of the American College of Nutrition . In these individuals, increased salt (sodium chloride) sends their blood pressure through the roof! However, many people who are avoiding the salt shaker in an attempt to reduce their salt intake may be missing the enormous amount of "hidden salt" added to fast foods and processed foods. So, to adequately reduce your salt intake, a reduction in fast foods is also in order. In addition, check the label of all processed foods to determine how much salt you are actually eating.

Potassium is another component of the CVD prevention program worth mentioning. Although having no direct correlation to cholesterol, adequate potassium levels appear to play an important role in the prevention of cardiovascular incidents, (which is a nice way of saying heart attacks and strokes). In fact, in a 12-year study cited in the New England Journal of Medicine , individuals who died from strokes had significantly lower potassium intake than survivors of strokes and individuals who died from other causes. Another important fact outlined in this study was that eating just one serving of potassium-rich fresh fruits or vegetables daily may provide a 40 percent reduction in the risk of having a stroke. The lesson here is to eat a diet full of fresh fruits and vegetables. Some potassium-rich foods include avocados, bananas, chard, citrus fruits, lentils, nuts, parsnips, sardines and spinach.

Regardless of any food supplements you may be taking to reduce your risk for CVD, a healthy whole-food diet remains your best defense. In fact, a healthy diet alone may be enough to prevent or reduce the risk of developing this disease. Epidemiological studies posted in the Journal of the American College of Nutrition clearly show that a higher consumption of fresh fruits and vegetables (rich in phytochemicals) is associated with a reduced risk of cardiovascular disease. In addition, the reduction of salt (for salt sensitive individuals) and appropriate use of monounsaturated olive oil will go a long way in maintaining a healthy cardiovascular system.

Now, many reading this article may have trouble eating the five fruit and vegetable servings per day recommended for optimal health and prevention of CVD. If this is you, taking a few food supplements may help you make up where your diet leaves off.

While there are many food supplements that are useful in maintaining cardiovascular health and preventing disease, only a few seem to have benefits that are specific to CVD prevention. These are: magnesium, vitamin E and C, Coenzyme Q1O, and Garlic.

A story in Natural Health Resources reports that magnesium deficiency has been associated with an increased incidence of atherosclerosis, hypertension, strokes, heart attack and diabetes.

Vitamin E has been shown to play a powerful role in the prevention of heart attacks because it can reduce platelet adhesion (clot formation) and prevent oxidation of LDL cholesterol. (Please note that dosages over 400IU of Vitamin E may cause blood thinning and prolonged bleeding. Those taking blood thinners such as Coumadin® should consult their healthcare professional before taking this supplement).

Vitamin C can also have an effect on cardiovascular disease. In a study cited in the American Journal of Clinical Nutrition , individuals consuming vitamin C at two to three times the RDA had improved lipid profiles, corresponding to a reduced risk of cardiovascular disease.

Coenzyme Q10 is involved in the production of energy at the cellular level and is also a key nutrient for the heart. Current theory suggests a significant portion of congestive heart failure may be due, at least in part, to a coenzyme Q10 deficiency.

Lastly, while not a vitamin or mineral, garlic is an herb that appears to benefit those with cardiovascular disease. According to an article in the British Journal of Clinical Pharmacology garlic is effective in lowering elevated serum cholesterol and triglycerides and inhibits platelet aggregation, which may help prevent a heart attack or stroke.

Although food supplements are beneficial to the cardiovascular system and help to reduce or prevent the development of CVD, a diet rich in fresh fruit and vegetables is still the best means of prevention. Food supplements are very useful and even necessary at times, but they can only do so much if your diet is poor.

As cardiovascular disease is predominately related to lifestyle, it is within the power of each of us to make the lifestyle changes today that will ensure we have a healthy and strong cardiovascular system tomorrow. Prevention is the key and a diet rich in fresh fruits and vegetables is a good start on the road to a healthy heart.

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