Heart Health Claims Shed Light on Cardiovascular Disease

The year 2000 was an instrumental period for heart health. Organizations such as the American Heart Association (AHA) and the Food and Drug Administration (FDA) attempted to address the number one killer among Americans by updating dietary guidelines and implementing a handful of important heart health claims.

It is estimated that almost 60 million Americans have one or more types of cardiovascular disease (CVD), which can encompass coronary heart disease (CHD), stroke, high blood pressure, congestive heart failure and rheumatic heart disease. According to the AHA, CVD claimed more than 953,000 lives (41.2 percent of all deaths) in the United States during 1997. The statistics continue to rise as more Americans are diagnosed with high blood pressure and CHD, which is the basis of heart attacks and angina (chest pain).

The study of CHD is complicated since no single cause can be pinpointed. Several factors such as an atherogenic or high fat diet and high cholesterol levels can cause coronary arteries to narrow. In addition, a combination of risk factors including genetics, sex, age, elevated blood lipid levels, hypertension, cigarette smoking, lack of physical activity, obesity and diabetes may trigger the disease.

While cholesterol seems to be a major culprit behind heart disease, the body actually needs a certain amount of it to function properly. Produced in the liver and absorbed from the diet, cholesterol helps build cell membranes and some hormones. It circulates in the body in several complex forms, including low-density lipoprotein (LDL) cholesterol, or "bad" cholesterol, and high-density lipoprotein (HDL) cholesterol, often referred to as "good" cholesterol.

People have assumed that as long as LDL cholesterol levels are low, the risk for heart disease is slim. However, research indicates this might not always be the case. For example, when HDL levels are low cardiac risk increases; when individuals have both low LDL and low HDL levels the risk for CHD can increase three-fold.

HDL protects arteries by scavenging and sending excess cholesterol back to the liver where it is metabolized into hormones and bile acids. Currently, there is no definite method to raise HDL; however, exercise, a healthy diet and weight loss has been said to help HDL levels. Other nutrients such as coenzyme Q10, L-carnitine, niacin and magnesium are being touted as nutritional supplements that raise HDL levels. A study in the January 1999 issue of the International Journal of Cardiology (68(1):23-29, Jan 1999) found that CoQ10 was shown to lower levels of lipoprotein alpha (another risk factor associated with heart disease) and raise HDL.

On the flip side, too much cholesterol can contribute to fatty buildup in the arteries (also known as atheroscelerosis), causing plaque deposits to narrow the arteries, making the heart work harder to force the blood through. If enough deposits accumulate in the coronary arteries, which supply blood to the heart, flow can be impeded and the heart can become starved for oxygen, resulting in chest pain. If a blood clot forms and completely obstructs the artery, a heart attack can occur.

Over the past two decades, considerable evidence has been gathered to support the hypothesis that soy, plant sterols, omega-3 fatty acids and various antioxidants have beneficial effects on cholesterol and high blood pressure. Soy protein, with naturally occurring bioactives, can lower cholesterol and may decrease plaque formation in the arteries; plant sterols and plant stanol esters absorb cholesterol from the diet, also lowering cholesterol levels; and omega-3 can reduce irregular heartbeats associated with sudden cardiac death and lower triglcyerides, a type of fat in the blood associated with low levels of HDL.

In an attempt to promote these benefits and educate consumers, several manufacturers and organizations, under the FDA Modernization Act of 1997, submitted notifications for a health claim to the FDA (which is based on an authoritative statement from an appropriate scientific body of the U.S. government or the National Academy of Sciences) As a result, FDA approved four heart health claims during 1999 and 2000.

Soy And Heart Health

In terms of heart health, soy has been heralded as an important supplement in lowering and maintaining cholesterol levels and reducing the production of plaque deposits. Studies investigating the role of isoflavones in soy products have shown that genistein, a component of soy, interferes with the action and accumulation of platelets by reducing the production of platelet-derived growth factors and by inhibiting the action of thrombin, an enzyme that converts fibrinogen into fibrin to form a blood clot. Research also indicates that soy protein with naturally occurring bioactives is effective in delivering consistent, favorable impacts on blood cholesterol (J Nutr, 126:43-50, 1996) (A Int Med, 159: 2070-2076, 1999).

A multitude of studies conducted on soy indicate that daily consumption of 25 g of soy protein can reduce high cholesterol and heart disease risk. St. Louis, Mo.-based Protein Technologies International (PTI), a unit of the Dupont Co., submitted a petition for a heart health claim in 1998. In October 1999, FDA ruled that qualifying low fat foods containing at least 6.25 g of soy protein per serving could add a heart health claim on their product label. The product also must contain less than one gram of saturated fat and no more than 20 mg cholesterol, three grams of fat and 480 mg of sodium.

In the AHA's dietary guidelines published on Oct. 31, soy was included as an important part of a heart-healthy diet. "We are emphasizing the positive message of what people should eat--for example, more plant based foods," said Ronald M. Krauss, M.D., the principal author of the guidelines and a senior scientist at the Lawrence Berkeley National Laboratory at the University of California. "In the past, we have focused rather heavily on the percent of calories as fat and amounts of cholesterol. These are still important considerations, but the emphasis has shifted to allow consumers to understand the importance of an overall eating plan."

Soy is just the latest addition to a growing list of foods including orange juice, bananas, leafy green vegetables and oatmeal that experts recommend eating every day to lower the risk of heart disease. Soy protein may also help reduce saturated fat and decrease cholesterol in diets. "We are thrilled that such a well-respected health care and consumer organization as the American Heart Association confirmed the contributions of soy protein to heart-healthy lifestyles," said Stephan Tanda, president of PTI.

A study conducted by John Erman, a professor of food science and human nutrition at the University of Illinois in Urbana, validated the soy claim, noting that Asians who have a high intake of soy and a low intake of meat and dairy have almost 50-percent less risk for CVD when compared to Europeans and Americans. Another study (Am J Clin Nutr 71(5): 1077-84, May 2000) further investigated the effects of replacing animal protein with soy protein as a way to reduce cholesterol concentrations and found that consuming as little as 20 g of soy protein instead of animal protein for six weeks reduces concentrations of non-HDL cholesterol by approximately 2.6 percent.

Plant Esters, Potassium Net Claims

With the implementation of the soy health claim, other manufacturers took note. The next heart health claim occurred when Englewood Cliffs, N.J.-based Lipton, manufacturer of Take Control spread, and McNeil Consumer Healthcare, located in Fort Washington, Pa., submitted petitions to FDA that plant sterol and plant stanol esters could reduce the risk of CHD. In September 2000, FDA authorized a health claim for plant sterol and plant stanol esters for their role in reducing the risk of CHD. The final rule was supported by more than 20 scientific studies from the United States and Europe that found these fatty plant tissues could block the absorption of cholesterol, thus lowering blood cholesterol levels. Researchers in Kuopio, Finland, attempted to compare the effects of these plant tissues found in margarines used to lower cholesterol. Thirty-four patients consumed three kinds of rapeseed oil-based margarines (both stanol ester and sterol ester-enriched margarine) as part of a low-fat diet. The researchers concluded that both margarines reduced significantly and equally serum total and LDL cholesterol concentrations as part of a low-fat diet (Eur J Clin Nutrition 54(9): 715-25, Sept. 2000).

Not only do certain margarine spreads qualify for this claim, but also salad dressings, snack bars and dietary supplements that contain plant sterol or plant stanol esters and that also meet the requirement of low saturated fat, low cholesterol and less than 13 grams of fat per serving and per 50 grams. Spreads and salad dressings are exempt from meeting the limit of fat per 50 grams if the label bears a disclosure statement referring consumers to the nutrition facts section for information about fat content. Additionally, the food must contain at least 10 percent of the Reference Daily Intake (RDI) or Daily Reference Value (DRV) of vitamin A, vitamin C, iron, calcium, protein and fiber. FDA also requires that the claim state that plant sterol and plant stanol esters should be consumed as part of a diet low in saturated fat and cholesterol.

Around the time these companies were awaiting approval by the FDA for the plant sterol and plant stanol esters heart health claim, Tropicana Products submitted a proposed claim concerning the relationship of potassium-containing foods to blood pressure and stroke.

High blood pressure, or hypertension, is the most prevalent cardiovascular disorder in the United States, affecting 24 percent of American adults. Most people using dietary means to control hypertension usually think of decreasing sodium intake. The potassium heart health claim offers an additional strategy. By increasing the intake of foods that are rich in potassium, individuals can leverage their blood pressure. "We have known that potassium is a key player in blood pressure and stroke regulation for some time, but we haven't passed this message along to our patients," said Lawrence Appel, M.D., M.P.H, associate professor of medicine at John Hopkins University. Appel led the Dietary Approaches to Stop Hypertension (DASH) trial (Am J Hypertens, 13(9): 949-55, Sept. 2000) that proved a diet consisting of potassium-rich fruits and vegetables can lower blood pressure in people with normal and high blood pressure levels. "So much of what people know about nutrition today comes from what they read on food labels. This health claim will be a tremendous help in teaching people about potassium's benefits," Appel said

In order for the claim to be approved, the notification cited two statements from the report Diet and Health: Implications for Reducing Chronic Disease Risk as authoritative statements for the claim. The first statement said, "epidemiological and animal studies indicate that the risk of stroke-related deaths is inversely related to potassium intake over the entire range of blood pressures, and the relationship appears to be dose dependent. The combination of a low-sodium, high potassium intake is associated with the lowest blood pressure levels and the lowest frequency of stroke in individuals and populations. Although the effects of reducing sodium intake and increasing potassium intake would vary and may be small in some individuals, the estimated reduction in stroke-related mortality for the population is large." The second statement noted that, "vegetables and fruits are also good sources of potassium. A diet containing approximately 3.5 g of elemental potassium daily may contribute to reduced risk of stroke, which is especially common among blacks and older people of all races."

A Fishy Matter

A more controversial heart health claim is based on omega-3 fatty acids and its potential effects of reducing the risk of CHD. While fish oil, which is rich in omega-3, may have a beneficial effect on CHD, the lack of current scientific agreement (the precursor for qualifying for a health claim) does not permit the omega-3 heart health claim to read "omega-3 fatty acids may reduce the risk of CHD." Instead, omega-3 received a "qualified" health claim because the evidence for the claim outweighed the evidence against it.

This qualified claim focuses specifically on a potential relationship between the long-chain omega-3 fatty acids eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and low rates of CHD. "This is an important area of distinction that has been needed for a long time," said Dr. Mary Van Elswyk, vice president of Scientific Affairs at OmegaTech. "There are many omega-3 fatty acids but they do not all have the same benefits. Consumers have been misled by products that promise heart health benefits associated only with the marine-type fatty acids EPA and DHA. The FDA was very clear in stating that the evidence is not sufficient to suggest that LNA (linolenic acid found in flaxseed) may reduce the risk of heart disease." According to the new claim, any product that provides only LNA and uses the health claim could be considered misbranded and subject to FDA enforcement.

On Oct. 31, 2000, FDA published a letter defining the qualified health claim for the link between CHD and the fats DHA and EPA. In this letter, FDA noted that an acceptable omega-3 claim should read, "Scientific evidence about whether omega-3 fatty acids may reduce the risk of coronary heart disease (CHD) is suggestive, but not conclusive. Studies in the general population have looked at diets containing fish and it is not known whether diets or omega-3 fatty acids in fish may have a possible effect on a reduced risk of CHD. It is not known what effect omega-3 fatty acids may or may not have on CHD risk in the general population."

However, many believe this claim is too wordy, including Jonathan Emord, a lawyer for the plaintiffs in Pearson v. Shalala. He stated that companies in the omega-3 business plan to inundate the market with a consumer-savvy revised version of the FDA claim, not only on dietary supplements but on food products as well.

The FDA opted for the qualified claim based on the data that omega-3 benefits were strongly favorable in a disease population (those with heart disease), but for the general population, FDA stated that the evidence regarding omega-3 fatty acids and its relationship to heart disease was suggestive but not conclusive. Also, FDA stipulated that labels must guide customers to consume less than two grams (preferably only one gram) per day so as to not exceed the upper intake level of three grams per day; the agency explained in its letter that this is a safety precaution, as every individual has different omega-3 baseline levels.

In the Spotlight

The topic of cardiovascular health continues to flourish as Americans begin to lead more heart-healthy lives. For them, these heart health claims are an important first step in tackling the disease. As more heart-friendly products enter the market, alternatives to traditional methods are giving consumers more options to address and defeat this fatal disease. By offering literature and books on these supplements and functional foods, as well as visiting the AHA's Web site (www.americanheart.org) for the latest news on heart health, retailers can be better positioned to answer questions about these heart health claims and any others poised in the horizon.

Share this article: Email, Slashdot, Digg, Del.icio.us, Yahoo!MyWeb, Windows Live Favorites, Furl
Add this article feed to: RSS, My Yahoo, Newsgator, Bloglines