Heart disease remains the leading cause of death for men and women in the U.S. coronary heart disease (CHD), the most common type, kills nearly 380,000 people annually. The health costs are staggering, coming at a cost of nearly $109 billion per year in health care services, medications and lost productivity. Although diet is the most controllable risk factor for heart disease, few Americans come close to meeting dietary goals for proven heart-healthy foods like fruits and vegetables and whole grains. According to the Center for Disease Control’s (CDC) “State Indicator Reports” in 2013, the median intake of fruits for adults is 1.1 servings per day and for vegetables is 1.6 servings per day.
According to the USDA dietary guidelines, Americans should be consuming half of their grains as whole grains, yet the U.S. National Health and Nutrition Examination Survey (NHANES) for 2009 to 2010 showed that 39% of children and teens, and 42% of adults, reported consuming no whole grains at all. In fact, only 3% of children and 8% of adults are meeting recommended intake levels of whole grains. This is in spite of massive efforts by food manufacturers—especially those making bread and other bakery products—and food and beverage product developers to convert formulations to whole-grain versions and to create new, whole grain-centered products.
There are multiple reasons why fruits, vegetables and whole grains are associated with a reduced risk of heart disease in particular and cardiovascular diseases in general. From vitamins such as A, C, E and folate to minerals such as calcium, potassium, selenium and zinc, to phytochemicals such as resveratrol, quercetin and anthocyanin, plant-derived foods pack systemic health in multiple forms.
These ingredients also are great sources of soluble fibers, defined by their water-binding ability. Soluble fiber has been shown to lower undesirable cholesterol levels, particularly low-density lipoprotein (LDL) cholesterol, considered by some experts to be a primary risk factor for heart disease.
The ability to form a gel allows soluble fiber to bind bile acids, which are secreted into the small intestines to aid in the digestion of fat and prevent their reabsorption. This forces the liver to pull more cholesterol, the precursor to bile, out of the blood. There are many different soluble fibers in foods and each food has its own characteristic mix. All work by the same mechanism, so any food rich in soluble fiber provides this benefit.
The most notable heart-healthy grains are oats and barley. These are especially rich in beta-glucans. Beta-glucans are glucose polysaccharides connected via beta-glycosidic bonds. They activate the immune system by binding to immune cells and triggering their ability to distinguish between “self” and “non-self” and have also tumor-fighting capacity. However, they also have the ability to lower cholesterol levels and promote cardiovascular health.
Mushrooms and certain yeasts are also sources of beta-glucans. Other whole grains rich in soluble fiber include, quinoa, millet, buckwheat and teff. All legumes (peas, beans, and lentils) are also rich sources of soluble fiber as well as many fruits and vegetables.
A Matter of Function
Healthy heart function is dependent on a number of nutrients, and is potentially benefited by numerous phytochemicals in whole foods. However, from a marketing standpoint, there are in fact a very limited number of foods or food ingredients for which heart health claims can be made.
Beta-glucans are allowed a claim in relation to contribution to normal blood cholesterol. Also, nuts of all kinds have been shown to reduce the risk of heart disease, earning these foods the following qualified statement by the FDA: “Scientific evidence suggests but does not prove that eating 1.5 ounces per day of most nuts [such as name of specific nut] as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease.”
A similar claim can be made for omega-3 fatty acids. And a more cautious claim may be made for omega-9 (monounsaturated fatty acids) from oils like olive oil and canola oil: “Limited and not conclusive scientific evidence suggests that eating about 2 tablespoons (23g) of olive oil daily may reduce the risk of coronary heart disease due to the monounsaturated fat in olive oil. To achieve this possible benefit, olive oil is to replace a similar amount of saturated fat and not increase the total number of calories you eat in a day.” These particular fatty acids and other fat-soluble substances, including sterols and fat-soluble vitamins, are grouped as “bioactive lipids”—lipids that do more than provide energy. Over the decades, much study has been—and continues to be—devoted to determining their effect on health and how to incorporate them into foods and beverages when determined beneficial.
Polyunsaturated fatty acids from the omega-6 family include linoleic acid (LA) and its isomer, conjugated linoleic acid (CLA). The former is found in oils like corn, soybean, sesame, and many others. The amount of LA in the American diet has changed greatly over the past several decades due to the increased use of corn and soy oils rich in this fatty acid.
This has generated some controversy over the role of LA in the modern diet. Nevertheless, the American Heart Assn. recommends that 5 to 10% of energy be derived from foods rich in LA. CLA, a naturally-occurring trans-fatty acid is found in dairy products and the meat from ruminant animals and is under investigation for its potential role in weight management. It has none of the negative effects of trans fatty acids derived from partial hydrogenation.
The fatty acids most closely associated with reduction of risk factors for cardiovascular disease are the omega-3 polyunsaturated acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fractions are derived from alpha-linolenic acid (ALA), the omega-3 fatty acids abundant in algae consumed by marine life lowest on the food chain. They are converted to the longer chain more highly unsaturated EPA and DHA by specific enzymes in animals.
Non-nutritive Heart Helpers
Many green plants, along with walnuts, soybeans and other legumes and seeds, also contain ALA. “Health benefits of plant-derived alpha-linolenic acid,” a paper recently published in the American Journal of Clinical Nutrition, described the relationship between ALA and cardiovascular diseases. The determination is that ALA confers modest protection against CVD. Although the strength of the evidence is not considered to be as strong as that for EPA and DHA, the last 10 years have witnessed an increase in the number of studies that do support this protective association.
Carotenoids are an important class of bioactive lipids. They include beta-carotene, most notable as the compound the body converts to vitamin A, along with lycopene responsible for the red color in many foods. Xanthophylls are a lipid-soluble phytochemical related to carotenoids. This class includes lutein and zeaxanthin, antioxidants also known to protect the macula portion of the retina from degeneration with age. The antioxidant potential of these lipids has demonstrated the ability to help to reduce the buildup of plaque in the arteries. This indicates these compounds are important for the heart as well as the eyes.
Another class of so-called bioactive lipids include phytosterols, plant chemicals with a structure similar to cholesterol in animals. They have been under investigation for decades because of their ability to interfere with the absorption of dietary cholesterol. The FDA allows the following health claim: “Foods containing at least 0.65g per serving of plant sterol esters, eaten twice a day with meals for a daily total intake of at least 1.3g, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. A serving of [name of the food] supplies___grams of vegetable oil sterol esters.”
As with the cells of any hard-working muscle, the cells of the heart are rich in mitochondria, the minute powerhouses that complete the task of converting food into adenosine triphosphate (ATP), the energy currency of the body.
The creation of ATP from the carbohydrates, fats and even proteins requires a coordination of B-vitamins and minerals such as magnesium and iron. Muscle contraction is highly dependent upon consistent levels of blood calcium. Both calcium and magnesium at RDA levels are associated with normal blood pressures or even reduction of hypertension. Hypertension is one of the primary risk factors for heart disease. The amino acid, homocysteine, is associated with increased risk of CVD. It is thought to promote atherosclerosis by damaging the inner lining of arteries, beginning the response to injury scenario. Homocysteine levels in blood are influenced by diet and genetic factors. Folic acid, along with vitamins B6 and B12, help to break down homocysteine. Though the AHA stops short of labeling high homocysteine levels a risk factor for CVD, the group does recommend foods rich in these vitamins.
On the Q
In addition to the B vitamins that help to transform dietary fuel into ATP, iron is necessary to run the mitochondrial energy systems that produce about 90% of the ATP. The ubiquitous coenzyme Q10 (CoQ10) could be considered one of the most unique lipid-soluble compounds.
CoQ10 has a duel role in heart function. As an integral part of the electron transport chain, CoQ10 is critical to ATP synthesis.
The body makes far more CoQ10 than is necessary for energy production. CoQ10 is also a primary fat- soluble antioxidant, one that aids
vitamin E in protecting cell membranes from oxidation. This oxidation can be thought of as a kind of biological rust that can also damage proteins and DNA. In addition, CoQ10 supplementation has been shown to inhibit oxidation of LDL cholesterol.
Atherosclerosis, the buildup of plaque in the arteries, is best described by the “response to injury hypothesis,” whereby immune cells known as monocytes are recruited to the blood vessel walls in response to a small injury or change in the integrity of the blood vessel endothelium. This recruitment requires that the monocytes express adhesion molecules called integrins.
Early experiments on healthy men and women consuming 200 mg/day of CoQ10 for 10 weeks resulted in significant decreases in monocyte expression of integrins. This suggests that CoQ10 may offer protection from cardiovascular disease by a mechanism that is independent of energetics or antioxidant protection. The process of mitochondrial respiration that generates ATP, requires oxygen and as a result creates some reactive oxygen species (ROS), the very free radicals that can cause so much potential damage. CoQ10 is one of many endogenous (self-produced) antioxidants that function to protect the organism from self-generated oxidation. Pollution and various diseases increase a variety of dangerous free radicals and subsequent oxidative damage. Endogenous antioxidants are complemented by vast array of plant-derived antioxidants known generally as flavonoids. There are hundreds of these potentially beneficial compounds, mostly in fruits and vegetables that are studied for their cardioprotective potential.
The Other E
While vitamin E has a long history of study as an antioxidant, until recently attention was focused almost exclusively on the form of the vitamin known as tocopherol. However, there are two main forms of the vitamin—tocopherol and tocotrienol—each with four subforms, alpha, beta, gamma and delta. All forms are lipid soluble, however these forms also can all be microencapsulated for inclusion in water-based liquids.
Although studied for a wealth of surprising and formidable health benefits, including protection against cancer as well as the ability to trigger apoptosis (cancer-cell death), tocotrienols have been shown in studies to have up to 400 times the antioxidant effect of the tocopherol form. This would make them especially desirable as a component of heart-health formulations.
In a review of tocotrienols released in 2011 in the peer-reviewed medical journal Current Pharmaceutical Design, author Kedar Prasad, Ph.D., presented an overview of the importance of tocotrienols to cardiovascular well-being. “Tocotrienols reduce serum lipids and raise serum HDL-C,” Prasad wrote. “Alpha-tocopherol, on the other hand, has no effect on serum lipids. Tocotrienols have greater antioxidant activity than tocopherols. Both reduce the serum levels of C-reactive protein (CRP) and advanced glycation end products, and expression of cell adhesion molecules. The CRP-lowering effects of tocotrienols are greater than tocopherol. Tocotrienols reduce inflammatory mediators, delta-tocotrienol being more potent, followed by gamma- and alpha-tocotrienol.”
Prasad also noted that tocotrienols are antithrombotic and curb the expression of matrix metalloproteinases, suppressing, regressing and slowing the progression of atherosclerosis. Comparing it to vitamin E’s better-known “sister” form, Prasad noted, “Tocopherol only suppresses, and has no effect on regression and slowing of progression of atherosclerosis” noting also that tocotrienol “reduces risk factors for destabilization of atherosclerotic plaques.”
Phytochemicals and Vitamins
Flavonoids constitute a related group of compounds that plants synthesize often as protection from ultraviolet light and an oxygen environment. They are subdivided into several classes under investigation for their potential to explain some of the health benefits associated with diets rich in fruit, vegetables, whole grains and nuts. A class of these flavonoids, anthocyanidins are the chemical compound that colors fruits, berries, grapes and other plants red, blue and purple.
Flavanols are a similar class of flavonoids compounds and include catechins from green and white teas, chocolate, berries, grapes and apples. They also include theaflavins found in black and oolong teas and proanthocyanidins from chocolate, apples, berries, red grapes and red wine.
Red, blue and purple berries, as well as other fruits, have enjoyed a great deal of popularity as heart-healthy fruits, with recent years seeing blueberries, strawberries and raspberries regaining ground from more exotic superfruits, such as açai and mangosteen. But a resurgence in popularity for exotics is adding to a national love affair with cardiofriendly fruits.
Pomegranates are enjoying a renewed popularity, and relative newcomers to the U.S. scene, such as aronia berries, are getting noticed. Aronias have higher antioxidant levels than other high ranking fruits and vegetables, and demonstrated an ability to improve the circulation of blood, make blood vessels stronger and reduce the risk of heart disease.
Other flavonoids include isoflavones from soybeans. Resveratrol—a polyphenol also found in red and purple berries and grapes—has been shown to inhibit platelet aggregation and inflammatory enzymes under laboratory conditions. Many ingredients are associated with heart health via a variety of mechanisms.
Heart health is linked to many different physiological systems. This principle is demonstrated by recent studies into the effect of the fat-soluble vitamin K. The results of an observational study on vitamin K intake and CVD were published in the April 2 issue of Clinical Nutrition.
Taking data from 24-hour dietary recall as part of NHANES III, researchers compared vitamin K intake with National Death Index records through 2006. Participants with higher than recommended adequate intake for vitamin K were associated with lower risk of both all-cause mortality and CVD mortality. The link between vitamin K and CVD could be via coronary artery calcification (CAC), a known predictor of CVD.
Vitamin K normally modifies certain proteins such that they bind calcium, which is how the vitamin performs its essential role in blood clotting and mineralization of bone. CAC occurs when calcium accumulates in the muscular layers of the vessel wall of the coronary arteries contributing to the atherosclerotic plaque. Vitamin K could help reduce the potential for CAC by activating a calcification inhibitor expressed in the arties called matrix Gla protein (MGP).
There are two natural forms of vitamin K1, phylloquinone and K2, menaquinone, with different subtypes. K1 is the type found in green plants where it is necessary for photosynthesis. In the body, K2 is synthesized in the gut and stored mostly in the liver, which accounts for about half of our needs. It is K2 that is a believed to have the potential to reduce or prevent CAC.
There is much interest in food components that might act in a manner independent of their nutritional function. For example, biologically active peptides (“bioactive peptides”) are defined as food-derived peptides that exert hormone-like effect in humans that go beyond simple nutritional function. Many of these peptides (tiny fragments of proteins) are found in whole protein foods, such as milk, eggs, meat, fish and a variety of plants.
Some bioactive peptides have demonstrated antihypertensive effects. Reduction of hypertension (high blood pressure) reduces the risk of heart disease. Others have exhibited antioxidant effects. Of recent interest are the bioactive peptides derived from microalgae.
Algae has a long history as a food source. In Japan, annual per capita consumption of algae is up to 1.6 kg. We may recognize these products as the seaweed covering sushi, or dulse sprinkled as a seasoning. Algae are valuable additions to the diet, rich in vitamins A, C, D and E, along with the B vitamins (riboflavin, niacin, pantothenic acid, and folic acid). They contain significant sources of minerals like calcium, phosphorus and potassium, and can be valuable sources of soluble fiber.
According to the recent article “Heart Health Peptides from Macroalgae and Their Potential Use in Functional Foods,” published in the Journal of Agricultural and Food Chemistry, “microalgae hold promise as a new source of bioactive peptides in addition to their high protein content and overall nutrient dense profile.”
There is no nutritional magic bullet that completely reduces the risk of CVD. There are, however, a number of dietary ways to hedge our bets in favor of heart health. And this includes a wealth of ingredients suitable for use in foods and beverages as well as supplements. While presently, there are a limited number of health claims that can be made for heart-healthy ingredients, research is ongoing into a parade of new and re-examined functional ingredients that are both sustainable and beneficial to consumers.