Functional Foods and Nutraceuticals
Melissa H. Frisvold
In the 21st century, the focus of the relationship between eating habits and health is changing from an emphasis on health maintenance through recommended dietary allowances of nutrients, vitamins, and minerals to an emphasis on the use of foods to provide better health, increase vitality, and aid in preventing disease and many chronic illnesses. The connection between food and health is not new. Indeed, the adage “Let food be your medicine and medicine your food” was adopted by Hippocrates (trans. 1932). Today, the philosophy that supports the paradigm of nutraceuticals as functional foods is once again at the forefront.
The U.S. consumer has become increasingly interested in the use of functional foods and nutraceuticals to improve health. There has been a paradigm shift from a reliance on prescription drugs to the realization that food can and should play an important role in health and well-being. This shift has created a market for functional foods and nutraceuticals (Bagchi, 2008). With the developing market of functional foods, it is estimated that in 2010 consumers in the United States spent approximately $126.31 per capita out of pocket on functional foods (Deloitte, 2012).
The vast array of nutraceutical products is staggering. Products range from single-ingredient nutrients such as calcium to drinks fortified with electrolytes and cereals fortified with iron (Haller, 2010). Many companies are using soy protein isolates in foods ranging from candy bars and salad dressings to infant formulas. Plant stanols and sterols are being added to margarinelike spreads in an effort to reduce total cholesterol and lowdensity lipoprotein (LDL) levels.
Coverage of all nutraceuticals is beyond the scope of this chapter. There has been a plethora of functional foods developed in recent times. An estimate is that more than 100 million people in the United States use nutraceuticals. This makes the nutraceutical industry an $86 billion industry (National Nutraceutical Center, 2012). In the interest of brevity, several selected products are covered in depth in this chapter. Because the use of nutraceuticals is so prevalent and because their use may impact health and wellness, it is important that nurses know about nutraceuticals and their potential benefits and risks.
DEFINITIONS
According to Haller (2010), the term nutraceutical is a portmanteau of the words nutrition and pharmaceutics. Originally coined by Dr. Stephen DeFelice, nutraceuticals are defined as “food, or parts of food, that provide medical or health benefits, including the prevention and treatment of disease” (National Nutraceutical Center, 2012). Nutraceutical categories include dietary supplements such as Ginkgo biloba, functional foods such as plant stanols, and medicinal foods such as health bars with added medication (National Nutraceutical Center, 2012). Nutraceuticals encompass any food part that may offer a benefit to health (Haller, 2010). These terms are often used interchangeably. The number and variety of nutraceuticals available in the United States are staggering, For example, many grocery stores carry cereals fortified with omega-3 fatty acids, Ginseng-enriched sports drinks, dairy products with various strains of probiotics, and orange juice that contains added calcium. The intent of the Dietary Supplement Health and Education Act, passed in 1994, was to protect the rights of consumers to have access to dietary supplements (and thus nutraceuticals and functional foods) to promote good health (Food and Drug Administration [FDA], 2012). Under the provisions of the law, dietary supplement ingredients are exempt from drug regulations; and thus premarketing approval, including demonstration of benefit and safety, is not required (Haller, 2010).
Functional foods are defined as manufactured foods for which scientifically valid claims can be made. They may be produced by food-processing technologies, traditional breeding, or by genetic engineering. Functional foods should safely deliver a long-term health benefit. Accordingly, a functional food may be one of the following:
A known food to which a functional ingredient from another food is added
A known food to which a functional ingredient new to the food supply is added
An entirely new food that contains one or more functional ingredients (Pariza, 1999)
The Japanese, who were among the first to use functional foods, have highlighted three conditions that define a functional food:
It is a food (not a capsule, tablet, or powder) derived from naturally occurring ingredients.
It can and should be consumed as part of a daily diet.
It has a particular function when ingested, serving to regulate a particular body process: enhancement of the biological defense mechanism, prevention of a specific disease, recovery from a specific disease, control of physical and mental conditions, and slowing of the aging process (PA Consulting Group, 1990).
According to these definitions, unmodified whole foods such as fruits and vegetables represent the simplest form of a functional food. For example, broccoli, carrots, or tomatoes would be considered functional foods because they contain high levels of physiologically active components such as beta-carotene, lycopene, and sulforaphane. Modified foods, including those that have been fortified with nutrients or enhanced with phytochemicals, are also within the realm of functional foods.
SCIENTIFIC BASIS
During the past century there have been many changes in the types of foods people eat. This reflects the application of scientific findings and technological innovations in the food industry. Although much research has been conducted on nutrition and health and disease, scientific exploration on the use of nutraceuticals has been more limited.
Interest in foodstuffs has generated investigation to link nutrient and food intake with improvements in health or prevention of disease. Studies in the epidemiological literature have been reviewed and suggest a possible association between a low consumption of fruits and vegetables and the incidence of certain diseases such as heart disease (He, Nowson, & MacGregor, 2006; He, Nowson, Lucas, & MacGregor, 2007), and a recent research article in the Journal of the National Cancer Institute (2013) suggests that vegetable consumption may reduce the risk of certain types of breast cancer (Rathner, 2013).
Much scientific study has been conducted on the role of the various products added to normal foods to enhance their ability to inhibit or prevent diseases. Many regard dietary intake as the best means of acquiring necessary nutrients (Kottke, 1998). For example, a report by the World Cancer Research Fund/American Institute for Cancer Research (2007) suggests that although there may be evidence to support that the consumption of some fruits and vegetables may protect against certain types of cancers, it is important to point out that these foods contain various
micronutrients and therefore it is difficult to tease out that a certain element of the food alone is responsible for this protective effect. However, supplementation of nutrients is common. Therefore, the findings of scientific research focused on selected nutraceuticals are summarized below.
micronutrients and therefore it is difficult to tease out that a certain element of the food alone is responsible for this protective effect. However, supplementation of nutrients is common. Therefore, the findings of scientific research focused on selected nutraceuticals are summarized below.
Dietary Plant Stanols and Sterols
The cholesterol-lowering potential of dietary plant stanols and sterols has been known for many years (Plat et al., 2012). Modifying plant stanols and sterols structurally makes them easily incorporated into fat-containing foods without losing their effectiveness in lowering cholesterol (Cater & Grundy, 1998). Dietary plant stanols and sterols inhibit the absorption of cholesterol in the small intestine, which in turn can lower LDL blood cholesterol (de Jong, Plat, & Mensink, 2003). In fact, it has been suggested that lifestyle modification, which includes dietary changes such as the inclusion of plant stanols and sterols, should be the primary treatment for lowering cholesterol (Turpeinen et al., 2012). Thus functional foods offer a safe and easily attainable method to decrease heart disease risk (Turpeinen et al., 2012). Currently, the recommended intake dose of plant stanols and plant sterols is 2g a day (Plat et al., 2012). However, it has been demonstrated in a limited number of clinical trials that a further reduction in LDL cholesterol may be achieved at doses as high as 9g a day but additional research is necessary before this can be recommended (Plat et al., 2012).
Plant sterols and their esters are generally recognized as safe (GRAS) food-grade substances, a designation indicating that there has been a history of safe intake of these products with no demonstrated harmful health effects found in the research (Wrick, 2005). Overall, the Nutrition Committee of the American Heart Association advises that stanols and sterol esters not be used as a preventive measure in the general population with normal cholesterol levels, in light of limited data regarding any potential risks. They may be used, however, for adults with hypercholesterolemia or adults requiring secondary prevention after an atherosclerotic event (Lichtenstein et al., 2006).
Glucosamine and Chondroitin Sulfate
Glucosamine, an amino sugar the body produces, and chondroitin sulfate, a complex carbohydrate found in and around cartilage cells, are natural substances (National Center for Complementary and Alternative Medicine, 2013). Glucosamine and chondroitin sulfate are two separate products; however, they are often sold together to diminish the pain and stiffness of osteoarthritis. Historically, German physicians were reported to be the first to use glucosamine in 1969 to diminish pain and increase mobility in patients with osteoarthritis (Natural Standard, 2013a). According to Kolata (2006), glucosamine and chondroitin sulfate are the most popular
supplements in the United States. Natural Standard ranks glucosamine and chondroitin sulfate as grade A (strong scientific evidence) for osteoarthritis of the knee, and chondroitin sulfate without glucosamine as grade A for general osteoarthritis (2013b). The results of several studies in the literature, however, have been mixed. A National Institutes of Health trial conducted by Clegg, Red, and Harris (2006) on glucosamine and chondroitin and their potential use in arthritis (GAIT) was inconclusive. Meta-analyses by McAlindon, LaValley, Gulin, and Felson (2000) and by Towheed and Hochberg (1997) reviewed clinical trials of glucosamine and chondroitin in the treatment of osteoarthritis. McAlindon and colleagues included 13 double-blind, placebo-controlled trials of more than 4 weeks’ duration, testing oral or parenteral glucosamine or chondroitin for treatment of hip or knee arthritis. All 13 studies were classified as positive, demonstrating substantial benefits in treating arthritis when compared with placebo. Towheed and Hochberg reviewed nine randomized, controlled studies of glucosamine in osteoarthritis. Glucosamine was superior when compared with placebo in seven randomized trials. Two of the randomized trials compared glucosamine with ibuprofen. In these two trials, glucosamine was superior in one and equivalent in the other. A recent meta-analysis in 2010 concluded that compared with placebo, glucosamine, chondroitin, or the combination of these two products did not reduce joint pain (Wandel et al., 2010).
supplements in the United States. Natural Standard ranks glucosamine and chondroitin sulfate as grade A (strong scientific evidence) for osteoarthritis of the knee, and chondroitin sulfate without glucosamine as grade A for general osteoarthritis (2013b). The results of several studies in the literature, however, have been mixed. A National Institutes of Health trial conducted by Clegg, Red, and Harris (2006) on glucosamine and chondroitin and their potential use in arthritis (GAIT) was inconclusive. Meta-analyses by McAlindon, LaValley, Gulin, and Felson (2000) and by Towheed and Hochberg (1997) reviewed clinical trials of glucosamine and chondroitin in the treatment of osteoarthritis. McAlindon and colleagues included 13 double-blind, placebo-controlled trials of more than 4 weeks’ duration, testing oral or parenteral glucosamine or chondroitin for treatment of hip or knee arthritis. All 13 studies were classified as positive, demonstrating substantial benefits in treating arthritis when compared with placebo. Towheed and Hochberg reviewed nine randomized, controlled studies of glucosamine in osteoarthritis. Glucosamine was superior when compared with placebo in seven randomized trials. Two of the randomized trials compared glucosamine with ibuprofen. In these two trials, glucosamine was superior in one and equivalent in the other. A recent meta-analysis in 2010 concluded that compared with placebo, glucosamine, chondroitin, or the combination of these two products did not reduce joint pain (Wandel et al., 2010).
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