| Let Food Be Thy Medicine and Medicine Be Thy Food: What Every Healthcare Professional Should Know About Nutraceuticals and Functional Foods John Russo, Jr., PharmD |
| Functional foods and nutraceuticals are assuming a middle ground between food and drugs due to a growing body of evidence that supports their role in maintaining health and contributing to the treatment of diseases. Since Hippocrates advised to “Let food be thy medicine and medicine be thy food,” we have defined medicines and foods based on what is known about each substance in terms of efficacy, safety and the significance of its perceived contribution to health. Over time, we tend to redefine these substances as our experience and expectations change. The ancient Greeks, for example, looked upon garlic as a performance-enhancing drug and officially sanctioned it for this use during the first Olympic games.
During the age of sailing ships, lemons were dispensed to sailors to prevent and treat scurvy. John Woodall, the father of naval hygiene and a “Master in Chirurgerie,” published “The Surgeon’s Mate” in 1636 in which he wrote, “The juyce of lemmons is a precious medicine… It is to be taken each morning two or three teaspoonfuls, and fast after it two hours.” Modern functional foods became available in the 1920’s, when iodine was added to salt to prevent goiter. This was followed by vitamin D milk. Today, many Americans start their day with calcium-fortified orange juice (to strengthen their bones). Then, they spread a margarine that lowers cholesterol on folate-enriched toast (to protect their hearts and prevent birth defects). Distinguishing between functional foods and nutraceuticals It is not surprising that the terminology to define and promote these products is escalating (Table 1). For practical purposes however, two terms (functional food and nutraceutical) can be used to distinguish among nutritional products that make health claims beyond basic nutrition. Table 1. Categories of healthful foods and dietary supplements Category / example Description Dietary supplementsProducts containing one of more of the following: ·Vitamin, mineral, herb or other botanical ·An amino acid or metabolite ·An extract ·Any combination of the above · Products (other than tobacco) intended to supplement the diet · May be marketed in a food form if not “represented” as a conventional food and labeled as a dietary supplement · Specific health or structure/function claims* can be made if the FDA deems adequate scientific substantiation exists Fortified foods· Breakfast cereal · Vitamin B added to baked goods · Foods enriched with vitamins and minerals, usually up to 100% of the DRI · Often mandated by law to replace nutrients lost during processing Functional foods· Soy · Salad dressing with omega-3 polyunsaturated fatty acids · Carrots with 170% of daily requirement of vitamin A · A food or ingredient that may provide a health benefit beyond the “traditional nutrients” it contains† · Specific health or structure/function claims can be made if the FDA deems adequate scientific substantiation exists · Super fortified foods have more than 100% of the DRI and/or foods with added botanicals or other supplements Medicinal foods· Food to treat diabetes, obesity, or heart disease, sold through physicians, not by conventional retailers · Food formulated to be consumed or administered internally while under the supervision of a physician · Intended for specific dietary management of a disease or condition for which distinctive nutritional requirements are established Nutraceuticals· Orange juice with calcium · Dietary/herbal substances in pharmaceutical dosage forms · Dietary supplements and fortified foods enriched with nutrients not natural to the food Structured snacks (“fusion products”)· Lean On Me for weight loss · Level Best for Type 2 diabetes · Target people with potentially serious medical conditions · Cost more than some prescription medications · Recommended as snacks · Marketed mostly to physicians DRI = dietary reference intake * Structure/function claims state that a product may affect the structure or function of the body (eg, calcium builds strong bones, antioxidants maintain cell integrity, fiber maintains bowel regularity), but may not claim that a therapy can prevent or cure a disease (eg, alleviates constipation). † “Traditional nutrients” refer to vitamins and minerals considered essential to the diet and/or to correct a classical nutritional deficiency disease. For example, foods containing vitamin C to correct scurvy or vitamin D to alleviate rickets are not functional foods. However, soy, which contains soy protein and is associated with a reduced cardiovascular risk, is a functional food (Source: Modified from Mulry, 2000). Functional foods, as defined by the American Dietetic Association, are products whose nutritional value is enhanced by the addition of natural ingredients. Functional foods may provide specific health benefits beyond basic nutrition when consumed as part of a varied diet. Nutraceuticals, according to the American Nutraceutical Association, are functional foods with potentially disease-preventing and health-promoting properties. They also include naturally occurring dietary substances in pharmaceutical dosage forms. Thus, they include “dietary supplements” as defined by the Dietary Supplement Health and Education Act of 1994 (DSHEA). Figure 1. Options for categorizing functional foods and nutraceuticals. From the FDA regulatory perspective, all substances that influence our health can be divided into two groups: food and drugs, with food further divided into conventional food and dietary supplements (Figure 1). Despite the fact that many terms are used to describe nutritional substances that influence health, each of these terms fits into one of these categories. When viewed in this way, healthcare professionals will be less susceptible to the vague claims that tend to characterize this growing field (Lewis, 2000). Examples of functional foods All foods are functional; however, the term “functional” refers to an additional physiological benefit beyond meeting basic nutritional needs (Table 2). For example, epidemiological data tend to show that cancer risk in people consuming diets high in fruits and vegetables is about one-half that seen among people consuming few of these foods (Block et al, 1992). Certain components from animal sources make similar contributions to health, including omega-3 fatty acids found in fish, calcium in dairy products, and the anticarcinogenic fatty Table 2. Examples of functional foods, their key components, and potential health benefits Functional food Key component Potential health benefits Reduce risk for cancer & heart disease Garlic Sulfur compounds Reduce risk for cancer & heart disease Oats & oat-containing foods Soluble fiber beta glucan Reduce cholesterol Purple grape juice & red wine Polyphenolic compounds Support normal, healthy cardiovascular function Once the benefits of a key component in food are documented, the challenge is to increase its concentration, and presumably its benefits, while maintaining safety. For example, isoflavones in soy are phytoestrogens with a chemical structure similar to estrogen. Isoflavones may reduce cholesterol, but what is the risk of increasing the intake of a compound that may modulate estrogens? Knowledge of the toxicity of functional food components is crucial to improve their benefit:risk ratio. The efforts that go in to making these determinations are costly. As a result, companies that are successful can be expected to market products that will be branded and extensively promoted (Table 3). Table 3. Examples of products marketed or planned to be marketed as functional foods by pharmaceutical companies Novartis: Aviva product line Breakfast bars, cereals, and beverages Claims: Benefits the heart, bones, and digestion Marketed in United Kingdom and Switzerland US launch planned McNeil Consumer Health, Division of Johnson & Johnson Benecol brand margarine, salad dressing, and health bars in US Claim: Reduce LDL cholesterol up to 14%, within two weeks of product use In first few months, Benecol margarine captured ~2% of US margarine sales Mead Johnson division of Bristol-Myers Squibb EnfaGrow nutrient-enriched oatmeal and snack line for toddlers, marketed primarily to physicians Allergy alert: EnfaGrow Nutritional Oatmeal for Toddlers in Maple Brown Sugar & Cinnamon and Strawberry flavors may contain trace amounts of milk protein, not listed in the ingredients* Viactiv Soft Calcium Chews sold in US grocery and drug stores Claim: To meet women’s special nutritional needs * SafetyAlerts.com, 2000. Challenges facing nutraceuticals Some of the most popular nutraceutical products marketed today are botanicals such as St. John’s wort, echinacea, ginkgo biloba, saw palmetto, and ginseng. Unfortunately, manufacturers are not required to prove their safety or efficacy before marketing them. Dosages are not standardized. The quality of the raw source and the plant parts used are not regulated. And, unlike prescription drugs or over-the-counter medicines, there is no federal quality control standard to ensure that the label reflects what is in the bottle. The problem is illustrated by reports that labeled concentrations of active ingredients often significantly overestimate the content in the dosage form. In one report, nearly one-third of the brands tested did not contain what their manufacturers claimed (Hemphill, 2000). In another test of 14 samples from over-the-counter products containing ginkgo biloba, 11 did not contain all of the active ingredients associated with ginkgo biloba as specified by the World Health Organization (WHO). When levels of a possible allergen, ginkgolic acid, were tested, the levels of this compound in 13 products ranged from 16 to 733 times more than the WHO recommendation. Only one sample met the limit for the possible allergen, but this product failed in terms of its active ingredient content (Reuters, 2000). This is a serous problem that undermines the nutraceutical market, encourages skeptics who criticize the value and role of nutraceuticals, and (most importantly) is potentially harmful to the public. An organization that conducts assays of supplements and reports the results versus the labeled ingredients is www.consumerlab.com. Manufacturers are charged a fee to participate in this service. Products that pass the test are permitted to include the ConsumerLab.com seal on their products. Significance for pharmacists The issues surrounding nutraceuticals and functional foods are important to pharmacists for two reasons. It is important to their patients and is certain to be the source of questions. Also, the growing field of nutraceuticals and functional foods is likely to change the practice of pharmacy over the next decade. More than 100 million Americans regularly use dietary supplements, and in the year 2000, consumers spent about $16 billion on them (Augsburger, 2000). Furthermore, 39% of Americans say they have made dietary changes to reduce their risk of getting cancer, 43% claim to take a daily multi-vitamin for cancer protection, while 21% take another form of nutritional or dietary supplement (ie, concentrated doses of single vitamins, minerals or herbal substances) to lower their cancer risk (AICR, 2000). Americans are concerned about their health and they view their pharmacist as an important resource for health matters. Almost two-thirds of respondents in one sample stated that they regularly talk with their pharmacist when choosing an OTC product, and 58% have come to think of their local pharmacist in the same terms as their family doctor (AICR, 2000). In the future, according to Dr. Benadette Marriott, who is vice president of programs and communications at the Burroughs Wellcome Fund, the need to guide consumers through the maze of functional foods and nutraceuticals may lead to significant changes in pharmacy practice. Food stores will continue to evolve into “one-stop wellness centers,” where consumers go for basic wellness screening activities, nutritional counseling and medication advice. At the center will be the pharmacy, where pharmacists will work with nutritionists and others to help consumers recognize their options and select among several sources of an ingredient in order to safely treat or lower their risk for disease (Marriott, 2000). Case history: year 2010 Mr. D is a 50 year-old man with a family history of prostate cancer and a personal history that is remarkable for a diet high in saturated fats. He comes to the pharmacy knowing that his family and dietary history place him at risk. He has no symptoms or laboratory values consistent with prostate cancer but is committed to making changes in his life that will lower his risk. Part of his strategy includes eating more tomatoes to increase his intake of the antioxidant, lycopene. However, he is confused because of a news story in which researchers reported that lycopene administered to mice as a supplement acted as a pro-oxidant and encouraged tumor growth (Moyad, 2000). In addition to wanting to take an effective source of lycopene, Mr. D wants to know which is safest and most economical. In the year 2010, there are no fewer than five sources of lycopene, listed here in order of increasing cost. Nutritional lycopene: Vine-ripened tomatoes (and other foods) Guidelines The challenge facing the pharmacist is to guide this patient through the maze of study results and conflicting claims. There are few absolute answers, but there are guidelines that can help consumers make intelligent decisions (Moyad, 2000). And it is likely that the guidelines for today will be valid a decade from now. Regard Advertising and Articles about Supplements with Caution Be cautious of any product that claims to “boost” the immune system or “rejuvenate” health. Advise consumers to look for specific findings, not vague claims. Natural first, supplement second When there is a choice between a vegetable and a pill, recommend to eat the vegetable. Read the label. Then, get a second opinion Before buying anything, read the label. Moderation is best More is not always better, vitamin C, selenium, and vitamin D are examples where too little has no effect, but too much has adverse effects. Keep everything in perspective Supplements are only part of the picture. They are not substitutes for a healthy diet, stress reduction, exercise, weight control, and (when needed) prescription drug therapy. Finally, remind consumers to not become obsessed by one disease. For example, men concerned about prostate cancer, and women concerned about breast cancer, should not ignore their risk factors for heart disease. Note: * Currently, not marketed References AICR. Seniors prefer taking supplements to changing diet. American Institute for Cancer Research (AICR). 31 August 2000 [Accessed 12 November 2000.] Available at http://www.newswise.com/articles/2000/8/SUPSURV.CR1.html. Augsburger LL. Introduction and welcoming remarks. AAPS Dietary Supplements Forum: Exploring the Science of Nutraceuticals. Washington, DC, June 28–30, 2000. Block, G.; Patterson, B.; Subar. A.: Fruit, vegetables, and cancer prevention: A review of the epidemiological evidence. Nutr Cancer. 1992, 18,1-29. Hasler, C. M.: Functional foods: Their role in disease prevention and health promotion. Food Technology. 1998; 52 (2), 57-62. Hemphill. C.: Putting dietary supplements to the test. The New York Times. June 20, 2000. [Accessed 20 June 2000.] Available at URL: http://www.nytimes.com/library/national/science/health/062000hth-lab-tests.html. Lewis CL. Keynote address: Dietary supplements: The regulatory interface. AAPS Dietary Supplements Forum: Exploring the Science of Nutraceuticals. Washington, DC, June 28–30, 2000. Marriott B. M.: Dietary supplements: Clinical studies and trials to evaluate the efficacy and safety of nutraceuticals and dietary supplements: Approaches, stumbling blocks and the consumer quandary. AAPS Dietary Supplements Forum: Exploring the Science of Nutraceuticals. Washington, DC, June 28–30, 2000. Moyad, M. A.: The ABC’s of Nutrition and Supplements for Prostate Cancer; Sleeping Bear Press: Chelsea, MI, 2000. Mulry, M.: Functional foods and nutraceuticals. Nutrition Science News. July 2000, 5 (7), 292-296. Reuters. Ginkgo remedies fail WHO standards. 17 November 2000. [Accessed 27 November 2000]. Available at http://dailynews.yahoo.com/h/nm/20001117/hl/gingko_1.html. SafetyAlert.com. Mead Johnson Issues Allergy Alert for Two Flavors of EnfaGrow Nutritional Oatmeal For Toddlers. 10 January 2000. [Accessed 13 November 2000]. Available at URL: http://www.safetyalerts.com/recall/f/00/enfgrw.htm. |