Belief in the medicinal attributes of foods has directed attention to foods that may have health benefits over and beyond their supply of essential nutrients. The links between several so-called functional foods and health continue to mount. However, a clear understanding of the impacts of dietary exposure on the health of individuals is still evolving. What is evident is that truly miracle foods or food components do not exist. Functional foods must be considered in the context of the other constituents of the diet as well as the consumer’s genetics and environmental exposures. Insults such as excess or insufficient calories, viruses, bacteria, and environmental toxins can influence the biologic response. Nevertheless, evidence from clinical trials, epidemiologic observations, preclinical models, and cell culture systems provide clues to the biologic consequences of individual foods and their components as a function of amount and duration of exposure. To take advantage of factors in eukaryotic cells that influence growth, development, and disease prevention, one must understand genetic and epigenetic events, transcription regulation, protein targets, and the formation of small-molecular-weight signals more clearly. Although all food and beverages can influence these key cellular processes, the circumstances under which maximum benefits occur remain to be determined. Deciphering who will benefit most or be placed at risk from specific functional foods is exceedingly complex, but it holds promise to influence human health and disease risk.
DEFINITION OF FUNCTIONAL FOODS
Functional foods are foods and food components that provide health benefits beyond basic nutrition. They do more than simply provide nutrients because they assist in maintaining health and thereby reducing the risk of disease. Collectively, these foods represent a continuum of items that contain ingredients or natural constituents in conventional, fortified, enriched, and enhanced foods. The term first surfaced in Japan in the 1980s, when government approval was granted for functional foods called Foods for Specified Health Use (FOSHU) (1
). In Japan, a manufacturer who wishes to apply to the government for approval under FOSHU must tabulate and summarize all available publications as well as internal reports that deal with the effectiveness of the product and its ingredients. The summary must include in vitro metabolic and biochemical studies, in vivo investigations, and randomized controlled trials in Japanese people (2
). Since the 1980s, this concept has been embraced by many in the scientific and lay communities to promote healthy eating throughout the world.
Belief in functional foods by consumers is driven by multiple factors, including “natural is good,” a plethora of health and structure function claims and other communications, the perception that prevention through food is less costly than the use of drug or other medical treatments, belief in diminished side effects of foods versus drugs, and the increasing acceptance that a healthy diet promotes general well-being and curbs the risk of disease (3
). This concept is not new. Almost 2500 years ago, Hippocrates, considered by some to be the father of Western medicine, proclaimed “Let food be thy medicine, and medicine be thy food.”
Although consumers appear to identify with foods having health benefits (6
), the positive and negative actions of specific bioactive foods constituents continue to captivate the scientific community (7
). The study of bioactive food constituents is becoming more common in the
scientific literature. Approximately 3000 publications listed in PubMed in 2011 were captured by the term “functional foods.” Evidence of the ability of some functional foods to affect health is building, yet the response varies, depending on the study design and a host of factors discussed in more detail later. Functional foods with the strongest evidence of a biologic response are depicted in Table 36.1
TABLE 36.1 FUNCTIONAL FOODS WITH POTENTIAL HEALTH BENEFITSa
SUSPECTED HEALTH-PROMOTING FUNCTIONAL FOOD
POTENTIAL BIOACTIVE INGREDIENT
Genistein, daidzein, equol
n-3 fatty acids
Oats and other grains
Fiber, β-glucan, flavonoids
aWhile considerable evidence indicates that each of these foods provides health benefits, all do not appear to provide the same benefits, and thus significant variability exists in the scientific literature. Controlled intervention studies that adequately evaluate changes in key biomarkers associated with health as a function of exposure (concentration and time) are needed.
The earliest functional foods in the United States arose from the addition of poorly consumed nutrients to broadly consumed foods or ingredients. Examples include iodized salt to prevent goiter and vitamin D-fortified milk to prevent rickets. Today, products such as calcium-fortified orange juice, spreads with n-3 fatty acids, folate-enriched flour, and green tea extract-fortified drinks are just some examples of items that fall under the functional foods umbrella. Not all are new items, given that fermented foods such as kimchee and yogurts with live bacteria are also considered functional. Unfortunately, the definition of a functional food is so inclusive that nothing is excluded, and thus a truly “nonfunctional food” appears not to exist.
The functional food industry, consisting of food, beverage, and supplement sectors, continues to experience incredible growth. BCC Research, a resource of highquality market research, estimated that the global market of functional foods may reach $176.7 billion in 2013. Although foods and supplements are projected to do much better than average, the best growth may occur in the beverage sector (10
). This kind of growth is propelled not only by innovation and new products that satisfy the demand by consumers for more healthy food choices but also by health claims covering a gamut of issues.
DEFINITION OF NUTRACEUTICALS
Nutraceuticals are also receiving increased recognition because of their link with health. The term itself is a portmanteau of the words nutrition and pharmaceutical and congers images of a nutrient with a druglike action. The term was coined by Dr. Stephen L. DeFelice, founder and chairman of the Foundation for Innovation in Medicine in Mountainside, New Jersey. Typically, such products range from isolated nutrients, dietary supplements, and specific diets to genetically engineered foods, herbal products, and processed foods. Nutraceuticals are typically considered components of alternative medicine. As research has progressed, however, nutraceuticals have become more widely accepted (11
In the United States, the Food and Drug Administration (FDA) is responsible for regulations and oversight of claims that manufacturers propose to make about the nutrient content and biologic response to functional foods in terms of health or body function. The FDA does not officially recognize the term “functional food.” Nevertheless, the FDA does regulate these foods according to whether it is considered a conventional food, a food additive, a dietary supplement, a medical food, or a food for special dietary use (12
Dietary supplements are products that contain nutrients derived from food products. They are typically provided in concentrated form as a liquid or a capsule and are intended to supplement the diet. The Dietary Supplement Health and Education Act of 1994 (DSHEA) provided clarification on the constituents of dietary supplements. Ingredients may include vitamins, minerals, herbs or other botanical products (excluding tobacco products), amino acids, and substances such as enzymes, organ tissues, glandular material, and metabolites. A dietary supplement may also include extracts or concentrates, provided in the form of powders, tablets, capsules, soft gels, or liquids. Concerns about the adequacy of the food supply and health care costs are surely factors that have fostered interest in the use of dietary supplements. Unfortunately, evidence to support the health benefits of these supplements is scant, and concern is increasing that the overzealous intake of these supplements may be harmful (13
). The terms nutraceuticals
, functional foods
, bioactive food components
, and dietary supplements
are often used interchangeably, and thus these compounds are difficult to separate in terms of definition and biologic consequences.
DRIVERS FOR FUNCTIONAL FOODS AND NUTRACEUTICALS
Noncommunicable diseases (NCDs), including cancer, cardiovascular disease, diabetes, and the metabolic syndrome, account for 60% of all deaths globally (14
). In low- to middle-income countries, the prevalence of NCD is increasing as these countries undergo socioeconomic improvement (15
). The United Nations General Assembly agreed
that an international summit should be held to address the challenge of NCDs, especially in low- and middle-income countries (16
). The increase in NCDs is linked to the adoption of a Western lifestyle. This finding is in accordance with the fundamental principle of life that maintains that inputs from the environment during embryogenesis generate novel genetic variation, with dramatic consequences for development (17
). By 2030, yearly worldwide deaths resulting from chronic NCDs are expected to increase to 52 million, whereas deaths caused by infectious diseases, maternal and perinatal conditions, and nutritional deficiencies are expected to decline by 7 million (18
Considerable evidence suggests that altered developmental processes in utero, in infancy, and in early childhood can have a lifelong influence on disease risk, including cardiovascular and metabolic function (19
). These precipitating factors appear heritable or at least to have a familial component of susceptibility because multiple NCDs, such as allergies, cardiovascular disease, and obesity can be transmitted transgenerationally (22
CLAIMS ABOUT FUNCTIONAL FOODS, NUTRACEUTICALS, AND SUPPLEMENTS: WHO IS WATCHING?
The public is increasingly inundated with information and guidance of varying quality about food and health. No regulation governs communication by noncommercial entities, even when the topic is human health. Therefore, science-based information must be made widely available, and misinformation must be corrected.
Communicators know that the public is more likely to hear and internalize information that is encountered multiple times, in many places, and from numerous sources. Proactive engaging in this manner has been coined “360-degree communication.” For example, companies touting the health benefits of their products share the benefits on food labels, in advertising, on their websites, in social media networks, at scientific and health professional conferences, and in traditional media venues. The healthrelated research and health care professional communities have traditionally communicated less broadly, although both professions are frequently interviewed by the media, and some use blogs and social media independently. Advocacy groups, both science-based and others, communicate heavily online.
Any communication related to the sale of a food product in the United States is regulated by the FDA, the US Department of Agriculture, or the Federal Trade Commission (FTC). As described earlier, the FDA is responsible for regulations on and oversight of the safety and labeling of foods and dietary supplements (12
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