Defining Nutrients Are Some Antioxidants Left on the Sidelines? (Originally published in AgroFOOD)

Claims on the content of antioxidants in products have been increasing as the public becomes more aware of their function. At their most basic, claims are added to food labels to bring to the consumer’s attention the benefit(s) of one or more of the components of the food product or, as is often the case with fats, the reduced level of said component. Claim types in the U.S. include health claims, structure/function claims and nutrient content claims.

Nutrient content claims typically provide a statement regarding the level of one or more of the nutrients contained in a serving of the food product (e.g., “Contains twice the RDA of vitamin C per serving”). Nutrient content claims are generally based on levels of nutrients that have been recommended by various nationally- and internationally-recognized scientific boards, such as the U.S. National Academy of Sciences’s Institute of Medicine (IOM) or the European Union’s Scientific Committee on Food (SCF). The levels of nutrients that are recommended are “based on the principle that most, if not all, individuals of a population or a specific population group should obtain an adequate nutrient intake to satisfy their requirements”.[1]

But how is a substance defined as a nutrient? The U.S. Food and Drug Administration (FDA) states that a substance has “nutritive value” when a substance has “a value in sustaining human existence by such processes as promoting growth, replacing loss of essential nutrients, or providing energy”.[2] Defining certain substances according to this standard has been relatively easy – the intake of Vitamin C prevents scurvy and the intake of iron ensures adequate hemoglobin levels in the blood. Substances such as Vitamin C and iron have been known and studied for many decades and their interactions with the body are well defined because they affect physiological processes that, when these types of components are removed from the diet, fairly immediate and deleterious effects on human health occur (e.g., the development of scurvy and anemia). There are, however, many other substances that humans consume on a daily basis that have yet to be adequately defined but are suspected of also being essential to the maintenance of life, although perhaps not in the same overt way as substances such as Vitamin C and iron. Antioxidants are one of the classes of chemicals that have been receiving a lot of recent attention. Because antioxidants are typically found in plant-based foods, they are not new to the human diet. In broad terms, antioxidants are substances that inhibit the oxidation of other substances and, thereby prevent oxidative damage. Oxidative damage is the damage caused by oxygen free radicals to DNA or other molecules in cells that ultimately leads to tissue damage. Although the adverse effects of oxidative damage may not be immediately apparent, oxidative damage has been shown to influence the health and well-being (i.e., quality of life) of an individual and, oftentimes, ultimately, the lifespan.[3]

Recently, a number of claims have surfaced that describe substances such as bioflavonoids, β-carotene, anthocyanins and astaxanthin as “antioxidant nutrients”. Scientific bodies such as IOM and SCF do not specify these substances as “nutrients” per se. While β-carotene and other carotenoids have, for instance, been associated with lower risk of several chronic diseases, carotenoids have not been found to confer any benefit in the prevention of major chronic diseases, and, therefore, have not been defined as nutrients.[4] Based on information from IOM, the only antioxidants that have clearly been defined as nutrients are vitamin A, vitamin E and selenium. Further, the European Food Safety Authority (EFSA) has stated that in regard to the numerous antioxidant claims recently submitted, “no evidence has been provided to establish that having antioxidant activity/content and/or antioxidant properties is a beneficial physiological effect”[5] which indicates that having antioxidant activity alone cannot justify the statement that a food component is a nutrient. In the U.S., one must petition the U.S. Food and Drug Administration for a new (i.e., unauthorized) nutrient content claim.[6] The petition must include data supporting the view that use of the food component (i.e., what is being called a nutrient) characterized by the claim is important to human health, the levels at which the component is important to human health, and the nutritional benefit the public will derive from use of the claim as proposed. A lack of a determination of nutrient status does not impact the ability of a substance to be added as a food ingredient, as the U.S. courts have decided that “food” includes articles used by people “primarily for taste, aroma, or nutritive value”, and does not limit food to articles “solely” for taste, aroma or nutritive value, which would be “unduly restrictive” since some products such as coffee or prune juice may be consumed for reasons other than taste, aroma, or nutritive value.[7]

Because the science behind antioxidant consumption and the subsequent effect of antioxidants on the fine functioning of the human body has taken huge strides forward, it may be time for the regulatory bodies to re-evaluate the relevance of the definition of a nutrient. This is especially true when evaluating the definition for “micro-nutrients”, a term that has come into common usage by many in the scientific community. One recent example of re-evaluation of substances as having nutrient value has been the incorporation of vitamin K into the IOM dietary reference intake (DRI) recommendations in 2001.

Volumes of data have been published on various antioxidants and other chemicals that humans consume on a regular basis. Although some recent scientific literature indicates that consumption of high levels of antioxidants may not confer all the benefits once proposed, antioxidants may well be the key to a significant increase the quality of life and is therefore reason enough to add to the definition of a nutrient, the term “antioxidant nutrient”. Above all, science must be the driver to define any substance (such as an antioxidant) as being “essential to the maintenance and growth” and therefore defined as a nutrient.

References

[1] European Commission (2003) Opinion of the Scientific Committee on Food on the revision of reference values for nutrition labeling.

[2] U.S. FDA Code of Federal Regulations, Title 21, Section 101.14(a)(3) (2010).

[3] A.B. Salmon, A. Richardson et al., Free Radic Biol Med., 48(5), pp. 642-655 (2010).

[4] IOM 2000. Dietary reference intakes for vitamin C, vitamin E, selenium, and carotenoids: a report of the Panel on Dietary Antioxidants and Related Compounds, Subcommittees on Upper Reference Levels of Nutrients and Interpretation and Use of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes, Food and Nutrition Board, Institute of Medicine.

[5] Scientific Opinion on the substantiation of health claims related to various food(s)/food constituent(s) and protection of cells from premature aging, antioxidant activity, antioxidant content and antioxidant properties, and protection of DNA, proteins and lipids from oxidative damage pursuant to Article 13(1) of Regulation (EC) No 1924/2006; http://www.efsa.europa.eu/en/scdocs/scdoc/1489.htm; site visited October 14, 2010.

[6] Title 21 of the US Code of Federal Regulations, Section 101.69. Petitions for nutrient content claims (2010).

[7] Nutrilab, Inc. v. Schweiker, Nos. 82-2746, 82-2747. United States Court of Appeals, Seventh Circuit (1983).