Intended for healthcare professionals


Health claims for functional foods

BMJ 2004; 328 doi: (Published 22 January 2004) Cite this as: BMJ 2004;328:180
  1. Martijn B Katan, professor (wcfs1{at}
  1. Division of Human Nutrition, Wageningen University, Bomenweg 2, 6703 HD Wageningen, Netherlands

    Regulations vary between countries and often permit vague claims

    Functional foods are foods that claim to improve wellbeing or health.1 The health claim may be implicit (“rich in vitamin C”), or vague (“strengthens the body's defence system”), but invariably the product is presented with the suggestion of a benefit. Sales of such products are huge and growing. What ingredients do such foods contain—and who safeguards the truth of claims?

    Many functional foods contain added vitamins, minerals, and other essential nutrients. Some of these added nutrients indeed promote health: folic acid reduces the risk of neural tube defects, table salt with potassium reduces blood pressure, and polyunsaturated fatty acids reduce the risk of heart disease. But other claims are more dubious—for example, that zinc lozenges protect against colds or that drinks rich in vitamin C protect against cardiovascular disease.

    Functional foods may also contain non-nutritive ingredients. Examples of effective non-nutritive ingredients are sugar alcohols in chewing gum, which reduce risk of dental caries; plant stanols and sterols, which lower low density lipoprotein cholesterol (although effects on heart disease remain to be shown); and probiotic bacteria, which may diminish rotavirus diarrhoea in infants. But other effects of probiotics are insufficiently substantiated, as are effects of phytoestrogens against breast cancer,2 of oligosaccharides for “gut health,” of flavonoids against heart disease, and of conjugated linoleic acid for weight loss. Herbs such as Kava, St John's wort, and echinacea can also be considered non-nutritive ingredients. They are sold as supplements and added to foods, but their efficacy is controversial and concern remains over potential harm.3

    Functional foods are marketed directly to consumers, who are unable to assess the implied health claims. Consumers thus must rely on their governments to make sure that they are not misled. Unfortunately, current government regulations leave room for misleading claims. Deception is promoted by the fact that legislation of health claims for foods is layered: there are soft claims, which require soft evidence, and hard claims, which require harder evidence. For example, a draft regulation of the Codex Commission of the United Nations, which sets international food standards, recognises claims about nutrient content (“rich in calcium”) and disease reduction (“prevents osteoporosis”), as well as various intermediate categories. Manufacturers have therefore made the formulation of soft claims into a fine art, creating claims that imply health effects without actually naming a disease.

    Regulations differ between countries. Japan was the first country to recognise functional foods as a separate category when in 1991 it introduced the FOSHU (Foods for Specific Health Use) system to evaluate health claims. This system has valuable aspects: it regulates both safety and health, and it demands that the food be analysed for the amount of effective component.4 But it is voluntary, and even though the evidence required has been reduced in recent years and is minimal by pharmaceutical standards, most manufacturers opt for softer categories of claims, which require little evidence. An example is the unproved but lawful statement that extra vitamins help to maintain healthy skin and mucosa. Watering down of regulations has also occurred in the United States, which once had a solid system for disease reduction claims for foods, which were allowed only if there was “significant scientific agreement” that the claim was valid.5 However, the Food and Drug Administration's oversight over health claims has eroded, and the United States now allows “qualified health claims” for which there is hardly any evidence, as long as a disclaimer is included. In the European Union the safety of novel foods is thoroughly regulated but health claims are not—EU legislation for nutrition claims is complex, fragmented, and poorly enforced. paradoxically, current EU regulations prohibit claims that a food ingredient prevents a disease even when the claim is truefor example, that folic acid prevents neural tube defects. Finally, Canada, Australia, and New Zealand have introduced new systems to regulate health claims, but experience with these is still limited.

    The lack of proper regulatory oversight has led to some functional foods that are no more than quackery, while at the same time other functional foods do promote health and prevent disease. The potential for effective functional foods is certainly there. Foods and food components could prevent or ameliorate many diseases,6 7 but not enough research is being done to identify effective ingredients and substantiate their efficacy and safety. Whether such research will be done depends to a large extent on proper regulation. Major food companies are eager to expand into health promoting foods, but there is no incentive to underpin such health effects with solid research when products can be successfully marketed on the basis of vague allusions alone. But there is hope. After more than 20 years of deliberations the European Commission recently agreed on new regulations that would prohibit vague claims and that would allow hard claims of disease reduction for foods if the evidence is solid.8 The commission even wants to grant companies seven years of exclusivity for truly novel claims backed up by solid data. If the European parliament accepts these proposals it would be a step in the right direction.


    • Competing interests MBK is employed by the Wageningen Centre for Food Sciences, a research institute funded jointly by the Dutch government, seven food industries, and five research organisations. He has received educational grants from McNeil, Unilever, and Forbes for a meeting on plants and stanols.


    Log in

    Log in through your institution


    * For online subscription