Reply to GMA van Rosendaal et al

Department of Nutritional Sciences Faculty of Medicine University of Toronto Toronto, Ontario M5S 3E2 Canada E-mail: cyril.kendall{at}utoronto.ca

Dear Sir:

Health claims for foods have value if they inform the public of the exact nature of the proposed benefit, are accurate, and provide encouragement for the producer or manufacturer to produce food with added health benefits. In the United States, as a result of the Nutrition Labeling and Education Act of 1991, an attempt was made to address this issue by the acceptance of 12 generic classes of health claims. A company can therefore make a claim provided that it satisfies the criteria related to the claim.

Generic health claims may be excellent for getting a public health message across, such as "eat more fruit and vegetables because it may reduce the risk of..." but product-specific health claims may be required if industry is to be encouraged to aim for maximal efficacy of products that may form part of an effective cholesterol-lowering portfolio put together with dietary ingredients.

Product-specific claims may be particularly important in situations where active ingredients are processed in ways that reduce effectiveness to enhance palatability. In these situations, considerable manufacturing and research creativity may be required to maximize both palatability and efficacy of the product simultaneously. These research data should be used to establish the validity of the health claim. The public is then protected by having evidence that a specific product works. Taste and price they will judge for themselves. The company will be protected from competition from untested products for which the claim can only be generic. A very clear difference must therefore be established between claims made for tested compared with untested products.

For example, viscous fibers may be hydrolyzed to avoid a gummy mouth feel, resulting in the production of more appealing products. Nevertheless, viscosity may be a determining factor because other physiologic functions, including the ability to flatten postprandial glycemia, are greatly reduced as viscosity is lost (1, 2) and viscous fibers such as gum acacia do not lower serum cholesterol (3). On the other hand, in the case of guar gum, some cholesterol reduction is retained if hydrolysis is incomplete.

Soy may be combined with other proteins such as gluten for texture in meat analogues or the soy protein component may be washed with a solvent during extraction to remove isoflavones. Again, the amino acid profile of soy (4) and its isoflavone content (5) may be important to maximize the cholesterol-lowering properties of soy.

When health claim status is given to plant sterols, the effectiveness of the product in lowering cholesterol is also likely to be dependent on the sterol mix and its processing. There are differences related to the sterol and the sterol ester, and possibly to the medium (eg, the fatty acid profile of the margarine) into which the sterols are incorporated, not to mention possible differences between different mixes of phytosterols (eg, sitosterol and campesterol) (6). Each plant sterol–enriched product is therefore likely to be different in terms of palatability and effectiveness. Therefore, for functional foods with demonstrable therapeutic value, eg, the ability to lower cholesterol or blood pressure, it is important to have evidence of the degree of effectiveness of the product in question.

At present, Japan, by FOSHU (Foods for Specific Health Use) regulations, has taken this approach; Europe is still considering the approach to take; and Canada has recognized the potential value of both generic and product-specific claims. Regrettably, because of older regulations, it is uncertain what path Canada can take in establishing product-specific claims. However, in a recent meeting of industry, Health Canada representatives, and academia, it was unanimously agreed that both generic and product-specific types of health claims may play key roles in promoting public health (7). An important question remains as to how to stimulate industry to produce the products and how to provide the incentives necessary for long-term development of effective, palatable functional foods.

REFERENCES

1. Jenkins DJA, Wolever TMS, Leeds AR, et al. Dietary fibres, fibre analogues, and glucose tolerance: importance of viscosity. Br Med J 1978;1:1392–4.
2. Wood PJ, Braaten JT, Scott FW, Riedel KD, Wolynetz MS, Collins MW. Effect of dose and modification of viscous properties of oat gum on plasma glucose and insulin following an oral glucose load. Br J Nutr 1994;72:731–43.
3. Jensen CD, Spiller GA, Gates JE, Miller AF, Whittam JH. The effect of acacia gum and a water-soluble dietary fiber mixture on blood lipids in humans. J Am Coll Nutr 1993;12:147–54.
4. Carroll KK. Review of clinical studies on cholesterol-lowering response to soy protein. J Am Diet Assoc 1991;91:820–7.
5. Crouse JR III, Morgan T, Terry JG, Ellis J, Vitolins M, Burke GL. A randomized trial comparing the effect of casein with that of soy protein containing varying amounts of isoflavones on plasma concentrations of lipids and lipoproteins. Arch Intern Med 1999;159:2070–6.
6. Weststrate JA, Meijer GW. Plant sterol-enriched margarines and reduction of plasma total- and LDL-cholesterol concentrations in normocholesterolaemic and mildly hypercholesterolaemic subjects. Eur J Clin Nutr 1998;52:334–43.
7. Anderson GH, ed. An evaluation of Health Canada's Consultation Document Standards of Evidence for Evaluating Foods with Health Claims: a proposed framework. Toronto: University of Toronto, 24–25, 2000.