It was essential that standards should be set for dietary supplements, congress participants were told during a symposium on September 6.
Opening the symposium, Dr JEROME HALPERIN (US Pharmacopeia, Rockville, US) said that dietary supplements represented a unique class of products, different from both foods and drugs. In the US, dietary supplements were regulated as foods but tended to be used by consumers as drugs. However, in contrast to drugs, dietary supplements (according to the US Dietary Supplements for Health and Education Act 1994) did not require premarketing evidence of safety and efficacy and no specific quality standards were set.
Supplement labels could not generally make claims about prevention and cure of disease, although there were exceptions in the US, such as folic acid for prevention of neural tube defects, calcium for osteoporosis and soluble fibre for cholesterol lowering. However, supplement labels could make health claims and, like drug labels, they were allowed to make structure/function claims.
Further confusion arose from the fact that some substances (eg, calcium, capsicum, folic acid and psyllium) were present naturally in food and could also be used as supplements and/or medicines.
However, in many European countries, the situation was somewhat different. For example, some preparations that were supplements in the US were regulated as drugs in Europe. In addition, labelling requirements were different between the US and Europe, with Europe having more stringent regulations. Indeed, throughout the world, there was wide variability in information and labelling claims, and with the market for these products rapidly increasing, standards applied through regulatory agencies and pharmacopeias would be useful, something that the United States Pharmacopeia had started to work on, Dr Halperin concluded.
Standards had been developed for vitamin and mineral products, Dr V. SCRINI SRINIVASAN, (US Pharmacopeia, Rockville, US) said, and could be a model for other dietary supplements.
Although nutritional supplements and medicines were manufactured using similar technology, supplements differed from drugs in several fundamental respects, and this created the need for a different approach. For example, the benefits of supplements tended to be variable and qualitative unlike those of drugs which were quantitative; supplements tended to be consumed for prevention and well-being rather than cure; measurement of nutrient absorption lacked the precise characterisation achieved with drugs and supplements did not exhibit characteristic dose response curves.
All these differences should be reflected in setting the standards. Thus, the content uniformity requirement for medicines standardisation was an acknowledgement of the existence of well defined dose response curves for drugs. However, the absence of a well defined dose response with nutrients meant that such a standard was not necessary for dietary supplements and a standard for weight variation could be expected to provide evidence that the product had been made according to good manufacturing processes. A standard for dissolution was required, but in a typical multivitamin product containing several vitamins and minerals, it was not practical to apply dissolution standards to every nutrient. The USP had therefore developed a hierarchy of vitamins and minerals, such that in a combination product, an index vitamin and/or mineral would be chosen for application of the dissolution test.
Developing standards for botanical ingredients (eg, Ginkgo biloba, St John's wort) and other supplements represented a challenge greater than that for vitamins and minerals, according to Dr EZIO BOMBARDELLI (Indena SpA, Milan, Italy). This was because extracts used in botanicals were made from plants of different species, grown in different countries of the world, which could be harvested, dried and stored according to a variety of methods. This meant that active principles could vary enormously, both in range and concentration. However, by cultivating plants in an appropriate manner, it was possible to prepare products of uniform content - products that should be similar to pharmaceutical compounds in terms of stability, purity and so on.
The increasing burden of chronic disease (eg, cancer, arthritis and cardiovascular disease) meant that prevention was an important part of health management, and botanicals were increasingly used by the public for this purpose. Because these products were natural, however, consumers thought they were safe. Standardisation and characterisation of these substances was therefore essential to ensure as much as possible that they were indeed safe.