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Dr Roberfroid: I think we are going along the same line so far as nutrition is concerned in trying to include interdisciplinary approaches. There are also some plans to create new food safety agencies in the United Kingdom and France.
Dr Dwyer: Dr Marriott, many of us lack training in botany, natural products chemistry, and ecology. Some people who are from an agricultural tradition probably have such training, but for many of us these are new concepts. I share your enthusiasm for the insights that this may provide us.
Dr Harper: I would like to reinforce Dr Marriott's emphasis on the need for a scientific approach to nomenclature and definitions. Unless we have a scientific base for definitions, we are going to have definitions that are almost uninterpretable. They must be specific. I think there are still some problems with some of the new definitions proposed by the National Research Council in changing the approach to the recommended dietary allowances (RDAs). Two of the terms, RDA and adequate intake, are not separate terms. They are essentially terms for the same definition, an adequate intake of a nutrient.
Dr Fernstrom: To me, adequate intake means you don't know what a baby needs as a newborn, so you take the best values in breast milk for healthy babies and that's what you use.
Dr Dwyer: Yes, but we don't give breast milk to older people, so there is no gold standard for a single food or a single function. I think the concept of an adequate intake for adults needs to be clarified further.
Dr Hathcock: I think this conference is a good example of the changes that are occurring in the basic sciences. In the few decades immediately after the discovery of what are now recognized as the completely or totally essential vitamins and minerals, many nutritionists, including myself, had a reductionist view of human nutritional needs. That is, it was an energy source, protein, a couple of essential fatty acids, 13 vitamins, and 13 minerals. There were no other needs. Obviously we ate foods such as broccoli and beefsteak and oranges and so forth. We have always been exposed to a long list of chemicals in foods other than those classified as essential. We just didn't recognize that they had any physiologic impact.
Functional impact, physiologic impact, beneficial impact, avoiding adverse impacts—these are the things we need to consider to achieve optimum health. I don't think we have completely defined what is needed.
Dr Roberfroid: We can even expand that because we don't eat protein; we eat different proteins, different carbohydrates, different fats. We should also reclassify all those things.
Dr Harper: I'm not sure all of that is entirely true. The protein recommendation was not made to be just a minimum intake; it was 10% of food energy. One of the reasons for that recommendation was that we didn't know the significance of all of the constituents of foods. This provided a way of ensuring that other unknown nutrients or factors accompanying protein would be included in the diet.
Dr Milner: We have to look at a few more compounds than we started out to study.
Dr Dwyer: Dr Ross, I find this a difficult area. The process used by the Food and Nutrition Board for establishing nutrient requirements, the process used for establishing health claims, and the process used for establishing whether health claims conform with the law do not seem to correspond with one another. For example, some of the structure-function claims may not in fact meet some of the rigorous criteria of the scientists for establishing requirements on evidence-based data for substances such as folic acid. Perhaps the answer is to establish an umbrella agency that considers all these things together, but that would be a bureaucratic nightmare.
Dr Ross: It is a challenging area. Regulations also evolve.
Dr Milner: One of the issues raised yesterday was a scaling system for evaluating the quality of the information, the quantity of information, and what is needed to make a health claim. I worry at times that the claims are such a moving target. You never know exactly what's going to be allowed and what isn't. No one wants to commit to what is the "minimum requirement." Because we can't define minimum, we also can't define maximum.
Dr Fernstrom: I think the law should also be more concerned with safety. For example, one can look at the recent safety issue related to the lack of control subjects concerning the ephedrine content of ma huang preparations sold in the United States. The high ephedrine content of some of these preparations recently led to a number of deaths [Josefson D. Herbal stimulant causes US deaths. Br Med J 1996;312:1441]. The FDA [Food and Drug Administration] cannot control the access of such preparations to the market, or at least their safety and purity, because of the Dietary Supplement, Health and Education Act (DSHEA) of 1994. This legislative problem needs to be corrected before more such incidents arise. One may now be on the way with 5-hydroxytryptophan, another "dietary supplement," owing to some preparations containing the same contaminants found in tryptophan tablets linked some years ago to the occurrence of eosinophilia myalgia, a potentially life-threatening disorder [Williamson BL, Klarskov K, Tomlinson AS, Gleich GJ, Naylor S. Problems with over-the-counter 5-hydroxy-L-tryptophan. Nat Med 1998;4:983 (letter)].
Dr Ross: Right. The key point is "charged to do." FDA is very interested in and concerned about the safety issues, and we must also work within the limits of the Act.
Dr Milner: If we recall the debate over selenium, we weren't even allowed to put it in animal products for a while because it was thought to be a carcinogen, based on very little information, even though it was an essential nutrient.
Dr Hathcock: The tryptophan issue was the result of an impurity that occurred owing to a change in processing. Several countries had similar episodes related to the same batch of the same product from the same company. Among those countries were some that regulated tryptophan as a prescription drug. So, more restrictive regulations do not necessarily prevent all problems. They didn't in this case.
With regard to marketing pills, capsules, tablets, and other forms of packaging, there is an exception that a dietary supplement can be in conventional food form as long as it is not represented as a conventional food. Someone could market something that looked like a candy bar as long as it was represented only as a source of nutrients, not as a recreational snack.
To clarify another point with regard to the Nutrition Labeling and Education Act of 1990 health claims, in December 1997, the FDA Reform Act [Food and Drug Administration Modernization Act of 1997] was passed, which allows a company to use a statement made by an authoritative body. If that authoritative body has made a statement about the beneficial effects of some food ingredient, a company could presume significant scientific agreement without asking FDA first. I don't think this is a problem if you rely on an organization such as the National Academy of Sciences, the Centers for Disease Control and Prevention, or the National Institutes of Health.
With regard to the safety issue, the history is seriously complicated. I believe part of the explanation for where we are today with regard to regulation on dietary supplement safety has to do with "regulatory overreach" by the FDA. The Proxmire amendment of 1976 [which amended the Federal Food, Drug and Cosmetic Act of 1938] is widely cited as preventing FDA from regulating vitamin or mineral potency. That is not true. What it does state is that FDA cannot use potency as the sole reason to classify a vitamin or mineral as a drug. If it is unsafe, that can be used to regulate potency.
Immediately before passage of the DSHEA, FDA had attempted to regulate oils containing -linolenic acid as unproved food additives. The theoretical construct was that the oil was the food additive and the empty gel capsule it went into was the food.
With regard to the grandfathering of safety, the Food Additive Amendments of 1958 also took some ingredients out of FDA's review process. Those were the GRAS (generally recognized as safe) ingredients. They had been in the market a long time and were presumed safe, so they were grandfathered as safe. DSHEA did the same thing with dietary ingredients that had been used with dietary supplements. The ones that had been there already were presumed safe and were grandfathered as safe. If a new dietary ingredient is introduced, the burden is on the manufacturer to notify FDA and to assert that it has adequate evidence to support product safety. The FDA then has 75 d to take an action on a preemptive basis or a later action on a corrective basis.
Dr Harper: It is important to emphasize that a lot of the regulatory problem is not the result of FDA's failure to set standards for certain nutrients and food constituents as supplements but rather because this is a political issue. Certain decisions have been made by Congress, and the Proxmire bill that Dr Hathcock cited is an example. The bill removed the power of the FDA to require a company to demonstrate safety of some of these products, as they do for food additives before they were approved. It put the onus on FDA to do that, but FDA does not have the capacity to handle that. The only way a problem is discovered is when a specific incident occurs that harms an individual or group of individuals. Also, the bill sponsored recently by Senator Hatch has further removed some of the powers of the FDA to regulate. So the problem we have is not one that FDA created.