The Delaney Clause is a part of the Federal Food, Drug, and Cosmetic Act of 1958, Section 409, and it prohibits the addition to food of any substance that will cause cancer in animals or humans. The clause states "no additive will be deemed to be safe if it is found to induce cancer when ingested by man or animal, or if it is found, after tests which are appropriate for the evaluation of the safety of food additives , to induce cancer in man or animals..." The clause addresses the safety of food intended for human consumption and few, if any, reasonable individuals would argue with its intent.
There is however, an emerging scientific controversy over its application, and many now question the merits of the clause as it is written. For example, safrole occurs naturally as a constituent in sassafras tea and spices and thus permissibly under the Delaney Clause, but it is illegal and banned as an additive to natural root beer because it has been proven a carcinogen in animal tests. Coffee is regularly consumed by many individuals, yet more than 70% of the tested chemicals that occur naturally in coffee have been shown to be carcinogenic in one or more tests. Naturally occurring carcinogens are found in other foods including lettuce, apples, pears, orange juice, and peanut butter. It is important to note here that the National Cancer Institute recommends the consumption of fruits and vegetables as part of a regimen to reduce cancer risk. This is because it is widely believed that the positive effects of fruits and vegetables far outweigh the potential hazard of trace quantities of naturally occurring carcinogens.
It has been estimated that about 10,000 natural pesticides of plants are consumed in the human diet. These natural pesticides protect the plants from disease and predation by other organisms. Only a few of these natural plant pesticides (less than 60) have been adequately tested for carcinogenic potential and of these about half of them tested positive. Bruce N. Ames and his associates at the University of California estimate that 99.99% of the pesticides ingested by humans are not residues of chemicals applied by humans but are chemicals that occur naturally and therefore legally. It has been argued that such naturally occurring chemicals are less hazardous and thus differ in their cancer-causing potential from synthetic chemicals. But this does not appear to be the case; although the mechanisms for chemical carcinogenesis are poorly understood, there seems to be no fundamental difference in how natural and synthetic carcinogens are metabolized in the body.
The Delaney Clause addresses only the issue of additives to the food supply. It is noteworthy that salt, sugar, corn syrup, citric acid and baking soda comprise 98% of the additives listed, while chemical additives, which many fear, constitute only a small fraction. It should also be noted that there are other significant safety issues pertaining to the food supply, including pathogens which cause botulism, hepatitis, and salmonella food poisoning .Of similar concern to health are traces of environmental pollutants, such as mercury in fish, and cooking-induced production of carcinogens, such as benzopyrene in beef cooked over an open flame. Excess fat in the diet is also thought to be a significant health hazard.
Scientists who are rethinking the significance of the "zero risk" requirement of the Delaney Clause do not believe society should be unconcerned about chemicals added to food. They simply believe the clause is no longer consistent with current scientific knowledge, and they argue that chemicals added in trace quantities, for worthwhile reasons, should be considered from a different perspective.
[Robert G. McKinnell ]
Corliss, J. "The Delaney Clause: Too Much of a Good Thing?" Journal of the National Cancer Institute 85 (1993): 600-603.
Gold, L. S., et al. "Rodent Carcinogens: Setting Priorities." Science 258 (9 October 1992): 261-265.