What puzzles many people is how a food additive may suddenly be branded as
unsafe after many years of seemingly safe use. The case of saccharin is a good
example of how the shifting requirements of the law, the progress of science,
and new trends in food uses can change a substance's status from "safe" to
"unsafe."
Americans have been consuming saccharin for more than 100 years. It is - like
so many other food additives - made from petroleum-based materials. Discovered
by a Johns Hopkins University scientist in 1879, it was used initially as an
antiseptic and food preservative. Its use in foods developed gradually after the
turn of the century, surging during World Wars I and II because of sugar
shortages and rationing.
The Food, Drug, and Cosmetic Act provides, in the now-famous Delaney Clause,
tht no new food additive can be used if animal feeding studies or other
appropriate tests show that it caused cancer. The Delaney Clause, however, does
not apply to additives that were generally recognized by experts as safe for
their intended uses. Saccharin, cyclamate and a long list of other substances
were being used in foods before passage of the Delaney Clause in 1958 and were
considered "generally recognized as safe" -or what is known today as GRAS.
(Aspartame, on the other hand, became the first artificial sweetener to fall
under the 1958 amendment's requirement for pre-marketing proof of safety because
the first petition to FDA for is approval was filed in 1973.)
In 1968, the Committee on Food Protection of the National Academy of Sciences
said in a report that, although an adult's daily consumption of one gram of
saccharin or less probably was not a health hazard, available studies on the
cancer-causing potential of saccharin were inadequate. It urged additional
studies and repeated that recemmendation two years later. In 1972, with new
studies under way, FDA decided to take saccharin off the GRAS list and establish
interim limits that would permit its continued use until various studies were
completed.
Two of the studies that followed only increased public health concerns. One
was done in 1972 by the Wisconsin Alumni Research Foundation, the other in 1973
by FDA. In both tests, male and female rats were fed doses of saccharin from the
time of weaning. The offspring of those rats were given saccharin for their
entire lives. In both tests, the incidence of bladder tumors in the animals fed
saccharin was considered significant. However, arguments were made that an
impurity, not saccharin itself, was causing the tumors.
In February 1974, Canada's Health Protection Branch - FDA's counterpart there
- began a major rat study to resolve the scientific uncertainties surrounding
saccharin. The Canadian project, in which parent rats and their offspring were
exposed to saccharin, focused on the effects of the suspect impurity in
saccharin, orthotoluenesulfonamide (OTS). In early 1977, the study demonstrated
that neither OTS nor other alleged culprits - bladder parasites and bladder
stones - were causing the tumors. The substance responsible, the study showed,
was saccharin.
Despite clamorous public protests, Canada prohibited all uses of Saccharin
except as a table-top sweetener to be sold only in pharmacies, and then only
with a warning label. With the Canadian study now confirming the Wisconsin and
FDA studies, FDA proposed on April 15, 1977, to revoke its 1972 sanction for the
sweetener's continued use in foods and beverages. FDA did propose to allow the
sale of saccharin as an over-the-counter drug in the form of a table-top
sweetener.
Public clamor over the proposed ban erupted at once, fueled by mention in the
agency's announcement that the rats in the Canadian study were fed the
equivalent of 800 cans of diet soda a day. High doses of suspect carcinogens are
used in feeding studies to produce readily detectable rates of cancer, and the
statement was intended simply to describe this testing method. Taken out of
context, however, it was ripe for ridicule, and critics pounced on it.
The storm of protest led Congress, in November 1977, to pass the Saccharin
Study and Labeling Act, which imposed a two-year moratorium against any ban of
the sweetener. While permitting saccharin's continued availability, the law
mandated that warning labels be used to advise consumers that saccharin caused
cancer in animals. The law also directed FDA to arrange further studies of
carcinogens and toxic substances in foods, including saccharin, and to determine
whether there were any health benefits resulting from non-nutritive sweeteners.
FDA contracted with the National Academy of Sciences for these studies. The
first NAS report, in November 1978, concluded that saccharin was a carcinogen in
animals, although of low potency; that it was a potential cancer-causing agent
in humans; that the impurities in saccharin were not the carcinogenic agents;
and that saccharin seemed to promote the cancer-causing effects of other
carcinogenic that might be consumed with it. NAS's second report, in March 1979,
called for an overhaul of the entire food safety law - changes that might give
FDA a range of options in regulating substances like saccharin. The issue is now
before Congress. Since 1977, Congress has repeatedly extended the original
moratorium.
Although various studies since the proposed 1977 ban have led to varying
interpretations of the risks posed by saccharin, FDA's basic position remains
that the substance should not be used in food and beverages except as a
table-top sweetener
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