Taking vitamin C with each meal may help prevent stomach and esophageal
cancer, according to a study
published this fall in the journal Nutrition and Cancer. The
study was headed by Sidney Mirvish, Ph.D., a researcher at the Eppley Institute
for Research in Cancer and Allied Diseases at the University of Nebraska
Medical Center. Collaborators included Ann Grandjean, Ph.D., and Kristen
Reimers, both of the Center for Human Nutrition in Omaha.
Findings from the study indicate that taking 80 to 100 mg of vitamin
C three times a day with each meal significantly reduces the formation
of chemicals called nitrosamines. Many cancer researchers believe nitrosamines
cause some cancers, such as stomach and esophageal cancers. Currently,
the recommended allowance of vitamin C is 60 mg per day.
Nitrosamines can form in the body when components of certain foods
react with the nitrite in stomach juices. This nitrite is mostly produced
in the body from nitrate found in food and drinking water.
Study participants were given a nitrate salt one hour before each
meal and an amino acid called proline with each meal to induce formation
of a harmless nitrosamine. Researchers found that when a 120-mg dose of
vitamin C was given with the meal, formation of the nitrosamine was blocked.
Because the average amount of nitrate a person normally consumes is less
than the amount given in the experiment, it was estimated that taking 80
to 100 mg with each meal will effectively reduce the formation of nitrosamines.
A study by Dr. Mirvishs group in 1995 found that vitamin C will
produce this action only when it is taken from two hours before to one
hour after a meal.
The nitrosamine-reducing effect is one of several ways vitamin C can
help you maintain a healthier lifestyle, said Dr. Mirvish. Vitamin C
acts here by removing nitrite from the stomach for at least one hour after
the vitamin is taken.
Dr. Mirvish and his group first demonstrated the cancer-preventive
capabilities of vitamin C in 1972, in
laboratory experiments that showed the vitamin effectively prevented
nitrosamines from forming. This study was supported by grants from the
Nebraska Department of Health, the National Cancer Institute and the American
Cancer Society.
The Eppley Institute is a part of the UNMC Eppley Cancer Center,
which is one of more than 50 National Cancer Institute-designated cancer
centers. Of the $34 million in research grants awarded to UNMC in 1996-1997,
Cancer Center researchers generated more than $20 million.
UNMC is the only public academic health science center in the
state. Through its commitment to research, education and patient care,
UNMC has established itself as one of the countrys leading centers for
cancer research and treatment and solid organ transplantation. In addition,
UNMCs educational programs are responsible for training more health professionals
practicing in Nebraska than any other institution.