By Jeremy Appleton, ND, CNS
Healthnotes Newswire (August 10, 2006)—Higher blood levels of vitamin C can prevent stomach cancer, according to new European research. A large study, with participants from 23 centers in ten European countries, has found that vitamin C protects against a variety of cancers that arise in the stomach and esophagus.
According to Dr. Mazda Jenab, a scientist in the Nutrition and Hormones Group of the International Agency for Research on Cancer and lead author of the study, the protective effect of vitamin C was even more pronounced in red meat eaters. This may be because vitamin C can prevent nitrites (preservatives found in many meat products) from being transformed into carcinogenic compounds.
It is surprising that the study did not find any relationship between gastric cancer and vitamin C eaten in food. However, the highest intake tracked by the researchers was 160 mg per day, which may not result in maximum vitamin C concentration in the blood. Eating five or more servings of fruits or vegetables each day would give a person around 210 mg or more of vitamin C, which would come closer to maximizing blood levels.
Gastric cancer includes cancers of the stomach and of the lower esophagus, where it meets the stomach. Stomach cancer has few symptoms in the early stages; once discovered, it is usually untreatable, so prevention is critical.
Certain foods and beverages may raise the risk of gastric cancer. For example, a diet that is high in foods preserved by drying, smoking, salting, or pickling raises the risk because these foods usually contain nitrates or nitrites, which are transformed in the gut into carcinogenic nitrosamines. Drinking too much alcohol or smoking also can cause stomach cancer. Vitamin C has been shown to block the transformation of nitrites into cancer-causing nitrosamines.
Vitamin C is a powerful antioxidant and scavenger of dietary free radicals that can damage cells in the body. Foods rich in vitamin C include citrus fruits (oranges, lemons, limes, tangerines, grapefruit), rose hips, acerola cherries, papayas, cantaloupes, and strawberries. Many vegetables are also high in vitamin C, including red and green peppers, broccoli, Brussels sprouts, tomatoes, asparagus, parsley, dark leafy greens, and cabbage. Animal foods contain almost no vitamin C. Vitamin C supplements are either made from foods, or they can be synthesized from corn syrup.
“Stomach cancer prevention may be enhanced by eating a diet high in fresh foods, especially fresh fruits and vegetables,” said Alan R. Gaby, MD, Healthnotes chief medical editor and coauthor of Natural Medicine, Optimal Wellness: The Patient’s Guide to Health and Healing. “Limit your intake of smoked foods and nitrate- and nitrite-preserved foods. Consume alcohol moderately and don’t smoke.”
(Carcinogenesis 2006 Jun 14; [e-pub ahead of print])
Jeremy Appleton, ND, CNS, is a licensed naturopathic physician, certified nutrition specialist, and published author. Dr. Appleton was the Nutrition Department Chair at the National College of Naturopathic Medicine, has served on the faculty at Bastyr University of Natural Health Sciences, and is a former Healthnotes Senior Science Editor and a founding contributor to Healthnotes Newswire. He has worked extensively in scientific and regulatory affairs in the supplement industry and is now a consultant through his company Praxis Natural Products Consulting and Wellness Services.