July 21, 2003 -- Put the pizzeria on speed dial, but forget the Meat-Lover's Special. A simple thin-crust pizza -- olive oil, tomato sauce, a bit of mozzarella -- could help protect you against cancer.
A new study provides another "vote" for the Mediterranean diet -- which emphasizes having olive oil with most meals as well as abundant vegetables, fruits, legumes, nuts, and cereals; some fish; a bit of wine every day; and less meat and dairy than the typical American diet.
But behold, the pizza has not been given its due. "Pizza is one of the best-known Italian foods, but there is limited information on the potential influence of pizza and cancer risk," says Silvano Gallus, PhD, an epidemiologist at the Instituto di Ricerche Farmacologiche "Mario Negri," in Milan, Italy. He is the lead researcher of the study, which is published in the International Journal of Cancer.
Forget pasta, forget antipasto, forget fabulous breads. Pizza showed the most cancer-prevention promise, he says. But don't call Dominos just yet, he cautions: "Italian pizza is very different from other kinds of pizza. In Italy, we eat pizza from the pizzeria, where it is the main dish. It is very different from fast-food pizza."
In their study, Gallus and colleagues sifted through diet surveys completed by 5,500 Italians -- 598 cancer patients and 4,999 people without cancer.
Among the 78-item checklist, three questions referred specifically to pizza -- had they eaten less than one slice a month (considered non-eaters), one to three slices a month (occasional eaters), or a slice or more a week (regular eaters).
"We found that regular pizza eaters had 34% less risk of oral cavity and pharyngeal cancer, 59% less risk of esophageal cancer, and 25% less risk of colon cancer," says Gallus. In this group of patients, pizza also reduced risk of rectal cancer and laryngeal cancer, although not significantly.
Refined carbohydrates such as bread and pasta have been directly associated with cancer of the upper digestive tract and colorectal cancer, he says.
Italian pizza is less than 50% crust, 20% tomato sauce, 20% mozzarella cheese, and 4% olive oil, says Gallus. There's less refined carbohydrates, plus cooked tomatoes, which are a rich source of lycopene, a natural chemical that has been shown in numerous studies to protect against cancer.
"We think that there's a specific compound in cooked tomatoes that is protective," he tells WebMD. However, "tomato micronutrients remain difficult to identify."
Also important: Italian pizza contains olive oil in the dough and on the pizza. The monounsaturated fats in olive oil are also considered protective against cancer.
With a Grain of Salt
Pizza protective against cancer? "Take it with a grain of salt," says Maria Yaramus, PharmD, clinical coordinator of integrative medicine at the University of Pittsburgh Cancer Institute. "There are so many styles of pizza, so many ways of making pizza, that I think it's a bit presumptive to say it prevents cancer."
But yes, Gallus' study is indeed more evidence that a Mediterranean diet is a good idea. Lycopene in cooked tomatoes, tomato sauce, tomato paste, and tomato juice has been shown to slow the growth of breast, lung, and endometrial tumors and to reduce prostate, stomach, and pancreatic cancer risk.
Olive oil -- rich in antioxidants and natural chemicals called lignans -- has been linked with lower rates of cancer of the large bowel, breast, endometrium, and prostate, says Yaramus.
In fact, a "slew of research," due to be published soon, shows the beneficial effects of fatty acids in preventing cancer and in slowing tumor growth -- at least in animals, Yaramus says. She advises against substituting fish oil supplements for whole foods, such as salmon and other fatty fish.
To be true to the Mediterranean diet, she emphasizes eating whole "real" foods.