Many of us have heard that healthy nutrition plays an important role in preventing a number of types of cancer,and may help to reduce the spread of cancer once it has started.
Populations that consume less animal food and more plant food have a lower risk of cancer. In fact, the risk of cancer in vegetarians is about 50 percent lower than among people who eat meat on a regular basis.
A diet high in animal foods, especially meat and dairy products, may fuel cancer in a number of ways. The fat in animal foods can increase hormone levels in the blood, and the pesticides and hormones found in some of these foods may also fuel cancer growth. Animal foods are also devoid of fiber, and low-fiber diets are associated with a higher risk of cancer.
So it makes sense that eating less animal food might lead to less cancer.
But what about plants themselves — might they contain preventive ingredients? Plant foods are high in antioxidants, and antioxidants can protect DNA from damage that can lead to malignant transformation.
However, some intriguing newer research suggests plants may protect us from cancer in a far more novel way — they may block a cancer's ability to grow via a process known as angiogenesis.
What is angiogenesis? The term refers to a tissue's ability to grow new blood vessels. For example, if you cut your skin, new vessels are formed under the scab to help the tissue heal; when a woman becomes pregnant, angiogenesis leads to the formation of blood vessels that become the placenta.
In a healthy person, angiogenesis is finely regulated; it starts when new blood vessels are needed and stops when that new growth is complete. If the process of angiogenesis goes awry, however, new blood vessels don't form when they are needed, or blood-vessel formation continues out of control.
Cancer can be thought of as angiogenesis gone wild. All cancers begin as a single abnormal cell, and we all harbor these microscopic cancers, but most of them remain dormant — they cannot grow unless they have a blood supply to bring them oxygen and nutrients.
To multiply, cancer cells begin producing chemicals that initiate angiogenesis — in other words, they learn to feed themselves by creating their own blood supply. Cut off the blood supply to a cancer and you stop the cancer.
Researchers have developed some drugs that can help to shrink tumor growth or even reduce the spread of cancer by inhibiting angiogenesis, and while some of these have shown impressive results, they don't always work.
But now scientists like Dr. William Li, a researcher who heads the Angiogenesis Foundation in Cambridge, Mass., are looking at the power of certain foods to block angiogenesis. These foods include fruits such as apples, oranges, blackberries, blueberries and raspberries; vegetables such as kale, bok choy, tomatoes, artichokes, pumpkins and maitake mushrooms; legumes like soybeans; spices and herbs like turmeric, nutmeg, garlic and parsley; fish such as tuna; and finally red wine and chocolate (yay!).
The plant chemicals in these foods seem to be able to inhibit angiogenesis so that a single cancer cell or cluster of cancer cells is never able to grow enough to cause any mischief. Some plants also contain tumor-suppressor proteins, which help to curb the growth of cancer cells.
With the drop in fruit and veggie intake in the American diet, and the regular consumption of burgers and fries, many of us subject ourselves to the double-whammy of too much animal fat and too few cancer-fighting foods.
Might some cancer prevention be as simple as eating more of these healthy foods?
We already have some precedent for this. For example, studies have shown that men who eat cooked tomato products two to three times a week reduce their prostate cancer risk by about 50 percent.
Up to 35 percent of cancers may be caused by poor diet, and cancer risk is also much higher among people who are obese.
Our bottom line? Fight cancer with food: Eat a wide variety of fruits and veggies every day, throw in some spices like turmeric and garlic, trade in your steak for a veggie burger, and enjoy a glass of red wine now and then.
And if you need another reason to eat more produce, consider this: Fat cells also depend on angiogenesis to grow, so eating more fruits and veggies may help protect you from that spare tire as you get older!
If you'd like to watch a fascinating talk on this subject by Li, go to www.ted.com/talks/william—;li.html.
Drs. Kay Judge and Maxine Wreden are medical directors of Sutter Downtown Integrative Medicine program in Sacramento, Calif.