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Cancer is a massive problem that affects almost 2 million new people each year in the U.S. alone. But what if you could drastically decrease your risk for cancer later in life simply by changing your diet? While, unfortunately, there is no single magical fruit that can prevent cancer, evidence strongly suggests that eating a diet rich in whole grains, fruits, and vegetables, and low in certain animal fats and proteins can prolong the lifespan of cancer patients and lower the risk of developing cancer in the first place. In one study, women with breast cancer that ate more fruits and vegetables and less fatty foods lived longer than women who did not change their diet. Other studies looking at other types of cancer, including prostate and ovarian cancer, found similar trends with improved survival. So, why are vegetarian and vegan diets associated with a lower risk of cancer?
Well, one contributing factor is that typically vegetarians eat more foods with cancer-fighting properties than meat-eaters do, including a diverse array of vegetables, legumes, soy, and nuts and seeds. Whole grains and vegetables are massively rich in fiber, which has been shown to lower cancer risk. Eating more soluble fiber (good sources of soluble fiber include oats, nuts and seeds, avocado, oranges, and brussel sprouts) allows food to be digested slower, keeping you full longer and contributing to lower calorie consumption and maintenance of a healthy weight, which is critical to cancer risk reduction. Eating fiber helps to decrease blood levels of hormones such as estrogen that drive the growth of some breast cancers. Insoluble fiber (good sources of insoluble fiber include apples and whole grains) helps food pass more quickly through the digestive system. This means that toxins move more quickly through the intestines and the amount of time that intestinal cells are exposed to toxins is reduced. Additionally, fiber acts as a “pre-biotic” by interacting with good bacteria in the gut to form molecules called short-chain fatty acids (SCFAs). SCFAs directly kill intestinal tumor cells and can also enter the bloodstream to kill cancer cells in other tissues, including the breast, liver, bladder, lungs, and pancreas.
Additionally, cruciferous vegetables such as broccoli, kale, and collard greens are thought to be rich in cancer-fighting compounds, known as glucosinolates. Promising laboratory data shows that these compounds reduce damage to DNA which helps prevent cancer cell growth. Glucosinolates have also been shown to induce tumor cell death and reduce tumor growth at secondary sites, a process known as metastasis. Studies have found strong links between high glucosinolate consumption and lower risk of lung, colorectal, gastric, breast, and prostate cancers. Additionally, eating soy products such as tofu, tempeh, and edamame have been shown to potentially reduce the risk of certain cancers. One reason is that edamame, tofu, and tempeh are high in fiber. Soy has also been shown to decrease molecules that promote the growth of prostate (prostate-specific antigen or PSA) and some breast cancers (estrogen).
So, what if I just eat more fruits and veggies? Can I eat meat and still reap the cancer-fighting benefits of fiber, broccoli, and tofu? Well, it turns out that it depends on the type of meat you eat. While certain meat products, including poultry, have not been shown to have an association with cancer development or recurrence, processed and red meat have been shown to have cancer-causing properties. Processed and red meats, such as hot dogs, sausages, deli meats, hamburgers, and steaks contain cancer-causing mutagens called N-nitroso compounds (NOCs). These mutagen compounds interfere with cellular DNA and can lead to abnormal cell growth and division, which may lead to the formation of cancerous lesions. Additionally, when red meat, poultry, or fish is grilled or pan-fried at high temperatures, mutagens known as heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) can form. Okay, so I’ll stay away from hot dogs, but can I still eat chicken on occasion? Poultry has not been shown to have an association with cancer development or recurrence, although The World Cancer Research Fund (WCRF), American Cancer Society (ACS), and American Institute for Cancer Research (AICR) still recommend a diet that emphasizes eating fruits, vegetables, and whole grains with small amounts of meat if desired. All societies agree, however, to stay away from processed and red meat.
Edited by Sara Musetti
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