Which Dietary Factors Affect Breast Cancer Most?

One of my favorite cancer-specific charities, the American Institute for Cancer Research, lauds the China Study and the documentary Forks Over Knives, with which they share the same bottom-line message: The healthiest diets are those that revolve around whole plant foods.

They then translate that advice into their Ten Recommendations for Cancer Prevention. We now have evidence that those who follow such advice are actually protected against cancer. Breast cancer risk was reduced by 60% in women who met at least five recommendations compared with those who met none. The most important dietary advice was to be as lean as possible within the normal range of body weight, eat mostly foods of plant origin, and limit alcoholic drinks.

What about other cancers? Greater adherence to the AICR dietary guidelines was also associated with significantly less endometrial, colorectal, lung, kidney, stomach, oral, liver, and esophageal cancer. In other words, adherence to dietary recommendations for cancer prevention may lower the risk of developing most types of cancer. The drop in bladder cancer did not reach statistical significance, but a larger follow-up study following 469,000 people for 11 years (the largest to date) found that just a 3% increase in the consumption of animal protein calories was associated with a 15% higher risk of bladder cancer, whereas just a 2% increase in plant protein was associated with a 23% lower risk. 

AICR recommendation number ten is that cancer survivors should follow the recommendations for cancer prevention. The same diet that can help prevent cancer in the first place can be used to help save our life after diagnosis. Adherence to the guidelines for cancer prevention was found to be associated with lower mortality among older female cancer survivors, or breast cancer and other cancers in general.

A cancer diagnosis is considered a teachable moment to get people eating and living healthier. Oncologists revel at the growth in the number of cancer survivors in this country, now ten million strong and growing. It’s great that those with cancer are living longer, but even better to prevent it in the first place so we can all live longer. Not only does adherence to the guidelines lower cancer risk, but extends our lifespan because the guidelines are also significantly associated with a lower hazard of dying from heart disease and respiratory disease, suggesting that following the recommendations could “significantly increase longevity.”

Just like eating to prevent cancer helps to prevent heart disease, eating to protect our heart helps prevent cancer. It sounds self-evident, but adherence to a healthy lifestyle is therefore associated with a lower risk of mortality overall. And the more healthy behaviors we have, the longer we get to live. Such factors included not smoking, walking every day, or eating green leafy vegetables almost daily.

To help differentiate the effects of diet from other lifestyle behaviors like smoking and drinking on cancer incidence, Adventists were recently compared to Baptists. Both discourage alcohol and tobacco, but the Adventists go further, encouraging a reduction of meat. In general, the Adventists had lower cancer hazard rates than the Baptists, and within Adventist populations, the vegetarians did even better, and those eating the most plants, did the best.