When it comes to living well with cancer, some of the most common advice from doctors and patients alike is to follow a healthy diet. But if cancer tumors require energy and nutrients to metastasize in the body, might it not be better simply to stop eating so much in order to “starve” the tumors and stunt their growth? So asks an article in The Atlantic, which explains and debunks a growing myth around cancer and diet.
For years, certain online cancer sites have made dubious, overhyped claims suggesting that people fast or starve themselves to help kill their cancer. But that’s not the recommendation now, say scientists. However, researchers say changing what people eat may help slow the growth of certain types of tumors and reduce the destruction cancer wages on the body.
For example, last year, Columbia University researchers worked on a study that found that at least one chemotherapy drug can be made more effective by combining its use with a low-carbohydate, low-sugar, protein- and fat-rich ketogenic diet. That dietary approach helps regulate blood sugar and decreases the need for insulin. That study, published in Nature, suggested that decreasing the levels of insulin the pancreas releases into the blood in response to eating could help fight cancer.
Another study, published in Science Signaling around the same time, yielded findings suggesting that some cancer cells are acutely sensitive to glucose withdrawal, hinting that a low-sugar diet could help combat some cancers—but warning that the link is likely not as direct or simple as “eat less sugar to stop cancer.”
In fact, other research focusing on dietary protein has shown that restricting amino acids like serine and glycine may also affect certain cancer outcomes. According to a 2018 study in Nature, a few chemotherapy drugs appear to be affected by amino acids. One in particular, asparagine, was also implicated in the progression of breast cancer metastasis and brain tumors. Other research has found that restricting the amino acid methionine, found in eggs and red meat, may have antitumor effects. But the most effective way to limit one’s intake of methionine is by following a vegan diet, which is generally higher in carbohydrates than most ketogenic diets.
“For a long time, the prevailing thought was that altered metabolism in cancer cells was the result of genes and mutations that determined metabolism,” said Jason Locasale, PhD, a cancer biologist at Duke University. “Now, as we know, it’s a complex interaction of environment and genes, and one of the major factors at play is nutrition.”
Much more research is needed before researchers will be truly willing to prescribe special diets to patients. Because cancer is a term that encapsulates many different diseases it’s also unlikely that there will be a single way to use food to combat it.
For now, unless an oncologist has advised a specific diet tailored to your health and type of cancer, the best and most common recommendation is to eat a generally healthy diet, with lots of variety and little junk food. Furthermore, there is no evidence that starvation or fasting is good or even safe for people living with cancer.
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