Tailored diets could one day play a key role in cancer treatment by starving tumors of key nutrients and even boosting the effectiveness of certain drugs, according to a new review. "Unfortunately, we're still several steps away from actually making recommendations for specific nutritional additions or restrictions that will improve a specific therapy," said Dr. Naama Kanarek of Boston Children's Hospital and Harvard Medical School, the article's first author. "We need people to realize that this is, or can be, one of the new goals of cancer therapy in general, to consider the diet, to consider nutrition, really as part of the treatment," she told Reuters Health by phone. Dr. Kanarek and her colleagues cover three areas in their review: How restricting certain nutrients affects cell metabolism and interaction with signaling pathways; how supplementation with certain nutrients, or depletion of these nutrients, might be used to treat cancer; and the potential of combining diet and therapy to provide tailored cancer treatment. Dietary restriction of glucose and fructose, which fuel tumor growth, is likely to be helpful in the treatment of many cancers, the authors note. While there's not enough evidence to recommend, for example, a ketogenic diet, they add, "reducing glucose consumption, monitoring blood glucose levels and insulin secretion in patients, and assisting patients in maintaining low-carbohydrate diets will probably improve the survival of many patients with cancer." Other potential approaches Dr. Kanarek and her team discuss include dietary restriction of amino acids such as methionine and serine; supplementation with histidine or mannose; and pharmacological depletion of asparagine, arginine, cystine, folate. Other possible targets covered in the review include glutamine and glutamate, aspartate, alanine and fatty acids. "Although dietary manipulation of many of the metabolites reviewed here has shown a clear pre-clinical benefit, and some of them have shown promise in clinical trials, there are still no clear guidelines or recommended regimes of dietary modification for patients with cancer," they write. "More clinical work and preclinical research focusing on understanding how dietary modifications inhibit cancer in vivo must be completed before dietary interventions become a common approach to cancer therapy." Dr. Kanarek said: "Right now the best we can do is just make sure that the patient is not losing too many calories and is just getting enough to support their energy requirements, but what we can do right now can and should be improved by studying more." She and her coauthors report no conflicts of interest. —Anne Harding Source
