While many oncologists these days appreciate the effects of diet and nutrition, on occasion I have consulted with patients whom have been told to eat whatever they want because nothing, as far as diet, makes a difference in quality of life or side effect development. They've been told to go have a steak with fries, followed by a big milk shake. Heavy sigh and deep breath.
Empirically, that is by observation, we know that diet makes a difference. Furthermore, peer reviewed studies, document the positive effects diet has on patients during and after cancer treatment. In general, what we know is that patients who have received nutritional counseling during and after cancer treatment have better outcomes, and better quality of lives. This also includes the occurrence and degree of side effects -- both short and long term.
This finding is not surprising given the information we have on people and places with lower incidences of cancer. The diet that most people are familiar with is the Mediterranean diet which contains a rich variety of colored vegetables, oils, fruits and lean meats. Other countries with low cancer rates also consume diets rich in whole foods and use spices abundantly and frequently. These diets contain rich sources of antioxidants, minerals and vitamins that are very helpful in keeping the body working in a balanced fashion.
We also know from research how some nutritional aspects work to affect cancer growth. For example, insulin surges, created by high simple sugar or simple carbohydrate intake, can trigger growth of solid tumors. This connection from a research stand point has been studied for quite a while. Researchers were looking at the difference in cancer rates between diabetics with type I (no or little insulin) and type II (production of a lot insulin but the normal cells are resistant, that is they do not respond). Simple carbohydrates tend to be high in diets that contain lots of processed foods.
We also know from National Cancer Institute studies that foods containing higher levels of omega 9 fatty acids are associated with increased risk of developing cancers namely certain types of gastrointestinal and breast cancer. Red meat and pork are some foods that contain higher levels of omega 9's.
Really, everyone should be eating a relatively whole foods diet for well being, but when one is being treated for cancer a more specific diet is needed depending on the treatment type and here's why.
Each treatment has a different mode of action, expected side effects, tissue affinity and nutritional demand. Most chemotherapy will cause a deficiency in sodium, potassium, calcium, magnesium, or phosphorus; or all of them depending on the specific type of chemotherapy. Deficiency of any of these critical nutrients can cause exacerbation or creation of side effects.
Let's take a look at a couple of specific examples. Herceptin and Adriamycin are two chemotherapies that are standard in the treatment of breast cancer. They have different ways they work to kill cancer cells, but both can also weaken the heart. In this case, culinary nutrition that would be applied would be heart healthy foods. In the case of Herceptin (if Herceptin were taken alone) you could use foods that contain good levels of flavanoids, Vitamin C, ribose, glutathione and L-carnitine. Because of the way Adriamycin works you wouldn't want to use antioxidants such as Vitamin C, but you could relay on foods containing helpful amino acids such as carnitine and ribose.
Another example is the use of 'platin' drugs, Taxol and Taxotere. These are notorious for causing something called peripheral neuropathy. What we know is that when a certain amino acid called L-glutamine begins to decrease in quantity in the body, the risk of developing peripheral neuropathy increases. Foods high in this amino acid should be consumed consistently through treatment. These chemos also can create a shortage of magnesium in the body which in turn can cause muscle spasms, high blood pressure and insomnia. Foods rich in magnesium should be used during treatment with these drugs.
Anastrazole, a hormone blocking treatment is associated with joint aches, in some people. Estrogen acts as a slight anti inflammatory. When it is withdrawn we may feel the effects. In addition, patients might be feeling some residual effects of chemotherapy on their joints as well. Omega 3 fatty acids are very helpful to help decrease achiness (and hot flashes too).
The list of examples goes on. From what I have observed and what is in the scientific literature the use of consistent culinary nutrition is extremely important and an effective treatment ally.
So does that mean that food can't be fun and all comfort food must be cut out? All my patients know my suggested rule: 80/20. Be on 'the bus' 80% of the time. Break bread with loved ones near and far even if it means that you get off 20% of the time. You always have a ticket to get back on!