Get the facts on cancer nutrition

A cancer diagnosis often sends patients to the web in search of dietary information that might help their outcomes. But with so much conflicting information available, a search can lead to more anxiety and confusion. While we know that not everything online is accurate or true, it can be tough to wade through nutrition information to figure out what is myth and what is truly beneficial.

Below are three myths that I'm commonly asked about by my cancer patients:

While it is true that cancer cells require sugar (glucose) for energy, this is true for all of our healthy cells as well. (However, because tumor cells are growing rapidly and have a high rate of metabolism, they take up more radioactive glucose, which causes them to "light up" on a PET scan). I have seen patients try to cut out ALL sugar and carbohydrates (including nutrient-rich fruits and whole grains) out of their diet after being diagnosed with cancer, leading to limited food options and rapid weight loss. I even had one young patient try to subsist on nothing but vegetables and nuts, while her weight rapidly decreased.

Even without any carbohydrates (which break down into glucose) in the diet, the body will make sugar from other sources, including dietary protein and fat. It is sensible to limit simple carbohydrates of all types in a healthy diet due to their lack of beneficial nutrients; however, most research shows that it is sugar's relationship to insulin levels that may influence cancer cell growth the most, particularly in those susceptible to insulin resistance. Choosing to eat a healthy, well-balanced diet, getting to a healthy body weight, and exercising can decrease insulin resistance. Other helpful hints include spreading carbs out during the day, focusing on high-fiber carbs, and adding healthy proteins or fats to your carbohydrate meals or snacks.

No research shows that eating organic foods specifically reduces the risk of cancer, or has any direct benefit in helping treat cancer.

Unfortunately, the increased cost of organic produce may lead some to buy, and therefore eat, fewer fruits and vegetables. There are so many cancer-protective benefits in all forms of fruits or vegetables that one should not restrict intake for the sake of only being able to buy a small amount or selection of the organics. Make sure to wash all fresh produce well with water.

Proponents of the Alkaline Diet believe that since cancer cells in a lab seem to thrive in an acidic environment, eating alkaline foods and avoiding  acidic ones must  make the blood pH level more alkaline and, therefore, hostile to cancer cells.

Although cancer cells do prefer an acidic environment, our bodies have regulatory mechanisms which maintain our blood pH level within a very tight range, and we are therefore unable to change it by altering the foods we eat (NOTE: We can, however, alter the pH of our urine by what we eat, which is what is used to test someone's pH in regards to this diet. Blood pH does not correspond to urine pH, which may be what leads to confusion).  It is better to choose a healthy, well-balanced diet, rather than focusing on the alkalinity/acidity of any specific foods. The upside is that the foods recommended on the Alkaline Diet are more fruits and vegetables and less processed foods, which is beneficial in its own right, but not because of the alkalinity.

When evaluating the latest dietary guidelines on cancer, follow these tips:

Avoid chasing the latest nutrition headlines. Sound health advice is based on a body of research, rather than on a single study.

Monica H. Crawford in an outpatient oncology dietician at the, Sidney Kimmel Cancer Center at Thomas Jefferson University.

Read more Diagnosis: Cancer here »