Simple Diet Advice for Cancer Patients
Jacob Schor ND, FABNO
August 16, 2015
Patients who have been diagnosed with cancer frequently seek information on what they should eat, or what sort of diet would serve them best. The best general advice is that they should try to follow the guidelines for a Mediterranean diet  and in addition reduce carbohydrates more than is typical and use the ‘foods that fight cancer’ list on the American Institute of Cancer Research’s website. 
Many fruits and vegetables supply micronutrients and phytochemicals that help curb cancer growth and these diet suggestions increase consumption of these foods for the average patient.
It is often important to limit overconsumption of animal protein and carbohydrates in this patient population. This is because many types of cancer are responsive to insulin-like growth factor-1 (IGF-1). This growth factor is made in the liver in response to Human Growth Hormone made in the brain and tells cells to grow. Many cancer cells over express receptors for IGF-1 and so respond to it more strongly than healthy cells do.
Lower animal protein:
The main determinant of IGF-1 production in humans appears to be animal protein in the diet. The more animal protein consumed, the more IGF-1 produced. This is quite apparent in first generation immigrants to the United States as they often eat more protein than their parents did and are notably taller than their parents. IGF-1 appears to be particularly stimulated by dairy protein consumption. The new food fad of eating “Greek Yogurt” that has been centrifugally concentrated to increase protein levels should be done with great caution in people who have been diagnosed with cancer.
Lower insulin: eat fewer carbs
Lowering insulin production is probably equally important as controlling IGF-1 levels. Insulin binds to some of the same receptors on cancer cells as IGF-1 and is ‘mistaken’ for this growth factor. Thus high starch, high sugar diets that increase insulin production often increase tumor cell growth.
There are several ways to lower insulin production. The most obvious is to reduce daily sugar and starch consumption. Many patients read on the internet that “sugar feeds cancer” and cut our sugar from their diets entirely. While this equation may not be exactly factual, the end result is helpful, lower insulin production.
Not all carbohydrates are equal when it comes to insulin stimulation. Starches may be an even problem than sugars as almost all of their caloric content is derived from glucose and so require more insulin than sugar, which is only half glucose (the other half is fructose that doesn’t require insulin to handle). It isn’t just the type of carbohydrate that matters when it comes to insulin production. Other components in food, particularly fat and fiber content, influence how fast the glucose in the food reaches the blood and in turn how much insulin is produced.
Lower Glycemic Index:
We commonly share a list with patients that expresses the differing impacts on blood sugar different foods have. Lists like this are called “Glycemic Index Lists”. Our favorite of late is one put out by Harvard University.  It compares the rise in blood sugar (which is glucose) caused be particular foods to that caused be an equal amount of carbohydrates from pure glucose (think corn syrup). It is worth reading through this list and pondering why foods vary so much and using that knowledge to inform dietary choices. As mentioned, fat and fiber lower blood sugar increases. Starches, in particular white flour and white potatoes are digested almost instantly and are often on par with straight glucose. White sugar appears to have less impact than these simple starches.
Timing of carbohydrate consumption may also be important if results of a recent study prove to be true. In fact simply adjusting timing of when we eat carbohydrates may prove to be the easiest way to achieve our end goal of lowering insulin levels.
Timing matters with carbohydrates.
Eating refined carbohydrates on an ‘empty stomach’ has a far greater impact on blood sugar than eating the same foods after a meal. Diabetes Care published a paper by Louis Aronne et al this past July that surprised us with the magnitude of the difference.
Study participants were twice served a meal of grilled chicken, steamed vegetables and a salad dressed with vinaigrette on different days. On one of those days, they ate a standard-sized ciabatta before the meal. On another day they save the bread until after they had eaten everything else.
Peak blood sugars were 30% lower when the bread was saved for last.  Thus simple as it sounds, patients can lower the impact that eating carbohydrates has on blood sugar, and we would assume insulin production, simply by changing when they eat those carbohydrates.
Finally we have a good reason to save dessert for last. We may live longer if we do. In an ideal restaurant, dinner would start with salad, then soup, then fish and vegetables, followed by bread and maybe dessert. This seems remarkably easy and even though the evidence is still weak, there seems to be a low risk for patients to adopt this practice. It may prove to be even more important to change the order we eat breakfast, a meal in which modern culture starts with fruit juice. Better to eat the proteins first and save the toast and juice for last. Or our more modern readers who think that starting their day with a fruit smoothie is healthy, might in fact be better served to save these relatively high carb drinks until after a more substantial meal.
To sum it up, this is how cancer survivors should eat. They should follow a Mediterranean style diet, selecting foods that have anticancer effect and that have a low glycemic index whenever possible. If consuming simple carbohydrates, in particular starches, they should save them until the end of their meal.
Carbohydrates and breast cancer recurrence: http://naturalmedicinejournal.com/journal/2014-10/carbohydrates-and-breast-cancer-recurrence
Adherence to Mediterranean diet reduces mortality:
Insulin-like growth factor and longevity: http://naturalmedicinejournal.com/journal/2014-09/lower-insulin-growth-factor-1-and-live-longer
High protein diets and longevity:
Glycemic load and colon cancer: