By Adam McLeod, ND, BSc —
I tell virtually every cancer patient that they should avoid sugar as much as possible. Some doctors insist sugar has no effect on cancer. This is simply not what the scientific literature states. If you are trying to fight cancer or prevent the recurrence of cancer, then you should make an effort to reduce your sugar intake.
Study after study has demonstrated a direct connection between sugar intake and cancer risk. There is a wide range of cancers associated with increased sugar intake. Cancer cells often have significantly more insulin receptors than normal cells. In other words, they respond very rapidly to insulin and they will always be more effective at grabbing sugar from the blood stream and utilizing it as an energy source. Cancer cells will always grab the sugar before normal cells due to this fundamental shift in their metabolism.
The sugar acts as a direct source of energy for the cancer cells. These abnormal cells are often dependent on a constant supply of sugar, which is pushed through anaerobic glycolysis to provide them with energy. Essentially, the sugar acts as fuel which directly stimulates the growth of cancerous cells. The fundamental challenge is that normal cells also require sugar and it is simply not possible to eliminate sugar completely.
It turns out that although sugar acts as fuel to cancer cells, the mechanism for the enhanced tumour growth from sugar is different than you would expect. There is a big difference in the metabolism of a food rich in simple sugars compared to a food that contains complex carbohydrates. When you eat a food rich in simple sugars such as candy, the body rapidly absorbs the sugar. This causes a rapid and significant elevation of the sugar concentration in your blood. In response to this sugar spike, the pancreas secretes insulin, which circulates through the entire body in an effort to bring the sugar levels back to normal.
Insulin interacts with the receptors on the surface of both normal and cancerous cells. Upon interacting with the cells, it helps them to pull sugar in from the blood until the blood sugar level drops back to a normal level. Remember that cancer cells have more insulin receptors, so they will always take advantage of this insulin spike more effectively than normal cells. It is this spike in insulin and insulin-like growth factors that stimulate the growth of cancerous cells. In other words, it is not the sugar content that is stimulating growth; it is the response to sudden increases in sugar levels.
Complex carbohydrates are metabolized very differently in the body. They do not cause a sudden spike in blood sugar levels. The sugar in complex carbohydrates is slowly released as the food passes through the gastrointestinal tract. As the sugar is being slowly released, it is also being metabolized by cells within the body at a similar rate. As a result, it is not necessary for the pancreas to secrete as much insulin because there is no spike in blood sugar that needs to be controlled.
Despite the overwhelming evidence, some skeptical health care professionals insist that avoiding sugar makes no difference because everything we consume has sugar in it. Although it is true that virtually everything we eat contains some sugar, this simple logic is completely incorrect and demonstrates a lack of understanding of the mechanism. The sugar is not directly stimulating the growth of cancer, but there is no question that our body’s response to sugar does stimulate cancer.
Dr. Adam McLeod is a Naturopathic Doctor (ND), BSc. (Hons) Molecular biology, First Nations healer, motivational speaker, and international best-selling author. He currently practices at his clinic in Vancouver, British Columbia where he focuses on integrative oncology.