According to the World Health Organization cancer is responsible for 12.5% of the deaths globally per year. Diet is linked to 30% of cancers in the developed, and 20% in the developing world. Though those numbers are strong, there is a lack of cohesion in the medical world regarding their validity. Some recent studies have shown much less profound links between cancer and nutrition. So who is right? What is the role that food plays in preventing cancer? And who do we believe?
In articles published by the Journal of the National Cancer Institute it is pointed out that the most recent, rigorous studies show only a 2-3% percent correlation of diet to cancer prevention, rather than a 30% one. Other interesting data shows a strong correlation between certain supplements and increased rates of cancer, specifically a 163% increase in prostate cancer when 1200 mg folate supplements were administered.
An article in the Journal of the American College of Nutrition argues that lifestyle and nutrition are the key factors in preventing cancer. In their estimate the use of supplements and the focus on single nutrients in studies are responsible for the weaker numbers that have been found. This article argues that a balanced diet of whole foods is where the highest rate of prevention can be found. The JACN article also criticizes the reactionary focus of western medicine and highlights the need for society as a whole to make a profound shift in their approach to food.
Between the two points of view there are two points of agreement. Supplements are a greater risk than remedy and that more, better, research must be done. In exploring all the arguments out there and the recommendations being made I think that no one really knows. No one nutrient has been shown to be a magic cure for cancer, no particular diet has yet come to light that absolutely prevents cancer.
Taking a step back, why are we even exploring the impact of food and nutrition on cancer? To understand let’s quickly look at what cancer is, and what food can do for the body in preventing it.
Cancer is basically a cell gone bad. One whose intended function is derailed and which begins to reproduce wildly. We all have these cells in our bodies. In the countless cell divisions that occur daily in our bodies there are always errors that have the potential to create cancer cells. Most of the time our immune system finds those cells and kills them. Cancer as a disease manifests when our immune systems fails and those cells run amok.
How does food effect this process? Food is what makes your body go. Calories fuel our body, nutrients provide chemicals that run our systems and are the building blocks of our tissues. Even the parts we don’t digest help us, ensuring that our digestive track has enough in it to move our waste along. Eating the proper foods helps to ensure that we have the energy for cellular and nerve activity, are able to build strong protein and fatty acid chains, that our chemical messaging systems has the right messengers who do not get lost. A healthy immune system ensures that we have the Natural Killer Cells (yes, they are really called that) in proper numbers and strength to destroy the erroneous cells that do occur. Proper nutrition also ensures that our tissues are healthy and less vulnerable. There are also substances in food that help to interfere with the activity of harmful substances in the body, some block access to cells, some destroy free-radicals, some ensure a quick passage through the body to lessen exposure to a particular substance.
What really got me thinking in the JNCI was that though no significant reduction in cancer rates were noted, there was a 30% decrease in heart disease in groups with better diets. Our lack of strong, consistent, rigorous research hasn’t stopped a large number of laymen and medical professional, and their organizations from promoting a very consistent type of diet. Keep your calories and fat low, your fibre and whole grain high and eat a wide variety of vegetables and fruits. Where is the harm in this? Maybe you won’t stop cancer, but you will likely stave off diabetes, heart disease and obesity.