By Ori Hofmekler
Experimental studies show that all thermolyzed (ultra-heated) proteins can promote colon cancer and so do thermolyzed carbohydrates and fried fat.
Thermolyzed casein in particular has shown to cause the growth of aberrant crypt foci (ACF tumors) and colon cancer.
Ultra-heating makes proteins less digestible as a consequence of cross-linking and racemization – which involve formation of unnatural peptides and amino acids.
As a result of decreased digestibility, more proteins escape from the stomach to the large bowel, where they're fermented into tumor promoting waste products such as ammonia and a variety of toxic phenols.
The colonic protein fermentation could explain several known associations between diets rich in fried food, roasted meats or ultra-heated cheese and colon cancer.
There is growing evidence that conventional household cooking preparations of protein play a major role in the pathogenesis of colon cancer. Exposure of food to high cooking temperatures (over 180ºC) such as with oven roasting or frying can lead to the formation of toxic carcinogenic compounds which include aromatic hydrocarbon, benzopyrene and heterocyclic amine.
Our society likes roasted and fried food. We like grilled meats, French fries and pizza. We like to caramelize or "brown" our food when we cook, particularly our proteins.
Colon Cancer Increases with Heated Protein Intake
Studies sponsored by the National Cancer Institute, Toronto, Canada, indicated that the number of colon cancers increase threefold in animals consuming a diet in which approximately one half of the protein has been heated to a golden brown color. Note that in the typical diet, most of animal flesh and marine protein foods are heated to a golden brown color. Scientists suggest that heat treatment of proteins can lead to isomerization, deamination and other modifications of amino acids. The most obvious cancer promoters are heterocyclic amines which could result from racemization of proteins into d-amino acids and cross linking of proteins into unnatural peptides such as lysinoalanine.
Technically, heated proteins get carcinogenic due to changes in their molecular integrity; reduced digestibility and increased nitrogen waste. The reduced digestibility of cooked proteins increase the load of nitrogenous waste material reaching the colon via fermentation to ammonia and phenols – both of which are cancer promoters.
Note that colon cancer is the third deadliest cancer in the U.S. According to the American Cancer Society, an estimated 150,000 people will be diagnosed with colon cancer every year and 55,000 will die as a result of the disease during that time period.
Digestive Resistant Fiber Can Help Prevent Protein Fermentation and Related Cancer
The good news is that starches resistant to digestion (such as digestive-resistant maltodextrin) and other natural water soluble fibers serve as substrates to feed gut flora (friendly gut bacteria) and increase colonic carbohydrate fermentation. This then increases the level of energy reaching the friendly bacteria and thereby REDUCES the level of colonic protein fermentation along with the risk of colon cancer formation.
- Avoid eating roasted or fried proteins and melted cheese – yes, this includes grilled meat or fish, fried chicken, roast beef, barbeque, and pizza. To be on the safe side, avoid all kinds of carmelized sugar, toasted starch and roasted nuts.
- If you still choose to eat grilled, roasted or fried food, try cutting off the burned or browned outer layer part.
- Time under heat is a crucial factor. Short pasteurization is safer than long pasteurization – the longer a protein is heated the more degraded and toxic it gets.
- Make sure your protein product does not include thermolyzed casein – which has shown to be the most carcinogenic among all other thermolyzed food.
- You can still enjoy eating most of your protein foods warm if you cook them in a broth. This will limit the cooking temperature to a 100º Celsius threshold, which has shown to be quite safe and presents minimum health risk. Cooking, stewing or poaching fish, meat or eggs in a broth can be your alternative to frying, grilling or roasting. But note that cheese must be eaten raw.
Heating destroys fragile peptides and amino acids in cheese so to be on the safe side, avoid all kinds of pizzas and melted cheese treats.
- Avoid protein powders which are exposed to ultra heat or heat/acid treatment. These often include protein isolates such as casein and whey isolates as well as soy, hemp and rice protein isolates.
- Avoid whey proteins derived from ultra pasteurized milk. If the whey manufacturer fails to provide you with a certificate of conformity (CoC) which clearly declares that their whey is manufactured from raw milk, then most likely the product is ultra pasteurized.
- Increase your fiber consumption particularly in your protein meals. Note that protein supplements formulated with digestive resistant fiber are more digestible, and safer.
About the Author
- Corpet, D.E., Yin, Y., Zhang, X.M., Remesy, C., Stamp, D., Medline, A., Thompson, L., Bruce, W.R., Archer, M.C. Colonic protein fermentation and promotion of colon carcinogenesis by thermolyzed casein. Nutr. Cancer. 1995:23(3), 271-281.
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