Fad Diets and Colon Cancer. Are They Worth the Risk?

Fad diets will always be part of the “diet culture” and have become normalized in today’s society. But outside of weight-loss and other health benefits, what effects are they having on the colon? Colorectal cancer is the third most diagnosed cancer and the second most common cause of cancer death in the United States. While much progress has been made in the screening and treatment for colorectal cancer, other preventative measures like diet don’t always get the same attention.

The ketogenic or keto diet has been around a while, so while it’s past “fad” status, is remains popular for its weight-loss benefits. However, some nutritionists consider it a dangerous, high-risk lifestyle for serious disease. On this diet, 70 to 80 percent of calories you eat come from fat, 10 to 20 percent of calories from protein, and 5 to 10 percent of calories from carbohydrates. This approach can be harder to follow long term and promotes nutrient deficiency, which deprives the body of fiber that is essential for digestion. This approach to dieting also has negative effects on the microorganisms in the digestive tract that play a central role in several aspects of health, including digestion, immune function and disease prevention.

Those diagnosed with Type 2 diabetes who follow the keto diet have reported immediate improvements in blood sugar levels, as less sugar and refined carbs means less in the bloodstream. Reducing carbohydrate consumption allows the body to begin using fat to fuel the body versus carbohydrates or glucose leading to lower insulin level. Aspects of the keto lifestyle are sometimes used to help treat those who suffer epileptic seizures and neurological disorders, as a keto diet helps the brain produce natural neuroprotective antioxidants known to help protect brain cells.

A paleolithic or paleo diet attempts to replicate the dietary patterns of Stone Age humans who “hunt and gather” meals that consist mainly of nuts, meats, eggs, fruits and vegetables while eliminating dairy, grains, legumes and processed foods. Paleo diets can negatively affect certain beneficial bacteria in the gut and increase levels of harmful bacteria. The good bacteria found in the gut are needed to break down compounds in red meat, eggs and dairy, so the absence or decrease in this compound prohibits the gut from functioning properly. Advocates of the paleo diet report improvements in their skin, as limiting dairy, sugar and refined carbohydrates and an increase in healthy fat consumption protect the skin from aging and promote collagen production. The paleo diet, at least in the beginning, can also lead to small improvement in blood pressure in people with metabolic syndrome.

But, despite potential benefits, there are studies that attribute paleo and keto diets -- high in animal products and fat -- to a 29-percent increased risk of developing colorectal cancer. One study linked women who regularly consume red meat to an increased risk of colon cancer as compared to women who consumed smaller amounts or no meat at all. And, high-meat and low-carbohydrate diets may even shorten a person’s life expectancy according to this research.

On the other hand, a study in the JAMA Journal of Internal Medicine states that a vegan or vegetarian diet that is heavy in fruits, vegetables, nuts, beans and whole grains may lower the risk of colon cancer by 16 percent. Foods rich in dietary fiber are associated with a decreased risk of colon cancer, while red and processed meats are associated with an increased risk. Adopting a vegan or vegetarian lifestyle can also have positive effects on chronic illnesses such as heart disease, diabetes and some cancers. Vegetarians have up to 12 percent lower rates of cancer, are 50 percent less likely to have type 2 diabetes than meat eaters and typically have lower cholesterol levels, blood pressure and lower body mass index (BMI), all of which positively affect longevity and overall health.

It’s important to note that both genetic and lifestyle factors play a role in the risk associated with any type of cancer, but evidence strongly suggests that physical inactivity and poor diet play an important role in the occurrence and progression of colon cancer.

Regular screenings, recently moved up to age 45, is the key to prevention. The U.S. Prevention Services Task Force recommended that adults age 45 to 75 be screened for colorectal cancer. Symptoms of colorectal cancer should not be ignored and can include rectal bleeding, changes in bowel movements, and abdominal discomfort. It is also important to talk to your doctor about any family history of inflammatory bowel disease or polyps as these can also increase your risk of developing colon cancer.