Colorectal cancer is the third most commonly diagnosed cancer, and the third leading cause of cancer death in men and women in the United States. A recent study published in the British Journal of Cancer, involving over 5,000 women from the Women’s Health Initiative study, has found a link between high blood sugar levels and colorectal cancer in postmenopausal women.1

At the beginning of the study, and on several more occasions over 12 years, fasting blood sugar and insulin levels were measured. At the end of the 12-year study, 81 women out of over 5,000 had developed colorectal cancer. Women with the highest blood glucose levels were twice as likely to have developed colorectal cancer as the women with the lowest levels.

The next step, the researchers stated, is to find the mechanism, or to find out how high blood sugar leads to colorectal cancer. The lead researcher, Geoffrey Kabat, Ph.D., states, “It’s possible that elevated glucose levels are linked to increased blood levels of growth factors and inflammatory factors that spur the growth of intestinal polyps, some of which later develop into cancer.” Other studies have found a link between elevated insulin levels, which occur as a result of prolonged elevation of blood sugar levels, and colorectal cancer.2

Elevated blood sugar does a whole lot more than lead to colorectal cancer. High blood sugar leads to insulin resistance, metabolic syndrome, type 2 diabetes, gestational diabetes, heart disease, non-alcoholic fatty liver disease (NAFLD), Alzheimer’s disease, and more. Furthermore, insulin resistance increases fat deposition which will lead to further production of inflammatory cytokines and more inflammation throughout the body.

Maintaining healthy blood sugar levels is crucial for optimal health. I recommend a glucose and insulin tolerance test, measuring glucose and insulin at one and two hours. Also, the A1c test is will help to measure how well blood sugar levels are managed over time, as it’s a measure of your average blood sugar level for the past two to three months.

If your blood glucose and insulin levels are out of normal range, you’re in trouble. In fact, if you are overweight, or if you have abdominal fat, you’re in trouble. Belly fat is considered to be an organ of its own,3 churning out pro-inflammatory cytokines, and contributing to many different chronic diseases. If you are overweight or have belly fat, it’s likely you also have elevated blood sugar or insulin, or that you’re heading in that direction, which leads down a path of chronic disease.

The Standard American Diet (SAD) is high in grain-based carbohydrates and low in vegetable-based carbohydrates, high in refined sugars and low in fiber, and high in unhealthy fats and low in healthy fats. All of these factors contribute to poor health. Elevated blood sugar and insulin levels occur as a result of eating the SAD diet. Change your diet if it’s not high in vegetables, healthy fats, leans proteins, seeds and nuts. These foods will help protect against high blood sugar levels.


  1. G.C. Kabat, et al., “A longitudinal study of serum insulin and glucose levels in relation to colorectal cancer risk among postmenopausal women.” Brit J Cancer.2011 Nov 29; advanced online pub.
  2. M.J. Gunter, et al., “Insulin, insulin-like growth factor-I, endogenous estradiol, and risk of colorectal cancer in postmenopausal women.” Cancer Res. 2008 Jan 1;68(1):329-37.
  3. E.E. Kershaw and J.S. Flier, “Adipose tissue as an endocrine organ.” J Clin Endocrinol Metab. 2004 Jun;89(6):2548-56.