The dark side of insulin We all know that too much circulating insulin is bad news, but new research indicates it has a darker side than we first thought. Recent studies reveal diabetes drugs that promote insulin release increase cancer risk and the longer a diabetic is using insulin the greater their cancer risk becomes. A study from the Centers for Disease Control and Prevention indicates that type 2 diabetes patients who currently use insulin, the prevalence estimate for cancers of all sites was about 1.3 times higher than among those who did not use insulin.
Among men who had been diagnosed with diabetes more than 15 years ago, there was a 3-fold higher prevalence for colon cancer and a similar increase for urinary-tract cancers (including both bladder and kidney) than those diagnosed with diabetes for less than 15 years. For women, there was an approximately 2-fold higher prevalence of cancers of the breast and reproductive tracts in those with longer duration of diagnosed diabetes compared with shorter. Lead researcher Dr. Li suggests "These results support the notion that exposure to a high circulating concentration of insulin might result in mitogenic effects on breast tissue that stimulate the growth of endometrial stromal cells" increasing the risk of cancer.
Another study looked at the effect of diabetes drugs on liver cancer by reviewing ten studies reporting 22,650 cases of liver cancer in 334,307 patients with type 2 diabetes. Those given sulphonylurea drugs, which promote insulin release, had a 62% increased risk, while those injecting insulin had a 161% increased risk of having liver cancer. Conversely, those given metformin which, like chromium, improves insulin sensitivity which means the body needs to make less, had a 50% reduced risk. Insulin, and insulin-like growth factor (IGF-1) are known to stimulate cancer cell growth. The more sugar and refined carbs you eat the more insulin you make. Also, the more dairy products consumed the higher the circulating levels of IGF-1. Both dairy and sugar consumption is linked to increased cancer risk.
Another recent study finds that the higher the GL (glycemic load) of a person’s diet the greater is a person’s risk of developing diabetes. If you are then put on the wrong diabetes medication (sulphonylureas); or badly managed to the point where you need insulin, that compounds the risk, probably due to the cancer cell growth promoting effects of insulin. We also know that too much insulin switches on the DAF-3 gene, which increases diabetes risk, and switches off FOXO genes associated with anti-ageing effects. The best way to keep your insulin level down is by following a strict low GL diet, also low in dairy and meat which promote IGF-1. There is also increasing evidence that ‘alternate day’ dieting, eating less on alternate days, may also help.
Combining low GL eating with alternate day principles is the crème del la crème for keeping insulin levels at bay. However, diabetics should be careful to maintain blood sugar stability and are best to start by getting stable blood sugar balance by following my low GL diet, as explained in Say No to Diabetes. You may also want to join my Sugar Control Club for week by week support getting established in the Low GL way of eating. Something else that really helps stabilise blood sugar and keep insulin levels at bay are super-soluble fibres based on glucomannan. One animal study found that PGX was more effective than metformin at stabilising insulin and blood sugar. Glucomannan-based powders and supplements need to be taken before main meals (3 grams = 1 teaspoon, or three capsules) with a large glass of water. The fibre absorbs the water, fills up the stomach and slow-releases carbohydrate, thus assisting weight loss.