The Paleo Diet - Loren Cordain [44]
Many women, worried about breast cancer, have adopted vegetarian diets in an attempt to reduce their risk. Unfortunately, it may be that these grain- and starch-based diets actually increase the risk of breast cancer, because they elevate insulin—which, in turn, increases IGF-1 and lowers IGFBP-3. A large epidemiological study of Italian women, led by Dr. Silvia Franceschi, has shown that eating large amounts of pasta and refined bread raises the risk of developing both breast and colorectal cancer.
Most vegetarian diets are based on starchy grains and legumes. Sadly—despite continuing perceptions of these as healthy foods—vegetarian diets don’t reduce the risk of cancer. In the largest-ever study comparing the causes of death in more than 76,000 people, it was decisively shown that there were no differences in death rates from breast, prostate, colorectal, stomach, or lung cancer between vegetarians and meat eaters.
Cancer is a complex process involving many genetic and environmental factors. It is almost certain that no single dietary element is responsible for all cancers. However, with the low-glycemic Paleo Diet, which is also high in lean protein and health-promoting fruits and vegetables, your risk of developing many types of cancer may be very much reduced.
Myopia and Insulin Resistance
Because insulin resistance changes the hormonal profile of the blood to one that facilitates tissue growth, scientists have good reason to suspect that insulin resistance lies at the root of any disease in which abnormal tissue growth occurs. One extremely common such disease is myopia—nearsightedness—which affects an estimated one-third of all Americans. Myopia results from excessive growth of the eyeball. Although the eye looks normal from the outside, inside it’s too long for the eye to focus properly. Myopia typically develops during the childhood growth years and usually stabilizes by the time people reach their early twenties. New evidence that implicates insulin resistance in the childhood development of myopia may be useful in preventing nearsightedness in young children.
Eye doctors generally agree that nearsightedness results from an interaction between excessive reading and your genes. If you spent your youth with your nose in a book and if nearsightedness runs in your family, chances are good that you’re now wearing glasses or contact lenses. Myopia is thought to stem from a slightly blurred image on the back of your eye (the retina) that’s produced as you focus on the written page. This blurred image causes the retina to send out a hormonal signal telling the eyeball to grow longer. Experiments in laboratory animals suggest that the hormonal signal is produced by retinoic acid. Excessive reading slows the retina’s production of retinoic acid, a substance that normally checks or prevents the eyeball from growing too long. Additionally, recent research shows that elevated insulin also directly contributes to the excessive growth of the eyeball. This may mean that if your children’s diet prevents insulin resistance during growth and development, their risk of developing myopia may be lower.
Polycystic Ovary Syndrome
Polycystic ovary syndrome (PCOS) affects 5 to 10 percent of all North American women. Women with PCOS ovulate irregularly or not at all, and their ovaries produce high levels of male hormones such as testosterone. Women with PCOS are prone to obesity, excessive body hair, acne, high blood pressure, and type 2 diabetes. They also have a seven times greater risk of heart disease and heart attack than other women do. Almost 60 percent of all women with PCOS are insulin resistant, and most of these women have elevated levels of IGF-1. Numerous clinical studies have shown that simply changing the diet—eating foods that improve insulin metabolism—can reduce many of the symptoms of PCOS. The Paleo Diet, which normalizes insulin metabolism, can greatly help women with this problem.
Acne
For years, many dermatologists believed that diet had absolutely nothing to do with acne. But very new scientific evidence