The Insulin Connection
One hormone may cause cancer, heart attacks, and many more ills.
Diabetes drugs have made a big difference to George Marincin and Kristin Chapman. For a few weeks last year, Marincin, 77, from Tacoma, Wash., took artificial insulin, the hormone that's deficient in diabetics. And every day Chapman downs doses of Glucophage, a drug that helps the 38-year-old from Atlanta to better control the hormone.
But neither Marincin nor Chapman has diabetes.
What Marincin does have is Alzheimer's disease. He took insulin to test the idea that low levels might be linked to memory problems. "I did wonder how insulin could help George because he's not diabetic," says his wife, Mabel. "But it has. It's wonderful." Her husband has regained his sense of humor and can even complete simple tasks again like making a cup of tea, she says. Last month his doctors reported in the Archives of Neurology that other patients also seemed to benefit.
Chapman was just as surprised that adjusting insulin levels could help her. She has polycystic ovary syndrome, which causes infertility and dramatically raises her risk for heart disease. But her problem wasn't too little insulin but too much, which prevents ovulation. After seven years of struggling to conceive, she started taking Glucophage and was pregnant in a month. "It's mind boggling, isn't it?" she says. Now the happy mother of two kids, she'll stay on the drug for the rest of her life to keep her high insulin in check.
Insulin problems--too much or too little--go far, far beyond diabetes. The condition is called insulin resistance and, in addition to the ailments dogging Chapman and Marincin, doctors are now discovering it is linked to heart attacks, strokes, and several kinds of cancer and may affect 1 in 3 American adults. These findings have alarmed many specialists. "Insulin resistance is very common, and it's associated with the biggest killers," says endocrinologist Ronald Kahn, director of the Joslin Diabetes Center at Harvard University. "If we don't start paying attention to this now, we're all going to be paying a huge price for this condition." Physician David Katz, director of the Prevention Research Center at Yale Medical School, adds that "we're just beginning to understand that insulin throws a lot of big switches in the body. Is insulin the master control of all disease? I don't know, but it's certainly a candidate for that role."
Insulin's main job is to escort sugar out of the blood and into muscle and fat cells. But sometimes those cells resist letting it in. So the pancreas, which makes insulin, tries to crank out even more. If it can't, blood sugar climbs to dangerous levels and the result is Type II diabetes. More often, however, the pancreas does make more insulin. The extra hormone may restore blood sugar to normal, but it overwhelms the rest of the body. That spells trouble, because insulin is more than just a sugar ferry. It tells the kidneys, for example, to hold on to salt. And more salt means hypertension. It tells cancer cells to grow, and that can mean a tumor.
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