What makes for a long and healthy life? Why, you say, how about a healthy diet and liberal quantities of exercise? True! A healthy lifestyle keeps you in shape and is one factor that promotes longevity. But have you ever wondered exactly how this works on a physiological level? How does the brain understand you skipped the gym all summer and had French fries for lunch yesterday?

The answer, according to the results of a new study published in Science (July 2007), could relate to insulin levels in the brain. Researchers induced lab mice to overeat until they became obese and some exhibited symptoms of diabetes. Yet some of those same mice actually lived eighteen percent longer than their slender mice buddies. The researchers attributed that longevity to a gene that affects insulin. Put simply: the longevity gene (called Irs2) effectively "tricked" the brains of those mice into thinking they were slim and fit, when in fact the opposite was true.

For diabetics, the study raises an additional question: if raising insulin levels decreases the body's sensitivity to it, is it really desirable to treat type 2 diabetics with insulin over the long-term? Lead author of the study, Morris White of Children's Hospital in Boston, says it's highly preferable (when possible) to get type 2 diabetes under control through old-fashioned diet and exercise, rather than through insulin or other meds.

A popular article from The New York Times is worth a look. It's all about how people are so much more robust and healthy than were previous generations, particularly comparing today's Americans with those from the mid-1800s or the early 1900s. One of the topics discussed at length in the feature is disease, specifically chronic diseases that used to be commonplace and affected people from relatively early ages.

The article discusses various studies that link health and longevity to health in early childhood (and, specifically, the availability of good food, vaccinations and antibiotics). These studies have also identified a link between individuals' health and longevity and the state of their mothers' health during pregnancy.

One example: researchers studied the health of babies born to women who were pregnant during the Dutch famine, which occurred during World War II, between November 1944 and May 1945. These babies seemed no worse for their mothers' terrible suffering - their birth weights were normal, for example. However, it was found that now, as age catches up with those people, they are developing chronic diseases, including diabetes, at unusually high rates.

Similarly, a study of children born to mothers who were pregnant during the influenza epidemic of 1918-19 found that they were also more likely to suffer from chronic illnesses than were children born to women pregnant before or after the epidemic. Again, the incidence of diabetes was higher than for other people - in this case, twenty percent higher by the age of sixty-one.

The conclusion? When a mother is ill or starved during pregnancy, the danger is not just the health of the baby, but for that child as he or she grows, and even for the rest of his/her adult life. That is, the experience of the mother may predispose the child to illnesses that typically do not develop until later in life (middle age or later).

Richard Kahn, Chief Scientific & Medical Officer for the American Diabetes Association, is blogging the American Diabetes Association's 66th Annual Scientific Sessions. From June 9 - 13, the annual convention brings together leading scientists and health professionals to present the latest study findings and to discuss the current and future progress in the field of diabetes prevention and care.

So far, some of Kahn's posts have covered such topics as: insulin and longevity; endocannabinoids, oral insulin, the new A1C test, who is responsible for optimal diabetes care; the worm study; and you are what your mother ate during her pregnancy. The posting is written in a light and easy manner, not requiring the average person to being a textbook of medical definitions to make sense out of what is being said. I assume Kahn will continue blogging through June 13. You can read Richard's D.C. Diary here.