Diabetes

Natural “exercise” hormone transforms fat cells

Heidi Godman
Heidi Godman, Executive Editor, Harvard Health Letter

Exercise makes cells burn extra energy—that’s one way it helps control weight. It also generates a newly discovered hormone, called irisin, that transforms energy-storing white fat cells into energy-burning brown fat cells. Irisin also appears to help prevent or overcome cellular changes that lead to type 2 diabetes. The hormone does this by helping transform energy-storing white fat cells into energy-burning brown fat cells. White adipose tissue, more commonly known as body fat, is the tissue that dimples thighs, enlarges waists and derrieres, and pads internal organs. Each white fat cell stores a large droplet of fat. Brown fat, in comparison, is chock full of energy-burning mitochondria. Its main function is to generate body heat by burning fat. A team led by Dr. Bruce Spiegelman, professor of cell biology and medicine at Harvard Medical School, has identified irisin in mice and humans and showed how irisin transforms white fat cells into brown ones, at least in mice.

Experts recommend a more personal approach to type 2 diabetes

Howard LeWine, M.D.
Howard LeWine, M.D., Chief Medical Editor, Internet Publishing, Harvard Health Publications

The hemoglobin A1c reading is an important number for people with diabetes. It’s a measure of the average blood sugar level over the preceding three months. For years, the American Diabetes Association recommended that almost everyone with type 2 diabetes should aim for an HbA1c level less than 7%. Keeping blood sugar as low as possible, called “tight control,” was thought to limit the havoc caused by diabetes. New guidelines from the American Diabetes Association (ADA) and European Association for the Study of Diabetes recommend taking a more “patient-centered approach.” For people who are newly diagnosed with type 2 diabetes but who are otherwise in good health, the ADA still suggests aiming for an HbA1C of 6.0% to 6.5%. For people who have had diabetes for a while, an HbA1c goal of 7.5% to 8.0%, or even higher, may be more appropriate.

Late to bed, early to rise: a recipe for diabetes

Howard LeWine, M.D.
Howard LeWine, M.D., Chief Medical Editor, Internet Publishing, Harvard Health Publications

Sleeping poorly night after night—because you are trying to burn the candle at both ends or you work night or rotating shifts—has long-term health consequences. People who don’t average at least six hours of sleep a night are more likely to be overweight or develop various medical problems. New research from Harvard-affiliated Brigham and Women’s Hospital shows that lack of sleep plays a complex and powerful role in the development of type 2 diabetes. Among volunteers who lived in a sleep lab for several weeks, their bodies made less insulin after meals when they got under 5.5 hours of sleep a night for three weeks. As a result, their blood sugar levels went haywire. Some of the people had blood sugar levels high enough to have been diagnosed as prediabetic.

Personalized medicine experiment details diabetes development

Patrick J. Skerrett, Former Executive Editor, Harvard Health

The term “personalized medicine” is still something of an abstract idea. In an audacious experiment, Stanford molecular geneticist Michael Snyder gave it a face—his own—and showed what it can do. Snyder and a large team of colleagues first sequenced his DNA, revealing his complete genetic library. Then they analyzed blood samples he gave every few weeks for two years. This was akin to taking a 3-D movie of his inner workings to observe how genes, the molecules that read and decode them (RNA), the proteins they make, and other substances interact during health and illness. The team saw how Snyder’s body responded to a cold at the very beginning of the study. Midway through, they watched as molecular changes wrought by a respiratory infection tipped him into full-blown diabetes.

New report provides a plan for living with type 2 diabetes

Anthony Komaroff, M.D.
Anthony Komaroff, M.D., Executive Editor, Harvard Health Letter

These

Pregnancy-related high blood pressure, diabetes linked to later heart disease

Howard LeWine, M.D.
Howard LeWine, M.D., Chief Medical Editor, Internet Publishing, Harvard Health Publications

Most of the changes that come with pregnancy—growing a belly “bump,” being tired, mood swings, cravings for particular foods, and the like—are normal, temporary, and harmless. Two other changes, pregnancy-related high blood pressure and diabetes, may have long-lasting implications for heart health. The development of high blood pressure during pregnancy is known as preeclampsia; pregnancy-related diabetes is called gestational diabetes. They are different from “regular” high blood pressure and diabetes because both are “cured” by delivery. A new study published this week in the journal Circulation suggests that these complications boost a woman’s risk of cardiovascular disease during middle age.

Long-term survivors are helping unlock the mysteries of type 1 diabetes

Patrick J. Skerrett, Former Executive Editor, Harvard Health

Type 1 diabetes, once called juvenile-onset diabetes, takes a toll on health and longevity. Some people, though, have managed to live with the disease for decades. Since 1970, almost 3,500 men and women who have lived with type 12 diabetes for a half century have been recognized by the Joslin Diabetes Center in Boston with bronze 50-year medals. Forty-five of them have passed the 75-year mark. A study that includes several hundred 50-year Medalists is changing experts’ understanding of type 1 diabetes. Many of the 50-year Medalists have no signs of diabetes-induced eye or kidney damage, and some still continue to make small amounts of insulin. This work may uncover new ways to protect people from the damage diabetes can cause and point ways to new treatments for it.

Implants, tattoos, and tears could measure blood sugar without pain

Patrick J. Skerrett, Former Executive Editor, Harvard Health

Today, the only reliable way to check blood sugar is by pricking a finger, squeezing out a drop of blood, and placing it on a small test strip attached to a meter. For some people, this means five to ten finger sticks a day. Researchers across the country are exploring pain-free ways to measure blood sugar. University of California, San Diego researchers have developed a titanium sensor the diameter of a quarter that would be implanted under the skin and wirelessly send blood sugar readings to an external monitor. At Northeastern University in Boston, researchers are working on a blood sugar “tattoo” by injecting glucose-detecting nanosensors under the skin. Arizona State University researchers are working to perfect a device that measures blood sugar using tears instead of blood.

Diabetic neuropathy—the agony of da feet

Patrick J. Skerrett, Former Executive Editor, Harvard Health

More than half of people who live with diabetes eventually develop diabetic neuropathy, or damage to nerves. It can range from merely aggravating to disabling or even life threatening. The first nerves to be affected tend to those in the toes and feet. Diabetic neuropathy can be felt as a tingling in the toes and feet, a constant burning feeling in the feet, sharp pain that may be worse at night, or extreme sensitivity to touch. In some people, it robs the feet of their ability to sense pain. So far, there isn’t a cure for diabetic neuropathy. Controlling blood sugar is the most important step to preventing or managing it. Controlling blood pressure, not smoking, and staying active also help. People with diabetes should have a doctor examine their feet at least once a year, and should check their feet every day or so.

Do chronic diseases have their origins in the womb?

Patrick J. Skerrett, Former Executive Editor, Harvard Health

Heart disease, stroke, diabetes, asthma, osteoporosis and other common chronic diseases are often blamed on genes, pollution, or the wear and tear caused by personal choices like a poor diet, smoking, or too little exercise. An intriguing hypothesis is that these and other conditions stem from a developing baby’s environment, mainly the womb and the placenta. During the first thousand days of development, from conception to age 2, the body’s tissues, organs, and systems are exquisitely sensitive to conditions in their environment during various windows of time. A lack of nutrients or an overabundance of them during these windows, so the thinking goes, programs a child’s development and sets the stage for health or disease.