Above DNA: Epigenetics and Diabetes

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Research suggests that risk for type 2 diabetes in some people may have begun very early in life, as a result of differences in how nutrients were reaching the developing baby. Differences in nutrition, either too few or too many calories, differences in the types of foods eaten, or differences in how the placenta and umbilical cord functions to deliver nutrition to the baby, can all increase babies’ risk for developing type 2 diabetes much later in life.

This concept came to light in the mid-20th century, particularly from studying a group of people who survived the Dutch Hunger Winter of 1944-45, a period of famine in the Netherlands during World War II. Affected women who were early in their pregnancy during that time gave birth to babies who grew up with a higher rate of type 2 diabetes and obesity than the rest of their generation who weren’t exposed to those stresses.

This type of increased incidence of metabolic disease has been seen in a number of other studies. Scientists attribute this phenomenon to something called epigenetics.

Everyone has their own genetics—that’s the stuff we inherit from our parents through DNA. Many cases of diabetes, both type 1 and type 2, have this kind of genetic link. But then there’s epigenetics, the regulator of the DNA, deciding when to turn certain genes on or off.

Epigenetic changes happen based on environmental influences. And the uterus, where babies grow, is as much of an environment as any other. When a mother eats too many or too few calories, that can signal for a change in how certain bits of DNA are read.

The lab of Mary-Elizabeth Patti, M.D., Investigator, Director of the Joslin Genomics Core, explores these epigenetic changes and how they relate to type 2 diabetes. Studies in her lab have shown that babies exposed to fetal under- or over-nutrition have more fat cells and fewer muscle cells.

A decreased number of muscle cells is problematic in a couple of ways. First, muscle takes up glucose better than fat does. Less muscle also makes it more difficult to sustain exercise. More fat cells increases insulin resistance—all combining to start the baby off on an uphill battle.

It’s not just the mother’s nutrition that contributes to these changes. Studies out of the Patti lab have shown that fathers who are obese can pass along these epigenetic changes. Grandparents aren’t off the hook, either. Epigenetic changes can be passed down from generation to generation.

Birth weight is a good indicator of what your exposure was in the womb. If you had a high or low birth weight, or were born premature, you might be at a greater risk for becoming obese or developing type 2 diabetes.

Dr. Patti emphasizes that even with these factors working against you, you aren’t destined for disease. Being aware of your risk as soon as possible can help you make better nutrition and exercise choices, lowering your chances of getting the disease down the line.

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