Monthly Archives: April 2007

Ask the expert: Vitamin D and chronic disease

The Expert: Dr. Edward Giovannucci

Dr. Edward Giovannucci

Professor of Nutrition and Epidemiology, Departments of Nutrition and Epidemiology, Harvard School of Public Health

1. There’s been a lot of news lately about vitamin D’s role in prevention of cancer, heart disease, and other chronic diseases. What do we know today—and what questions remain?

Vitamin D has a well-established role in maintaining calciumlevels in the body and in building strong bones. That’s why vitamin Ddeficiency could increase the risk of osteoporosis. In addition, elderly whodon’t get enough vitamin D have weaker muscles and are more prone to falls,which could further increase the risk of fractures.

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Ask the expert: Controlling your weight

 The Expert: Dr. Walter Willett

Dr. Walter Willett

Fredrick John Stare Professor of Epidemiology and Nutrition, Departments of Nutrition and Epidemiology, and Chair, Department of Nutrition, Harvard School of Public Health


1. How much control do we have over our body weight? And how much of our weight is controlled by our genes?

Genes do play a role in controlling our weight, but clearly they do not explain the huge increases in overweight and obesity we have seen in the last 30 years. We gain weight when our “calories in” (the food we eat) exceeds our “calories out” (the energy we burn). Given the genetic package we are born with, we can all improve our weight by paying attention to diet and getting regular physical activity, but some people will need to work harder than others to maintain a healthy weight. In other words, if we all eat and work out the same, we will not all look the same. Only a very small percentage of people have such a strong genetic predisposition that they will be obese no matter how hard they try. Even people who are genetically predisposed to obesity can reduce their risk of chronic disease by eating a healthful diet and staying active.

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