Nutrition society president says eat less, move more

Physician Robert Russell became president of the American Society for Nutrition earlier this year. A policy consultant to the National Institutes of Heath, Russell spent a quarter century with the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Medford, Mass., most recently as its director. He has authored hundreds of papers on nutrition science, many in the fields of vitamins, food-derived antioxidants and gastrointestinal disease. Science News senior editor Janet Raloff spoke with him about today’s most prominent nutrition issues.

ROBERT RUSSELL “The public is aware of obesity’s risks…. Unfortunately, that awareness has not translated into major behavioral change.” Tufts University

What’s the biggest issue facing the nutrition community today?

It’s got to be obesity. But it’s a medical issue as much as a nutritional one because obesity can play a role in so many diseases, from cancer and diabetes to arthritis, stroke, cardiovascular disease — almost every chronic disease of aging.

The public is aware of obesity’s risks because they hear about it almost every day on the news. Unfortunately, that awareness has not translated into major behavioral change for the vast majority of the overweight population. We used to think that just getting the word out and providing education would be all that’s needed to change things, but we’ve been learning that it’s not all that’s needed. We also need to involve communities, families, schools — many, many actors — in order to really catalyze effective behavioral change.

Is this because we’re working against our biology?

Essentially. Evolutionarily, our bodies developed to make very efficient use of energy. Particularly in storing calories that we don’t need to use right away. Now that our lifestyles are dominated by computers and television viewing, people are becoming increasingly sedentary. And this energy-use efficiency, which is built into our genes, is no longer so necessary.

So we have to change food habits — working against the way our bodies have been programmed.

To do that in ways that will be effective, we need to understand the biochemical and molecular mechanisms that are involved. We need to better understand all aspects of appetite regulation and aspects of energy metabolism by muscle and fat cells. You’ve probably been reading about the body’s brown fat, which is far more metabolically active than white fat. But we really don’t understand the mechanisms that control the activity of brown fat in burning energy.

Another big data gap: behavior. We don’t have enough research to know what really drives the behavior to eat or make specific food choices. There can be a host of drivers — culture, genetics, family issues, economics, community factors. We now have to understand their relative roles.

The federal government’s most recent dietary guidelines included a chapter on exercise. Is that something ASN wants to put on the dietary radar screen as well?

Definitely…. Another one of those data gaps is understanding what drives the behavior to exercise — or not. And that’s important because it’s half of the equation that explains obesity, which reflects a mismatch between energy in and energy used.

What other issues need more attention?

With the demographic changes in our country — our graying population — we have to investigate more closely the relationships between nutrition and chronic diseases of aging. For instance, inflammation now is thought to be the common denominator in many chronic diseases. We’re also learning that obesity is related to chronic inflammation.

Nutritionists have been interested for many years in trying to modulate inflammation through antioxidants. But research has shown that in trials using fairly high doses of single antioxidants, or small combinations of them, that they don’t work. In fact, they can become harmful prooxidants.

So now we have to learn more about finding optimal combinations of different antioxidants, rather than looking to prescribe just one or two.

Diet can also be related to cognition in aging. We have a lot of clues that food can be very important in preventing or slowing cognitive decline through nutrients such as omega-3 fatty acids, for example, and the B vitamins, such as B12. These need to be explored more.

Finally, we have to realize that because of genetic differences, the dietary recommendations that work for me might not be right for you. Although we don’t have all of the scientific data that we need, it’s becoming clear that increasingly we may need to begin tailoring recommendations, based on the individual’s genetic makeup.