Researchers from Tufts University recently joined thousands of scientists at the Experimental Biology conference, an annual international meeting that presents world-class nutrition research, to exchange and discuss the newest findings. Tufts experts presented over 50 papers and led several symposia that reported research on nutrition and immune function, energy metabolism, hunger and satiety, and diet and exercise. Study findings include:
While evidence of the beneficial effects of dietary fiber on certain diseases accumulates, until now, little scientific information has been available on the type of fiber that is best and its effect on hunger and weight loss. A preliminary study from the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University shows that when it comes to hunger, satiety, and body weight, there is no difference between fermentable and nonfermentable fiber when consumed in supplement form. Fermentable fiber breaks down higher in the digestive track and nonfermentable fiber dissolves lower in the digestive track. Researcher Nancy Howarth and colleagues compared the effects of two high fiber supplements — almost 30 grams — using each type of fiber in a group of men and women with mostly normal body weights. The study participants consumed the fiber supplements a half hour before each meal for three weeks. Although there was a trend for nonfermentable (insoluble) fiber to be more satiating, the researchers found that in supplement form neither fiber type had a significant effect on hunger, satiety, or weight. “We suspect that the same types of fiber consumed intact in foods have more effect, but this needs to be tested,” said Howarth. The best advice is to consume the recommended 25 – 30 grams of fiber per day from food to get its many potential health benefits, including improving insulin sensitivity and reducing the risk of cancers and heart disease.
Many older people believe that consuming the recommended 15 milligrams per day of vitamin E is sufficient for their bodies as they age but according to Tufts University researcher Simin Nikbin Meydani, DVM, PhD, they should consume more. Vitamin E is an antioxidant that helps to repair stress damaged cells in the body. “As people age, immune function starts to decline and there is an increase in immune-related diseases such as infections and cancer. Vitamin E has also been shown to help stave off other age-related diseases such as cataract, heart disease, and Alzheimer’s disease,” said Dr. Meydani. “Our data show that increased vitamin E reduces oxidative stress while improving immune function.” Scientists at Tufts have found that vitamin E supplements significantly improve the immune system in older adults when compared with a placebo. Through their research Meydani and her colleagues have determined that boosting vitamin E levels from 14 mg to 200 mg of vitamin E per day can have an effect on age associated disease. Therefore, the elderly and other populations who have compromised immunity should boost their intake of foods high in vitamin E such as plant oils, nuts, green leafy vegetables, and wheat germ.
Does drinking a soda in the morning set you up for eating more throughout the day? Preliminary research from scientists at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University indicates that soda may cause increased hunger even if the hunger doesn’t lead to overeating. Cheryl Hajduk and colleagues gave a group of teenagers identical breakfasts on three separate visits varying only the group’s beverage each time, which was milk, caffeinated soda, and non-caffeinated soda. The groups were monitored for their blood glucose levels, insulin, hunger level and desire to eat. When it came time to eat lunch the soda group, regardless of the amount of caffeine, reported a greater level of hunger and greater desire to eat. The researchers believe that this study may lead to others on satiety and eating behaviors. For now, the bottom line is milk at breakfast may provide more “staying power,” staving off hunger, in addition to providing milk’s known health benefits.
If you are interested in learning more about these topics, or speaking with a faculty member at the Friedman School of Nutrition Science and Policy at Tufts University, or another Tufts health sciences researcher, please contact Siobhan Gallagher at (617) 636-6586 or Peggy Hayes at (617) 636-3707.
The Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University is the only independent school of nutrition in the United States. The school’s eight centers, which focus on questions relating to famine, hunger, poverty, and communications, are renowned for the application of scientific research to national and international policy. For two decades, the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University has studied the relationship between good nutrition and good health in aging populations. Tufts research scientists work with federal agencies to establish the USDA Dietary Guidelines, the Dietary Reference Intakes, and other significant public policies.