The Department of Nutrition’s annual Stair Hegsted Lecture focuses on carbohydrate quality, glycemic index and metabolic health.
October 17, 2024 – When low-carbohydrate diets first became popular in the late 1970s, researcher David Jenkins and colleagues wanted to find a way to measure the health value of this category of foods. Otherwise, it would be hard to justify encouraging people to eat more plant-based foods, he recently told an audience at the Harvard T.H. Chan School of Public Health.
David Jenkins and Frank Hu, Fredrick J. Steer Professor of Nutritional Epidemiology and Chair of the Department of Nutrition
Jenkins, a physician and professor at the University of Toronto, and his team have developed a glycemic index that shows how quickly and by how much a food raises blood sugar levels after a meal. He shared his research at the 19th Annual Stair Hegsted Lecture held at Kresge G-2 on October 7th. The event, sponsored by the Department of Nutrition, honors the department’s founders, Frederick Steer and D. Mark Hegsted.
Foods made with highly processed grains and containing little fiber (such as white bread) score higher on the glycemic index. This means that those foods are rapidly digested, causing large fluctuations in blood sugar levels. Eating large amounts of these foods can increase your risk of developing type 2 diabetes and other chronic diseases. Foods with more intact grains, such as steel-cut oats, have a slower impact on digestion and blood sugar, so they score lower.
To assess the health value of foods, in addition to dietary fiber and whole grain content, we use glycemic index and glycemic load (measures developed by other researchers that look at the amount of digestible carbohydrates in a food) ), Jenkins said. He and Professor of Epidemiology and Nutrition Walter Willett recently published a paper on this topic, calling for improved nomenclature for classifying carbohydrate-rich foods in nutritional research. For example, “whole grains” can include both highly processed foods that use whole grains, which are less healthy, and healthier foods that contain whole grains, researchers say. pointed out.
Professor Jenkins highlighted research showing that heavier people are at greater risk of adverse health effects from diets with a high glycemic index, as well as oxidative stress, a measure of an imbalance in the body’s ability to process oxygen that damages tissues. They cited additional studies, including one suggesting that Related molecules caused by fluctuations in blood sugar levels may be the mechanism that causes health problems in people eating a diet with a high glycemic index.
Jenkins has also recently collaborated with Willett and other Harvard Chan School researchers on a plant-based portfolio diet. A study published last year in the journal Circulation found that it may have benefits for cardiovascular health.
– Amy Lauder
Photo: iStock/fcafotodigital;Liu Binkai
