The Benefits of a Low-Glycemic Diet for Macular Degeneration
Did you know that the food you eat can affect your eye health? Sheldon Rowan, PhD, recently joined a BrightFocus Chat to discuss the best foods to eat for long-term eye health and highlighted the importance of a low-glycemic diet. Rowan, a past BrightFocus Macular Degeneration Research grantee, is an assistant professor of ophthalmology at Tufts University School of Medicine in Boston and a scientist on the Nutrition and Vision Research Team at the Jean Mayer USDA Human Nutrition Research Center on Aging.
His research has linked the gut microbiome—a community of bacteria, fungi, viruses, and their genes, living naturally in our stomachs—to the development and progression of age-related macular degeneration (AMD).
Dr. Rowan was among the first to make a connection between a high glycemic diet and an increased risk of AMD. “You can certainly get a signal going from the gut that [leads to] inflammatory processes [elsewhere in the body],” he said. “We know [that inflammation is] part of what happens in macular degeneration.”
Foods high in refined sugar and carbohydrates have a high glycemic index, which is a value used to measure how much specific foods increase blood sugar levels. Notably, high glycemic foods don’t just include sugary treats. Foods with simple starches in them can be high-glycemic, even when they don’t have any added sugar, such as some corn-based breakfast cereals. “The way our body treats that particular kind of processed corn starch, it almost instantly gets converted into glucose,” Dr. Rowan said.
For people looking to reduce their intake of high-glycemic foods, Dr. Rowan recommends swapping refined grains for more whole grains. “So, whole-grain bread instead of white bread,” he said. Swapping steel-cut oats instead of instant oats, or basmati rice for regular white rice, can also help.
Dr. Rowan also recommends eating fruits and vegetables red or orange in color, like peppers, carrots, and tomatoes, as well as broccoli, cauliflower, and Brussels sprouts. Fish is also especially beneficial for macular degeneration.
Eating for long-term eye health also means making healthy food combinations. “The way we combine foods together can really reduce the glycemic index of a meal,” Dr. Rowan said.
He wore a glucose monitor for two weeks to see how different approaches to eating high-glycemic foods affected his blood sugar. He found that “if you eat a bagel together with another food—like, a bag of almonds—it effectively lowers your body’s glycemic response to the bagel.”
During Dr. Rowan’s two weeks with the glucose monitor, he also experimented with exercising after eating. “I had a bagel and then went for a quick 15-minute walk,” he said, “and my blood sugar was significantly lower than when I had the bagel and was sedentary for the same period of time.”
The eye doesn’t have a natural regenerative process to heal from damage. So, eating well—both in what and how we eat—functions as an essential tool for staving off AMD. Luckily, this evolving field of research shows that healthy lifestyle choices improve AMD outcomes, even among people at high genetic risk for developing the disease.
“No one should feel like there’s no point to them doing these things,” Dr. Rowan said. “There’s never an inevitability of macular degeneration—you can always do something.”
Listen to the full conversation with Dr. Rowan.
BrightFocus Chats are monthly in-depth conversations with expert scientists and clinicians about new treatments and discoveries around ending diseases of mind and sight. Learn more.