Higher intake of magnesium was associated with a lower risk for diabetes, particularly in people with diets too high in low-quality carbohydrates or low in fiber, according to a study in Diabetes Care.
Researchers analyzed health data on more than 200,000 people from the Nurses’ Health Studies and the Health Professionals’ Follow-up Study. Consistent with past research, participants with the highest versus the lowest intake of magnesium were 15% less likely to develop diabetes over the 28‑year study period.
But the new study found that the association between magnesium and diabetes risk was stronger in participants with diets high on the Glycemic Index (GI) or low in fiber from grains. Higher-GI diets include low-quality carbohydrates, like refined grains and added sugars, that cause blood sugar (glucose) to rise relatively rapidly after meals, whereas lower-GI foods are associated with more gradual glucose increases. In diabetes, the body can’t adequately control blood sugar.
The study is observational, so cannot show cause-and-effect relationships between magnesium, carbohydrate quality and diabetes. However, it suggests that getting the recommended amount of magnesium may work together with a diet rich in high-quality carbohydrates and fiber—from foods like whole grains and whole fruits and vegetables—to help prevent diabetes.