By Annie Hauser
Beta carotene, the nutrient that gives red and orange fruits and vegetables their color, might lower a person's risk for type 2 diabetes if they have a certain genetic predisposition to the disease, Stanford University School of Medicine researchers report in the journal Human Genetics.
Meanwhile, gamma tocopherol, the major form of vitamin E in the American diet, could increase a person's risk for type 2 diabetes, the study finds. This conclusion doesn't necessarily mean that vitamin E, which is most commonly found in seeds and nuts, is bad for you, researchers caution.
More research is needed to determine whether beta carotene and vitamin E truly prevent or cause type 2 diabetes, or whether they are simply markers for the disease.
The scientists used what they call a "big data" approach to reference gene variants associated with type 2 diabetes risk and blood levels of different nutrients. In people with one such predispositioning gene variant, researchers saw that beta carotene reduced type 2 diabetes risk while gamma tocopherol was correlated with risk for the disease.
Because both nutrients interacted with the same genetic variant, researchers also believe this finding paves the way for more study of the specific gene — SLC30A4. Some 50 percent to 60 percent of Americans have SLC30A4, which previous research has linked to type 2 diabetes risk. But it's just one of 18 genetic variants associated with an increased risk for the disease.
In 2010, lead researchers Chirag Patel, PhD, and Atul Butte, MD, PhD, compared people with or without high blood sugar — a defining marker of type 2 diabetes — to the two groups' exposures to environmental substances. That analysis found five environmental substances, including gamma tocopherol and beta carotene, that affected type 2 diabetes risk.
Now, Patel, Butte, and their colleagues are conducting mice studies of purified beta carotene and gamma tocopherol to see whether the substances themselves prevent or accelerate type 2 diabetes.
Until more research is done, it's impossible to say whether beta carotene can prevent diabetes. But because higher levels of beta carotenes and other carotenoids have previously been linked to a reduced risk of cancer and other diseases, it can't hurt to eat a few more yellow-orange vegetables, such as carrots, sweet potatoes, pumpkin, and winter squash.