Early Diabetes Interventions May Also Reduce Heart Disease Risk

Two treatments that slow the development of diabetes also may protect people from heart disease, according to a recent study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).

Researchers examined the effect that making intensive lifestyle changes or taking the medication metformin had on cholesterol and triglyceride levels. The study, part of the National Institutes of Health's Diabetes Prevention Program, found that both treatments induced positive changes in the level of particles that carry cholesterol and triglycerides through the blood stream. These changes could lower the chances of plaque building up in blood vessels.
"Cardiovascular disease is the most significant cause of death and disability in people with diabetes," said the study's lead author, Ronald Goldberg, MD, of the University of Miami's Miller School of Medicine. "Our findings demonstrate that the same therapies used to slow the onset of diabetes also may help allay the risk of heart disease."
The randomized clinical trial analyzed blood samples from 1,645 people with impaired glucose tolerance. Participants were randomly assigned to one of three groups -- one taking the medication metformin, another taking a placebo and a third undergoing an intensive lifestyle modification program. Researchers compared baseline blood samples from the start of the study to samples taken a year later to measure the interventions' effects. The study used advanced techniques to obtain a detailed picture of the various particles in the blood.
People who took part in the lifestyle modification program had lower levels of triglycerides and the particles that carry this kind of fat in the blood after a year. Both the metformin and lifestyle interventions were linked to reductions in the number of small low-density lipoprotein (LDL) particles, which carry cholesterol that may contribute to plaque formation, and increases in high-density lipoproteins (HDL), the form of cholesterol that reduces heart disease risk.
"Preventing or slowing the development of diabetes with these treatments also improves the cholesterol and triglyceride profile of a person's blood," Goldberg said. "Thanks to the added benefits of existing diabetes interventions, we stand a better chance of lowering the risk of heart disease in this patient population."

Eating Whole Fruits Linked to Lower Risk of Type 2 Diabetes

Eating more whole fruits, particularly blueberries, grapes, and apples, was significantly associated with a lower risk of type 2 diabetes, according to a new study led by Harvard School of Public Health (HSPH) researchers. Greater consumption of fruit juices was associated with a higher risk of type 2 diabetes. The study is the first to look at the effects of individual fruits on diabetes risk.

"While fruits are recommended as a measure for diabetes prevention, previous studies have found mixed results for total fruit consumption. Our findings provide novel evidence suggesting that certain fruits may be especially beneficial for lowering diabetes risk," said senior author Qi Sun, assistant professor in the Department of Nutrition at HSPH and assistant professor at the Channing Division of Network Medicine, Brigham and Women's Hospital.
The study appears online August 29, 2013 in BMJ (British Medical Journal).
The researchers examined data gathered between 1984 and 2008 from 187,382 participants in three long-running studies (Nurses' Health Study, Nurses' Health Study II, and Health Professionals Follow-up Study). Participants who reported a diagnosis of diabetes, cardiovascular disease, or cancer at enrollment were excluded. Results showed that 12,198 participants (6.5%) developed diabetes during the study period.
The researchers looked at overall fruit consumption, as well as consumption of individual fruits: grapes or raisins; peaches, plums, or apricots; prunes; bananas; cantaloupe; apples or pears; oranges; grapefruit; strawberries; and blueberries. They also looked at consumption of apple, orange, grapefruit, and "other" fruit juices.
People who ate at least two servings each week of certain whole fruits -- particularly blueberries, grapes, and apples -- reduced their risk for type 2 diabetes by as much as 23% in comparison to those who ate less than one serving per month. Conversely, those who consumed one or more servings of fruit juice each day increased their risk of developing type 2 diabetes by as much as 21%. The researchers found that swapping three servings of juice per week for whole fruits would result in a 7% reduction in diabetes risk.
The fruits' glycemic index (a measure of how rapidly carbohydrates in a food boost blood sugar) did not prove to be a significant factor in determining a fruit's association with type 2 diabetes risk. However, the high glycemic index of fruit juice -- which passes through the digestive system more rapidly than fiber-rich fruit -- may explain the positive link between juice consumption and increased diabetes risk.
The researchers theorize that the beneficial effects of certain individual fruits could be the result of a particular component. Previous studies have linked anthocyanins found in berries and grapes to lowered heart attack risk, for example. But more research is necessary to determine which components in the more beneficial fruits influence diabetes risk.
"Our data further endorse current recommendations on increasing whole fruits, but not fruit juice, as a measure for diabetes prevention," said lead author Isao Muraki, research fellow in the Department of Nutrition at HSPH. "And our novel findings may help refine this recommendation to facilitate diabetes prevention."