A Mediterranean diet combined with a reduced calorie intake, moderate physical activity and professional weight loss support can reduce the risk of type 2 diabetes by 31%. This is the conclusion of a new study involving researchers from the Harvard T.H. Chan School of Public Health. “We are facing a global diabetes epidemic,” said co-author Frank Hu, Fredrick J. Stare Professor of Nutrition and Epidemiology and chair of the Department of Nutrition. “Using the best available evidence, our study shows that moderate, sustained changes in diet and lifestyle could prevent millions of cases of this disease worldwide.”
A Mediterranean Diet and Moderate Exercise Could Serve as Important Diabetes Prevention Measures
Previous research has linked the Mediterranean diet – characterized by a high intake of fruits, vegetables, whole grains and healthy fats, moderate consumption of dairy products and lean proteins, and little to no consumption of red meat – with better health outcomes, including a lower risk of type 2 diabetes through improved insulin sensitivity and reduced inflammation. A team of collaborators from the PREDIMED-Plus clinical trial, the largest randomized diet and lifestyle trial in Europe, sought to understand how the benefits of diet can be enhanced by additional healthy lifestyle changes.
Researchers from 23 universities in Spain and Harvard Chan School divided 4,746 PREDIMED-Plus participants into an intervention group and a control group and tracked their health outcomes over a six-year period. The intervention group followed a Mediterranean diet, reduced their caloric intake by about 600 calories per day, engaged in moderate physical activity such as brisk walking and strength and balance exercises, and received professional weight loss support. The control group followed a Mediterranean diet without calorie restriction, exercise guidance or professional support. The participants were between 55 and 75 years old, overweight or obese and had metabolic syndrome, but were free of diabetes at the start of the study.
The study found that participants in the intervention group had a 31% lower risk of developing type 2 diabetes than those in the control group. In addition, the intervention group lost an average of 3.3 kilograms and reduced their waist circumference by 3.6 centimeters, compared to 0.6 kilograms and 0.3 centimeters in the control group. In practical terms, supplementing the Mediterranean diet with calorie control and physical activity prevented the development of diabetes in about three out of 100 people – a clear, measurable public health benefit,” said co-author Miguel Martínez-González, professor at the University of Navarra and associate professor of nutrition at Harvard Chan School.
Tiny Green Tea Pearls Bind Fat and Melt Pounds Without Side Effects
Excessive fat intake is closely linked to the increasing prevalence of obesity and associated metabolic disorders. There are various research approaches to counteract these problems. Now scientists have developed edible microspheres made from green tea polyphenols, vitamin E and algae that bind to fats in the gastrointestinal tract when consumed. Preliminary results from tests on rats fed a high-fat diet show that this approach to weight loss could be safer and more accessible than surgery or drugs. “Losing weight can help some people avoid long-term health problems such as diabetes and heart disease,” says Wu, a PhD student at Sichuan University. “Our microspheres work directly in the gut, blocking fat absorption in a non-invasive and gentle way.”
Some drugs inhibit certain stomach enzymes from breaking down dietary fats, resulting in less fat being absorbed by the body. In some people, however, these drugs often cause serious side effects, including liver and kidney damage. Therefore, Wu and her colleagues wanted to target the fat absorption process with their weight loss intervention, but without unwanted side effects. Initially, the team developed tiny plant beads that spontaneously form through a series of chemical bonds between green tea polyphenols and vitamin E. These structures can form chemical bonds with fat. These structures can form chemical bonds with fat droplets and serve as the fat-binding core of the microspheres. The researchers then coated the beads with a natural polymer from algae to protect them from the acidic environment of the stomach. Once ingested, the protective polymer coating expands in response to the acidic pH, and the green tea polyphenols and vitamin E compounds bind to and trap partially digested fats in the gut. The microspheres are virtually tasteless and the researchers assume that they can be easily integrated into people’s diets. For example, the microspheres could be processed into small tapioca or boba-sized balls and added to desserts and bubble teas.
The researchers investigated the microspheres as a means of weight loss in rats. They divided the animals into three groups (eight rats per group): those that received a high-fat diet (60% fat) with or without microspheres for 30 days and those that received a normal diet (10% fat). Rats that received the high-fat diet and microspheres:
- lost 17% of their total body weight, while rats in the other groups did not lose weight.
- had less adipose tissue and less liver damage compared to rats fed the high-fat diet and normal diet without microspheres.
- rats excreted more fat in their feces than rats that were not given microspheres. The extra fat in the rats’ feces had no obvious negative effects on the animals’ health.
In addition, the eight rats that were fed a high-fat diet and consumed microspheres exhibited similar fat excretion, but without the gastrointestinal side effects that the researchers observed in a fourth group of rats they treated with the drug orlistat. Wu and her team have begun working with a biotechnology company to produce the plant-based beads. “All the ingredients are food-grade and FDA-approved, and their production can be easily scaled up,” says Yunxiang He, associate professor at Sichuan University and co-author of Wu’s presentation. In collaboration with West China Hospital of Sichuan University, they have also initiated a human clinical trial. “This is an important step towards the clinical implementation of our polyphenol-based microspheres according to our basic results,” Wu said. “We have officially enrolled 26 participants in our investigator-initiated study and expect to have preliminary data within the next year.”