Eating more green leafy vegetables can significantly cut the risk of developing diabetes, scientists said.
British researchers who reviewed six earlier studies on links between diabetes and the consumption of fruits and vegetables found that eating an extra serving a day of vegetables like spinach, cabbage, and broccoli reduced adults' risk of getting type 2 diabetes by 14%.
The findings don't prove that the veggies themselves prevent diabetes. People who eat more green leafy vegetables may also have a healthier diet overall, exercise more, or may be better off financially than people who don't load up on greens. Any of those factors could affect how likely they are to get diabetes.
But, "the data suggest that green leafy vegetables are key," said Patrice Carter of the diabetes research unit at Leicester University, the study's lead author. The review, published today in the British Medical Journal, looked at six studies, which covered more than 200,000 people between 30 and 74 years old, in the United States, China and Finland.
"Fruit and vegetables are all good, but the data significantly show that green leafy vegetables are particularly interesting, so further investigation is warranted," Carter said.
Green leafy vegetables contain antioxidants, magnesium and omega 3 fatty acids all of which have been shown to have health benefits, she added.
Each of the studies that Carter and her colleagues analysed followed a group of adults over periods of four-and-a-half to 23 years, recording how many servings of fruits and vegetables each participant ate on a daily basis then examining who was diagnosed with type 2 diabetes.
The researchers found no significant difference in diabetes risk with higher intake of vegetables in general, fruits in general, or combinations of vegetables and fruits. Green leafy vegetables stood out, however, with an increase of 1.15 servings a day producing a 14% decrease in an individual's risk of developing diabetes.
Type 2 diabetes is caused by the body's inability to adequately use insulin, a hormone produced by the pancreas, to regulate levels of glucose produced from food. Uncontrolled, the sugar levels rise and can damage the eyes, kidneys, nerves, heart and major arteries.
The chronic condition is often linked to poor diet and lack of exercise and is reaching epidemic levels as rates of obesity rise. An estimated 180 million people worldwide have diabetes. The costs of caring for those with the disease are soaring in wealthy nations and becoming an increasing burden in developing countries too.
Minimise chances of getting sick
Although there is no cure for diabetes, people with the condition can minimise their chances of getting sicker by being more active and losing weight. Some people with diabetes need medications to control their blood sugar and insulin levels for others, it's enough to keep a close watch on their diet.
"We already know that the health benefits of eating vegetables are far-reaching, but this is the first time that there has been a suggested link specifically between green, leafy vegetables and a reduced risk of developing Type 2 diabetes," said Dr Iain Frame, director of research at the advocacy group Diabetes UK.
But Frame, who was not involved with the current study, added that because of the relatively small number of studies grouped in this analysis, "it is too early to isolate green leafy vegetables and present them alone as a method to reduce the risk of developing Type 2 diabetes."
It's important not to point to green leafy vegetables as a "magic bullet" for diabetes prevention and forget the broader picture of whole food groups wrote Dr Jim Mann, of the Edgar National Centre for Diabetes and Obesity Research at the University of Otago in New Zealand and Dagfinn Aune of London's Imperial College in an accompanying editorial. However, they added, "the findings are also a useful reminder to clinicians that giving dietary advice may be just as beneficial, if not more so, than prescribing drugs to patients at risk of chronic disease."
World not eating enough veg
According to Carter and her colleagues, low consumption of fruit and vegetables is common throughout the world. They cite a 2005 study published by the World Health Organistion estimating that inadequate consumption of fruit and vegetables could have accounted for 2.6 million deaths worldwide in the year 2000.
Separate research found that in 2002, 86% of adults in Britain ate fewer than the recommended five portions of fruit and vegetables a day, with 62 percent consuming fewer than three portions.
The US Centres for Disease Control and Prevention found similar patterns among Americans. In 2005, just 33% of US adults said they ate at least two servings of fruit a day, and 27% reported eating three or more vegetable servings daily. (Reuters Health/ 23 August 2010)
Read more: Diabetes and diet - the basics