After a recent spate of media claims for the health benefits of isolated foods such as green leafy vegetables, garlic and asparagus, the latest food to be hailed in the press as a potential breakthrough for diabetes is grapefruit.
A substance which gives grapefruit its bitter taste may increase sensitivity to insulin and be involved in breaking down fats in the liver instead of storing it, which could be relevant to diabetes research. The findings, published in the Public Library of Science from research carried out in Jerusalem and Boston, appear to show the antioxidant naringenin mimics the process found in fasting, where fatty acids are broken down instead of carbohydrates.
"It is a fascinating find," said Yaakov Nahmias, PhD, of the Hebrew University of Jerusalem. "Remarkably, naringenin is a dietary supplement with a clear safety record. Evidence suggests it might actually protect the liver from damage." Speaking to the Daily Express, Dr Nahmias admitted that "someone would need to eat 400 grapefruits in one sitting. We really don’t recommend this... but you can buy naringenin as a nutritional supplement which gives you the pure molecule. You would need about one pill per dose, and maybe three doses a day."
Not a magic bullet
"This is a step forward in this research area but we shouldn’t get carried away that eating large amounts of grapefruit will be a magic bullet – it won't. There is also no evidence to link this research to a supplement that would have the benefits the researchers are claiming. We are a long way from seeing whether these findings from cell lines in the laboratory would have the same effects in people," warned Dr Iain Frame, Diabetes UK Director of Research.
He continued: "We know from other research into naturally occurring products (such as those in chocolate and red wine) that, to have any benefit, the amounts needed are huge and unrealistic in a normal diet. The benefits of eating grapefruit could also be outweighed by an increase in the consumption of sugar."
No one food in isolation
Following on from a recent flurry of media stories claiming health benefits from other isolated foods, Dr Iain Frame added: "Diabetes UK would still emphasise that it is unwise to focus on any foods in isolation. Eating a balanced diet which includes the recommended five fruits and vegetables a day, maintaining a healthy weight and being more physically active can help to reduce your risk of developing Type 2 diabetes and can also help people diagnosed with the condition to manage it more effectively and lower the likelihood of developing serious complications."
Previous research, which Diabetes UK reported on last year, also claimed that naringenin could prevent weight gain and balance glucose and insulin levels. However, Diabetes UK warns that some statins can’t be taken with grapefruit juice because it affects the absorption of the drug.