A combination of compounds derived from red grapes and oranges could offer a promising treatment for obesity, type 2 diabetes, and cardiovascular disease, say researchers.
In the journal Diabetes, researchers reveal that the two fruit compounds work together to reduce blood glucose levels, improve insulin activity, and boost the health of arteries.
At the same time, cardiovascular disease (CVD) - a term used to describe diseases of the heart and blood vessels - is responsible for around 1 in 3 deaths in the U.S., while diabetes affects around 9.3 percent of Americans.
Such statistics highlight the need for more effective treatment strategies for these conditions.
Now, study leader Paul Thornalley, professor in systems biology at Warwick, and colleagues suggest red grapes and oranges may pave the way for such treatments.
Fruit compound combo increases Glo1 expression
For their study, the team investigated the effects of a compound called trans-resveratrol (tRES), found in red grapes, and a compound found in oranges called hesperetin (HESP).
On testing a combination of the compounds in cell culture, the researchers found that it increased expression of glyoxalase 1 (Glo1) - an enzyme that neutralizes a compound called methylglyoxal (MG).
The team explains that MG is a key driver of sugar's harmful effects on the body; a combination of high MG levels and a high-calorie diet is a cause of insulin resistance, which can lead to type 2 diabetes. It also damages blood vessels and can drive high cholesterol levels - a risk factor for CVD.
As such, the team hypothesizes that blocking MG by increasing Glo1 expression could reverse these effects.
"Obesity, type 2 diabetes and cardiovascular disease are at epidemic levels in Westernized countries. Glo1 deficiency has been identified as a driver of health problems in obesity, diabetes and cardiovascular disease," notes Prof. Thornalley.
Discovery could 'defuse the obesity time bomb'
Next, the team tested the tRES-HESP combination on 32 adults aged 18-80 who had a body mass index (BMI) of between 25-40, falling into the overweight or obese categories.
Participants were given the fruit compound combination in the form of a supplement, which they were asked to take once a day for 8 weeks.
During the study period, subjects were asked to continue with their usual diets and not to increase physical activity, enabling the researchers to gain a more accurate picture of the supplements' effects.
Blood samples were taken from participants on a regular basis during the 8-week period and analyzed for sugar levels and other blood markers. The artery health of the participants was assessed by measuring artery wall flexibility.
The researchers found that participants who had a BMI of more than 27.5 demonstrated increased Glo1 activity with the daily supplement, as well as reduced insulin levels, improved insulin activity, better artery function, and reduced blood vessel inflammation.
Subjects who were given a placebo showed no such effects, the researchers note.
Prof. Thornalley and his team point out that the doses of tRES and HESP used in this study are too high to get from fruit consumption.
However, they hope their findings will encourage pharmaceutical companies to create a drug using the compounds, paving the way for a new treatment for obesity, diabetes, and CVD.
"This is an incredibly exciting development and could have a massive impact on our ability to treat these diseases. As well as helping to treat diabetes and heart disease it could defuse the obesity time bomb."
Prof. Paul Thornalley
"As exciting as our breakthrough is," he notes, "it is important to stress that physical activity, diet, other lifestyle factors and current treatments should be adhered to."
"Our new pharmaceutical is safe and expected to be an effective add-on treatment taken with current therapy," he adds.
Prof. Thornalley says the team is currently seeking commercial investors and partners in order to test the effectiveness of their treatment for diabetic kidney disease.