It is widely recognized that type 2 diabetes is the result of poor diet and not enough exercise, resulting in obesity and a metabolic shift towards insulin resistance and poor glucose control. Now almost endemic in the Western world, it is also becoming more and more of an issue in developing countries because of these very same issues as processed foods continue to make up a large part our diets and technology-related hobbies replace physical activity, leading to the prevalence of sedentary life styles.

Primary treatment for type 2 diabetes is through management of these variables—combining weight loss and exercise, moderating the intake of high calorie, fatty, sugary and salty foods as well as decreasing alcohol intake. The difficult part of self-management is the adherence to life-style changing regimens, which often results in failure to treat and the introduction of pharmaceutical agents, metformin being the most common.

One of the fundamental influences over both weight and glucose control is diet, and if this is managed effectively it’s a great assistance on the road to effective blood glucose control. Berries are one of the foods strongly advocated by physicians across the board. However, although they are touted because they are low in carbohydrates and patients can generally eat large portions of them, hard scientific evidence relating to any proven medicinal benefit is difficult to find. Experts believe they may well have therapeutic properties beyond simply having a positive impact on weight management.

Blackberries, blueberries and other berries contain chemical compounds in their skins, which have been researched for their potential influence on glucose control and insulin sensitivity. These berries contain anthocyanins, the red, blue and purple pigments that color the skins of the different berries depending on their pH. There is a theory that the anthocyanins may also act as antioxidants. However, due to their physiological placement their ability to scavenge free radicals may be limited because they are located remotely from metabolically active locations.

The ‘super food’ status that these berries carry has created a large amount of research interest in them for their potential ability to influence disease states. The University of Illinois recently presented research results indicating that a ‘tonic’ made from fermented berries, minus the alcohol, creates a berry ‘wine’ that might have an enhanced impact on diabetic markers such as hyperglycemia, while also improving insulin sensitivity and secretion in mice.

Previous research has shown that fermenting berries of various varieties can increase the concentration and availability of anthocyanins—blanching berries can also have a similar effect. It is also recognized that blueberries can have an impact on glycemic control in mice, and there has also been indication that these little gems may improve insulin sensitivity in human subjects too.

The research team at the University of Illinois had already illustrated in-vitro that a dealcoholized concoction could reduce the activity of glucose absorbing enzymes, and moved to an in-vivo study. The work, which was headed up by Elvira de Mejia, a food scientist based in the Department of Food Science and Human Nutrition, employed a wine consisting of 70% fermented blackberries and 30% fermented blueberries as the medicine. Following fermentation, the alcohol was removed from the solution alongside some of the remaining sugars and then watered down. Different concentrations of the drink were prepared, containing differing amounts of anthocyanins (0.1x, 1x and 2x). Blackberries are known to contain the highest concentrations of antioxidants and anthocyanins compared to all other fruits, and the combination of blackberries with blueberries is a wise combination for creating concentrated anthocyanin potions.

The ‘super wine’ was administered to mice, which had diet-induced obesity and hyperglycemia—a comparator to many type 2 diabetic humans. They were randomized into groups for the 3 different wine concentrations, as well as into a group given sitagliptin and a control placebo group. All dietary intake, calories and sugar were controlled throughout the investigation.

The researchers found that in all the groups who drank the berry wine there was a beneficial effect on the diabetic markers. However, in the group who were fed the strongest tonic there was the most dramatic improvement. In addition, this particular group of mice showed no weight gain at all. Although this wasn’t set as an end-point of the study, it is an interesting observation, especially bearing in mind one of the primary causes of type 2 diabetes is lack of weight control and weight gain.

Upon tissue investigation, the investigators found that much more glucose had been taken up into the tissues than remained circulating in the blood, and this was consistent across the groups taking the differing concentrations of the berry wine. All these results point to the fact that the antioxidant effect is strong, potentially providing a protective effect on the DNA of the cells. There were other anti-inflammatory benefits observed in all the berry wine groups, but as all the pathways are metabolically linked, this isn’t a surprise. However, this does give rise to an additional route of investigation into the super power of these fruits.

The true reality is that this research probably has more relevance to the wine manufacturing industry in the near future than anything else. Creating good tasting alcohol-free wine is something that the wine industry has struggled with over the years, and although it is commercially available, it doesn’t always taste the best. The other thing to bear in mind from a medicinal viewpoint is that anthocyanins are only found in the skins of berries, and because the fermentation process of white wine doesn’t include the use of the skins, any beneficial effect will only be seen with the red variety.

Although we’re some way off from being able to scientifically state that it’s possible to treat diabetes with blackberries and blueberries, for anyone with a pre-disposition, obesity, hyperglycemia or insulin resistance, it might not be a bad idea to make a blackberry/blueberry smoothie every now and then, rather than a chocolate shake.
Harnessing the power of anthocyanins and encapsulating them in an alcohol-free wine may well be the future of enhanced type 2 diabetes treatment combined with traditional pharmaceutical therapies. In the interim, for those of us who are fortunate enough to be healthy, I’d suggest a nice large glass of red.