Most berries, including fermented berries are viewed as ‘superfoods’ and they are being demonstrated to be particularly important for type-2 diabetics according to the American Diabetes Association.
Research continues to examine the potency of fermented berries in reducing both obesity and blood glucose levels so they are especially relevant to those seeking to manage their diabetic condition. The suspicions are however that alcohol might be the confounding factor in this because of the implications in solubilising valuable componentry in the fruit or the solvent effects itself. The last investigative series of studies looked at how consumption of blueberries could reduce hyperglycaemia in obese rats and influence various markers of diabetes. The latest study has found that a ‘wine’ of fermented blueberries and blackberries which has had the alcohol removed would improve the effects of the phenolic compounds in the fruit.
The researchers from the Department of Food Science and Human Nutrition at the University of Illinois published their findings in the Journal of Nutritional Biochemistry which looked at the effect of their dealcoholized wine on various diabetic markers in a mouse model.
The study established that fermentation at low temperature improved the production and concentration of the colour pigments in the fruit, – the anthocyanins. These anthocyanins help to increase insulin production and its sensitivity which in turn reduces blood glucose levels. The levels of blood sugar and obesity were subsequently measured in hyperglycaemic mice which were kept on a fat rich diet, and were then fed with and without the fermented fruit beverage.
The drink contained a ratio of 70% blackberries to 30% blueberries. The berries were collected from varieties grown at the university’s Dixon Springs Agricultural Research Station in southern Illinois. Alcohol was removed from the beverage by a process of rotary evaporation and the losses replaced with the equivalent volume of water to achieve a similar brix. A small amount of sugars which remained after fermentation were also removed during dealcoholisation.
During the study, the groups of mice were given the fermented berry drink or one with higher or lower enriched concentrations of the anthocyanins (0.1x, 1x, or 2x). Another group was given the drug sitagliptin, a commonly used medication for diabetes, and another group was given only water. All the mouse groups ate the same diet, calories, and amount of sugars to ensure consistency in calorific content and nutritional value.
According to the results, the lead researcher stated:-
“In this in vivo study, as we increased the concentration of these anthocyanin-enriched extractions from blueberries and blackberries we saw an improvement in the uptake of glucose, meaning that the animals with the increased concentration were not as much in a state of hyperglycaemia as the other animals.”
The researchers observed that all groups drinking the fermented beverage enjoyed a number of nutritional benefits. The group on the highest concentration of anthocyanins (2x) exhibited the best results, comparable to those observed in the group on sitagliptin. This included the finding that there was no substantial increase in body weight. The researchers also observed that glucose was deposited into tissues slightly more than was absorbed by or was present in the blood. They also noted that the mice on twice the level of enriched anthocyanins had lower oxidative species levels, which is significant given oxidative stress can damage protein and DNA.
The authors noted:-
“There needs to be more studies to see how the anthocyanins work in the presence of medication, to see if they work synergistically, for example. Then, maybe, you could decrease the amount of the drug. All of these drugs for diabetes have adverse effects after so many years of use, even the safest ones.
We need to consider diet, exercise, lowering body weight, and all the different strategies that the American Association of Diabetes recommends, and maybe in the long run, of course with approval of a physician, you could decrease the level of the drug to keep glucose under control.”
The researchers believe such a beverage might help reduce the levels of medication required in managing diabetes.
The paper can be accessed online at http://dx.doi.org/10.1016/j.jnutbio.2015.12.013.
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