Blackcurrants are favorable for glucose metabolism

December 03, 2020

Blackcurrants have a beneficial effect on post-meal glucose response, and the required portion size is much smaller than previously thought, a new study from the University of Eastern Finland shows.

Blackcurrants have a beneficial effect on the blood glucose response after a meal. They balance the glucose response of ingested sugar by attenuating its rise and delaying its fall. The effect is likely associated with berry-derived polyphenolic compounds, anthocyanins, which are rich in blackcurrants.

The beneficial health effect of blackcurrants was supported by a recent study conducted at the University of Eastern Finland. In the clinical meal study (Maqua) the beneficial effect on postprandial glucose response was achieved by 75 g (1.5 dL) of blackcurrants, a remarkably smaller portion size than in earlier studies. Blackcurrants are often consumed with added sugar because of their natural sourness, which may be a cause of concern for health-conscious consumers. However, it seems that sugar consumed with blackcurrants is not as unhealthy as sugar consumed without berries.

The study was conducted in collaboration between the Institute of Public Health and Clinical Nutrition at the University of Eastern Finland and Savonia University of Applied Sciences by utilizing the regional Food Valley ecosystem.

Berries are an important component of a healthy diet, being rich in vitamins, minerals, dietary fibre and polyphenols. So far, however, the EU has not authorised health claims for berries. In recent years, there have been many studies monitoring the effects of berries on glucose metabolism, with the dark berries, such as blackcurrant and bilberry, having the most convincing results. Black-coloured berries, rich in anthocyanins, seem to attenuate the blood glucose response to added sugar, compared to a control product having the same amount of sugar. The same effect is demonstrated by anthocyanins extracted from blackcurrants. Polyphenolic compounds may slow down the absorption of glucose from the small intestine by interacting with carbohydrate-digesting enzymes and glucose transport proteins. In addition, polyphenolic compounds may reduce oxidative stress and inflammation.

In the Maqua study, 26 healthy participants (22 female, 4 male) consumed three different test products and sugar water as a control product at four separate study visits. The test products were a blackcurrant purée with added sugar, a blackcurrant product containing fermented quinoa, and a blackcurrant product base without blackcurrants. Each of them and the control product contained 31 g of available carbohydrates and had a similar composition of sugar components. Blood samples were taken before the meals in fasting state and postprandially in 15, 30, 45, 60, 90, 120 and 180 minutes after consuming the meal, and analysed for glucose, insulin, and free fatty acids.

Compared to sugar water, both blackcurrant products had attenuated postprandial glycaemic response, which was seen in reduced maximum glucose and insulin, delayed fall of glucose, and delayed rise of free fatty acids because of hypoglycaemia. The effect was enhanced for the blackcurrant product because of the innovative product base. The results support earlier findings on the beneficial effects of blackcurrant on blood glucose response after a meal, showing the effect with a smaller portion size. Over a longer period of time, smaller variations in the blood glucose and insulin levels, and improved insulin sensitivity, may decrease the risk of type 2 diabetes.

Blackcurrants are an interesting raw material for the food industry because of their high content of anthocyanins and easy availability. Blackcurrants have potential for being developed into new healthy and tasty products.
-end-
For further information, please contact:

Professor Marjukka Kolehmainen, University of Eastern Finland, marjukka.kolehmainen@uef.fi, tel. +358 40 355 3617, https://uefconnect.uef.fi/en/person/marjukka.kolehmainen/

Research article (Open Access): Lappi J, Raninen K, Väkeväinen K, Kårlund A, Törrönen R, Kolehmainen M. Blackcurrant (Ribes nigrum) lowers sugar-induced postprandial glycaemia independently and in a product with fermented quinoa: a randomized crossover trial. Br J Nutr 2020, Nov 9;1-28.

DOI:https://doi.org/10.1017/S0007114520004468

Information about the Food Valley ecosystem:
https://www.ruokalaakso.fi/eng/https://uefconnect.uef.fi/en/group/food-valley/

University of Eastern Finland

Related Insulin Articles from Brightsurf:

US Insulin prices 8 times higher than in other nations
Insulin list prices in the United States have increased dramatically over the past decade, with per person insulin spending doubling between 2012 and 2016.

A gatekeeper against insulin resistance in the brain
The brain plays a major role in controlling our blood glucose levels.

Sorting and secreting insulin by expiration date
Visualizing the age of insulin secreting granules in cells allowed researchers to investigate how cells' preference for secreting newer granules is disrupted in diabetes.

Researchers develop a new ultrafast insulin
Stanford researchers tested a new insulin drug in diabetic pigs and found that it was twice as fast-acting as traditional insulin.

Insulin signaling suppressed by decoys
The discovery of an insulin 'decoy' molecule from the lab of Matthew Gill, PhD, in Florida shakes up understanding of insulin signaling, with implications for diabetes, longevity and aging research.

New mechanism for dysfunctional insulin release identified
In a new study, researchers at Uppsala University have identified a previously unknown mechanism that regulates release of insulin, a hormone that lowers blood glucose levels, from the β-cells (beta cells) of the pancreas.

Type 2 diabetes is not just about insulin
Obesity, by promoting the resistance to the action of insulin, is a major risk factor of diabetes.

The insulin under the influence of light
By understanding how the brain links the effects of insulin to light, researchers (UNIGE) are deciphering how insulin sensitivity fluctuates according to circadian cycles.

Does insulin resistance cause fibromyalgia?
Researchers led by a team from The University of Texas Medical Branch at Galveston were able to dramatically reduce the pain of fibromyalgia patients with medication that targeted insulin resistance.

Insulin insights
Insulin triggers genome-wide changes in gene expression via an unexpected mechanism.

Read More: Insulin News and Insulin Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.