Blackcurrant anthocyanins and blood sugar after a meal
What it found
In a small trial in people, a high dose of blackcurrant anthocyanins in a drink lowered the early rise in blood sugar and insulin after a high-carb meal.
Lower doses made no difference.
What they found
Studies in people
Early blood sugar
The 600 mg dose reduced the early rise in blood sugar over the first 30 minutes compared with the placebo drink. The 150 mg and 300 mg doses made no difference.
Early insulin
The 600 mg dose also reduced insulin levels in the first 30 minutes compared with placebo. There was no difference in peak insulin or the full 120-minute response.
Gut hormones
The 600 mg dose lowered GIP levels across the whole 120 minutes and lowered GLP-1 at 90 minutes compared with placebo.
Later rebound
After the 600 mg dose, blood sugar and insulin were higher at 75 to 90 minutes than after placebo.
Oxidative stress and vessels
There were no differences between drinks in 8-isoprostane F2α, blood pressure, or measures of arterial stiffness.
Blood fats
There was no effect of the drinks on blood triglycerides or free fatty acids.
What the authors conclude
“In conclusion, anthocyanin-rich blackcurrant extract, providing a similar quantity of polyphenols to that found in five heaped tablespoons of blackcurrants, delayed the appearance of glucose in the blood and inhibited the secretion of insulin and incretins.”
Also in their conclusions
- They conclude that anthocyanin-rich blackcurrant extract, providing a similar quantity of polyphenols to that found in five heaped tablespoons of blackcurrants, delayed the appearance of glucose in the blood and inhibited the secretion of insulin and incretins.
- They suggest that regular consumption of berries as main meals or with snack foods may help lower postprandial glycemia, which may reduce the vascular burden of glucose-induced oxidative stress and endothelial dysfunction involved in the progression of atherosclerosis.
- They say this evidence supports current dietary advice that a predominantly plant-based diet may help prevent cardiovascular disease and Type 2 diabetes.
How it was done
The authors wanted to test whether an anthocyanin-rich blackcurrant extract would lower the rise in blood sugar after a carbohydrate meal, in a dose-dependent way, compared with a matched placebo drink.
14 men and 9 postmenopausal women, average age 46, took part in a randomised, double-blind, crossover trial. On separate visits at least a week apart, they drank a low-sugar fruit drink with 150 mg, 300 mg or 600 mg of blackcurrant anthocyanins, or no extract, right before a high-carbohydrate meal. Blood was measured for 120 minutes.
What it can’t tell you
- The study was small and only included healthy men and postmenopausal women, so the results may not apply to other groups.
- The trial only looked at a single meal, so it cannot show what happens with long-term consumption.
- The placebo and lower-dose drinks contained added tannins to match taste, which may have masked some effects.
Who paid
- Funding
- Funded by Biotechnology and Biological Sciences Research Council (from the PubMed record).
- Authors work at
- King's College London, UK
The paper
- Title
- Drinks containing anthocyanin-rich blackcurrant extract decrease postprandial blood glucose, insulin and incretin concentrations
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Castro-Acosta ML, Smith L, Miller RJ, McCarthy DI, Farrimond JA, Hall WL (2016). Drinks containing anthocyanin-rich blackcurrant extract decrease postprandial blood glucose, insulin and incretin concentrations. The Journal of nutritional biochemistry. doi:10.1016/j.jnutbio.2016.09.002Free full textPubMed 27764725DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error