Can blackcurrants improve control of blood sugar?
Research type
Research Study
Full title
Dose response effects of New Zealand blackcurrant extract on glucose tolerance in overweight and obese individuals
IRAS ID
331251
Contact name
Sam Shepherd
Contact email
Sponsor organisation
Liverpool John Moores University
Clinicaltrials.gov Identifier
23/SPS/027, LJMU UREC REF
Duration of Study in the UK
1 years, 0 months, 1 days
Research summary
Diet and/or lifestyle changes are proven approaches to reduce type 2 diabetes risk. One simple dietary change that is generating interest is to increase the intake of anthocyanins; the bioactive part of many fruits, vegetables and whole-grains, with particularly high levels found in blackcurrants. Typically branded as a nutraceutical, anthocyanins are thought to exert anti-inflammatory, antioxidant and anti-hyperlipidemic effects. Despite these widely cited and attractive health benefits, anthocyanin intake is usually very low in the general population. In addition to this list, emerging evidence has highlighted the potential anti-diabetic effects of anthocyanins to induce physiological and metabolic adaptations leading to improved insulin sensitivity and glucose regulation (Curtis et al., 2022). In a recent pilot study, we showed that supplementing the diet with an anthocyanin-rich New Zealand blackcurrant extract (NZBC; 600 mg/day) for just 8 days improved insulin sensitivity in overweight individuals by 22% (Nolan et al., 2020). However, the optimal dose and dosing strategy for NZBC extract is yet to be determined. Moreover, if short-term NZBC extract supplementation is able to improve insulin sensitivity, it is not clear whether the observed responses are attributable to adaptations as a result of the supplementation, or the acute effects of the last ingested dose. To tackle this, we plan to subject participants to a 7 day supplementation period with four difference doses of NZBC extract and then make an assessment of glucose tolerance on day 7 (~1 h after the last dose) and day 8 (~24 h after the last dose). This will allow us to delineate any acute vs. chronic effects of NZBC extract, as well as understand the optimal dose to improve glucose tolerance.
REC name
Wales REC 2
REC reference
23/WA/0328
Date of REC Opinion
15 Nov 2023
REC opinion
Unfavourable Opinion