Black Currants
Also known as: Black currant, blackcurrant, Ribes nigrum
Overview
Ribes nigrum, commonly known as black currant, is a small dark berry native to Europe and parts of Asia. It is primarily utilized as a dietary supplement due to its rich content of polyphenols, particularly anthocyanins, which are responsible for its distinctive deep purple color. Black currants are recognized for their antioxidant properties and are investigated for potential benefits in areas such as athletic performance, cardiovascular health, and cognitive function. Research, especially on New Zealand blackcurrant extracts standardized for anthocyanin content, is moderately mature, with several randomized controlled trials (RCTs) and systematic reviews supporting its use. The quality of evidence is generally good, with studies published in peer-reviewed journals.
Benefits
Black currant supplementation offers several evidence-based benefits. A systematic review and meta-analysis of 9 RCTs demonstrated a small but statistically significant improvement in sport performance, with an effect size of 0.45. This benefit, observed with 105 to 210 mg of total blackcurrant anthocyanins taken prior to exercise, includes improved endurance and reduced fatigue, likely due to enhanced blood flow and oxygen delivery to muscles. Additionally, a 2-week RCT showed a 21% increase in fat oxidation at rest with 600 mg daily of New Zealand blackcurrant extract (210 mg anthocyanins), suggesting potential for weight management and endurance training adaptations. However, a systematic review and meta-analysis of 4 studies found no significant effect on systolic or diastolic blood pressure, indicating limited cardiovascular benefits in this specific regard.
How it works
Black currant anthocyanins primarily exert their effects by promoting vasodilation. They achieve this by increasing the release of nitric oxide, which leads to the relaxation and widening of blood vessels. This enhanced blood flow facilitates improved oxygen delivery to working muscles during physical activity, potentially reducing fatigue and boosting performance. While black currants possess antioxidant properties, the direct evidence for their impact on oxidative stress markers is limited. Anthocyanins are absorbed in the gastrointestinal tract, though their bioavailability is moderate, and their metabolites may also contribute to the observed physiological effects.
Side effects
Black currant supplementation is generally considered safe, with no serious adverse effects reported in randomized controlled trials. The reviewed literature does not document any significant side effects or contraindications. While no specific drug interactions have been widely reported, individuals taking anticoagulants should exercise caution due to the potential for black currant to influence blood flow. Overall, black currant appears to have a favorable safety profile when consumed within recommended dosages.
Dosage
The effective dosage for black currant supplementation typically ranges from 105 to 210 mg of total anthocyanins per day, usually derived from standardized New Zealand blackcurrant extract. This translates to approximately 300–600 mg of the extract daily. For performance benefits, it is often recommended to take the supplement about 1 hour prior to exercise. While acute dosing before exercise is effective, some studies have also utilized 7-day supplementation protocols. The maximum safe dose has not been definitively established, but studies using up to 600 mg of extract daily have demonstrated safety. Standardized extracts with quantified anthocyanin content are preferred for consistent efficacy, and co-ingestion with food may influence the moderate bioavailability of anthocyanins.
FAQs
Does black currant improve blood pressure?
Current evidence does not support significant blood pressure reduction with blackcurrant supplementation.
How soon before exercise should blackcurrant be taken?
Approximately 1 hour prior to exercise is recommended for optimal performance effects.
Are there any side effects?
No significant side effects have been reported in controlled trials with black currant supplementation.
Is blackcurrant effective in hypoxic conditions?
Some evidence suggests reduced efficacy under hypoxia, but more research is needed to confirm this.
Research Sources
- https://pubmed.ncbi.nlm.nih.gov/32460873/ – This systematic review and meta-analysis by Mills et al. (2020) analyzed 9 RCTs and found a small but significant improvement in athletic performance (effect size 0.45, p=0.01) with blackcurrant anthocyanin supplementation. The study assessed risk of bias using Cochrane guidelines but noted insufficient data on oxidative markers and cognition.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC9900079/ – Zhang et al. (2023) conducted a systematic review and meta-analysis of 4 RCTs involving 97 participants. The findings indicated no significant effect of blackcurrant or raspberry supplementation on either systolic or diastolic blood pressure (p>0.05), with studies ranging from 6 to 12 weeks and doses up to 700 mg polyphenols daily.
- https://athletetrainingandhealth.com/the-effects-of-new-zealand-blackcurrant-extract-on-sport-performance/ – This source references a study by Cook et al. (2015), an RCT with 16 cyclists, which reported a 2.4% improvement in 16.1 km cycling time trial performance after 7 days of supplementation with 300 mg New Zealand blackcurrant extract (105 mg anthocyanins) taken 1 hour before exercise. Limitations included a small sample size and testing only under normoxic conditions.
- https://www.healthspanelite.co.uk/knowledge-hub/nutrition/the-performance-benefits-of-blackcurrant-supplements/ – This article discusses the performance benefits of blackcurrant supplements, highlighting their role in improving endurance and reducing fatigue. It suggests that these benefits are likely due to enhanced blood flow and oxygen delivery to muscles, aligning with the mechanisms of action described in scientific literature.
- https://sportsmedicineweekly.com/blog/why-blackcurrant-berries-are-making-big-waves-in-sports-nutrition-as-a-superfood/ – This blog post emphasizes the growing interest in blackcurrant berries within sports nutrition, labeling them as a 'superfood'. It likely covers their rich anthocyanin content and potential to act as an ergogenic aid, supporting athletic performance and recovery.
- https://www.puresportsnutrition.com/blogs/pure-sports-nutrition/blackcurrant-benefits – This source from Pure Sports Nutrition outlines the various benefits of blackcurrant, particularly in the context of sports and exercise. It likely details how blackcurrant supplementation can contribute to improved performance, fat oxidation, and overall athletic well-being.