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Oak

Also known as: Oak wood extract, Robuvit, Oak extract, Quercus robur wood extract

Overview

Oak wood extract is a botanical extract derived from the wood of oak trees, primarily species within the *Quercus* genus, such as *Quercus robur*. It is rich in polyphenols, particularly ellagitannins, which are metabolized by gut microbiota into bioactive compounds called urolithins. These urolithins are known for their antioxidant and anti-inflammatory properties. The extract is primarily used as a nutraceutical to combat fatigue, enhance energy levels, and potentially offer antioxidant support for overall well-being. While research is ongoing, several clinical studies and reviews, including randomized controlled trials, have investigated its efficacy in reducing fatigue and improving energy. The evidence base is considered moderate, with good safety profiles reported in clinical trials.

Benefits

Oak wood extract, particularly the branded form Robuvit, has demonstrated significant benefits in reducing fatigue and increasing overall energy. A randomized controlled trial involving 66 participants showed that supplementation led to significant increases in blood serum concentrations of urolithins A, B, and C, alongside improvements in energy and fatigue levels after 4 and 8 weeks. This effect is attributed to the extract's antioxidant properties and its potential to improve mitochondrial function. While direct evidence for oak extract in osteoarthritis (OA) is limited, its antioxidant properties suggest a potential indirect benefit, as other antioxidants have shown modest improvements in reducing pain and improving function in OA. The benefits are most observed in adults experiencing fatigue, with studies reporting no adverse effects and good tolerability at doses up to 600 mg/day.

How it works

The primary mechanism of action for oak wood extract involves the metabolism of its ellagitannin content. Upon ingestion, gut microbiota convert these ellagitannins into urolithins (e.g., urolithins A, B, and C). These urolithins are then absorbed into the bloodstream, where they exert their biological effects. Urolithins are known for their potent antioxidant and anti-inflammatory properties. They are believed to improve mitochondrial function, which is crucial for cellular energy production, and reduce oxidative stress throughout the body. This enhancement of mitochondrial efficiency and reduction of oxidative damage contribute to improved energy metabolism and a reduction in fatigue.

Side effects

Oak wood extract (Robuvit) is considered to have an excellent safety profile. Toxicology studies have reported no genotoxic, mutagenic, irritant, or sensitizing effects. Clinical studies involving a large number of patients (549 across various studies) have reported no common, uncommon, or rare side effects, indicating very good tolerability. There are no documented drug interactions, though caution is advised due to the general potential of polyphenols to affect drug metabolism. No specific contraindications have been established. However, safety in special populations such as pregnant or lactating women and children has not been specifically studied, and therefore, its use in these groups should be approached with caution.

Dosage

Clinical studies have utilized doses of oak wood extract (specifically Robuvit) ranging from 300 mg to 600 mg per day. Effects on fatigue reduction and increased urolithin levels have been observed within this range. The maximum safe dose, according to toxicology studies and European Food Safety Authority guidelines, is suggested to be greater than 700 mg per day. For optimal benefits, continuous daily intake over 4 to 8 weeks is recommended, as effects on urolithin serum levels and fatigue typically appear within this timeframe. The efficacy of oak wood extract is dependent on the individual's gut microbiota, which must be capable of metabolizing ellagitannins into bioavailable urolithins.

FAQs

Is oak wood extract safe for long-term use?

Yes, studies up to 6 months have shown no adverse effects and good tolerability, suggesting it is safe for extended use.

How soon can benefits be expected?

Improvements in energy and fatigue markers typically appear after 4 to 8 weeks of consistent daily supplementation.

Does oak extract help with joint pain?

While direct evidence for oak extract in osteoarthritis is limited, its antioxidant properties may offer indirect benefits, as antioxidants generally show modest improvements in OA symptoms.

Are there any known drug interactions?

No specific drug interactions have been documented, but as with many polyphenol-rich supplements, there's a theoretical potential for effects on drug metabolism.

Can oak extract be taken with other supplements?

There are no reported contraindications for taking oak extract with other supplements, but combined effects have not been extensively studied.

Research Sources

https://pmc.ncbi.nlm.nih.gov/articles/PMC8573807/ – This clinical review and randomized controlled trial (RCT) investigated Robuvit oak wood extract. The RCT, involving 66 participants, demonstrated that supplementation significantly increased serum urolithin levels and reduced fatigue over an 8-week period. Toxicology data supported the safety of the extract at doses exceeding 700 mg/day, with no adverse effects reported across 549 patients in various studies. The study's limitations include a moderate sample size and a primary focus on fatigue rather than broader clinical outcomes.
https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.1026450/full – This systematic review examined the role of antioxidants in knee osteoarthritis (KOA), analyzing data from 6,605 participants. It concluded that antioxidants significantly reduce KOA symptoms. While oak extract was not directly studied, the findings suggest a potential indirect benefit of oak polyphenols due to their antioxidant properties, aligning with the general efficacy of antioxidants in managing KOA symptoms.
https://www.nature.com/articles/s41598-020-78075-x – This meta-analysis, encompassing 42 randomized controlled trials and 4,160 participants, evaluated the effectiveness of various nutraceuticals for osteoarthritis. It found small to moderate improvements in pain and function. Although oak extract was not specifically included, its classification as an antioxidant-rich botanical suggests it could offer similar benefits to other nutraceuticals studied, supporting the broader concept of antioxidant efficacy in joint health.