Data published in the Journal of the International Society of Sports Nutrition found that beetroot ingestion within 48 hours of finishing a marathon did not lead to a faster recovery compared to placebo.
“This investigation not only supported previous findings of total metabolic recovery of athletes within 48 h post-marathon but further indicated that beetroot ingestion does not expedite the metabolic recovery process,” wrote the researchers from North-West University in South Africa, the Galway Mayo Institute of Technology in Ireland, and Newcastle University in England.
The researchers did observe increases in certain beetroot-related metabolites in the runners post-race, the majority of which were associated with the glycemic content of red beetroot, “as well as the increased microbial activity stimulated by this vegetable”.
“Whether these may provide an additional advantage during an extended period of recovery remains unknown, but as for immediate metabolic recovery, no additional advantage associated with these metabolites were annotated.”
Beetroot in sports nutrition
A lot of attention has focused on beetroot over the past decade for its potential cardiovascular benefits, linked to the nitrate content.
Recent studies have accelerated our understanding of the importance of nitrate in biological processes, including regulation of blood flow, blood pressure, cellular signaling, glucose homeostasis, and tissue responses to low oxygen levels (hypoxia).
Nitrate is one of the dietary ingredients endorsed by World Athletics as being generally regarded as boosting performance, and there have been reports of sports teams around the world adopting beetroot juice as part of their nutrition strategies.
The new study investigated if marathon runners could benefit from beetroot juice. The study included 31 marathon runners who ingested 250 ml of beetroot juice on three separate occasions on the day of the marathon (750 ml total), the same the day after the marathon, and one 250 ml juice on the second day after the marathon. The placebo group received the same quantities of the placebo beverage.
The results showed that the metabolic recovery trends in the beetroot group were similar to those seen in the placebo group.
When the researchers looked at specific metabolites, they focused on the four main metabolites: arabitol and xylose (carbohydrates) and nonanoate and undecanoate (odd-chain fatty acids).
“Of the four metabolites identified, the majority were associated with the glycemic content of red beetroot, as well as the increased microbial activity stimulated by this vegetable,” wrote the researchers. “Whether these may provide an additional advantage during an extended period of recovery remains unknown, but as for immediate metabolic recovery, no additional advantage associated with these metabolites were annotated.”
The research team called for future studies to examine if beetroot supplements could have a measurable effect at shorter incremental time-points along this recovery process, such as six hour intervals, or perhaps at higher doses.
“Furthermore, since the microbiome of athletes seems to be a key component in the conversion of red beetroot nitrate, the fermentation of sugar components, and metabolism of polyphenols, metabolic studies investigating the effects of beetroot on the gut microbiome and microbial function, could determine the fermentation preferences and possible causes for metabolic delays pertinent to phytonutrient uptake,” they concluded.
Source: Journal of the International Society of Sports Nutrition
2021, Volume 18, Article number: 72, doi: 10.1186/s12970-021-00468-8
“Beetroot juice — a suitable post-marathon metabolic recovery supplement?”
Authors: Z. Stander et al.