beetroot

Beetroot (Beta vulgaris) is the red root vegetable, sold as a supplement most often in the form of beetroot juice, concentrate, powder, or extract. Beets and beet juice rank among the richest dietary sources of nitrate. According to the NIH Office of Dietary Supplements, the body converts some of that nitrate into nitric oxide, a compound that widens blood vessels and thereby increases blood flow and the delivery of oxygen and nutrients to exercising muscle.

The NIH Office of Dietary Supplements characterizes the evidence as limited clinical trials with conflicting results. It reports that beet juice might improve performance and endurance to some degree in time trials and time-to-exhaustion tests among runners, swimmers, rowers, and cyclists, while noting that not all studies have found a benefit. Any effect appears most likely in recreationally active people rather than highly trained or elite athletes, and whether strength or bodybuilding exercise is helped is not known. ODS also notes that whether beetroot powder supplements produce the same effects as beet juice has not been established. ODS does not present beetroot as a treatment or cure for any disease.

There is no official supplement dose. In the studies ODS summarizes, the common approach was to drink roughly 2 cups of beet juice about 2.5 to 3 hours before exercise. The specific milliliter and millimole-of-nitrate amounts sometimes cited come from individual research trials rather than from the ODS fact sheets and are not given as a recommendation. Because beetroot affects blood vessels and blood flow, talk to your doctor, pharmacist, or a registered dietitian before starting beetroot supplements, especially if you take any prescription medication, are pregnant or nursing, or have a health condition.

Beets and beet juice are common foods, and ODS reports no known safety concerns and no known adverse effects from short-term use of beet juice at the amounts commonly studied (about 2 cups). Beyond what the cited ODS sources cover, it is reasonable to check with a clinician first if you take blood-pressure or other cardiovascular medication or have a health condition, since beetroot is a concentrated nitrate source that can affect blood vessels; these are general precautions, not specific warnings from the ODS beetroot sections. As with any supplement, product quality is not guaranteed by the FDA, so the actual nitrate content of commercial juices and powders can vary.

A common and harmless effect noted by ODS is that beet juice can turn the urine (and sometimes the stool) pink or red, a phenomenon called beeturia caused by the natural pigments in beets; it is not a cause for concern. Some people separately report mild digestive upset such as cramping, bloating, or loose stools after drinking beet juice, though the cited ODS beetroot sections list no known adverse effects.

The cited ODS beetroot sections do not list specific drug interactions. As a general precaution, because beetroot's nitrate can promote blood-vessel widening, it could in theory add to the effect of blood-pressure-lowering or other cardiovascular medications, so discuss this with a clinician. (Separately, research outside these ODS pages has reported that antibacterial mouthwash can blunt the nitrate-to-nitric-oxide pathway because it relies on mouth bacteria; this is not stated in the cited sources.) Tell your healthcare provider about all supplements and medicines you use so they can check for interactions.