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Nutrients and phytochemicals

Beetroot is an excellent source of folate and a good source of manganese,^[7] and contains betaines which may function to reduce the concentration of homocysteine, a homolog of the naturally occurring amino acid cysteine. High circulating levels of homocysteine may be harmful to blood vessels and thus contribute to the development of heart disease, stroke, or peripheral vascular disease.^[8] This hypothesis is controversial as it has not been established yet whether homocysteine itself is harmful, or whether it is just an indicator of increased risk for heart disease.^[9]

The red colour compound betanin is not broken down in the body, and in higher concentration may temporarily cause urine (termed beeturia) and stool to assume a reddish colour. This effect may cause distress and concern due to the visual similarity to hematuria (blood in the urine) or blood in the stool, but is completely harmless and will subside once the food is out of the system.

A recent study highlighted beetroot as a source of acute dietary nitrate, which was used to test the influence of nitrate supplementation on resting heart rate and sustained apnea. 70 ml of beetroot juice, containing approximately 5 mmol of nitrate, was found to reduce resting blood pressure by 2% and increase the maximum duration of apnea by 11% in experienced divers, relative to a control group receiving a placebo containing 0.003 mmol nitrate.^[6]

Preliminary research

Basic research on both rats and pilot studies on humans have shown betaine may protect against liver disease, particularly the buildup of fatty deposits in the liver caused by alcohol abuse, protein deficiency, or diabetes, among other causes.^[8]

In preliminary research, beetroot juice lowered blood pressure and thus may help reduce the risk of cardiovascular disease.^[10][11] The effect is attributed to the high nitrate content of the beetroot. The study correlated high nitrate concentrations in the blood following ingestion of the beetroot juice and the drop in blood pressure. Dietary nitrate, such as that found in the beetroot, is thought to be a source for the biological messenger nitric oxide, which is used by the endothelium to signal smooth muscle, triggering it to relax. This induces vasodilation and increased blood flow.^[12]

One study found positive effects beetroot may have on human exercise performance, showing that distance runners ran 5% faster times after consuming baked beetroot