Applied nutritional investigationPharmacokinetic study of amaranth extract in healthy humans: AÂ randomized trial

•This was a human study on absorption of nitrate from amaranth extract.•Nitrate is converted into nitrite and then into nitric oxide.•The results demonstrated that amaranth extract increased the concentration of nitrate and nitrite in blood and saliva.

ObjectiveNitric oxide (NO) is one of the most important signaling molecules produced within the body. Continuous generation of NO is essential for the integrity of the cardiovascular system. The aim of this study was to assess whether oral intake of a nitrate (NO3ˉ)-rich dietary supplement (amaranth extract) is able to increase NO3ˉ and nitrite (NO2ˉ) levels in blood plasma and saliva of healthy adults.MethodsIn the present study, bioavailability and pharmacokinetics of NO3ˉ and NO2ˉ from amaranth extract (2 g as single dose) was studied in 16 healthy individuals and compared with placebo in a crossover design. The NO3ˉ and NO2ˉ levels in plasma as well as saliva were measured up to 24 h.ResultsAfter administration of amaranth extract, the NO3ˉ levels in plasma as well as saliva were found to be significantly (P < 0.001) higher than in the placebo group. The NO2ˉ level in plasma was slightly higher (P < 0.05) in the amaranth group (test group) compared with that in the placebo group, whereas the saliva NO2ˉ level was significantly high (P < 0.001) in the amaranth extract-treated group than the placebo group.ConclusionsThese results clearly indicate that a single oral dose of amaranth extract is able to increase the NO3ˉ and NO2ˉ levels in the body for at least 8 h. The increase in NO3ˉ and NO2ˉ levels can help to improve the overall performance of people involved in vigorous physical activities or sports.