The question of whether beetroot increases red blood cells (RBCs) is common, rooted in the vegetable’s association with blood health and physical performance. While beetroot is often linked to improvements in oxygen transport, the answer is nuanced. The primary benefit of consuming beetroot does not lie in stimulating the long-term production of new RBCs. Instead, the effects center on enhancing the efficiency of the blood that is already present.
Beetroot’s Actual Effect on Blood Oxygen Efficiency
Beetroot does not cause a significant, rapid increase in the number of red blood cells circulating in the bloodstream. Increasing the count of red blood cells is a complex physiological adaptation, typically regulated by the hormone erythropoietin (EPO), which takes weeks to manifest. The effect of beetroot is immediate and focuses on how efficiently the existing red blood cells can deliver oxygen to working muscles.
This efficiency is achieved by lowering the oxygen cost of exercise, meaning the body requires less oxygen to perform the same amount of work. Studies have shown that individuals can perform a given task with a lower rate of oxygen consumption after consuming beetroot products. This improvement in oxygen utilization allows muscles to sustain activity for longer periods before fatigue sets in, enhancing physical performance and endurance.
The Role of Dietary Nitrates and Nitric Oxide
The powerful effects of beetroot on blood flow and oxygen efficiency are directly attributable to its high concentration of inorganic dietary nitrates. Once consumed, nitrate enters a specific biochemical pathway known as the enterosalivary circuit. About 25% of the circulating nitrate is concentrated in the saliva by the salivary glands.
In the mouth, commensal oral bacteria convert the nitrate into nitrite using specific reductase enzymes. Since human cells lack these enzymes, this initial step relies entirely on a healthy oral microbiome. The nitrite is then swallowed and absorbed into the bloodstream, where it can be further reduced to nitric oxide (NO) under low-oxygen or acidic conditions, such as those found in active muscle tissue.
Nitric oxide is a potent signaling molecule that acts as a vasodilator, relaxing and widening the inner walls of blood vessels. This vasodilation increases blood flow, improving the delivery of oxygen and nutrients to the muscle cells. By widening the vessels, nitric oxide effectively reduces the pressure needed to push blood through the circulatory system, contributing to a measurable reduction in blood pressure. This improved circulation and oxygen supply to the muscles is the core mechanism behind the performance benefits.
Optimal Consumption and Timing
To maximize the physiological benefits of beetroot, research has established specific consumption methods and timing protocols. The most effective way to ingest the high concentration of nitrates is typically through concentrated beetroot juice, which provides a reliable dose of inorganic nitrate. The effective amount is generally between 5 to 9 millimoles (300 to 550 milligrams) of nitrate.
Timing for Acute Performance
For acute performance enhancement, the optimal time for consumption is two to three hours before physical activity. This window allows sufficient time for the nitrates to be converted to nitrites by oral bacteria, absorbed into the bloodstream, and reduced to nitric oxide. To ensure successful conversion, avoid using antiseptic mouthwash or chewing gum immediately after consuming beetroot, as these products can kill the necessary oral bacteria.
Loading Phase
Some athletes employ a loading phase, consuming the effective dose daily for several days leading up to a major event. This strategy helps to maintain consistently elevated levels of circulating nitrite, potentially offering more sustained benefits. However, for most people seeking daily circulatory benefits, a single pre-activity dose within the optimal window is sufficient.
Current Scientific Findings and Caveats
Current scientific literature supports the use of beetroot products for improving endurance performance, particularly in activities lasting between 4 and 30 minutes. Performance gains are often quantified by an increased time to exhaustion or faster completion times in trials like cycling or running. Systematic reviews have shown that beetroot consumption can lead to performance improvements equivalent to a 48-second gain in a 10-mile cycling time trial.
Limitations and Variability
The effects are not universal across all populations. The most pronounced benefits are typically observed in recreationally active or moderately trained individuals. Highly elite athletes often show less benefit, possibly because their bodies have already optimized oxygen delivery through rigorous training. Furthermore, a phenomenon known as “non-response” exists, where some individuals do not experience any measurable performance improvement despite consuming the recommended dose.
The effects of beetroot are temporary, lasting only until the elevated levels of nitric oxide return to baseline, necessitating continued consumption to maintain the performance edge. Research also indicates a distinction between the effects of pure nitrate salts and whole beetroot juice, suggesting that other compounds, such as antioxidants, may offer additional advantages. While beetroot has demonstrated a consistent ability to reduce blood pressure, its use should supplement, not replace, prescribed medical treatment for hypertension.