Nitrate supplements provide concentrated amounts of the inorganic anion nitrate, a molecule naturally found in high concentrations within certain vegetables. These compounds have gained significant attention in both the athletic and health communities due to their ability to influence the body’s circulatory and metabolic functions. Ingested nitrate serves as a precursor for a powerful signaling molecule that affects blood flow and cellular efficiency.
Common Forms and Dietary Sources
Nitrate supplements primarily come from concentrated vegetable sources, with beetroot being the most common and widely studied source. Beetroot juice, often available in concentrated “shots” or powders, provides a standardized dose of nitrate, typically ranging from 350 to 650 milligrams per serving. Other plant extracts, such as those derived from amaranth or leafy greens like spinach and arugula, are also used due to their high natural nitrate content. Supplements deliver a much higher, concentrated amount than whole foods, which is required to achieve a measurable physiological effect.
The Nitrate-Nitrite-Nitric Oxide Conversion Pathway
The functional effects of nitrate supplementation begin with a specific biological cascade known as the nitrate-nitrite-nitric oxide pathway. After ingestion, nitrate is rapidly absorbed into the bloodstream, and about 25% is concentrated in the saliva by the salivary glands. Specialized bacteria on the tongue then reduce the swallowed nitrate into nitrite. This nitrite-rich saliva is swallowed, and once in circulation, the nitrite acts as a reservoir for nitric oxide (NO), a potent signaling molecule.
Nitrite to Nitric Oxide Conversion
The final conversion of nitrite to nitric oxide occurs primarily in tissues experiencing low oxygen levels or an acidic environment, such as working muscles or areas of restricted blood flow. This process is independent of the body’s primary NO synthase (NOS) pathway. Instead, it is catalyzed by various enzymes like deoxygenated hemoglobin and myoglobin. Because this pathway is activated under low-oxygen conditions, it selectively increases nitric oxide availability precisely where it is most needed during intense exercise.
Effects on Oxygen Efficiency and Blood Flow
The increase in nitric oxide availability has two primary functional consequences: improved blood flow and enhanced muscular efficiency. Nitric oxide is a powerful vasodilator, signaling the smooth muscle cells surrounding blood vessels to relax and widen the vessel diameter. This vasodilation improves the delivery of oxygen and nutrients to active skeletal muscles while simultaneously helping to reduce blood pressure.
Muscular Efficiency
The second effect involves the mitochondria, the energy-producing organelles within muscle cells. Increased nitric oxide appears to make the mitochondria more efficient, lowering the amount of oxygen required to produce a given amount of muscular force. This reduction in the oxygen cost of exercise allows individuals to perform at a higher power output or for a longer duration before reaching exhaustion.
Usage Protocols and Safety Considerations
The typical usage protocol involves consuming a dose of approximately 350 to 650 milligrams of nitrate. For an acute performance benefit, this dose is most effective when consumed two to three hours before exercise, coinciding with the peak concentration of nitrite in the blood plasma. Some individuals also employ a “loading” phase, consuming a daily dose for three to seven days leading up to an event to maximize circulating nitrite stores.
Safety Considerations
A significant safety consideration relates to the conversion pathway: using antibacterial mouthwash shortly after supplementation can eliminate the oral bacteria responsible for converting nitrate to nitrite, neutralizing the supplement’s effect. Side effects are generally mild and may include pink coloration of urine or stools from beetroot pigments, as well as occasional gastrointestinal discomfort. The antioxidants present in plant-based nitrate sources, like beetroot, are thought to mitigate the risk of forming potentially harmful N-nitrosamines, making whole-food supplements a preferred choice over pure salt forms.