Nitric oxide is an important signaling molecule in the body that impacts circulation, athletic performance, and even cognitive function. Tissues throughout the body rely on nitric oxide production for optimal function, and deficiencies in nitric oxide production have been linked to inflammation, aging, and a variety of chronic diseases. Nutritional and supplemental interventions can help support the nitric oxide system in the body as part of a lifestyle geared toward optimal health and longevity.
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What is Nitric Oxide?
Nitric oxide (NO) is a molecule produced naturally in the body that is important for vascular health, playing roles in blood vessel dilation and helping to improve blood flow. NO can become toxic inside the body when levels get too high, so regulation of NO is essential to reap the benefits of this compound. Additionally, nitric oxide contributes to the signaling and regulation of neurotransmitters and can stimulate the release of insulin and growth hormones. While no supplements contain NO directly, the amino acids L-arginine and L-citrulline - which are used by the body to produce nitric oxide - can be taken in supplement form to raise NO levels in the body.
What is The Importance of Nitric Oxide in The Body?
Nitric oxide is a powerful vasodilator, helping to improve blood flow to various regions of the body. It also plays a role in hormone stimulation, immune system function, neurotransmitter regulation, and cognitive function. Additionally, NO may have a beneficial impact on exercise performance, particularly for untrained or moderately trained individuals.
It should be noted that the production of nitric oxide by the enzyme NOS (nitric oxide synthase) does create free radicals in the process, so regulation of nitric oxide production pathways is important. Having adequate nutrients to neutralize and eliminate free radicals is important as a bigger picture of optimal health when considering interventions to improve nitric oxide production.
What Are The Functions of Nitric Oxide?
Nitric oxide has many different roles throughout the body, ranging from blood vessel function to exercise performance, among others.
Nitric Oxide’s Role in Blood Vessel Function and Cardiovascular Health
Nitric oxide is essential for optimal cardiovascular health and function, acting as a vasodilator to help improve blood flow and decrease blood pressure as needed. Nitric oxide has additional roles that support cardiovascular health, including inhibition of platelet aggregation (clotting), promoting angiogenesis (growth of blood vessels), and an anti-inflammatory role. When nitric oxide is not readily available in the body, there is dysfunction of the endothelial lining of blood vessels, leading to an increased risk of atherosclerosis and cardiovascular disease.
Nitric Oxide’s Impact on Exercise Performance and Endurance
Nitric oxide also has several functions related to exercise capacity and performance. Production of nitric oxide increases in skeletal muscle after physical activity, helping to increase the energy supply to muscle tissue. It also acts as a key regulator of mitochondrial biogenesis in skeletal muscle cells, increasing mitochondrial concentration in response to exercise. Additionally, nitric oxide’s role in blood vessel dilation helps deliver more oxygen and nutrients to muscles during a workout for peak performance.
Nitric Oxide's Role in Immune System Support
Nitric oxide may act as an anti-inflammatory and immunosuppressive agent within the immune system, sending signals for certain cells to undergo apoptosis (programmed cell death). It also helps regulate the Th1/Th2 balance in the immune system, an important piece of the inflammatory response. Lastly, studies have found that nitric oxide may also play a role in the development and control of infectious diseases, tumor progression, autoimmunity, and chronic degenerative disorders, likely through its impact on the aforementioned aspects of the immune system.
Nitric Oxide’s Influence on Cognitive Function and Brain Health
Nitric oxide plays important roles in neuroplasticity, learning, and memory formation. It is synthesized in the brain upon demand for these cognitive needs and has an unconventional role as a neurotransmitter, as it’s released as soon as it’s made and isn’t dependent on membrane depolarization as other neurotransmitters are. Its vasodilatory effect improves blood flow to the brain, thereby enhancing cognitive function. Additionally, it’s been found that interventions that increase nitric oxide concentration in the brain have a therapeutic effect in those with age-related neurodegenerative diseases such as Alzheimer’s disease, giving nitric oxide a neuroprotective role as well.
Natural Ways to Boost Nitric Oxide Production
There are plenty of ways to increase your body’s nitric oxide production through nutrition, physical activity, and even just by getting outdoors.
Dietary Sources of Precursors to Nitric Oxide
Foods like beetroot and dark leafy greens such as arugula and spinach are sources of dietary nitrates. When nitrates are consumed, the body can convert the nitrate to nitric oxide, which can then have a relaxing effect on blood vessels, lowering blood pressure. Beetroot juice, in particular, has been found to decrease both systolic and diastolic blood pressure through the nitrate to nitric oxide conversion.
Flavonoids that are found in antioxidant-rich fruits and vegetables can also increase nitric oxide production and decrease its breakdown, promoting higher levels of nitric oxide overall. The effect on levels depends on flavonoid structure and the concentration of antioxidants in the plant. Some of the major antioxidants that can boost nitric oxide production include vitamin C, vitamin E, polyphenols, and glutathione. Including citrus fruits, pomegranate, berries, pumpkin, bell peppers, leafy greens, almonds, spices, cacao, tomatoes, mushrooms, and avocado can increase the supply of these four antioxidants in the diet, helping to boost nitric oxide levels as part of a healthy lifestyle.
Importance of Exercise and Physical Activity
Nitric oxide contributes to the cardioprotective benefits of exercise, like decreased blood pressure and improved circulation. Even a 4-week home-based training program has been found to help increase nitric oxide to unlock the benefits of the regulatory molecule.
Exercise boosts nitric oxide production to help deliver more oxygen and nutrients to muscle tissues, though the amplified nitric oxide levels can help to improve mitochondrial biogenesis overall, leading to higher levels of mitochondria to meet higher energy demands.
Sunlight and Vitamin D for Nitric Oxide Synthesis
Sunlight exposure provides another way to increase nitric oxide synthesis in the body. The skin contains large stores of nitric oxide, and the outer epidermis has a notable expression of NO synthase, the enzyme that makes nitric oxide. UVA rays have been found to be primarily responsible for increasing the synthesis of nitric oxide in the skin, though vitamin D3 has also been linked to the regulation of nitric oxide stores. Interestingly, it’s been found that less nitric oxide is produced the further a person is away from the equator, so the benefits of sunlight for improving NO stores are somewhat location-dependent.
Top Nitric Oxide Supplements for Optimal Health
The most well-researched supplements to improve nitric oxide levels include L-arginine, L-citrulline, and beetroot juice.
L-Citrulline
L-citrulline, a precursor to nitric oxide, has been shown to decrease muscle soreness, likely by increasing nitric oxide production and improving blood flow to active muscle. It helps increase nutrient and oxygen delivery and clear out metabolic waste, decreasing symptoms of soreness. Up to 6g taken an hour before exercise has been linked to higher nitric oxide availability in muscle tissue.
L-Arginine
L-arginine is a precursor of nitric oxide, which is a naturally occurring amino acid found in food that plays a role in protein synthesis. Supplementation in healthy individuals has been linked to increased blood flow due to the impact of L-arginine on nitric oxide production, conferring health benefits like improved performance, better recovery, and lower blood pressure. The average dose is 6-30 mg daily, divided into 3 doses to minimize the risk of side effects such as gastric discomfort.
Beetroot Juice
Beetroot juice is rich in dietary nitrates and has been found in several studies to increase nitric oxide production. During exercise, it can help to improve blood flow endurance and even stimulate stronger muscle contractions due to the increased delivery of oxygen and blood to muscle tissue. Benefits have been seen with as little as 70 mL (2.37 ounces). Individuals who are sensitive to oxalates or prone to kidney stones should talk to their doctor before including beetroot juice in their routine, as beets are a high-oxalate food and may aggravate symptoms.
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Summary
Nitric oxide can have beneficial impacts on a variety of physiological systems in the body due to its role in improving blood flow and circulation. There are many ways to improve nitric oxide production, such as eating specific foods, exercising, and getting sunlight exposure. Supplementing with nitric oxide precursors is common in the athletic population, with L-citrulline, L-arginine, and beetroot juice showing the most promising effects of amplifying the power of nitric oxide for performance and recovery.
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