Many recent studies have consistently shown the link between nitrates and enhanced physical performance. They can come in whole, plant-based or more synthetic, isolated forms. Today, they are considered an efficient performance-enhancing supplement from endurance training to weight lifters.
Natural forms of nitrates, such as beetroot juice — the most popular source — not only can boost exercise performance but can also play a much bigger role in our heart and brain health.
On the other hand, although nitrate salts (sodium, potassium) provide similar results concerning physical performance, they also come packed with not-so-good side effects for our health. Thus, the source of dietary nitrates are very important to be considered.
With that said, let’s dig into the wonderful properties of nitrates.
What Are Nitrates?
Nitrates are inorganic compounds found naturally in plants (particularly in fruits and vegetables) as well as in the water, air, and environment. Dark leafy greens have the highest concentration of nitrates in plants.
Although beets are the most popular source of nitrates, they are not the highest sources. On a mg/100g basis, whole beets (110) have 4x less concentration than the winner arugula (480). The complete rank goes as follow:
1. Arugula (480)
2. Rhubarb (281)
3. Beet Juice (279)
4. Cilantro (247)
5. Butter lettuce (200)
6. Spring greens (188)
7. Basil (183)
8. Beet greens (177)
9. Oakleaf lettuce (155)
10. Swiss chard (151)
Plants absorb through their roots nitrates present in underground water streams. They supply nitrogen to plants, allowing them to form essential proteins and grow healthily. Besides that, fertilizers dumped on soil are high in nitrates and are essential for the production of chlorophyll in plant leaves — a key agent of photosynthesis.
They are also found naturally in many fruits & vegetables, in different concentrations. The levels of naturally occurring nitrates depend on a series of factors, including the species, fertilizer and soil conditions, environmental influences (light, season, temperature), production (storage time and temperature), and processing methods (blanching, boiling, peeling, washing, etc.).
Although the beneficial properties of dietary nitrates for human health are well-established, more isolated forms of nitrates that are used in food production have the opposite effect.
Nitrates in Cured Meats
Nitrate salts like sodium nitrate are utilized as a food additive and preservative in processed food like cured meats due to their powerful antibacterial properties.
Since 1999, the FDA has prohibited the commercial use of nitrates in the production of cooked meats, sausages, and even cheese, for safety reasons. However, they allow the use of sodium nitrate in uncooked, cured meats, with a limit of 200ppm.
Once in contact with the meat, sodium nitrate gets converted into sodium nitrite by meat bacteria, then followed processed into nitrous (within an induced acidic environment), and finally converted into nitric oxide, which reacts with the myoglobin proteins, giving cured meats their pinkish color and salty flavor.
Although increased bioavailability of nitric oxide in our bloodstream is associated with positive health outcomes, sodium nitrite can bind with certain byproducts of amino acid degradation in our liver, leading to the formation of N-nitroso components like nitrosamines (or nitrosamides) that damage our cells and DNA.
Because of that, nitrosamines are labeled as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO). This means that there is enough evidence that this compound is carcinogenic. In the same category are things like smoking, asbestos (silicate minerals), aflatoxins (fungi), etc.
Although being on this group does not mean that YOU WILL have cancer if you consume these substances, it does mean that your chances will be highly increased.
Nitrates from Plant-Based Sources
Dietary nitrate from whole, plant-based sources, are highly associated with a number of benefits to human cardiovascular health, including helping to control vasodilation, regulating blood pressure, and improving blood flow. Furthermore, they are closely associated with brain health and cognitive function.
Dietary nitrates get converted into nitrites in our mouths, which then travel down our digestive tract, where they get converted into nitric oxide (due to stomach acid conditions), and finally entering our circulation system via resistance arteries, where their magic starts to happen.
Excess nitrates which did not get converted are excreted by our kidneys and get picked up by our salivary glands, where they accumulate and are released back to our body’s nitric oxide cycle on a demand basis.
To counteract the formation of nitrosamines, nitrate-rich plants are full of phytonutrients such as caffeic acid, ferulic acid, ascorbic acid (vitamin C), and other natural inhibitors of nitrosamine formation. You can find the complete list here.
Thus, it seems that plant-based sources of nitrates have the complete package to increase the bioavailability of nitric oxide in our bodies without harming it at the same time.
Nitrates and Health
There is a plethora of studies on the effects of daily consumption of plant-based dietary nitrates in both young and older adults. They have consistently shown solid and promising results concerning their positive health implications on all sorts of individuals, from clinically diagnosed patients to healthy adults.
Systemic hypertension (aka high blood pressure) is the largest attributable risk factor for mortality worldwide. Both high diastolic & systolic blood pressure are associated with increased risk of strokes, heart attacks, atherosclerosis, kidney failure, and cerebral hemorrhage. According to the WHO, an estimated 1.13 billion people worldwide have hypertension and numbers are predicted to increase by 1.57 billion by 2025 (slightly 1-3 adults).
A 2014 study found that a single daily dose of dietary nitrates (250ml beetroot juice) given to patients with hypertension during 4 weeks significantly lowered their blood pressure, even beyond conventional pharmacotherapy. They went further, suggesting a diet rich in dietary nitrates to be a cost-effective, affordable, and favorable approach for public health and treatment of patients with high blood pressure and at risk of cardiovascular diseases.
Another study published in the same year found similar results in overweight adults. They reported a decrease in daily systolic blood pressure via daily beetroot juice supplementation. However, these effects would not sustain after a week from the interruption of dietary nitrate supplementation.
A 2015 study focusing on younger healthy adults with Chronic Obstructive Pulmonary Disease (COPD) — a group of lung diseases (emphysema, chronic bronchitis, and refractory asthma) characterized by increasing breathlessness — observed increased levels of plasma dietary nitrate and nitrite, reduced blood pressure (systolic & diastolic), and ultimately improved exercise performance, with a significant reduction in the cost of oxygen during moderate- and high-intensity exercises.
A 2010 study investigated the relationship between a nitrate-rich diet on brain perfusion (aka cerebral perfusion pressure) in older adults. They observed a direct impact on cerebral blood flow, specifically within the patients’ white matter — the brain tissue responsible for transporting messages between different areas of gray matter within our central nervous system. Despite the improved neurovascular response (or cellular metabolism), they noted that nitrates act preferentially on hypoxic conditions — when a specific region of the body is deprived of adequate oxygen supply at the tissue level.
Conditions that infringe the blood supply to vital organs of our body like CPP (brain) and ischemia (heart et al.) are closely associated with cognitive decline and dementia. Also, aging is strongly correlated with a decrease in cognitive function and degeneration of the brain’s white matter, which is vital for daily tasks such as memory and performing tasks.
A 2017 study concluded that the combination of regular exercise with beetroot juice yield improved brain function in older patients, with neural networks resembling those associated with younger adults. Moreover, the results showed a potentially enhanced neuroplasticity — the phenomenon of altered neural structure, function, and connection in response to environmental or bodily demands — which tends to deteriorate with aging.
A 2013 study reported a close relationship between a diet poor in fruits & vegetables with the risk of erectile dysfunction in Canadian diabetic men. They reported a 10% decrease in ED with one extra serving of fruits & vegetables per day.
Although these results might seem vague, ED is closely associated with a poor lifestyle lacking in physical activity and proper diet, as well as a number of conditions such as atherosclerosis (clogged blood vessels), high cholesterol, high blood pressure, heart disease, diabetes, etc. A 2014 report found that ~18.4% of U.S. adult males age 20+ suffered from this condition (~18 million male Americans). These figures were drastically higher in men with diabetes (~51.3%).
Based on all the evidence listed, it would not be illogical to reason that a diet rich in plant-based sources of nitrates could reverse many of the symptoms that can lead to ED, heart problems, and aging-related conditions.
Furthermore, it’s broadly accepted that only a plant-based diet is capable of reversing heart disease and is effective in regulating and preventing type 2 diabetes.
Nitrates and Gym Performance
Dietary nitrates are commonly referred to as ergogenic aids — substances or devices related to enhanced energy production and efficiency, leading to a competitive advantage in athletic performance. Beetroot juice and nitrate salt supplements (sodium & potassium) are the most popular sources. Many studies have linked them to enhanced physical performance in both endurance and strength scenarios.
A 2007 study investigating the effects of dietary nitrates on cycle ergometer performance after two separate 3-day periods of supplementation (0.1mmol/kg of sodium nitrate) on 9 healthy young, well-trained, men found increased muscle efficiency via lower oxygen demand during submaximal work on subjects given the nitrate supplementation. They observed no alteration in their lactate concentration (which tends to build up in the bloodstream when there is not sufficient oxygen available to break down glucose for energy), suggesting that energy production had become more efficient (most likely via improved basal mitochondrial efficiency).
A 2009 study went another route and gave subjects (8 active, healthy, men) 500 of beetroot juice for 6 days. During this time, they were asked to abstain from nitrate-rich food in their diets and were tested on different cycling exercises. During the trials, they found on subjects given the nitrate supplementation a reduction of oxygen cost (~5%) during low-intensity exercises and enhanced tolerance (~16%) to high-intensity exercises, suggesting improved mitochondrial respiration and muscle contraction efficiency. They also reported a significant reduction in resting blood pressure.
A (2015) study went further and tested cognitive function during exercise. Cognitive ability is sensitive to alterations in arousal, mood, and physical demands; consequently, high-intensity athletes tend to have their reaction time deteriorated over activity time. 16 male team-sport players were given beetroot juice supplementation for 7 days and tested with cognitive tasks during a prolonged intermittent sprint on a cycle ergometer on the 7th day after supplementation. The results suggested that dietary nitrates enhanced repeated sprint performance and likely attenuated the decline in reaction time that tends to occur during prolonged exercise.
A 2016 study investigated the effects of dietary nitrate supplementation on resistance exercise performance, particularly on the bench press. 12 active, resistance-trained, men were given 70ml of “BEET It Sport” nitrate shot (~6.4 mmol of nitrates) and tested at an intensity of 60% of their 1RM within controlled parameters until failure. The results appointed to a significant improvement in repetitions to failure to subjects given the nitrate supplementation, no significant difference between blood lactate during trials, and no differences in fatigue measured by (RPE).
A 2018 study tested the effects of beetroot juice (BRJ) consumption on muscle power. They target 13 men and 7 women (ages 22–79), all normally active but none engaged in competitive sports. During the trial, subjects were tested on maximal knee extensions 2 hours after the ingestion of 140ml of commercial beetroot juice supplement. Compared to the placebo group, results showed a significant average increase in maximum velocity and power in individuals supplemented with BRJ. They found a correlation between maximum power and increased concentrations of plasma nitrites in all subjects and, particularly in females, a greater overall increase in maximum power.
All studies listed in this portion were randomized, double-blinded, placebo-controlled, and crossover-designed.
I’m not sure why the majority of physiological studies I’ve read focused on male subjects. However, it’s safe to assume that these results apply for all healthy individuals, regardless of gender.
…Why Not Just Buy Pre-Workouts?
If many pre-workouts already contain combined nitric oxide stimulating substances, why not just go for them?
Based on personal experience, even though some pre-workouts worked as they were marketed, they also came with a number of drawbacks which makes their relative worthiness questionable. Among the negatives were:
Most are overpriced
Most ingredients (blends) are unknown for the regular consumer, which require proper, time-consuming investigation
Many ingredients have little scientific literature besides marketing claims
Side effects like post-workout anxiety, dizziness, headaches, and even heart arrhythmia in some cases (perhaps from excessive caffeine)
All these were reasons why I decided not long ago to ditch them and rely more on plant-based whole-foods to sustain my workouts. The main reason was that when put on a balance, the short-term benefits of taking them would not outweigh their potential negative short- and long-term effects. Credible scientific literature has also helped to support my decision.
A 2012 study investigated the effects of sodium nitrate supplementation on the performance of endurance athletes. They found an increased concentration of plasma nitrate & nitrite, but no improvement in physical performance. Furthermore, there was a significant increase in the concentration of plasma ET-1 after supplementation, which is present in high levels in patients with chronic heart failure (CHF), thus making their long-term safety questionable.
A 2014 review concluded that, when administered orally, most molecules marketed as nitric oxide boosters— L-arginine, carnitine, 2-nitrooxy ethyl 2-amino 3-methylbutanoate, arginine-alpha-ketoglutarate, etc. — have modest or no evidence available relating them to performance improvement following supplementation. This means that you could be overpaying for ineffective ingredients.
An interesting 2016 study tested the effects of 6-day dietary nitrate supplementation on peak anaerobic power in 12 trained Crossfit male athletes. Subjects were given 8mmol of potassium nitrate and were supposed to be tested 24 hours after the final dose. However, there were a number of reported gastrointestinal distress followed the ingestion of nitrate supplementation, a common side effect of nitrate salts. Because of that, subjects were tested 48 hours after the last dose in order to avoid the influence of stomach discomfort in performance. Nevertheless, results showed that peak power increased significantly overtime on subjects given the nitrate supplementation, but overall CrossFit performance (strength & endurance) remained unchanged.
This study recognized a series of limitations that probably impacted on the results. Among them were the extended period of time (48 hours) between the last dose and the test day, which most likely influenced on the concentrations of plasma nitrate & nitrite, and the actual CrossFit protocol which required all participants to lift the same amount of weight despite the variances in body mass and strength, which resulted on failed lifts and ultimately impacted on the time taken by each participant to complete the test. Because of the reported gastrointestinal distress, the conductors of the study advise the consumption of dietary nitrate via whole food forms like beetroot juice, which has also shown to have a greater impact on the metabolic cost of exercise comparted to nitrate salts.
‘Some might say you can’t beet beats’
Beetroots come with several benefits that go beyond their ergogenic properties, making it very hard to ignore the nutritional quality they bring to our diet and overall health.
They are full of phytochemicals such as nitrogenous betalains, a range of phenolics compounds, folate, and other potentially bioactive compounds that aid our body to combat inflammation and oxidation. Besides that, they are particularly rich in folates, which are essential to convert carbohydrates into energy, among other vital body functions.
However, as cited before, beets are shy from being the best source of dietary nitrates. Thus, even though it’s perfectly fine to rely on beetroot juice as a natural pre-workout, it’s advisable to consume a variety of nitrate-rich plant-based sources, such as other leafy greens. As a rule of thumb, you should be consuming a variety of fruits & vegetables every single day to rip the benefits that only plants can bring to our health!
Beets are rich in natural pigments called beeturia, which turn urine and stool red in high concentrations. Although the probable initial shock, these unusual colorations are not a cause for concern.
Always remember to check with your healthcare professional and do your own research before making any significant changes to your diet. Although incorporating plant-based dietary nitrate is deemed safe, any predetermined conditions like low blood pressure can raise a question mark. Always better safe than sorry!
Other than that, beets are relatively high in oxalates, which are compounds found naturally in plants that you may want to avoid if you are already at a higher risk of having kidney stones.
How Much and When Should I Be Taking BRJ?
The FAO & WHO Joint Expert Committee on Food Additives (JECFA) recommends an acceptable daily intake of 0–5mg per kg expressed as sodium nitrate or 0–3.7mg p/ kg expressed as nitrate ion. Regarding beetroot juice, there are no established limits. However, anywhere around 8oz (~1 cup) of BRJ is a commonly accepted dose.
Be sure to check what other nitrate-rich sources of food you are already incorporating into your diet if you want to quantify and track the number of daily nitrates you are regularly having.
Regarding the time of the day, consume BRJ at least 30min before your workout or exercise. To optimize its benefits, it’s recommended to consume it first thing in the morning though.
Need Further Help?
If you are not excited about reviewing studies for hours and hours or simply lack the time, I suggest researching for anecdotes and personal experiences from certified fitness coaches & nutritionists, YouTubers, and athletes. A personal favorite of mine is the natural vegan bodybuilder and YouTuber Brian Turner who vlogged the benefits he experienced with BRJ.
I hope that my article has helped or motivated you to give dietary nitrates a chance and see what benefits they can bring to your physical performance and health.
I’m personally going for BRJ so that I can see the results for myself (as I have always done!). Although placebo effects might take place initially, I’m pretty convinced that I’ll be able to comprehend the cause-effect relationship of BRJ consumption in the long-run. That might become another article.
Peace & eat your plants! 💪🌱