Nitrates. You’ve heard the term. You’ve seen it in running magazines. You’ve tried a post-race product sample. At least one of your running buddies is all into nitrates and has told you that you need them!
But wait – weren’t you always told that nitrates are bad for you? Hot dogs are full of them, and hot dogs aren’t exactly touted for their nutritional benefits. And wasn’t there a bunch of research that nitrates cause cancer? And now they suddenly help you run better? What gives? Are nitrates good or bad?
Well, like most things in nutritional science, the answer is it depends. (Insert annoyed emoji.) Nutrition is a young science, and it has to be a fluid science. Many things affect how compounds act in the body, and sometimes a small change in a compound can change its affect. We have to adjust our thinking accordingly – and often we can’t judge all books by the same cover. Nitrates from processed meats like hot dogs aren’t ideal, but naturally occurring nitrates from vegetables offer several protective benefits and can help boost performance for us runners.
First a Quick Chemistry Lesson
Nitrates are inorganic (meaning they don’t contain carbon) compounds made up of one nitrogen molecule and three oxygen molecules (NO3). Once ingested, nitrates (NO3) are absorbed from the bloodstream by the salivary glands where mouth bacteria convert them into nitrites (NO2). NO2 eventually becomes nitric oxide (NO), which helps dilate blood vessels.
NO3 is ingested –> bacteria make NO2 –> NO is produced and dilates blood vessels
Here’s why that matters to runners: dilated blood vessels mean lower blood pressure, increased blood flow, and increased oxygen delivery. These in turn mean improved muscle contraction, glucose uptake, and cellular respiration. The bottom line: your initial ingestion of naturally occurring nitrates (NO3) leads to a decreased energy cost of exercise, meaning you can perform longer at the same perceived exertion. You improve your endurance.
The Type Matters – A Lot!
So just eat more hot dogs, right? Not quite. Naturally occurring nitrates in vegetables have a beneficial effect on cardiovascular function and exercise endurance. They are converted by the body to nitrites and then nitric oxide. Almost all leafy green vegetables contain nitrates, as does beetroot juice.
Nitrates and nitrites in processed meats like bacon and hot dogs produce compounds linked to the production of cancer and other serious health concerns. For this reason, the USDA, EPA and WHO have all placed limits on the amount of nitrates and nitrites that are added to food and water.
If you’re looking to add nitrates to your intake through supplementation, consider the following: not a ton of research has been done on nitrate and nitrite supplementation, but the little that is available has basically led researchers to determine that nitrate supplementation in theory shouldn’t be harmful (since conversion to nitrite and nitric oxide would still need to happen through bacteria in the body), but direct supplementation of nitrite is just a really bad idea. Since most runners aren’t chemists, you can see how that can get super confusing (and potentially dangerous) really quickly.
So what do you do to get the benefit of nitrate supplementation without causing short-term or long-term harm? Easy: choose food over supplements, skip the bacon, and up your intake of whole vegetables – that’s a good life rule in general!
What, When, and How Much
We’ve established that your nitrates should come from food sources that naturally contain them. The best vegetable sources of dietary nitrates are spinach, arugula, celery, and beetroot juice. About a cup of nitrate-rich leafy greens will deliver the recommended dose of 300mg of dietary nitrates. You don’t have to eat like a rabbit – go ahead and throw those leafy greens on top of pizza or sauté them to add to baked potatoes or eggs. The nitrate benefit remains.
To reap the easiest training and racing benefit from nitrates, look to beetroot juice. Not only is beetroot juice naturally rich in NO3 (leading to the performance increase discussed above), but it may also improve the efficiency of mitochondria, your body’s powerhouse cells responsible for producing usable energy. (It’s more likely to have this type of effect in recreational runners versus seasoned veterans and elites, and chronic beetroot juice supplementation may be needed to achieve this effect.) Concentrated powders (which you simply mix with water to rehydrate) are readily available on the market and make intake easy.
NO production in the body peaks about 2-3 hours after ingestion of NO3, so timing is important. The chart below lists some suggestions, but you should experiment during training runs to find the best window for you.
|Exercise/Race Duration||Timing of Intake|
|30 minutes or less||2-2.5 hours before start|
|30-60 minutes||1-1.5 hours before start|
|60-90 minutes||30-60 minutes before start|
|Over 90 minutes||0-30 minutes before start|
Side Effects and What to Avoid
There are few side effects of taking beetroot juice, the main one being the potential for stomach upset and general GI issues (especially for those with FODMAP sensitivities). Pink-tinted urine and stool can also happen – both are harmless. As with most things, more is not necessarily better. Stick to recommended dosage that works for you (300-600mg/day), and don’t go crazy.
It’s important to remember that mouth bacteria is needed for the conversion of NO3 to NO2, so avoid mouthwash and gum in the hours before and after intake. There’s also evidence that the prolonged endurance effects of beetroot juice may be undermined by caffeine taken at the same time, so consider the timing of coffee, caffeinated gum, or caffeinated hydration/fueling products.
Whether or not to add nitrates to your training plan is ultimately an individual decision. If you’re looking for ways to push past “The Wall” during training or racing, NO3 might be just the ticket. I suggest experimenting during training runs (never try anything new on race day) for several weeks to see if you notice a difference. Beetroot juice will give you the best chance of hitting the recommended dose in a quick and accessible fashion, and you can easily control the timing of intake.
As with all endurance fueling, for professional guidance talk to a Registered Dietitian. If you’d like a personalized consult, click here to send me a message or here to check out my service offerings. Happy training!
Domínguez, R., Cuenca, E., Maté-Munõz, J. García-Fernández, P., Serra-Paya, N., Estevan, M., Herreros, P. and Garnacho-Castaño, M. (2018). Effects of Beetroot Juice Supplementation on Cardiorespiratory Endurance in Athletes. A Systematic Review. [online] PubMed – NCBI [online] Ncbi.nlm.nih.gov Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5295087/ [Accessed 3 Jul. 2018].
Jones, A. (2018). Dietary Nitrate Supplementation and Exercise Performance. PubMed – NCBI [online] Ncbi.nlm.nih.gov Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4008816/ [Accessed 3 Jul. 2018].
Wylie LJ, e. (2018). Beetroot juice and exercise: pharmacodynamics and dose-response relationships. – PubMed – NCBI [online] Ncbi.nlm.nih.gov Available at: https://www.ncbi.nlm.nih.gov/pubmed/23640589 [Accessed 3 Jul. 2018].
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