I’m typically pretty cautious when reports of a particular ingredient or 'super' food are linked to boosts in athletic performance, but like others, I’m intrigued by the possible endurance benefits of drinking beetroot juice. If you haven't been following the topic and this is the first you're hearing about the potential power of beets, here's the quick gist: A handful of studies performed over the past several years have found that consuming beet juice lowers the oxygen cost of exercise, due to the high concentration of nitrates found in beets(1-3, 5-8, 15).
I like this for two reasons: 1) this performance benefit doesn’t require a special pill, powder, or extract …..just good old-fashioned beets from the farmer’s market (I found them for $0.99/lb at mine), 2) almost everyone can benefit from adding more vegetables to their diet, and the possible ‘ergogenic reward’ might be enough to encourage kids and adults to do just that.
How does it work? Although researchers aren’t sure of the exact mechanism behind the beet juice advantage, it has been shown that the high presence of nitrate is responsible(6). In more detail, nitrate from the beets (NO3-) is converted to nitrite (NO2-) by natural bacteria in saliva. The swallowed nitrite is then converted to several nitrogen-oxygen compounds in the stomach, one of which is nitric oxide (NO). Nitric oxide, a known vasodilator that contributes to several functions in the body, is behind the endurance benefits that the researchers believe may be 1) allowing muscle contractions to work in a more energy efficient manner, thus ‘sparing’ ATP and delaying fatigue and/or 2) decreasing the slow component of oxygen consumption, or in other words, delaying the point at which you reach ‘redline’
In general, studies have administered beetroot juice via one of the three dosing schedules: 500 mL (containing about 380 mg of nitrate) for 4-6 consecutive days, 500 mL for 1 day (2.5 hours prior to an exercise test), or a concentrated dose of 140 mL (containing 550 mg) for 6 days. More research can (and hopefully will) help figure out the ideal timing and dosage, but based on the current available data and what your digestive system can handle, you may want to start experimenting at the low end (500 mL the day of the event) and work your way up to see what works best for you. The more you can dial this in the better, mainly because drinking beet juice gets pretty old after the 3rd or 4th day (believe me!). Two medium beets (each about the size of a baseball) yield about 500 mL in my juicer. I assumed that 500 mL of freshly juiced beets would differ slightly as compared to a bottled drink, which is the source of beetroot juice used in the studies (BEET IT produced by James White Drinks, with 384 mg nitrate per 500 mL) so I did a search for nitrate levels in fresh beets and although limited, did manage to find a few sources which report a nitrate content ranging from a mean of 1100-1700 mg/kg(4, 13). Applying these values to the beets I juiced (total weight of 1.6 lbs) gives an estimate of 800-1200 mg/kg present in my 500 mL volume– quite a bit more than the amount of nitrate present in the BEET IT drinks. I can’t fully explain why this is so, but will venture a guess that it could be due to one or more of the following factors: 1) dilution (apple juice is added to BEET IT at a 10% level), 2) heat processing (BEET IT is hot-filled) and/or 3) BEET IT is made from organically sourced beets (which generally possess lower nitrate levels than conventional sources).
Okay, say you’re able to follow the regimen-- what kind of a performance benefit can you expect? Studies have reported a 1-3% improvement in a race type situation(3, 5). Is it really worth enduring 2 cups (500 mL) of beet juice for several consecutive days to only gain an advantage of 1-3%? It doesn’t sound like much at first glance, but if you apply these to a standard distance such as a 5K running race, it provides a rough idea of the ‘return on investment’. Let’s say your personal best at this distance is 18:00. Taking the average from above, a mere 2% improvement in race time equates to crossing the line in 17:38 – a significant improvement of 22 seconds over a 5K distance (I’d take that!). Consider longer events and a seemingly small improvement of just 2% could mean the difference between a 3:00:00 marathon and a 2:57:36 one…again, a huge PR many folks would be elated to achieve from the small cost of a few pounds of ingested beets.Table 1 shows additional distances and times.
|Race Distance||Performance Improvement|
|1 %||2 %||3 %|
|5K (Starting 'best' time of 20:00)||19:48||19:36||19:24|
|10K (Starting 'best' time of 40:00)||39:36||39:12||38:48|
|Half Marathon (Starting 'best' time of 1:30:00)||1:29:06||1:28:12||1:27:18|
Marathon (Starting 'best' time of 3:00:00)
If you want to plug in your own numbers, pick an event and distance and convert your current personal best to seconds (18:00 is equivalent to 1080 seconds e.g.). Multiply this number by a percent improvement (0.03 e.g) and subtract from your starting value. Finish by converting back to mm:ss (1080 x 0.03 = 32 seconds; 1080-32 = 1047.6 seconds or 17:28).
So, why beets? Other vegetables, particularly leafy green ones, also contain very high levels of nitrates, and since nitrates are the key to the effect, isn't it plausible to assume that following a similar regimen with various nirate-rich lettuces (see Table 2) will elicit the same beneficial results on performance? I realize no studies have been done to validate this, but if you're not very keen on the earthy flavor of beets it seems worthwhile to try out some alternatives. Take spinach for example, which has a nitrate content around 2,200 mg/kg.(4,13,11,12). Targeting the same level of nitrates consumed in the studies, you can attain 384 mg by eating 6-7 oz of spinach. If you like rocket lettuce (I love the double-entendre there!) you're even better off. Also known as arugula, it ranks #1 as the vegetable with the highest concentration of nitrates (averaging a whopping 4,800 mg/kg and about 3-4X that of beets)(4,13), meaning you'd only have to settle down to a 3 oz plate, which is about the size of a side salad. For fun, consider trying my recipe for 'Rocket Salad' containing roasted beets, spinach and arugula. It tastes great and delivers an estimated 500 mg of nitrates.
|Vegetables With Very High Nitrate Content|
|Oak leaf lettuce|
In lieu of beetroot juice or other vegetables, don’t rush out to buy a nitrate supplement, found in salt form as potassium nitrate (saltpeter) and sodium nitrite. Both are used in the food industry for food preservation (think cured meats), with potassium nitrate also used to make gunpowder and remove stumps (do you really want to ingest that?!). A lot of confusion exists between the two and accidental overdosing can occur--sodium nitrite has a toxicity similar to cyanide (low doses of only 200-300mg/kg can be lethal)(10). It should be noted that safe levels of dietary nitrate intake are still controversial, but most of the debate centers around sodium nitrite ingested via cured meats or drinking water. Nitrates attained from vegetable sources, on the other hand, are likely harmless and also contain high levels of antioxidants and phenols--beneficial bioactive compounds you won’t get in supplement form.
In summary, beetroot juice is worth keeping an eye on as an ergogenic aid. More research needs to be done, but there's little harm in giving them a try (as well as other nitrate-rich veggies) prior to an upcoming race to see if your percceived level of effort and/or finishing time is affected. If nothing else, you'll only end up improving your diet.
A few helpful notes in closing….
- 2 medium-large beets produce about 500mL of juice.
- If the beet juice is too sweet, try squeezing half a lemon to add some acidity/tartness. If it’s not sweet enough, juice half an apple or a whole carrot into the mix.
- Don’t be alarmed to experience beetinuria (pink/red urine) and red/purple stool(s)—this is a common (and comical) effect from drinking beet juice.
- Use common sense: moderation is usually always best. The health effects of a chronically high nitrate diet are unknown. Pick a few key races to target using nitrates, but revert back to your typical dietary routine in the interim periods.
- I wasn’t really serious when I mentioned a beet flavored energy gel in the title of this article….although I guess it could be done using a concentrated source. It would need to be taken as a pre-event ‘meal’ (morning of your race) to have any hopes of being effective. Contact me if you’re actually considering it and I can suggest a recipe/method.
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