Tag Archives: beetroot juice

Does beetroot juice work for you?

Drinking beetroot juice before a race has become very popular, as it can make you go faster. However, a new study suggests that beetroot juice will not help you if you are already very fit.2631746551_ba1338f5b7

Studies have shown that a single intake or a short term (3-6 days) supplementation of beetroot juice shortens your time on a time-trial event and allows you to tolerate high intensity exercise much better. This is because beetroot contains nitrates (NO3-).

Your body absorbs NO3- and secretes it into your saliva, where your mouth bacteria transform it into NO2-, which is then taken up by your stomach as you swallow. (That is why beetroot has no effect if you use antibacterial mouthwashes.) NO2- becomes NO in tissues which are in need of oxygen, such as working muscles.

NO dilates blood vessels and makes your body more efficient at using oxygen to produce energy. It also improves the contractibility of your muscle fibres.
This is great news, not only for athletes, but also for the elderly who have a reduced aerobic capacity, and for people suffering from hypertension as it will lower their blood pressure.
However, there is a problem. Most studies showing a benefit have been done on sedentary or moderately fit people. Studies on elite athletes on the other hand, are rather disappointing.

To try to understand this better, Simone Porcelli and her colleagues have studied the effect of beetroot juice on 21 young men of different aerobic fitness levels. The VO2 max values of the participants ranged from 28.2 ml/kg/min (sedentary people) to 81.7 ml/kg/min (elite level).
The researchers tested their fitness by a run to exhaustion, a series of 6-min sub-maximal runs on the treadmill, and a 3 km time trial. All the participants performed the tests twice, once after taking 500 ml/day beetroot juice for 6 days and once after drinking the same amount of a placebo for the same time.

There was an inverse relationship between the VO2max of the participants and the benefits of taking beetroot juice. In other words: the participants with the highest VO2max showed the least benefits, while those with the lowest VO2max benefitted most. The researchers also measured the blood levels of NO3- and NO2- of the participants, and noted that the fitter ones showed a smaller increase after drinking beetroot juice.

These results are not easy to explain, and Simone Porcelli and her colleagues have come up with 3 possibilities:

1) NO2- is mainly transformed into NO when tissues need oxygen. Elite athletes will have more blood vessels in their muscles due to many years of training, and it is therefore possible that the right conditions to form NO happen only rarely.

2) Athletes might take in much more nitrates with their normal diets, as they are likely to eat more than sedentary people. In this case the supplements would not matter anymore, and could just end up in their urine. Unfortunately, the researchers did not check the urine levels.

3) Our bodies can also make NO via a completely different pathway, without the need of any dietary NO3-. It is possible that many years of training have optimised this system and fine-tuned the athletes’ metabolism, making nitrate supplements superfluous.

The researchers noticed a higher NO3- and NO2- blood level in the fittest participants before taking any juice, which makes one of the two last possibilities (or both) more likely than the first one.

Whatever the reasons, if beetroot juice does not work for you, you should be happy!

photo credit: <a href=”http://www.flickr.com/photos/24987280@N00/2631746551″>Beetroot</a&gt; via <a href=”http://photopin.com”>photopin</a&gt; <a href=”https://creativecommons.org/licenses/by-sa/2.0/”>(license)</a&gt;

 

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Is drinking beetroot juice helpful for runners and cyclists?

The beetroot, also known as the table beet, ga...
The beetroot, also known as the table beet, garden beet, red beet or informally simply as beet, is one of the many cultivated varieties of beets (Beta vulgaris) and arguably the most commonly encountered variety in North America and Britain. (Photo credit: Wikipedia)

Drinking beetroot juice has become very popular between runners and cyclists. It might indeed be the right thing to do, because it contains dietary nitrate, which can reduce the oxygen cost of exercise. Whenever you want to produce power, you need oxygen, and if you need to go harder you need more oxygen.   If your body can produce the same power with less oxygen, you have the possibility to go faster and longer.

Scientists have therefore wondered if consuming nitrate-rich food, such as beetroot and leafy green vegetables, could help competitors, and in 2009 a study showed indeed that drinking 0.5l of beetroot juice reduced the oxygen cost by 20%. This is phenomenal, and it sparked a real rage.

However, the initial results were obtained in volunteers who ate a nitrate-free diet, and in 2010 the same group demonstrated that people who had a normal Western diet decreased the cost “only” by 5%.

Our normal diet does not contain that many nitrate rich vegetables, and the whole story reminds me of vitamins and minerals: if you have a real deficiency, a boost will help you, but if not, you are much better off with a healthy diet. If this is the case here as well, could we obtain the same effect by changing slightly the kind of vegetables we eat? That would be the safest, cheapest and easiest solution.

To make matters even more complicated, a recent study could not notice any improvement in elite athletes.

Would this mean that as you get fitter and/or exercise more, dietary nitrate becomes less beneficial? Or is the other way around, and would very fit athletes need more to see an effect?

There are many more questions, such as: should we take it during training as well, so that we can work harder and therefore (hopefully) perform better at races? Or is it better to train without it to make our bodies used to work hard without help, and only take it during the last week before a race?

The most important question is probably this: could it reduce the benefits we get from exercise in the long-term?

As long as these questions are not answered, I will not spend my money on beetroot juice, but I am going to eat more nitrate-containing vegetables all year round…

Does anybody have experience with this?

If you want more details about the effects of beetroot juice, you can read my article in Suite 101.