What’s the deal with beet juice? It’s being used as an all natural exercise supplement over recent years, but why?
Beet juice is a great pre-workout drink because it’s ability to enhance oxygen flow to the muscles translates to enhanced fuel utilization through aerobic metabolism (which requires oxygen to break down food into energy that can be used by the body). Enhanced fuel utilization may delay feelings of fatigue, as well as lactic acid buildup (the burning sensation often felt during exercise as a result of anaerobic metabolism), which can lead to stronger workouts.
Nitrate can be converted to nitrite by bacteria located in saliva via the enzymes called nitrate reductases. Nitrite can then be reduced to nitric oxide (NO) by a variety of enzymes, which remain to be the subject of study (and still remain controversial). NO then enhances vasodilation (widening of blood vessels) through signaling via soluble guanylate cyclase, which ultimately allows for increased blood flow and increased oxygen and nutrient delivery to muscles. It should be noted that the existence of oral bacteria is essential for this conversion to occur, and so the use of antibacterial dental products (such as mouthwash or antibacterial gum) is not recommended directly before consuming nitrate-rich foods and beverages.
How do beets (and other veggies) get their nitrates?
While plants may receive small amounts of nitrates from the air and water, the majority of nitrates are usually delivered to the plant from soil. Specifically, nitrogenous sources in the soil can be converted to ammonia, which can then be converted to nitrates by bacteria. The plant can then absorb the nitrates to use for development and growth. High-nitrogen soils now exist in order to enhance nitrate absorption by the plant. Since the majority of nitrates used by the plant come from the soil, fruits and vegetables that grow in the ground (like beets!) generally contain a higher amount of nitrates.
I thought nitrates were bad for me? I’m told to avoid them in meat…
The difference between nitrates in processed meats and those found in fruits and vegetables has to do with other existing compounds in the food. Nitrates can be converted to small amounts of nitrosamines (carcinogenic compounds) in the presence of protein and heat (>300oF). However, fruits and vegetables do not contain the amounts of protein required for this reaction to occur. Additionally, veggies can also be consumed raw, meaning heat is not present, either. Regardless, both protein and heat are required for nitrosamines to form, so nitrates in fruits and veggies are safe.
So how do I use beet juice to my benefit?
Beet juice is generally used as an ergogenic aid (or an exercise supplement) prior to aerobic exercise (running, biking, etc.). Ideally, beet juice should be consumed about 15-30 minutes before the event (whether it is a race or training). This allows time for vasodilation to occur throughout the beginning of the exercise. Always remember to check regulations of your sport if this is not for recreation, to ensure that beet juice is allowed. Also, remember that consumption of beet juice does not guarantee an improvement in training or time – rather, the literature to date suggests that it may benefit the production of nitric oxide, which in turn could promote vasodilation and may lead to less fatigue during a workout.
*beet photo courtesy of: http://www.elizabethrider.com/wp-content/uploads/2013/09/benefits-of-beets.jpg