When we think about nutrition for cycling, we’re often concerned with fuelling long, endurance rides that last for several hours. But, what about the shorter stuff? What do we need to eat to put the hammer down and sprint out of the saddle for a few seconds?
Regardless of whether you’re more of a climber, audax rider or downhill mountain biker, there’ll probably be times when you need to exert maximum effort for short spurts. One key nutrient we need to fuel these efforts is betaine. Originally discovered in sugar beets, betaine is a molecule that is used in the production of creatine – an important energy source for intense exercise lasting under 10 seconds.
The body is capable of making betaine itself (from choline), but we can also obtain betaine from our diet, with foods such as shrimp, wheat bran, spinach and quinoa being particularly rich sources. The amount of betaine we need in our diet, however, varies from person to person, with our genetics playing a large role here.
Why do I need betaine?
Betaine is responsible for an important stage in a series of metabolic reactions called the methionine cycle. Without wanting to get too bogged down in complex biochemistry, betaine helps in three main ways:
- It reduces levels of homocysteine – a molecule linked to cardiovascular disease.
- It is needed to replenish supplies of methionine – an amino acid needed for building various proteins in the body.
- It helps produce SAM (S-adenosylmethionine) - a key molecule needed to make proteins and neurotransmitters, switch genes ‘on’ and ‘off’, and produce the fuel source creatine (which we’ll talk about in the next section).
Aside from the above, betaine also allows cells to stay well hydrated and maintain their volume and structure. This is particularly important for our muscle cells, which are liable to damage from changes in volume caused by intense exercise.
How does betaine help my cycling?
In order to contract, our muscles require chemical energy in the form of a molecule called ATP (adenosine tri-phosphate). Muscle fibers actually have small stores of ATP, but this is typically only enough to fuel 1 – 2 seconds of intense exercise. If we want to go on longer than this, we’ll need to generate more ATP. We can do this by breaking down glucose either with (aerobic-) or without oxygen (anaerobic respiration), but this takes time. This is where betaine comes in.
Betaine (via the production of SAM) is used to make molecules called creatine and phosphocreatine. These are both central players in an energy system called the phosphagen energy system, which rapidly provides us with ATP for a further 5 – 8 seconds of intense exercise.
We make use of this energy system during short (10 seconds of less) hill sprints, intervals, and attacks off the peloton.
Moreover, when we recover from a short, sharp effort, the phosphagen energy system is quickly replenished (taking about 3-5 minutes to fully rebuild stores of phosphocreatine), allowing us to sprint off again. So, both our ability to sprint and recover from sprinting rely upon an effective phosphagen energy system, which, in turn, requires that we consume enough betaine.
On this note, one study found that consuming a sports drink containing 2.5 g betaine daily (over a week), led to significant improvements in power output during 12-second sprint cycling bouts.
Why do my genetics matter?
Some gene variants can reduce betaine production, while others can increase the rate at which our bodies use up betaine. If you carry these gene variants, you may need to up your betaine intake. An inadequate intake of betaine can impoverish your cardiovascular and liver health, and is likely be detrimental to your performance on the bike.
As we constantly look to get the most out of our athletes, knowing the levels of betaine in the body is vital. Being able to understand the level of betaine we need to add into our diet is something that will help many athletes exceed in their training sessions. With the help from our nutritionists, we can monitor what food will provide the best results to match the individuals training plan.
This blog comes courtesy of Dr. Haran Sivapalan, Science Writer at FitnessGenes, with input from the Jake Yarranton, Spokes coach, for the ‘Coaching Perspective’.
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