Should I supplement with beta-alanine?
Thursday, June 28, 2018. Author Dr. Haran Sivapalan
Thursday, June 28, 2018. Author Dr. Haran Sivapalan
Some FitnessGenes members may notice a Personal Insight advising them to consider taking a beta-alanine supplement.
So, what is beta-alanine, how does it work, and should you take it?
Unlike many other amino acids (molecules which are the building blocks of proteins), beta-alanine isn't incorporated into a much larger protein. Instead, it combines with another amino acid (histidine) to form a small but essential molecule called ‘carnosine'.
Carnosine is found in many tissues, but it is particularly abundant in skeletal muscles. Here, it plays a significant role in maintaining the pH (acidity/alkalinity) of tissue, regulating enzymes and aiding muscle contraction.
Before we explore the role of carnosine in the body, let's get back to basics. Whether you're working out or just resting, the cells in your muscles require energy to survive. They get this energy by unlocking the chemical energy stored within glucose – a process called ‘respiration'.
In the first stage of respiration (also known as ‘glycolysis), glucose is broken down into an intermediate molecule called pyruvate. During lower intensity aerobic exercise, when your muscle cells have enough oxygen, pyruvate is combined with the available oxygen to yield energy (in the form of ATP, your cells' energy currency). We call this aerobic respiration.
However, when you perform moderate to high-intensity exercise, the oxygen demands of your muscles soon outweighs the supply of oxygen, posing a dilemma for your muscle cells: in the absence of oxygen, how do your cells get energy? The answer, as you've probably guessed, is through anaerobic respiration.
During anaerobic exercise such as sprinting or weight lifting, your muscle cells convert pyruvate into another molecule, lactate.' Lactate is a useful molecule which can then be reused as an energy substrate, either by being recycled into pyruvate or made into glucose. (Note that lactate is often used interchangeably with lactic acid, but lactic acid is technically a different molecule composed of lactate and an acidic H+ ion).
Anaerobic respiration doesn't require oxygen but still yields energy for your muscles. Unfortunately, it also makes the cell environment more acidic in the process. It is this rise in acidity (rather than the rising levels of lactate) that is thought to be responsible for the ‘burning' feeling that accompanies intense muscle activity – the infamous ‘burn' of that motivational ‘feel the burn' mantra. Ultimately, this increased acidity from muscle metabolites causes muscles to fatigue, impairing their ability to contract.
It's for this reason that levels of carnosine are especially high in anaerobic, fast-twitch muscle fibers: the type generally associated with sprinters and weightlifters. Interestingly, in the animal kingdom, creatures that readily perform explosive sprints, such as greyhounds and horses, are shown to have higher levels of carnosine in their muscles.
Back in the human world, studies suggest that eight weeks of sprint training on a cycle ergometer boosts the concentration of carnosine in thigh muscles, as your body adapts to the demands of anaerobic exercise.
As previously mentioned, your body converts beta-alanine into carnosine. In theory, by consuming more beta-alanine, your muscles' levels of carnosine ought to rise. In turn, having more carnosine will enhance your muscles' ability to buffer acid, delaying muscle fatigue and allowing you to exercise longer.
Beta-alanine does seem to work.
A review of the literature by the International Society of Sports Nutrition found that taking 4-6 g of beta-alanine supplement per day increases carnosine levels by between 40 and 60% over four weeks.
And what effect does this have on exercise performance?
Beta-alanine seems to be particularly effective at enhancing performance for high-intensity anaerobic exercises lasting between 1 and 4 minutes: sprint running, sprint cycling, weightlifting, short distance rowing, to name a few.
As hypothesized, the primary benefit of supplementation seems to be an extended time to muscle exhaustion, allowing individuals to work at high-intensity for longer. For example, one study showed that those supplementing with beta-alanine could cycle at high-intensity (110% of their maximal power output) for 13-14% longer before their muscles fatigued. Couched in slightly different terms, we can say that beta-alanine improves muscular endurance.
While the benefits for short-duration, high-intensity exercise are well founded, the effects of beta-alanine supplementation on longer, aerobic activities are less clear-cut. One study reported a modest increase in rowing speed over a 2,000m time trial.
When it comes to endurance activities that are longer than 25 minutes, however, there doesn't seem to be any substantial evidence that beta-alanine will help. So, if you're training for a marathon or an Ironman triathlon, don't expect to see massive direct benefits from taking this supplement.
We're not all the same, and due to our differing genetic make-ups, some people are likely to reap more benefits from supplementing with beta-alanine than others.
Individuals with the ‘slow lactate clearing' version of the MCT1 gene, for example, may be more susceptible to muscle fatigue, as they are slower to clear and recycle lactate as an energy substrate. Such people therefore particularly stand to benefit from supplementing with beta-alanine.
Our baseline levels of carnosine also vary from person to person. Typically, men have more carnosine than women. As carnosine is more concentrated in fast-twitch muscle fibers, those with a more significant proportion of fast twitch muscle fibers will also have higher baseline levels of carnosine. To this end, genes that affect your muscle-fiber proportions, such as your ACE gene, will also influence your requirement for beta-alanine.
FitnessGenes recommend that, depending on your gene results, you take up to 1.5g of beta-alanine up to 4 times per day, which is congruent with the research studies showing a beneficial effect of 4-6 grams per day.
Beta-alanine has been known to cause numbness and tingling (‘paresthesia') as a side-effect. This potential side-effect is short-lived (if it occurs) and can be overcome by gradually increasing your dosage over time, which is why we recommend starting off with a lower dose of 1.5g twice a day. Alternatively, you can take sustained-release supplements.