Evidence, Benefits, Dosage, Side Effects
Beta alanine it is an non-essential amino acid that is not used by the body to build proteins. It is more importantly a precursor to carnosine, an important intramuscular dipeptide with a role during muscle contraction and activity. It has gained much interest in the recent decade and has been extensively studied by the medical community.
WHERE IS BETA ALANINE NATURALLY FOUND?
Beta alanine is normally present in the human body and can be consumed with food. Meats are an excellent source, where it is stored in the form of carnosine or anserine.
Pork has been found to have the highest amount of carnosine (250 mg in 100 grams/3.5 oz. of meat), followed by beef, chicken and fish meat. However, the highest blood concentration was measured after ingestion of chicken broth, followed by beef and chicken.[1,2] After digestion, both carnosine and anserine are digested by the gut, where they release beta alanine. Since meats are the main source, vegetarians and vegans have been found to have lower levels of beta alanine and carnosine.
HOW DOES BETA ALANINE WORK?
Carnosine is composed of and synthesized from two amino acids – beta alanine and L-histidine. The human body normally has L-histidine in abundance. On the other hand, beta alanine is the rate-limiting factor in synthesis of carnosine. Simply, its availability determines how much carnosine the muscles will synthesize; the greater the availability of it, the more carnosine is synthesized. It primarily works by increasing the muscle content of carnosine; it is not an amino acid that is incorporated into muscle proteins.
Why is carnosine important?
Exercising muscle utilize energy, which requires constant production and supply of energy. Under aerobic conditions, most of energy is produced by burning carbohydrates and/or fats; the end products of this process, known as oxidation, are carbon dioxide, water and energy. During high-intensity exercise, however, anaerobic metabolism predominates; anaerobic breakdown of carbohydrates – glucose, results in release of lactate and hydrogen ions. Accumulation of hydrogen ions drops muscle pH and an acidic environment in muscle occurs that has been associated with reduced muscle contractile force and muscle fatigue.[5,6]
Initially, muscle cells prevent a rapid fall in pH and therefore an acidic environment by the use of buffers, specific molecules that bind hydrogen ions. With an increased influx of hydrogen ions, the buffer capacity of cells soon becomes exhausted and accumulation ensues, dropping the pH value. Carnosine is an important muscular buffer. An increased muscle carnosine concentration means more buffer and greater buffer capacity of muscles, delaying muscle fatigue and improving muscle contractility during high-intensivity exercise.[5,6,7]
Studies have found that animals that naturally perform a lot of high-intensity exercise have much higher concentration of muscle carnosine. Measured amount among various species:
micrograms per gram of dry muscle tissue
|Greyhound dog|| |
Deep sea divers, who depend heavily on anaerobic metabolism during their activity, have similarly been found to have elevated levels of muscle carnosine thatn the general population.[8-12]
HAS BETA ALANINE BEEN TESTED ON HUMANS?
Over 20 clinical studies have evaluated beta alanine.
Studies have repeteadly shown that oral consumption of beta alanine supplements increases muscle carnosine levels. Human volunteers had a small piece of their muscles taken (a biopsy) prior and after weeks of beta alanine supplementation. It has been observed that muscle carnosine levels were increasing beyond 10 weeks of supplementation. Some authors believe there is no upper limit on how much carnosine the muscles can synthesize. The plot presents the average increase in human muscle carnosine concentration following two different beta alanine protocols as percentage of initial value.[6,13,14]
There can be little doubt that beta alanine supplement increases muscle carnosine levels and supplementation has been found to increase carnosine levels despite lack of training. On the other hand, it is still debated whether training alone (without beta alanine supplementation) can increase carnosine leveles to any significnat levels.
Does That Have Any Effect on Athletic Capabilities and Body Composition?
An interesting study studied beta-alanine in young wrestlers and football players. Twenty-two college wrestlers and fifteen college football players were randomly assigned to receive beta alanine (4 grams a day) or an equivalent placebo capsule for eight weeks. During the eight weeks, test subjects were exposed to high-intensity interval, repeated sprint, and resistance training and performance between athletes on the supplement and placebo was compared. This study had a low number of participants, hence it is difficult to draw statistical significance from the data. Nonetheless, compared to those on placebo, beta alanine improved 300-yd running time and flexed-arm hang, but the improvement was small. Also, athletes were evaluated for body composition and supplementation with beta alanine proved superior on placebo. All wrestlers lost total body weight, but on average, wrestlers on the supplement gained 1,1 lb of lean mass; wrestlers on placebo lost 0,98 lb of lean of mass (that is almost a 2 lb lean mass difference). Football players experienced gain in both total body weight and lean mass, regardless if they were taking beta alanine or placebo; however, football players on the supplement experienced on average a 2,1 lb lean mass increase, whereas 1,1 lb mass increase was observed among those on placebo. Again, it is difficult to draw any significance on such a small number of test subjects and such studies do have a low statistical power; however, a trend towards better body composition and athletic capability improvement can be discerned.
Two additional studies evaluated the effects of beta alanine on body composition. Both showed a significant increase in lean mass;[15,17] one of these additionally showed a decrease in body fat.
Another study evaluated the effects of beta alanine on carnosine muscle concentration and athletic performance in cyclists. They were assigned to receive the supplement, starting dose was 4 grams a day and then gradually increased to 6.4 grams daily, or a placebo for either 4 or 10 weeks. Muscle biopsies were performed to exactly measure muscle carnosine concentration; muscle carnosine increased on average by 59% and 80% after 4 and 10 weeks beta-alanine supplementation, respectively. There was no increase in muscle carnosine among cyclists on placebo. More importantly, cycling capacity improved 13% after 4 weeks of supplementation; a 3.2% further increase was seen by 10 weeks. Cyclists on placebo experienced no improvement.
Beta alanine supplements have been shown to increase performance in numerous other trials. On the other hand, it has proven inefficacious in sprinters, an activity that requires high muscular work output within a very limited amount of time.[4,18]
How useful is Beta Alanine?
There seems to be a discrepancy between how much of an improvement can be achieved, since studies’ report vary from negligible and up to 16%. The discrepancy is probably due to type of exercise included and dosage; studies using higher doses were able to achieve better results and reported improvements on the higher spectrum. According who Hobson et al, who analyzed 18 separated published studies with various dosage and training protocols, they calculated that beta alanine supplement would, on average, improve running time in a 1500 m race for about 6 seconds; in percentages, it is wise to expect anything from minimal up to 10% increase, again, depending on your training and dosage.
Beta alanine proves most efficient in short-duration high-intensity exercise, such as weight-lifting, running, cycling. It exerts most potent effects for activity that is 60 to 240 seconds in duration; it is still effective for activity above 240 seconds. However, it does not appear to offer any advantages for exercises that are of very short duration, below 60 seconds, such as sprinting.