Leucine e
A study from Australia showed that leucine helps athletes
exercise longer (European Journal of Applied Physiology, August
2006), so now athletes are lining up to waste their money on
supplements that are no more effective than any other source of
sugar.
Leucine is a branched chain amino acid that the liver
readily converts to sugar. Your body needs extra sugar during
endurance exercise, and it doesn't care where it gets it. Your
brain gets more than 95 percent of its energy from sugar in your
bloodstream. It cannot store extra fuel in its cells. However, there
is only enough sugar in your bloodstream to last three minutes.
To prevent blood-sugar levels from dropping, your liver constantly
releases sugar from its cells into your bloodstream. There is only
enough sugar in your liver to last up to 12 hours at rest, and you
run out of liver sugar much faster than that when you exercise.
Your liver then makes sugar out of certain protein building
blocks called branched chain amino acids in a process called
gluconeogenesis. So taking leucine, a branched chain amino
acid, helps to maintain blood sugar levels, but so will eating any
source of carbohydrates. Athletes buy special concentrated
sugar gels, mineral-sugar drinks, and all sorts of expensive
exercise foods. None are any more effective in prolonging
endurance than ordinary food sources of carbohydrates such as a
soda, an orange or banana, a peanut butter and jelly sandwich, a
bagel, cookies or whatever you like.
Checked 9/29/08