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Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "

27.12.2010

Fenugreek enhances endurance

The fenugreek extracts, which have been on the market for a couple of years now, might not only be of interest to strength athletes but maybe also to endurance athletes. An examination of a Japanese study brought us to this conclusion.

Active compounds
They don't mention it in their article, but the Japanese worked for the ingredients manufacturer TSI Health Sciences. TSI Health Sciences is the maker of the fenugreek seed extract Promilin, which consists for 20 percent of 4-hydroxy isoleucine. [Structural formula shown here] There are supplements on the market that contain only Promilin, but some of the eleven readers of this web magazine will have come across Promilin in their mass gainers: protein and carb mixtures meant for weight and muscle gain. The amino acid in Promilin is supposed to boost the effect of insulin and the absorption of glucose by the muscle cells.

The 4-hydroxy isoleucine you can forget. It's not the active ingredient in fenugreek, the researchers discovered. When they gave this amino acid in pure form to lab animals it had no effect. This is backed up by the results of an experiment at the University of Montana, where the researchers gave endurance athletes glucose 4-hydroxy isoleucine from fenugreek after a training session. The amino acid had no effect on the recovery of the subjects' glycogen reserves. [Amino Acids. 2008 Aug; 35(2): 439-44.]

It's other substances than 4-hydroxy isoleucine in fenugreek that enhance performance, according to the researchers.

Endurance
The Japanese gave mice every day for 4 weeks nothing [control] [squares], 150 [triangles] or 300 mg fenugreek [circles] extract per kg bodyweight. They pumped the supplement through a tube directly into the animals' stomachs. Once a week the animals had to swim in an aquarium with a weight attached, for as long as they could. The extract lengthened the amount of time the animals kept it up.

The fenugreek had no effect on the red blood cells, as you can see below. The extract did boost the fat burning of the muscles. The glucose level hardly went down during the sessions, but the concentration of free fatty acids [NEFA] did go down. After 4 weeks the fat reserves of the mice had shrunk, as the researchers discovered when they looked at the epididymal fat pads.

Once again, the extract used had been purified in such a way that made the amount of 4-hydroxy isoleucine optimal. That extract may not be the best for enhancing endurance.

Source:
J Nutr Sci Vitaminol (Tokyo). 2006 Aug; 52(4): 287-92.

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