Pre-workout supplementation with tea or cacao may lead to a higher concentration of the anabolic hormone testosterone in the body, and as a result a little bit more muscle growth. We base this bold statement on a test-tube study that researchers at Kingston University in London will soon publish in Steroids.
Painkillers such as diclofenac and ibuprofen inhibit the enzyme UGT2B17, which attaches sugar molecules to testosterone, thereby neutralising its effect. In this way these two painkillers can help boost the testosterone level for a short time, which we wrote about a couple of days ago.
And what diclofenac and ibuprofen can do, can probably also be done by substances found in food, suspect the Brits. Polyphenols such as epicatechin [structural formula below left], a substance found in cacao and green and white tea, and EGCG [structural formula below right], a compound found in green and white tea, inhibit lots of enzymes, so why not UGT2B17?
Besides, the concentration of these phenols can rise to high levels in normal human bodies. If you drink seven cups of green tea a day you can have as much as 21.2 nanomoles per litre of the tea flavonoid EGCG in your blood. [J Am Coll Nutr. 2005 Oct; 24(5): 342-6.] That is of the same order as the concentration of testosterone in the body of an adult man.
According to a 2002 study done at the State University of New Jersey, the concentration of phenols such as epigallocatechin-3-gallate (EGCG), epigallocatechin (EGC) and epicatechin (EC) reaches maximum levels 1-2 hours after consuming a green-tea extract. [Cancer Epidemiol Biomarkers Prev. 2002 Oct; 11(10 Pt 1): 1025-32.] The levels are so high that they must have an effect on enzymes.
The Brits decided to test it out. They bought dragon beard white tea (WT), Yunnan white tea leaf (WTL), sencha Japanese green tea bags (GT) and white tea powder (WTP).
The last mentioned product was from Burgundy Botanical Extracts, and was an extract intended for cosmetic use. [burgundy-extracts.com] The researchers bought the other products in an ordinary shop. They put 1.6 g tea in 80 ml boiling water, filtered out the leaves and used the cooled down tea for their trials.
In test tubes both the tea that the researchers had brewed and the extract inhibited the glycosylation of testosterone by UGT2B17. The white tea extract in particular worked well.
When the researchers examined some tea phenols separately, they discovered that EGCG was the strongest UGT2B17 inhibitor. EGCG performed as well as the anti-inflammatory diclofenac in the study we described a few days ago.
"A wider assessment of foodstuffs and their constituents for inhibitory activity against UGT enzymes is warranted", the Brits conclude.
A 'wider assessment' could be of considerable interest to natural athletes, as it would help give an idea of what an optimal pre-workout diet should consist of. There are indications that a heightened testosterone level during and after training results in more progression.
Steroids. 2012 May;77(6):691-5.