CHICAGO: Alternative medicine has long touted the benefits of garlic, from its antibacterial and antifungal properties, to its positive cardiovascular effects. Now physiologists have figured out why it is so valuable.
A new study reveals that the pungent clove boosts the body’s own production of a compound which relaxes blood vessels, increases blood flow, and prevents blood clots and oxidative damage.
“This will help us standardise over-the-counter garlic supplements, and ensure they have the ingredients that produce the key compound,” said David Kraus, a physiologist at the University of Alabama in Birmingham, U.S., and lead author of the study reported in the Proceedings of the National Academy of Sciences journal.
Pieces of the puzzle
Much existing research into the pharmacological benefits of garlic has focused on the organic polysulphides that the clove is rich in – the best known of which is allicin.
But the new study suggests that allicin and similar biologically active compounds are only a piece of the puzzle – and that it’s a chemical messenger that is produced when these compounds are metabolised which is really important.
In laboratory tests, Kraus’s team at the University of Alabama found that it was this chemical messenger – hydrogen sulphide (H2S), which is essential at low levels for cellular signalling – that appears to relax blood vessels, enhancing blood flow.
The researchers conducted a series of experiments, first extracting juice from supermarket garlic and adding minute amounts to red blood cells. The cells immediately began emitting H2S.
Additional experiments showed that the key chemical reaction took place mainly at the membrane of the red blood cells, although a fraction of H2S was also produced inside the cells.
Furthermore, when the team added a section of rat aorta (an artery in the heart), to a solution containing organic polysulphides, it began to relax as it produced H2S.
The study may explain why some studies showed there were no cardiovascular benefits to be gained from taking garlic supplements while many others showed that such supplements could halt the progress of cardiovascular disease, the authors said.
“In addition, our results suggest that the capacity to produce H2S can be used to standardise garlic dietary supplements,” the authors wrote.