Pomegranate reduces cortisol by a third
Pomegranate reduces the amount of the stress hormone cortisol in the body. This increases insulin sensitivity and, as a result, blood pressure decreases. English nutritionists at Queen Margaret University wrote about this in the Journal of Nutritional Science. The researchers studied people who drank half a litre of pomegranate juice daily.
The researchers got 28 overweight people to drink half a litre of pomegranate juice every day for four weeks. They used Pomegreat Pure, manufactured by RJA Foods. RJA Foods funded the study. On another occasion the researchers gave the participants a placebo for four weeks.
Half a litre of Pomegreat contains about 850 milligrams of pomegranate phenols. If you don't fancy drinking half a litre of juice every day you can also take a supplement containing the same amount of phenols.
For more information on the active ingredients in pomegranate juice click here and here.
After four weeks of drinking pomegranate juice the researchers found a third less cortisol in the participants' urine.
At the end of the supplementation period [Post PJ], the ratio of cortisol:cortisone had gone down in the participants' urine [grey bars] and in their saliva [striped bars]. This would seem to suggest that pomegranate inhibits the enzyme 11-beta-hydroxysteroid dehydrogenase type 1-beta. This enzyme converts relatively inactive cortisone into active cortisol.
Pomegranate juice lowered the participants' systolic [SBP] and diastolic blood pressure [DBP]. "The drop in SBP was from 0.5 to 22 mmHg and the drop in DBP was from 0 to 12 mmHg," the researchers wrote. "Those with higher baseline BP had the most marked drop in their BP following pomegranate juice consumption."
Drinking pomegranate juice lowered the basal insulin level of the participants, probably because their cells became more sensitive to insulin. At least, their HOMA-IR, a measurement of insulin resistance, decreased.
The increase in insulin sensitivity and the lower blood pressure were to a large extent a consequence of the lower cortisol levels, according to the researchers.
"These results suggest that pomegranate juice consumption can alleviate key cardiovascular risk factors in overweight and obese subjects that might be due to a reduction in both systolic and diastolic blood pressure, possibly through the inhibition of 11-beta-hydroxysteroid dehydrogenase type 1 enzyme activity as evidenced by the reduction in the cortisol/cortisone-ratio," the researchers summarised. "The reduction in insulin resistance might have therapeutic benefits for patients with non-insulin-dependent diabetes, obesity and the metabolic syndrome."
The participants did not lose weight as a result of drinking pomegranate juice. But the researchers did write, "however, we did observe a trend towards a reduction in waist circumference and plasma non-esterified fatty acids in some of our subjects."
J Nutr Sci. 2012 Aug 31;1:e9.
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