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01.07.2013


Hesperetin is an anti-oestrogen

Aromatase
Hesperetin is a flavonoid found in citrus fruits especially in the peel. Nutritionists at the Chinese University of Hong Kong have discovered that the compound reduces the effect of the enzyme aromatase, and therefore also the conversion of testosterone into estradiol. To do this you need a high dose, but luckily the Chinese discovered a couple of other common flavonoids that have a stronger anti-oestrogenic effect.

Flavonoids inhibit the working of enzymes. Which enzyme they affect depends on the structure of the flavonoid. Because our food contains lots of flavonoids, which you can ingest in daily doses of hundreds of milligrams without problems, nutritionists and supplements manufacturers are very interested in this group of compounds. This is because there are a few enzymes in our body that we'd be happier about if they were a little less effective.

Aromatase is one of these enzymes. For women with a high risk of breast cancer, but also for some cosmetic athletes, a supplement or 'superfood' capable of inhibiting aromatase would be a godsend.

The researchers studied three candidate compounds that manufacturers might be able to put into a natural aromatase inhibitor: hesperetin [HSP], naringenin [NGN] [found in citrus fruits] en apigenin [APG] [found in parsley].


Hesperetin

Naringenin

Apigenin


When the researchers mixed aromatase-producing breast cancer cells in a test tube with different concentrations of hesperetin, naringenin and apigenin, they observed that all three flavonoids were capable of inhibiting aromatase production. Hesperetin was the least effective and apigenin the most.

The researchers then implanted breast cancer cells in mice. To stimulate the growth of the cells, most of the mice were given an androstenedione [AD] injection every other day. Androstenedione is a testosterone precursor, which converts as easily as testosterone into estradiol.

In the mice that were given food containing 5000 mg flavonoids per kg the tumours grew less fast. Hesperetin in particular was a good tumour inhibitor, which is why the researchers concentrated on this substance in their study.


Hesperetin is an anti-oestrogen


Hesperetin is a flavonoid found in citrus fruits  especially in the peel. Nutritionists at the Chinese University of Hong Kong have discovered that the compound reduces the effect of the enzyme aromatase, and therefore also the conversion of testosterone into estradiol. To do this you need a high dose, but luckily the Chinese discovered a couple of other common flavonoids that have a stronger anti-oestrogenic effect.


Hesperetin is a flavonoid found in citrus fruits  especially in the peel. Nutritionists at the Chinese University of Hong Kong have discovered that the compound reduces the effect of the enzyme aromatase, and therefore also the conversion of testosterone into estradiol. To do this you need a high dose, but luckily the Chinese discovered a couple of other common flavonoids that have a stronger anti-oestrogenic effect.



The mice that received hesperetin in their food had a lower concentration of estradiol in their blood. Food containing 1 mg hesperetin per kg worked just as well as food containing 5 mg per kg.

If you convert these figures for humans, then they would need about one and a half grams of hesperetin daily to reduce their estradiol level. That's quite a lot.

How much apigenin would be needed to achieve the same effect?

Source:
J Nutr Biochem. 2012 Oct;23(10):1230-7.

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