A Feast of Science by Joe Schwarcz

Author:Joe Schwarcz
Language: eng
Format: epub
Publisher: ECW Press
Published: 2018-04-27T04:00:00+00:00

Hops, Beer, and Estrogen

Is there any food or beverage that is not the subject of some scare? Coffee has acrylamide, bread has gluten, hamburgers have polycyclic aromatics, colas have methylimidazole, peanuts have aflatoxins. It’s enough to drive you to drink. But there are issues here as well. Hops in beer harbor 8-prenylnaringenin, one of the most potent plant-derived estrogens ever discovered. Estrogenicity can be determined by seeing how strongly a suspect compound binds to estrogen receptors in the uterus of the rat, and 8-prenylnaringenin binds very strongly. This is why hops are often found in dietary supplements that are claimed to enhance breast size.

The theory behind the breast enlargement claim is that the female hormone estrogen is responsible for the so-called secondary sex characteristics, namely the features that first appear during puberty and distinguish men from women. Development of breasts is an obvious example. Indeed, transgender procedures that require feminization always include the administration of estrogen for breast development. But in women, there is no evidence that breast size is determined by circulating estrogen, and no reputable studies have ever shown that breast enlargement supplements work.

However, this does not mean that phytoestrogens in beer are devoid of any physiological activity. The flowers of the hop plant, Humulus lupulus, have been used since about the ninth century to give beer its characteristic bitter flavor and to keep it from spoiling. Hops do not interfere with the activity of brewer’s yeast but have an antimicrobial effect on other undesirable microbes. Until the advent of picking machines, hops were gathered by hand, often by women. Historical anecdotes claim that the menstrual cycles of these women were altered by the handling of hops.

There are also stories about beer-drinking men not being able to rise to the occasion with the ladies when required because they were afflicted by “Brewer’s Droop.” As if that weren’t enough, there are also allegations that drinking beer results in “man boobs.” Neither the menstrual problems nor the effects on men have been confirmed by studies, so they remain anecdotes. Beer, however, can add a lot of calories to the diet, resulting in the classic beer belly and excess adipose tissue around the chest, but this is not a hormonal effect. Also, it is known that excessive alcohol consumption can lead to erectile dysfunction, an effect that has nothing to do with hops.

Arguments that beer cannot have a significant hormonal effect are usually buttressed by referring to the amount of 8-prenylnaringenin that is detected in beer. Or better said, not detected. Most beers do not contain any detectable level of this phytoestrogen, but there is still a niggling little issue. Our gut contains trillions of bacteria, part of the human microbiome, that are capable of carrying out a variety of chemical transformations. One of these is the conversion of another compound found in beer, isoxanthohumol, into the estrogenic 8-prenylnaringenin. So while this compound may not be present in beer, it can form in the body after beer is consumed, meaning that we are not home free when it comes to dismissing any estrogenic effect that beer may have.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.