Beer benefits variably

[Guest guest]

Hi All,

Beer drinking appears to confer different benefits relative to other alcoholic

drinks, since it is uniquely prepared using hops for of yeast for fermentation.

Benefits for some individuals may be greater than previously thought to be the

case.

See the related not pdf-accessible below.

Activation of Proestrogens from Hops (Humulus lupulus L.) by Intestinal

Microbiota;

Conversion of Isoxanthohumol into 8-Prenylnaringenin

Sam Possemiers, Arne Heyerick, Veerle Robbens, Denis De Keukeleire, and Willy

Verstraete

J. Agric. Food Chem., ASAP Article 10.1021/jf0509714 S0021-8561(05)00971-4. Web

Release Date: July 16, 2005

Hop, an essential ingredient in most beers, contains a number of

prenylflavonoids,

among which 8-prenylnaringenin (8-PN) would be the most potent phytoestrogen

currently known. Although a number of health effects are attributed to these

compounds, only a few reports are available about the bioavailability of

prenylflavonoids and the transformation potency of the intestinal microbial

community. To test these transformations, four fecal samples were incubated with

xanthohumol, isoxanthohumol (IX), and 8-PN. Upon incubation with IX, present in

strong ales up to 4 mg/L, 36% was converted into 8-PN in one fecal sample and

the

estrogenic properties of the sample drastically increased. In an experiment with

12

fecal cultures, this conversion was observed in one-third of the samples,

indicating

the importance of interindividual variability in the intestinal microbial

community.

Eubacterium limosum was identified to be capable of this conversion

(O-demethylation) of IX into 8-PN, and after strain selection, a conversion

efficiency of 90% was achieved. Finally, strain supplementation to a

nonconverting

fecal sample led to rapid and high 8-PN production at only 1% (v/v) addition. Up

to

now, the concentration of 8-PN in beer was considered too low to affect human

health. However, these results show that the activity of the intestinal

microbial

community could more than 10-fold increase the exposure concentration. Because

prenylflavonoids are present in many beers with IX being the major constituent,

the

results raise the question whether moderate beer consumption might contribute to

increased in vivo levels of 8-PN and even influence human health.

Al Pater, PhD; email: old542000@...

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