Beer contains a powerful chemical that can prevent breast cancer, according to new research.
Found in hops, the flower cones used in brewing, it absorbs the toxins that cause the disease.
In herbal medicine hops are used to treat arthritis, insomnia, diabetes and menopausal symptoms.
Although findings from lab experiments and animal research indicate they may possess a number of benefits, few studies have tested their potential to boost human health.
Now lab tests have suggested an extract from the plant could also help fend off breast cancer, which strikes down 50,000 British women a year and will affect one in eight in their lifetime.
In experiments the plant oestrogen called 6-PN (6-prenylnaringenin) “detoxified” two different lines of breast cells.
Previous studies have shown breast cancer can be caused by a build up of toxins.
Professor Judy Bolton, of the University of Illinois in the US, said: “Hops are a popular botanical dietary supplement used by women as a sleep aid and for postmenopausal symptom relief.
“In addition to its efficacy for menopausal symptoms, hops can also modulate the chemical oestrogen carcinogenesis pathway and potentially protect women from breast cancer.”
She added the results, published in the journal Chemical Research in Toxicology, suggest 6-PN could have anti cancer effects, although more studies would be needed to further investigate the possibility.
Exposure to oestrogen has long been considered one of the risk factors associated with developing breast cancer, particularly in post menopausal women.
Women who are undergoing menopause often use HRT (hormone replacement therapy) to alleviate symptoms such as hot flushes. But HRT has been linked to an increased risk of breast cancer and heart disease, so some women are turning to hops supplements, which contain plant ooestrogens, as a natural alternative.
But their effect on cancer risk has been unclear, although preliminary lab studies have suggested certain active compounds from hops could have protective properties.
Prof Bolton added her results, published in Chemical Research in Toxicology, suggest 6-PN could have anti cancer effects, although more studies would be needed to further investigate the possibility.
Hops give beer its bitter flavour, so traditional bitters and ales will contain far more than light lagers.
Drinks such as Guinness owe their dark colour to malt and contain moderate levels of hops. Alcohol Concern warns you should only drink beer within recommended limits – two to three units a day for women, and three to four for men.