Hops extracts have not been shown to have anticancer effects in humans.
Hops are traditionally used in beer brewing as flavoring agents. Studies done in laboratory and in animals have shown that hops extract has anticancer effects. It has not been studied in cancer patients. Human studies with hops indicate benefits for patients with type-2 diabetes, osteoarthritis, and insomnia. Hops extracts have been used to reduce hot flashes in menopausal women. Because they have estrogenic effects, women with hormone-sensitive cancers should avoid hops.
When used in combination with rosemary leaf and oleanolic acid, hops extract reduced pain in patients with osteoarthritis. More studies are needed.
When used in combination with valerian, hops extracts improved sleep in patients with mild insomnia. More data are needed.
Hops extract decreased hot flashes in menopausal women but further studies are warranted.
In a small study, hops extract lowered blood glucose and improved insulin sensitivity in patients with type-2 diabetes. Larger studies are required to confirm such effects.
Hops are the female inflorescences of the plant Humulus lupulus L. They are used primarily in beer brewing to add bitterness and flavor. Hops is also used as an herbal medicine for mood disturbance and insomnia (1) and to treat menopausal symptoms. In vitro studies have shown that hops has chemopreventive (2), (3), (4) antitumor (5), antiangiogenic (6), anti-inflammatory (19) and antidiabetic (7) properties. Hops also reduces hyperlipidemia (8) and obesity (9) in mice.
In human studies, a hops-valerian combination product improved sleep quality (10)(16), and insulin sensitivity in patients with type-2 diabetes (7). Data from an observational study suggest benefits of a combination of hops, rosemary extract and oleanolic acid in reducing arthritic pain (11). However, it is not clear whether hops alone would exert similar effects.
A hops extract was shown to alleviate menopausal symptoms (13)(17), and may improve bone health (18) in postmenopausal women. Some studies also indicate that derivates of hops have phytoestrogenic effects (7)(12). Until more research is done, patients with hormone-sensitive cancers should avoid it.
Female inflorescences of Humulus lupulus L.
Isomerized hops extracts (IHEs) increase plasma HDL levels and decrease atherosclerosis index (AI) in mice on high fat, high cholesterol diet via PPAR-alpha activation (14). These extracts also reduced plasma triglyceride levels and induced hepatomegaly (8). Other studies show IHE rich in isohumulone can inhibit PGE2 production and reduce the formation aberrant crypt foci in the colon of mice. Xanthohumol, a flavonoid from hop exhibits antiangiogenic effect by inhibiting the NF-kB and Akt pathway (6). A product containing hops extract reduces levels of C-reactive protein in patients with inflammatory diseases (12).
Prenyl flavonoids from hops, xanthohumol, isoxanthohumol, and 8-prenylnaringen (8-PN) inhibit aromatase activity and breast cancer cell proliferation, and increase breast cancer cell apoptosis in vitro (5). They also inhibit prostate cancer cell proliferation in vitro (3). However, isoxanthohumols are converted in the distal human gut into the phytoestrogen 8-prenylnaringen (8-PN) via the action of intestinal microflora (12). This process also occurs in the liver and is regulated by the cytochrome P450 enzymes (15).
Patients with hormone-sensitive cancer should avoid hops extracts due to their phytoestrogenic effects (7)(12).
Cytochrome P450 substrates: Drugs that induce CYP1A2 may increase the estrogenic effect of hops extracts (15).
Paracetamol (Acetaminophen): Some hops species may slow clearance of paracetamol, thereby increasing its analgesic effects (20).
Isomerized hops extracts (IHEs) may increase plasma HDL levels (14).
Hops extract in combination with rosemary extract and oleanolic acid may reduce C-reactive protein in patients presenting with elevated levels (11).