There is much more to hops than its place in the beer brewing industry. In alternative medicine, hops are used as a digestive aid and diuretic, as well as a mild sedative and treatment for menstrual cramps.1 Agriculturally, hops, or Humulus lupulus, are grown in most parts of the world but favor those regions with a northern temperate zone.2 H. lupulus is a perennial plant that is a long twining vine with a very strong, flexible stem.2 At the junctures of the leaves and stem, flowers form in bunches, and the maturing flowers give way to the powdery resin that produces the flavor, or bitterness, of hops.2
Background
Although early brew masters understood the flavoring that hops added to ale (later known as beer), the main reason it was used was for its ability to prevent spoilage due to bacteria.3 Early brews contained small amounts of hops based on the local crop and tastes of the consumers. However, at the height of the British Empire, sailors found that casks of beer they brought onboard their ships spoiled on long voyages. The solution was twofold and would forever change the industry. A London brewer reasoned that alcohol and hops were the factors that prevented spoilage in beer. Consequently, he boosted the alcohol content by adding more grain and sugar, and he increased the amount of hops in each batch of beer.3
Science
Chemically, hops contain more than 100 different compounds, including substantial amounts of flavonoids, acids, resins, and protein.4 One group of acids, referred to as alpha acids, are responsible for the mild antibiotic and bacteriostatic effect of hops.5 These hops compounds can cross the outer cell membrane intact and then metabolize in the cytoplasmic contents, preventing further bacterial growth.5
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Hops is most commonly known for its sedative action. It acts as a gamma-aminobutyric (GABA) agonist that inhibits central nervous system (CNS) activity.6 A study in common quail, the circadian rhythm of which closely resembles that of humans, found that birds that were given nonalcoholic hops compounds showed a 59% reduction in nocturnal activity.6 The German Federal Health Agency’s Commission E, which is similar to the FDA in the United States, approves hops for use as a sedative and sleep aid.7
In humans, a study has been conducted in 17 healthy female nurses assigned to rotating shift work and given a standardized nonalcoholic liquid hops compound to consume before their pre-sleep meal. After taking the compound for two weeks, the subjects showed a decrease of 40% (or 8 minutes) in sleep latency. The total number of activity spikes decreased by 28%.8
Another action of hops that is not widely known is that it is an estrogen inhibitor. While earlier researchers believed that hops actually increased estrogenic action, more recent chemical research confirms hops decrease the production of aromatase, which is an estrogen catalyst.9 One study found that three different types of beer, including an alcohol-free beer, showed significant reductions in aromatase activity, with resulting decreases in estrogen synthesis.9 In another study observing the metabolic effects of hops on the estrogen activity of human mammary cells, multiple points along the cytochrome P450 (CYP450) metabolic chain exhibited estrogen inhibition on exposure to hops.10
