Scientists in a recent study found that hop extract can effectively reduce belly fat in healthy overweight adults.
Hops are the flowers (also called seed cones or strobiles) of the Humulus lupulus plant.
They are primarily used as a bittering, flavoring, and stability agent in beer, contributing floral, fruity, or citrus flavors and aromas. Hops are also used in herbal medicine and other beverages.
Iso-α-acids, the bitter components of beer, have previously been found to reduce body fat in humans.
However, the strong bitterness at effective doses makes them difficult to use as a nutrient.
Matured hop bitter acids (MHBA) from oxidized hops have a milder, more pleasant bitterness compared to iso-α-acids.
Recent research shows that MHBA consists mainly of α-acid–derived oxides and is structurally similar to iso-α-acids.
In this study, the team examined the effects of matured hop extract (MHE)—which contains MHBA—on abdominal fat reduction in healthy overweight individuals with a body mass index (BMI) between 25 and under 30 kg/m². Matured hop extract is produced from aged hops through a water-extraction process. It has only one-tenth the bitterness of standard hops and can be mixed into various foods and beverages. It is considered essentially risk-free for people of all ages, including children.
The researchers tested 200 men and women aged 20 to under 65. Participants were randomly assigned to two groups. For 12 weeks, both groups consumed a daily 350 mL beverage. One group drank the active beverage containing MHE (with 35 mg of MHBA), while the other consumed a placebo without MHE.
CT scans were used to measure changes in belly fat.
The team found that, compared to the placebo group, the hop extract group experienced a significant reduction in visceral fat after 8 and 12 weeks, as well as a reduction in total abdominal fat after 12 weeks.
Visceral fat is the fat stored deep inside the abdomen around vital organs. More common in men, it is located beneath the abdominal muscles and around organs such as the liver, stomach, and intestines. This type of fat is considered dangerous and has been linked to heart disease, type 2 diabetes, high cholesterol, certain cancers, and stroke.
The researchers also observed a decrease in body fat percentage in the hop extract group compared with the placebo group. Body fat percentage is the total mass of fat divided by total body mass, including both essential and storage fat.
Importantly, no adverse effects or abnormal changes in blood, circulatory, or urine tests were reported in either group.
The team concluded that drinking matured hop extract could safely reduce body fat—particularly abdominal visceral fat—in healthy overweight people.
One limitation of the study is its 12-week duration, which means the effects of hop extract may reflect short-term rather than long-term changes. More research is needed to understand the long-term benefits of hop extract and whether its effects persist over time.
The research was published in Nutrition Journal and conducted by Yumie Morimoto-Kobayashi et al. at Kirin Company in Japan.
