Consumers of large amounts of calories who want to keep their weight under control may benefit from Grape Seed Extract. Dutch researchers at the University of Maastricht published an article on the subject eight years ago in the European Journal of Clinical Nutrition.
Grape Seed Extract is an interesting supplement. It improves blood circulation; animal studies have shown that it reduces the chance of prostate cancer, and epidemiological studies have shown that it reduces the chance of skin cancer. In-vitro studies have shown that it sabotages the conversion of testosterone into estradiol by the enzyme aromatase.
In test tube studies Grape Seed Extract also stimulates lipolysis: the release of fatty acids by fat cells into the bloodstream. [Int J Obes Relat Metab Disord. 2000 Mar; 24(3): 319-24.] This may mean that Grape Seed Extract suppresses the appetite, and to find out whether this is the case the Dutch researchers did an experiment with 51 test subjects aged from 18-65.
The researchers let their test subjects eat as much as they wanted during a three-day stay in a laboratory. About 30-60 minutes before their breakfast, lunch and dinner the subjects took a supplement containing 100 mg Grape Seed Extract. A couple of weeks later the researchers repeated the experiment, but gave their subjects a placebo.
The effect of supplementation was related to the caloric intake of the subjects. If calorie intake was lower than average then Grape Seed Extract had no effect on the energy intake, as shown in the table below. The ‘small eaters’ consumed an average of 1500 kcal per day.
In the subjects with an above-average energy consumption Grape Seed Extract did reduce energy intake, as shown in the table below. The average energy intake of this group was 2030 kcal per day.
Among the ‘big eaters’ the Grape Seed Extract supplement reduced their energy intake by 96 kcal per day. If that effect were to last for a whole year, then people with high caloric requirements could lose 3.7 kg body fat in that amount of time.
The effect of grape-seed extract on 24 h energy intake in humans.
Vogels N, Nijs IM, Westerterp-Plantenga MS.
Maastricht University, Human Biology, Maastricht, The Netherlands. N.Vogels@HB.Unimaas.NL
Since grape-seed extract has been shown to stimulate lipolysis in vitro and reduce food intake in rats, we assessed the efficacy of grape-seed extract with respect to energy intake (EI) and satiety.
In a randomized, placebo-controlled, double-blind, cross-over study, 51 subjects (age 18-65 y, body mass index 22-30 kg/m2) ate an ad libitum lunch and dinner twice in the University Restaurant for 3 days. Standard breakfasts and snacks were provided. Supplements were taken 30-60 min prior to each meal.
In the total study population, no difference in 24 h EI was found between the grape-seed extract and placebo. However, in the subgroup of subjects (n=23) with an energy requirement > or =the median of 7.5 MJ/day, EI was reduced by 4% (DeltaEI 352.1 kJ/24 h, P=0.05) after grape-seed extract compared to placebo treatment. Meanwhile, there were no significant differences in macronutrient composition, attitude towards eating, satiety, mood or tolerance.
Grape seed reduced 24 h EI, with on average 4% in subjects who had an energy requirement > or =7.5 MJ/day, without further effects on satiety, mood or tolerance. These findings suggest that grape seed could be effective in reducing 24 h EI in normal to overweight dietary unrestrained subjects, and could, therefore, play a significant role in body-weight management.
PMID: 15042136 [PubMed – indexed for MEDLINE]