Supplementation with indole-3-carbinol , a compound that occurs naturally in brassica vegetables such as broccoli and Brussels sprouts, inhibits the growth of fat reserves. According to researchers at Taipei Medical University in Taiwan, it may be a slimming agent.
The researchers performed experiments with mice. Some of the mice were given standard feed [B]; others were given food containing extra sugar and fat [HF] – which made them put on weight and become fatter quicker. A third group were given the same calorie-rich diet, but were also given a daily dose of 5 mg indole-3-carbinol, injected straight into their gut [HFI].
If you convert this dose to one suitable for a human adult weighing 80 kg you'd arrive at about thirty mg per day. If it were given orally you'd probably need a multiple of this, but anyway: there are supplements available on the market that contain 200 mg indole-3-carbinol per capsule.
The figure below shows how indole-3-carbinol reduced the weight increase in the mice and how it reduced the growth in fat tissue to a more or less normal level during the 12 weeks.
Indole-3-Carbinol changed the fat cells, the Taiwanese discovered. The figure above shows how it inhibited the synthesis of the enzyme acetyl coenzyme in the fat cells. This enzyme plays a key role in binding nutrients in the form of fat.
It sounds as though indole-3-carbinol exerted stress on the fat cells, but the opposite was actually true. It actually kept the fat cells healthy: fat tissues that get too big start to undergo a process of breakdown. They attract immune cells that clear up dead cells and at the same time dangerous inflammatory factors leak out into other parts of the body. The Taiwanese saw this process taking place in their HF mice, but not in the mice that had been given indole-3-carbinol.
Indole-3-Carbinol also boosts the secretion of adiponectin, raises the synthesis of leptin and lowers blood sugar levels.
"The results obtained from this study provide an alternative protective mechanism of cruciferous vegetable derivatives or their supplements in the prevention of obesity and its related metabolic disorders", the researchers conclude.
Nutrition. 2011 Apr;27(4):463-70.