Surely we all know by now that broccoli is good for us — like many other veggies. One of the sulfur-containing compounds in broccoli (and in other cruciferous vegetables like Brussels sprouts and cabbage) — sulphoraphane (SFN) — has been touted for its supposed anti-cancer effects — but the science is not really in on that. Last week though, Science Translational Medicine published a report on SFN that demonstrated the possibility that this compound could be useful in the treatment of type 2 diabetes (T2DM).
One characteristic of T2DM is that the liver, which produces glucose when blood levels are too low, doesn’t respond to insulin as it normally would by decreasing its glucose output. This insulin resistance results in excess glucose going into the blood from the liver and helping to cause the hyperglycemia that is the hallmark of diabetes.
A group of researchers from the Lund University Diabetes Center in Malmo, Sweden, led by Dr. Anders. H. Rosengren, investigated the effectiveness of SFN from broccoli in stemming the output of liver glucose. They performed a series of experiments whose results can be summarized thus:
- SFN suppressed the output of glucose from liver cells in a cell culture medium
- SFN acted by reducing the expression of genes coding for key enzymes in the liver that produce glucose
- In rats fed a high fat diet (which produces glucose intolerance), SFN administered into the peritoneum prevented the development of hyperglycemia that occurred in similar animals treated with a placebo.
- Rats that were already glucose intolerant, when treated with SFN improved their blood glucose profile.
- Mice made diabetic on a high fat diet also improved their blood glucose levels when treated with SFN.
- Finally, the investigators fed T2DM patients with a purified SFN powder derived from broccoli sprouts, and with the broccoli sprout extract itself. There were 97 T2DM patients involved in the study, and the investigators found that feeding the extract for 12 weeks lowered their levels of blood glucose in the fasting state, in a glucose tolerance test, and also lowered their levels of hemoglobin A1c. This last result indicated that the lower blood glucose levels had been maintained for a substantial period of time.
These results, moving from isolated liver cells in culture, to animal studies, to human studies provide solid evidence that SFN from broccoli can benefit people with T2DM.
What remains to be done? Of course, other investigators should replicate these results to demonstrate that they are robust (the results, not the investigators). And if such replication is successful, the effective dose of SFN must be defined, as well as any adverse effects that might occur.
So don’t rush out and buy SFN supplements just yet. Just keep eating broccoli and similar vegetables, and keep your eyes open for more SFN research.