Reproductive toxicology accounts for a decent percentage of the research represented at the Society for the Study of Reproduction meeting wrapping up today in Kona, HI. Most of this has been directed at estrogen mimetics and assorted endocrine disrupters like Bisphenol A, the chemical in polycarbonate plastic that’s has many ditching their Nalgene water bottles. Many of these are ubiquitous chemicals that we come in contact with, but don’t intentionally ingest. So, I was a bit surprised to see a poster on glucosamine, a dietary supplement that many take for joint health. I met Jeremy Thompson today who with his group in the University of Adelaide, has been amassing evidence putting him on the wrong side of the supplement industry in Australia. Cheryl Schelbach in his lab has been presenting data on birth defects caused by the supplement. Glucosamine is an amino sugar that interferes with glucose energy sensing pathways by bypassing the rate limiting step in hexosamine biosynthesis. Some studies indicated that the supplement seems safe if taken during pregnancy, not a lot of data exists as to whether it’s useful or not. Schelbach injected glucosamine into the stomachs of mice right around the time of conception. To see if there were synergistic effects with a diet that might induce hyperglycemia, she used groups of mice raised on high fat and low fat diets. The big result according to Thompson, who was presenting the poster in Cheryl’s absence, is that 45% of mice (9 out of 20) administered glucosmaine (with the low fat diet) had abnormal fetuses compared to none in the low fat, glucosamine free regimen. High fat diet alone led to 25% abnormal pregnancy. Adding glucosamine to the high fat diet didn’t elevate the effect. Thompson says they think the diet primed the mice to a high glycemic index in such a way that the glucosamine had little effect. While recognizing that their study had limitations, they thought it prudent to release their findings to the media prior to publishing them in a peer reviewed journal. And they offered a mild warning that women looking to become pregnant might want to avoid the supplement. Apparently the industry reaction was vitriolic. “The hostility we experienced was profound,” Thompson told me.