written by reader A Few Things to Keep an Eye On

"Doc Gumshoe" checks in on health and medical news

[ed note: Michael Jorrin, aka “Doc Gumshoe,” is a medical writer (not a doctor) who shares his thoughts with us once or twice a month. As with all our guest authors, his words and opinions are his own]

The stream – or should I say “torrent” – of medical and health-care related news doesn’t seem to be affected by any of the questions of the day, big or little. Will Bangladesh be totally under water by 2100? Will Chelsea Clinton’s baby run for president in 2048? Will we ever again be able to afford to put limes in our gin gimlets? No matter – the medical news keeps coming at us, and Doc Gumshoe tries sort it out with balance and skepticism, employing whatever scraps of sense he can muster.

Let’s start out with this tid-bit…

Can glucosamine supplements give you 8 more years of life?

If so, it could be excellent news for all of us, as well as for the glucosamine supplement manufacturers. The basis for this possibility is a study in which elderly mice were given glucosamine supplements, and in comparison with mice of the same mouse vintage which did not get the supplements, the glucosamine-fed mice lived approximately 10% longer. (Weimer S., Nature Communications, 2014)

Glucosamine, as no doubt lots of you know, is widely used as a supplement for joint pain. Of the currently available forms, only for glucosamine sulfate is there some evidence of effectiveness, and this evidence is not very robust. I personally take glucosamine in the hope that it will help with my creaky knees, and I can’t attest for sure that it does help. What I can say is that for several months I stopped taking it, and during that time I had a sense that my knees got worse, so for whatever that’s worth…

The rationale for glucosamine’s effectiveness in joint pain is that it is a precursor of substances called glycosaminoglycans, which are components of the cartilage providing cushioning and mobility to joints. In other words, glucosamines supposedly help build cartilage. Personally, I hope so!

However, for the mice in the study which is the basis for the claim that glucosamine might grant us an extra 8 years of life, it was certainly not relief of mouse-arthritis that conferred the benefit.

Most of the study did not focus on mice. Instead, it focused on nematodes, which you might know as very small worms. What glucosamine appeared to do in the nematodes is to interfere with glucose metabolism, so that it mimicked the effect of a reduced diet. And in doing so, it increased the life-span of the nematodes.

There wasn’t much in this study about the metabolic effects in mice, but it did report that when two-year-old mice (that’s old in mouse-years) were given glucosamine, most of them survived a bit more than another year, whereas the mice that didn’t get glucosamine survived only about nine months. So that’s where they got the extra 10% life-span, which translated into about 8 extra human years.

The assumption, not stated in the paper, is that the bonus came from the caloric restriction, which is a putative effect of glucosamine. There have already been studies that show that putting mice on severe diets – the equivalent of the diets that Brazilian fashion models follow – does seem to extend mouse life spans (although we have no data on the life-spans of Brazilian fashion models).

A caveat is that there is concern that glucosamine (in large doses) may damage pancreatic islet cells and thus possibly lead to type 2 diabetes. And it is known that people who take glucosamine for joint aches frequently take more than the recommended dose, perhaps upping their diabetes risk. However, there is zero evidence of glucosamine actually causing diabetes.

As for extending human life spans by 8 years (or even 8 months or 8 weeks), we’ll just have to wait and see.

Speaking of mice, a potential Alzheimer’s breakthrough?

No, as far as we know, mice do not develop Alzheimer’s dementia. However, they do develop amyloid beta deposits in their tiny brains, and amyloid beta is what is thought by most researchers to be a principal cause of the typical Alzheimer’s dementia symptoms in humans. Therefore, a Holy Grail in the quest for drugs that may be effective in treating Alzheimer’s disease is some agent that will slow, halt, or even reverse the deposition of amyloid beta plaque in the human brain.

A small digression: the evidence linking amyloid beta and Alzheimer’s dementia is very strong. But there are also bits of co