Scientific American is reporting that the smell of coffee is enough to give measurable benefits in coping with stress. I have written in the past that I find some claims for aromatherapy credible. One of the claims that some aromatherapists make is that simply smelling things can have health benefits.
This is a problem area for some scientists, and the problem is a real one. The amount of any agent that you can absorb through your nose is very small indeed. There is a similar problem with homeopathy. How can diluting something make its effect stronger?
But it seems that despite the very small number of actual molecules involved, what you smell can have a profound effect on your physiology. We may not understand how it works, but we have to accept the data.
This doesn’t mean that homeopathy has to be accepted. That has not been shown to work yet, and given how long it has been practiced and how much it has been studied the overwhelming probability is it doesn’t work. Likewise with aromatherapy – although there is some evidence that it might have some effects – there is yet to be a fully controlled double blind study showing any clinical benefits of aromatherapy in the way you would need to do it to get a full drug license. But short term mild physiological changes as a result of smelling something aren’t quite as surprising and don’t need quite such strong evidence behind them. And it looks like smelling coffee is one of them.