Everyone wants to promote the idea of “boosting the immune system” these days. Those who sell supplements lead the charge, with a regiment of alternative practitioners following closely behind. Immune boosting is also a favourite phrase with journalists, It’s a cheap and easy way of writing headlines. Scientists and science journalists succumb to its lure as well. This reported experiment with Barbary apes and alcohol is a good example.
Eight monkeys were allowed free access to alcoholic drinks for 7 months. Four of them were deemed heavy drinkers and the other four, moderate drinkers, depending on their freely chosen intake. There was a comparison group that was allowed no alcohol. The monkeys’ response to smallpox vaccine was tracked. It is not surprising that the heavy drinkers showed impaired immune function. Alcohol is toxic and large amounts of it will damage just about any bodily function you care to name.
What was more interesting is that the moderate drinkers had a better response to the vaccine than either of the other groups. We should, though, be skeptical about the size of the groups and the fact that the comparison groups were self-selecting rather than randomly allocated. Maybe the immune systems of those drawn to heavy drinking were different in some way to the more temperate beasts. We should also, always, be skeptical about making direct inferences from animal studies to human health.
For scientists, or science journalists, to talk about “boosting the immune system” is a bit like the mayor saying that some free-to-use bikes will boost the economy of the city, just because a few more energy drinks were sold in a few local kiosks. Like a city, the immune system is an immensely complex and intricate set of interlocking sub-systems. Millions upon millions of immune cells interact with billions of immune molecules to keep a body in a finely-balanced state of health. There are many different types of these cells and molecules - they are incredibly small and incredibly numerous. Strength of response to a single vaccine does not tell us anything about how the same immune system might cope with other vaccines, with TB, MRSA or the common cold. You cannot “boost” the whole thing – it’s a crazy concept. And we should never forget that an over-active immune system can be just as harmful as an under-active one – in allergies and the many auto-immune diseases for instance.
It’s New Year’s Eve – if you drink heavily you might be more likely to get an infection of some kind in the next few days. But if you exercise restraint and only have a glass or two, there are no promises that this will serve to actively improve your health. But drunk or sober, I hope you have a happy and healthy 2014.