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.
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