Which old wives’ tales qualify as sound advice?

Michael Hanlon puts an apple a day, a bad moon rising and pregnancy’s food rules to the test

YOU’LL find them first mentioned in the Bible. “Refuse profane and old wives’ fables, and exercise thyself rather unto godliness,” Paul warns in his first letter to Timothy. But most of us are still suckers for an old wives’ tale, presuming that homely wisdom passed down through the ages must contain at least a grain of truth.

Now that view has been bolstered by no less an authority than Yale University, which suggested that it is indeed easier to catch a cold when you get cold.

In fact, this issue has been one of the most fiercely debated questions in medical science. Conventional wisdom suggests that colds are caused by viruses — specifically rhinoviruses — not by low temperatures.

But in the Yale study, sci- entists found that the immune system is weaker in a cold nose than a warm one — meaning our frontline defence against the rhinovirus is compromised.

So which other old wives’ tales turn out to be true? And which can we safely dismiss? Here’s a selection:

An apple a day keeps the doctor away

Of course this statement cannot literally be true, but there is no doubt that eating raw fruit regularly is a very healthy thing to do. The flesh of an apple contains a protein called pectin, which lowers blood pressure and blood sugar levels. Apples, like most fruits, are also packed with vitamins and essential minerals, including vitamin C and boron, which are essential for maintaining healthy bones.

There is good evidence that regularly eating fresh, raw fruit lowers blood pressure, reduces the risk of heart disease and cancer, and promotes general wellness, including a boosted immune system.

This is perhaps unsurprising, as fruits are the only living objects that have evolved specif- ically to be eaten. Are apples the best fruit? The original saying probably came about simply because in the US and Europe apples are the cheapest and most abundant fruit around.

Verdict: Not literally true (apples will not make you immortal), but it is certainly the case that a diet packed with fresh fruit is the one to aim for.

Pregnant women should avoid eating unpasteurised cheeses, shellfish and other ’edgy’ foods

The idea that you should avoid runny, smelly cheese, prawns or other “grown-up” foods when pregnant probably comes under the category of a “new wives’ tale”, because it is certainly not something our grandmothers would have worried about. But it turns out that the science behind this advice is as dubious as the claim that masturbating makes you blind.

Raw (that is, unpasteurised) milk certainly contains potentially nasty pathogens that might cause diseases, such as listeriosis, which can — in theory — cause miscarriages. So surely it is wise for pregnant women to avoid such foods, just to be on the safe side? The problem here is defining “the safe side”. While, in theory, eating unpasteurised Brie could cause such a problem, there is no actual evidence that it will.

In France, where pregnant women consume unpasteurised cheese, shellfish and so on with apparent impunity rates of listeriosis are far lower than in the parts of the US, Australia and New Zealand where unpasteurised dairy is illegal.

Verdict: False. Be very suspicious of any health claim that appears to restrict the dietary choices of pregnant women.

There is a link between the moon and mad, bad behaviour

In many countries, police rotas are adjusted to take into account the lunar cycle — assuming that the age-old link between a full moon and “lunatic” behaviour is in some ways true.

But the evidence is limited, for the banal reason that during a full moon there is more light at night, so incidences of certain crimes, such as burglary, are less likely to occur.

A major study in 1985 by US scientists James Rotton and Ivan Kelly found no link between the full moon and psychiatric admissions, car accidents, suicides or violent crimes. But the myth persists. Verdict: False. Eating carrots allows you to see in the dark

The story that consuming large quantities of carrots could improve night vision arose in World War 2.

The story — actually propaganda — that British pilots were acquiring night vision capabilities thanks to their diet never really went away. The vegetables do contain carotene, a natural compound that is needed to construct the light-receiving apparatus in the retina, but they will not help your superpowers.