An attractive ‘healthy glow’ may help you win over a member of the opposite sex but it doesn’t necessarily mean you are actually healthier, according to new research.

According to one theory, a diet rich in fruit and vegetables is good for you and therefore makes you more fit – in an evolutionary sense – to be a sexual partner.

The effect of beta-carotenes, which produce the orange colour in carrots, on skin tone was seen as an “honest signal” of this. Evolution had, apparently, produced a simple mechanism to enable people to tell whether someone was in good enough condition to have a baby with.

However, researchers have now discovered that while taking beta-carotene supplements made a group of men significantly more attractive to a group of women, it did not actually make them any healthier.

Researcher Yong Zhi Foo, of The University of Western Australia, said: “Carotenoids are known to be responsible for the striking mating displays in many animal species.

“Our study is one of the first to causally demonstrate that carotenoids can affect attractiveness in humans as well.

“It also reaffirms the results of previous studies showing that what we eat can affect how we look.”

In the study, reported in the journal Behavioural Ecology, the researchers enlisted 43 white men with an average age of 21 to take beta-carotene supplements and a control group of 20 other white men.

They were photographed at the start of the trial and tested for the quality of their semen, immune system function and levels of oxidative stress.

For 12 weeks, the first group took supplements while the control group took a placebo.

They were then photographed again and the same tests of their health were carried out.

As expected, the supplements increased the overall yellowness and redness of the men’s faces, but not the lightness of their skin.

A group of 66 women, whose average age was 33, were then asked to rate the men’s faces for how attractive they were.

The faces of the men who took the supplement were 50 per cent more likely to be rated as attractive and healthy than the photographs taken at the start of the trial or the placebo group.

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A statement issued by Oxford University Press USA, the publisher of the journal, said: “Thus beta-carotene supplement significantly enhanced participants' attractiveness and appearance of health. Beta-carotene treatment did not, however, significantly affect any health functions.