By David Derbyshire
Men wanting to father babies should cut down on 'manly' food like steak and burgers, researchers claim.
A new study has shown that men can boost their sperm counts by eating more fresh fruit and vegetables - and reducing the amount of red meat and fatty foods like cream in their diets.
The link between healthy sperm and antioxidants emerged from a four year study into the links between fertility and dietary habits of 61 men.
The scientists wanted to find out whether vitamins can alter sperm quality.
'Our previous research showed that men who eat large amounts of meat and full fat dairy products have lower seminal quality than those who eat more fruit, vegetables and reduced fat dairy products,' said lead researchers Dr Jaime Mendiola of the University of Murcia, Spin.
'In this study, we have found that people who consume more fruits and vegetables are ingesting more anti-oxidants and this is the important point.'
Antioxidants are found in food such as oranges, peppers and spinach. They work by reducing the harmful effects of 'free radicals' - oxygen molecules that roam the body, damaging cells.
The study, published in the journal Fertility and Sterility, looked at 30 men with fertility problems and 31 who were healthy.
'We saw that, among the couples with fertility problems coming to the clinic, the men with good semen quality ate more vegetables and fruit than those men with low seminal quality', said Dr Mendiola.
Men who eat steak and hamburgers have slower sperm, according to scientists
Men who ate healthily had more sperm than those who ate large amounts of red meat and fat. Their sperm also swam faster.
'A healthy diet is not only a good way of avoiding illness, but could also have an impact on improving seminal quality,' he said.
'What we still do not understand is the difference between taking these vitamins naturally and in the form of supplements.'
In his next study he will examine if it matters if men receive their vitamins from food or from pills.
A growing number of scientific studies shows that the quality and count of sperm has fallen in the last few decades. Spanish men are among the least fertile in Europe.
In northern Europe, around 40 per cent of men have sperm quality below the recommended levels for fertility.
Obese men can improve their chances of fathering a baby if they lose weight. Smoking can also reduce fertility, as can stress and some environmental pollutants.
Two years ago, a study showed that some men can also boost their sperm quality by having regular sex.
Prescription drugs - including antidepressants - can reduce sperm counts. Other studies have linked low sperm counts to eating too much soya and heavy drinking.
Men who spent long periods sitting at desks or in cars are also at risk of sperm damage caused by the overheating of testicles.