London: Just one rasher of bacon a day can damage a man's fertility, while eating a portion of white fish such as cod or halibut every other day can improve it, researchers have suggested.

The study by Harvard University on 156 men in couples suffering problems conceiving examined their diet and the size and shape of their sperm.

A study has found that bacon and other processed meats are bad for men's fertility Credit:Fiona Morris

Researchers found that men who regularly ate processed meat had significantly lower amounts of normal sperm, compared with those who limited the amount of foods like bacon, sausages, hamburgers, ham and mince.

On average, those who ate the equivalent of less than a rasher of bacon a day had 30 per cent more normal sperm than those who ate higher quantities of processed meats.