The researchers made six healthy male volunteers consume a can of Heinz Cream of Tomato Soup every day for two weeks.
Results showed that a fortnight of soup-slurping had some effect on semen.
Seminal levels of lycopene, the component of tomatoes which makes them red, increased by between seven and 12 per cent.
Lycopene has antioxidant properties which can help protect DNA, mopping up harmful chemicals in the body called free radicals which can play a part in infertility.
The result, the company suggested, was the creation of "super sperm" with the potential to boost fertility.
"It's good to know that Heinz Cream of Tomato Soup could boost your mojo and give guys extra oomph. And for Heinz Ketchup lovers, the tomatoey goodness will put more ketchup in your bottle," the Daily Mail quoted, Nigel Dickie, a spokesman for Heinz, as saying.
Although the Portsmouth study found that while lycopene levels rose in semen after a period of soup consumption, there was "no measurable increase" in the sperm's ability to combat damaging free radicals.
The scientists said more research was needed to see if higher lycopene levels really would help boost fertility.