Professor Abraham Haim, an expert in biology at Haifa University, claims that because the colour of the light from energy saving bulbs has a blue tone, rather than the yellow tone of older filament bulbs, it could interfere with the body's hormone system.
Because blue light is more like natural daylight the professor thinks it could fool the body into not producing melatonin - a hormone your brain produces when it's dark. And since a lack of melatonin has been linked with some types of cancer - including breast cancer - not producing enough of it could mean we're losing out on our bodies' natural defence against the disease.
There could be something in Professor Haim's theory, which is published in the journal Chronobiology International. Another study published in 2007, for instance, has suggested female night shift workers and women who stay up late at night on a regular basis have a 60% higher chance than normal of developing breast cancer.
But before you rush off to swap all your low-energy light bulbs for old-style bulbs, other experts have dismissed the research as speculative, saying there really isn't any evidence to suggest light bulbs can cause cancer.
What's your opinion? Does modern living cause more health problems than we realise?