Islamabad - Could cling film really make us sterile or cause cancer? For decades, holistic health gurus have warned of the toxic impact of plastic. They have been dismissed as quacks – but now it seems their paranoia might have been justified.

New evidence suggests that heat makes chemicals in plastic storage boxes and bottles leach into food and drink: two major reports last year linked 175 compounds to health problems connected to cancers, fertility and foetal development. Even Cancer Research UK, which has so far been sceptical, is now warning that cling film should not be allowed to touch the food it is covering during microwaving. Laboratory studies have also linked BPA with breast and prostate cancer and early sexual development in women.

Andrea Gore, professor of pharmacology at the University of Austin in the US, who has studied the effects of chemicals on reproductive function, says: ‘I heat food only in glass or ceramic, and although I use cling film in my fridge to cover cooked food, I remove it before reheating that food in the microwave.’ So when is plastic OK to use – and when do the experts think we should avoid it? Here’s their advice…

You may feel it’s thrifty to refill and old Evian or Volvic bottle from the tap. But research shows that this should be avoided, says Prof Gore. ‘They are likely to be made using BPA, or bisphenol-A, which is a known endocrine disruptor. When brand new, this is least likely to cause problems, but as the plastic decays, particles of the BPA can be released into drink or food that touches it.

‘Many baby bottles now make a selling point of being BPA-free, but we don’t know what chemicals are replacing BPA and the manufacturers don’t have to tell us.’ Consumer tests have found BPA is still found in many plastic bottles and other plastic food utensils sold in the UK. 

Breast Cancer UK is calling for a British ban, bringing us in line with other European countries. Many scientists say bottles known to be free of BPA are safe to drink from and then throw away.

‘If you drink bottled water and then refill the bottle, it’s best to use for a short period rather than weeks, and then discard,’ says Ashley Grossman, professor of endocrinology at the Oxford Centre for Diabetes, Endocrinology and Metabolism. Switching to glass or lightweight metal sports bottles is an alternative.

Many reusable plastic food containers – including Tupperware – are also made with BPA. Old containers that are showing signs of wear are particularly suspect. Dr Thomas Zoeller, professor of biology at University of Massachusetts, advises: ‘Replace all those which have been used and washed harshly, as these are most likely to be unstable and prone to releasing BPA into the food.’

Whether it’s cutlery, storage containers or bottles, heating, even in a dishwasher, causes the compounds to become less stable making particles more likely to leech into food, says Prof Gore.  A study published in the journal Environmental Health Perspectives showed that 95 per cent of plastic products put through a dishwasher proved positive for leaching chemicals that had an oestrogen-like effect on the body.

‘Do not allow cling wrap to come into direct contact with food when heating it,’ advises Cancer Research UK.  Experts at Johns Hopkins University in the US concur, warning that heating food covered with plastic can melt the plastic on to the food.

Of particular concern is cling film made from PVC, which contains hormone-disrupting phthalates, a chemical that keeps plastic soft. PVC cling film has been banned in America, but it is still in use in Europe. ‘If you’re heating a plate in the microwave, just cover it with another plate or a chemical-free paper towel,’ adds Prof Gore.

Styrene, a component of polystrene cups and some egg cartons, has been classified as a possible carcinogen by the US’s International Agency for Research on Cancer, and benzene, also used in production, is another suspected carcinogen. Avoid, say the experts. Many takeaway chains now offer wooden disposable cutlery, and if your children use straws, switch from plastic to paper ones. Fizzy drinks may be packaged in bottles that contain formaldehyde, a known toxicant, so some experts recommend choosing cans. Concerns over its legal use in packaging were raised in last year’s report in the Journal Of Epidemiology And Community Health, as it is potentially a carcinogen. 

However, some scientists point out that formaldehyde is also found in some foods, including apples.

Reusable ice-cube trays can get heavy use in a kitchen – and over the years will show signs of decay. It is a myth, though, that freezing water in plastic ice-cube trays releases dioxins, another dangerous chemical.  The scare arose out of an internet hoax – and scientific studies have shown that the freezing process actually prevents chemicals leaching out of plastic.