Slow cookers have been making a gradual comeback in recent years, as we embrace the fuss-free, one-pot style of cooking that was popular in the 70s.

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But if you’ve been stewing up a storm in your original 70s one this winter, you might want to pop it on the backburner for a while. It seems there are some very real health concerns connected to old-fashioned slow cookers.

What’s the problem?

A probe into the lead content in kitchenware by Bill Gephardt of Salt Lake City’s KUTV found that some 20% of slow cookers were leaching measurable amounts of lead into food, according to the Daily Mirror.

The report claimed that when ceramic vessels are heated to 26 degrees, they release ten times as much lead as they do at room emperature – but that slow cookers heat up to more than 121 degrees.

It’s believed that lead leaches from the smooth glaze on the inside of the slow cooker pot – as, in the past, lead compounds like lead oxide were used to make such glazes.

These days, many brands state that their slow cookers do not contain leaded glaze, but it’s worth checking if you still have the box for your old one.

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The nutritionist’s view

Ella Allred, nutritionist from Nutricentre.com, says: “Slow cookers which have the inner food part as aluminium could lead to increased levels of aluminium in your food. Frequent consumption may lead to increased amounts stored in your body and may cause health issues.

“The best type of slow cooker to go for is one with a ceramic or glass inner. These are readily available on the market.

“Previously Teflon slow cookers were sold, however these release quite a lot of toxins into the air and into food. This became obvious when people started noticing their budgies dying. Budgies do not have the same liver enzymes that humans do. This showed how toxic the air in the whole house became.”

Lead poisoning: the facts

The World Health Organisation (WHO) has identified lead is one of its ten chemicals of major public health concern and they recognise one of the sources of exposure is through food – specifically from lead-glazed or lead-soldered containers.

Children are the most vulnerable, because they absorb four to five times as much ingested lead as adults from a given source.

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Exposure to lead in childhood is thought to contribute to 600,000 new cases of children with intellectual disabilities each year.

Lead exposure is estimated to account for 143,000 deaths per year – with the highest numbers being in developing regions.

The WHO factsheet on Lead Poisoning and Health states: “Young children are particularly vulnerable to the toxic effects of lead and can suffer profound and permanent adverse health effects, particularly affecting the development of the brain and nervous system.

“Lead also causes long-term harm in adults, including increased risk of high blood pressure and kidney damage. Exposure of pregnant women to high levels of lead can cause miscarriage, stillbirth, premature birth and low birth weight, as well as minor malformations.”