Pollution can make you fat, study claims

Children exposed to pesticide in womb twice as likely to be overweight, refuting idea of sole personal responsibility. Geoffrey Lean reports

Pollution can make children fat, startling new research shows. A groundbreaking Spanish study indicates that exposure to a range of common chemicals before birth sets up a baby to grow up stout, thus helping to drive the worldwide obesity epidemic.

The results of the study, just published – the first to link chemical contamination in the womb with one of the developing world's greatest and fastest-growing health crises – carry huge potential implications for public policy around the globe. They undermine recent strictures from the Conservative leader, David Cameron, that blame solely the obese for their own condition.

A quarter of all British adults and a fifth of children are obese – four times as many as 30 years ago. And so are at least 300 million people worldwide. The main explanation is that they are consuming more calories than they burn. But there is growing evidence that diet and lack of exercise, though critical, cannot alone explain the rapid growth of the epidemic.

It has long been known that genetics give people different metabolisms, making some gain weight more easily than others. But the new study by scientists at Barcelona's Municipal Institute of Medical Research suggests that pollution may similarly predispose people to get fat.

The research, published in the current issue of the journal Acta Paediatrica, measured levels of hexachlorobenzene (HCB), a pesticide, in the umbilical cords of 403 children born on the Spanish island of Menorca, from before birth. It found that those with the highest levels were twice as likely to be obese when they reached the age of six and a half.

HCB, which was mainly used to treat seeds, has been banned internationally since the children were born, but its persistence ensures that it remains in the environment and gets into food.

The importance of the study is not so much in identifying one chemical, as in showing what is likely to be happening as a result of contact with many of them. Its authors call for exposures to similar pesticides to be "minimised".

Experiments have shown that many chemicals fed to pregnant animals cause their offspring to grow up obese. These include organotins, long employed in antifouling paints on ships and now widely found in fish; bisphenol A (BPA), used in baby bottles and to line cans of food, among countless other applications; and phthalates, found in cosmetics, shampoos, plastics to wrap food, and in a host of other everyday products.

These pollutants – dubbed "obesogens" as a result of these findings – are so ubiquitous that almost everyone now has them in their bodies. Ninety-five per cent of Americans excrete BPA in their urine; 90 per cent of babies have been found to be exposed to phthalates in the womb; and every umbilical cord analysed in the new Spanish study was found to contain organchlorine pesticides such as HCB.

Two American studies have implicated phthalates in obesity in adult men, but the new research is much more conclusive, and is the first to show the effects of exposure in the womb, where humans are most vulnerable.

Dr Pete Myers, one of the world's leading experts on obesogens, told The Independent on Sunday last night: "This is very important. It is the first good study of the effects on the foetus. Its conclusions are not surprising, given what we know from the animal experiments, but it firmly links such chemicals to the biggest challenge facing public health today."

No one knows how HCB causes obesity. The Spanish scientists speculate that it may have made the mothers diabetic, which would increase the chances of their children becoming obese (see graphic, above).

Dr Myers, who is chief scientist at the US-based Environmental Health Sciences, which helps to increase public understanding of emerging scientific links, says this is "plausible", but adds that the animal experiments point elsewhere. These have shown that obesogens "switch genes on and off" in the womb, causing stem cells to be turned into fat cells. The children then grow up with a much greater disposition to store and accumulate fat.

Whatever the explanation, the research goes some way to undermining David Cameron's assertion in a speech this summer that obesity is purely a matter of "personal responsibility", a view echoed by his health spokesman, Andrew Lansley 10 days ago. The Tory leader said that the obese are "people who eat too much and take too little exercise".

Dr Myers calls that "wishful ideological thinking which does not accord with biological reality", adding: "We need to discover ways to reduce exposures to these chemicals so that changing diet and lifestyle has a chance to work."

Factors that may pile on the pounds

Why is the world getting so fat? Everyone agrees that people gain weight by taking in more calories in their food than they burn off through everyday activities and exercise. But many scientists are coming to believe that changes in diet and exercise do not sufficiently explain the rapid growth of the epidemic. As 'The Independent on Sunday' reported last week, there has been no reduction in physical activity in Britain since 1980, while obesity rates have quadrupled.

The genetic make-up of a population does not change rapidly enough to provide an explanation. So the hunt is on for other factors that might show why more people are gaining weight more easily.

Life before birth. Both overweight and underweight babies are more likely to grow up fat. So are those born to smokers. Evidence suggests pollution is also predisposing the unborn to obesity. The introduction and increase in the use of such chemicals coincides with the epidemic taking off.

Age of mothers. The chances of becoming obese increase with maternal age. And the average age of first giving birth has gone up by 2.6 years in Britain since 1970.

Less sleep. Both children and adults are more likely to get fat if they get too little sleep, partly because they become hungrier. Average daily sleep has fallen from nine to seven hours over recent decades.

Temperature. People burn up more calories when they are cold. Central heating has ensured that they spend most of their time in comfortable temperatures.

Prescription drugs. Some drugs – including anti-psychotics, antidepressants and treatments for diabetes – cause people to gain weight.

Stopping smoking. Though mothers who smoke may make their children fat, they – and all smokers – are themselves less likely to put on weight. As the habit has decreased, obesity has soared.

To have your say on this or any other issue visit www.independent.co.uk/IoSblogs

Arts and Entertainment
'The Archers' has an audience of about five million
radioA growing number of listeners are voicing their discontent; so loudly that even the BBC's director-general seems worried
Arts and Entertainment
Henry VIII played by Damien Lewis
tvReview: Scheming queens-in-waiting, tangled lines of succession and men of lowly birth rising to power – sound familiar?
Sport
tennisLive: Follow all the updates from Melbourne as Murray faces Czech Tomas Berdych in the semi-final
News
Sir David Attenborough
people
PROMOTED VIDEO
Life and Style
ebookNow available in paperback
ebooks
ebookPart of The Independent’s new eBook series The Great Composers
Life and Style
Young girl and bowl of cereal
food + drink
News
Comic miserablist Larry David in 'Curb Your Enthusiasm'
peopleDirector of new documentary Misery Loves Comedy reveals how he got them to open up
Sport
football
News
i100
Life and Style
Virtual reality headset: 'Essentially a cinema screen that you strap to your face'
techHow virtual reality is thrusting viewers into frontline of global events and putting film-goers at the heart of the action
Arts and Entertainment
Ready to open the Baftas, rockers Kasabian are also ‘great film fans’
musicExclusive: Rockers promise an explosive opening to the evening
Life and Style
David Bowie by Duffy
fashion
Arts and Entertainment
Hell, yeah: members of the 369th Infantry arrive back in New York
booksWorld War Z author Max Brooks honours WW1's Harlem Hellfighters in new graphic novel
News
advertisingVideo: The company that brought you the 'Bud' 'Weis' 'Er' frogs and 'Wasssssup' ads, has something up its sleeve for Sunday's big match
Arts and Entertainment
tv
News
i100
Environment
Dame Vivienne Westwood speaking at a fracking protest outside Parliament on Monday (AP)
environment
Latest stories from i100
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    iJobs Job Widget
    iJobs General

    Recruitment Genius: Front End Web Interface Developer - HTML, CSS, JS

    £17000 - £23750 per annum: Recruitment Genius: A Liverpool based international...

    Tradewind Recruitment: English Teacher

    Negotiable: Tradewind Recruitment: This post arises as a result of the need to...

    Tradewind Recruitment: Class Teacher Required ASAP In Uminster

    £120 - £150 per annum: Tradewind Recruitment: I am recruiting on instruction o...

    Ashdown Group: Head of Finance - Financial Director - London - £70,000

    £70000 per annum: Ashdown Group: Head of Finance - Financial Controller - Fina...

    Day In a Page

    Isis hostage crisis: Militant group stands strong as its numerous enemies fail to find a common plan to defeat it

    Isis stands strong as its numerous enemies fail to find a common plan to defeat it

    The jihadis are being squeezed militarily and economically, but there is no sign of an implosion, says Patrick Cockburn
    Virtual reality thrusts viewers into the frontline of global events - and puts film-goers at the heart of the action

    Virtual reality: Seeing is believing

    Virtual reality thrusts viewers into the frontline of global events - and puts film-goers at the heart of the action
    Homeless Veterans appeal: MP says Coalition ‘not doing enough’

    Homeless Veterans appeal

    MP says Coalition ‘not doing enough’ to help
    Larry David, Steve Coogan and other comedians share stories of depression in new documentary

    Comedians share stories of depression

    The director of the new documentary, Kevin Pollak, tells Jessica Barrett how he got them to talk
    Has The Archers lost the plot with it's spicy storylines?

    Has The Archers lost the plot?

    A growing number of listeners are voicing their discontent over the rural soap's spicy storylines; so loudly that even the BBC's director-general seems worried, says Simon Kelner
    English Heritage adds 14 post-war office buildings to its protected lists

    14 office buildings added to protected lists

    Christopher Beanland explores the underrated appeal of these palaces of pen-pushing
    Human skull discovery in Israel proves humans lived side-by-side with Neanderthals

    Human skull discovery in Israel proves humans lived side-by-side with Neanderthals

    Scientists unearthed the cranial fragments from Manot Cave in West Galilee
    World War Z author Max Brooks honours WW1's Harlem Hellfighters in new graphic novel

    Max Brooks honours Harlem Hellfighters

    The author talks about race, legacy and his Will Smith film option to Tim Walker
    Why the league system no longer measures up

    League system no longer measures up

    Jon Coles, former head of standards at the Department of Education, used to be in charge of school performance rankings. He explains how he would reform the system
    Valentine's Day cards: 5 best online card shops

    Don't leave it to the petrol station: The best online card shops for Valentine's Day

    Can't find a card you like on the high street? Try one of these sites for individual, personalised options, whatever your taste
    Diego Costa: Devil in blue who upsets defences is a reminder of what Liverpool have lost

    Devil in blue Costa is a reminder of what Liverpool have lost

    The Reds are desperately missing Luis Suarez, says Ian Herbert
    Ashley Giles: 'I'll watch England – but not as a fan'

    Ashley Giles: 'I'll watch England – but not as a fan'

    Former one-day coach says he will ‘observe’ their World Cup games – but ‘won’t be jumping up and down’
    Greece elections: In times like these, the EU has far more dangerous adversaries than Syriza

    Greece elections

    In times like these, the EU has far more dangerous adversaries than Syriza, says Patrick Cockburn
    Holocaust Memorial Day: Nazi victims remembered as spectre of prejudice reappears

    Holocaust Memorial Day

    Nazi victims remembered as spectre of prejudice reappears over Europe
    Fortitude and the Arctic attraction: Our fascination with the last great wilderness

    Magnetic north

    The Arctic has always exerted a pull, from Greek myth to new thriller Fortitude. Gerard Gilbert considers what's behind our fascination with the last great wilderness