Scientists investigate why obesity is good for polar bears

Science Editor

The secret of how the polar bear copes with a high-fat diet without getting a heart attack can be found in the creature’s genetic makeup according to scientists who have analysed the genome of the world’s greatest living land predator.

A study of the genomes of 79 polar bears from Greenland indicates that key genes enable the species to metabolise fats in the bloodstream and liver to prevent heart disease and the buildup of fatty deposits in the arteries and around the heart, a study has found.

A polar bear’s diet is rich in seal blubber and half of its own body weight is composed of fat. It has cholesterol levels that would result in furred-up arteries and cardiovascular disease if they were seen in humans, scientists said.

“For polar bears, obesity is a benign state. We wanted to understand how they are able to cope with that. The life of a polar bear revolves around fat,” said Eline Lorenzen of the University of California, Berkeley.

“Nursing cubs rely on milk that can be up to 30 per cent fat and adults eat primarily blubber of marine mammal prey. Polar bears have large fat deposits under their skin and, because they essentially live in a polar desert and don’t have access to fresh water for most of the year, rely on metabolic water, which is a by-product of the breakdown of fat,” Dr Lorenzen said.

The study, published in the journal Science, compared the genomes of the polar bear and its closest living relative, the brown bear. The analysis indicates that polar bears evolved from brown bears about 500,000 years ago and quickly became specialists in eating a high-fat diet, who was essential for surviving almost solely on seal blubber.

Start your day with The Independent, sign up for daily news emails
ebooks
ebooksAn introduction to the ground rules of British democracy
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

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

iJobs Job Widget
iJobs General

Recruitment Genius: Senior Solution Architect - Contract

£500 - £600 per day: Recruitment Genius: A Senior Solution Architect is requir...

360 Resourcing Solutions: Export Sales Coordinator

£18k - 20k per year: 360 Resourcing Solutions: ROLE: Export Sales Coordinato...

Recruitment Genius: B2B Telesales Executive - OTE £35,000+

£20000 - £35000 per annum: Recruitment Genius: The largest developer of mobile...

SThree: Talent Acquisition Consultant

£22500 - £27000 per annum + OTE £45K: SThree: Since our inception in 1986, STh...

Day In a Page

How to stop an asteroid hitting Earth: Would people co-operate to face down a global peril?

How to stop an asteroid hitting Earth

Would people cooperate to face a global peril?
Just one day to find €1.6bn: Greece edges nearer euro exit

One day to find €1.6bn

Greece is edging inexorably towards an exit from the euro
New 'Iron Man' augmented reality technology could help surgeons and firefighters, say scientists

'Iron Man' augmented reality technology could become reality

Holographic projections would provide extra information on objects in a person's visual field in real time
Sugary drinks 'are killing 184,000 adults around the world every year'

Sugary drinks are killing 184,000 adults around the world every year

The drinks that should be eliminated from people's diets
Pride of Place: Historians map out untold LGBT histories of locations throughout UK

Historians map out untold LGBT histories

Public are being asked to help improve the map
Lionel, Patti, Burt and The Who rock Glasto

Lionel, Patti, Burt and The Who rock Glasto

This was the year of 24-carat Golden Oldies
Paris Fashion Week

Paris Fashion Week

Thom Browne's scarecrows offer a rare beacon in commercial offerings
A year of the caliphate:

Isis, a year of the caliphate

Who can defeat the so-called 'Islamic State' – and how?
Marks and Spencer: Can a new team of designers put the spark back into the high-street brand?

Marks and Spencer

Can a new team of designers put the spark back into the high-street brand?
'We haven't invaded France': Italy's Prime Minister 'reclaims' Europe's highest peak

'We haven't invaded France'

Italy's Prime Minister 'reclaims' Europe's highest peak
Isis in Kobani: Why we ignore the worst of the massacres

Why do we ignore the worst of the massacres?

The West’s determination not to offend its Sunni allies helps Isis and puts us all at risk, says Patrick Cockburn
7/7 bombings 10 years on: Four emergency workers who saved lives recall the shocking day that 52 people were killed

Remembering 7/7 ten years on

Four emergency workers recall their memories of that day – and reveal how it's affected them ever since
Humans: Are the scientists developing robots in danger of replicating the hit Channel 4 drama?

They’re here to help

We want robots to do our drudge work, and to look enough like us for comfort. But are the scientists developing artificial intelligence in danger of replicating the TV drama Humans?
Time to lay these myths about the Deep South to rest

Time to lay these myths about the Deep South to rest

'Heritage' is a loaded word in the Dixie, but the Charleston killings show how dangerous it is to cling to a deadly past, says Rupert Cornwell
What exactly does 'one' mean? Court of Appeal passes judgement on thorny mathematical issue

What exactly does 'one' mean?

Court of Appeal passes judgement on thorny mathematical issue