Secondhand smoke makes people around you fat

Some people swear that smoking cigarettes keeps them slim.

But being exposed to cigarette smoke can actually make people pile on the pounds, new research shows.

And it is innocent victims of secondhand cigarette smoke are the most likely to gain weight.

'For people who are in a home with a smoker, particularly children, the increased risk of cardiovascular or metabolic problems is massive,' said lead author Professor Benjamin Bikman, of Brigham Young University in Utah.

Passive smoking damages the body because second-hand smoke contains more than 4,000 chemicals, many of which are irritants and toxins, and some of which are known to cause cancer.

Data shows half of the U.S. population is exposed at least once daily to secondhand cigarette smoke and approximately 20 per cent of young children live with someone who smokes in the home, The Daily Mail reports.

In the UK, it's estimated that second-hand smoke kills over 12,000 people every year from lung cancer, heart disease, stroke and the lung disease Chronic Obstructive Pulmonary Disease (COPD).

Professor Bikman, and his co-author Professor Paul Reynolds, wanted to investigate how cigarette smoke is tied to metabolism.

They wanted to pinpoint the mechanism behind why smokers become insulin resistant, which leads to weight gain.

To carry out their study, they exposed mice to or second-hand smoke and analysed their metabolic progression.

Sure enough, those exposed to smoke put on weight.

When they investigated at a cellular level, they found the smoke triggered a tiny lipid called ceramide to alter mitochondria in the cells.

This caused disruption to normal cell function and inhibited the cells' ability to respond to insulin.

The research shows that passive smoking alters a body's sensitivity to insulin, Professor Reynolds said.

The key to reversing the effects of cigarette smoke, the researchers discovered, is to inhibit ceramide.

The researchers found the mice treated with myriocin - a known ceramide blocker - didn't gain weight or experience metabolic problems, regardless of their exposure to the smoke.

However, when the mice exposed to smoke were also fed a high-sugar diet, the metabolic disruption could not be fixed.

Now Professor Bikman and his team are in a race with other researchers to find a ceramide inhibitor that is safe for humans.