Islamabad - Being cold helps you lose weight, a new study found. Exercise or being exposed to low temperatures creates more ‘good’ brown and beige types of body fat which burns calories in the body. Previous research has found being cold mimics the effects of exercise, protecting against obesity and improving metabolic health.

Now, a new study has discovered how exposure to cold dramatically alters the composition of bacteria the gut, and this leads to fat-burning, improved glucose metabolism, and reduced body weight.

The findings could provide new treatments for overweight or obese people, researchers said. Professor Mirko Trajkovski of the University of Geneva said: ‘We provide compelling evidence that gut microbes play a key role in our ability to adapt to the environment by directly regulating our energy balance.

‘We are excited about exploring the therapeutic potential of these findings and testing whether targeting some of these microbes could be a promising approach for preventing obesity and related metabolic conditions.’

While ordinary white fat- known as ‘bad’ fat - piles on when we eat more calories than we burn, brown fat seems to burn excess calories to generate heat. We know babies have lots of brown fat — they need it to keep warm — but studies have shown there are small amounts in the necks of adults, too.

Experts believe that certain activities could switch on this fat, potentially helping to burn calories at a greater rate. And studies have shown certain activities, such as sleeping in a cold, can trigger the formation of more brown fat in the body. 

Gut microbes have also been implicated in obesity and obesity-related conditions like Type 2 diabetes and heart disease.

It is thought the composition of millions of bacteria in our intestines can effect how we metabolise different foods and, therefore, how much weight we gain.  Researchers theorised the health benefits of being exposed to cold may be linked to gut bacteria. As part of the new study, they exposed mice to cold temperature of 6°C (43°F) for up to 10 days.

They discovered this caused a major shift in the composition of the mice’s gut microbes and preventing them from gaining weight.

Then, the cold-induced gut bacteria were transplanted into other mice that did not harbour gut microbes because they had been raised in a germ-free environment.

It was found these mice had improved glucose metabolism, increased tolerance to cold temperatures. The mice also lost weight as the changes in gut bacteria promoted the formation of beige fat. Professor Trajkovski said: ‘These findings demonstrate that gut microbes directly regulate the energy balance in response to changes in the environment.’

However, after three weeks of cold exposure, body weight began to stabilise.

The intestine grew so it absorbed more nutrients from food, offsetting any additional weight loss.

He added: ‘These findings demonstrate that gut microbes enable mammals to harvest more energy from food as a way to adapt to the increased energy demand associated with long periods of cold exposure, thereby helping to protect against hypothermia.

‘We were surprised to see that gut microbes had such dramatic effects on the structure and function of the intestine.’

The team now plans to study the molecular mechanisms by which gut microbes sense changes in the environment, such as cold, which affect how much energy a person uses up. They are also looking into how changing certain gut bacteria may prevent obesity by remodelling intestinal tissue and thereby decreasing the absorption of nutrients in the gut. 

Slow walking speed linked to Alzheimer’s disease

Elderly people who slow down in later life may be at greater risk of Alzheimer’s disease, according to French researchers. Slowing down may seem the privilege of the elderly but pensioners who take it too easy may be at risk of Alzheimer’s disease, a study suggests.

Older people who walk slowly could be suffering from a build-up of the sticky amyloid brain plaques which lead to dementia. A study of 128 people in their 70s with memory problems found that amyloid levels accounted for up to nine percent of the difference in walking speed. The average speed of those taking part was 2.3 miles per hour, but pensioners who walked more slowly had higher concentration of amyloid.

French researchers say lifestyle factors such as smoking and lack of exercise have been known to both hinder walking and raise the risk of developing dementia. But they say it is possible that a slow gait speed may also signal changes in the body which could make Alzheimer’s more likely. “It’s possible that having subtle walking disturbances in addition to memory concerns may signal Alzheimer’s disease, even before people show any clinical symptoms,” said study author Dr Natalia del Campo, of the Gerontopole and the Centre of Excellence in Neurodegeneration of Toulouse in France.

To find out the link between walking speed and Alzheimer’s, scientists scanned the brains of participants to find out how much amyloid was present and tested them on thinking and memory skills and how well they could complete everyday activities.

Walking speed was measured with a standard test that times people on how fast they can walk about 13 feet at their usual pace.

The researchers found an association between slow walking speed and amyloid in several areas of the brain, including the putamen, a key region involved in motor function.

Around 800,000 people in Britain suffer from Alzheimer’s disease, which is the most common form of dementia. The numbers are expected to increase as the population ages.

Charities said that a change in mobility was often associated with Alzheimer’s.

Dr Laura Phipps from Alzheimer’s Research UK, said: “While forgetfulness and confusion are usually the first symptoms that people associate with Alzheimer’s disease, there can also be a range of physical symptoms, such as mobility problems.

“It will be important to follow more people over a longer period of time to look at changes in walking pace to better understand whether slower movement could be a consequence of Alzheimer’s, or an independent event driven by other shared risk factors.

“There can be many reasons for someone’s walking speed to slow, but it’s important to explore why and when these changes occur in diseases like Alzheimer’s and how they can be managed to improve the lives of those affected.”

Dr Louise Walker, Research Officer at Alzheimer’s Society, added: “Memory problems are the most recognisable symptom of Alzheimer’s disease but the condition can also affect people in many other ways, such as problems with navigation or concentration.

“Research has already shown that people with Alzheimer’s disease may have difficulties with walking - but it is unclear if this is due to the condition itself or other factors, especially those associated with ageing.

“More long-term research is needed to determine whether a build-up of the protein amyloid, which is one of the hallmarks of Alzheimer’s disease, directly leads to slower walking and whether this could form a suitable part of a clinician’s diagnostic process.”