Gut-microbe swap changes Eating Habits

WEIGHT gain bugging you? Evidence is mounting for the central role that bacteria play in causing obesity.

Liping Zhao and his team at Shanghai Jiao Tong University in China put a morbidly obese man on a diet of whole grains, traditional Chinese medicines, probiotics and non-digestible carbohydrates for 23 weeks. The diet was designed to inhibit the bacteria thought to be associated with weight gain by increasing the pH in the colon.

The 175-kilogram volunteer lost 51 kg, despite not exercising. People who have had weight-loss surgery lose on average 49 kg.

Obesity can lower vitamin D levels in the body, a study suggests.

The report, in the journal PLOS Medicine, analysed genetic data from 21 studies – a total of 42,000 people.

It found every 10% rise in body mass index (BMI) – used as an indicator of body fat – led to a 4% drop of available vitamin D in the body.

As vitamin D is stored in fatty tissue, the authors suggest the larger storage capacity in obese people may prevent it from circulating in the bloodstream.

BMI it is calculated by taking weight (in kilograms) and dividing it by height (in metres) squared. Those with a BMI of 30 or above are considered obese.

Lead author Dr Elina Hypponen, from the University College London Institute of Child Health, said the study “highlights the importance of monitoring and treating vitamin D deficiency in people who are overweight or obese”.

Is Alzheimers Disease Type 3 Diabetes ?

THE human brain evolved to seek out foods high in fat and sugar. But a preference that started out as a survival mechanism has, in our age of plenty, become a self-destructive compulsion.

It is well known that bad diets can trigger obesity and diabetes. There is growing evidence that they trigger Alzheimer’s disease too, and some researchers now see it as just another form of diabetes.

If correct, this has enormous, and grave, implications. The world already faces an epidemic of diabetes. The prospect of a parallel epidemic of Alzheimer’s is truly frightening, in terms of human suffering and monetary cost.

This outcome will not be easily averted. Few people need to be told that too much high-fat, high-sugar food is a health hazard. And yet sales of fast food remain healthy (or should that be hefty?). Part of the reason is “future discounting”, another evolved feature of the human brain that makes us value short-term rewards over long-term risks.

What can be done? One option is to call in the lawyers. Some moderately successful attempts have already been made to sue food companies for their role in creating the obesity epidemic. If a causal link between fatty, sugary food and Alzheimer’s can be established, it is highly likely that more lawsuits will follow. Such actions have their place, but this is a laborious and expensive way to enact change.

Nor do the policy levers at our disposal appear promising. Public awareness campaigns have been of limited use in reversing the tide of obesity. Will the added threat of dementia prove harder to ignore? “Sin taxes” on unhealthy foods may work – Denmark and a handful of other countries are experimenting with them – but it is not yet clear whether they make any real difference. What’s more, they raise questions about personal responsibility and nanny-statism.

We may be left with only the option of medically blocking either the craving for fast food, or its consequences. That has its own complications, and sidesteps the problem rather than addressing it. But the human brain also evolved to find ingenious solutions to intractable problems. It may yet come to its own rescue.

Antibiotic use in Babies linked to Obesity later in Life

Giving antibiotics to young babies may increase their weight later in life, according to US researchers.

A study of 11,532 infants, published in the International Journal of Obesity, showed children under six months who were given antibiotics were heavier in later years.

Researchers say the drugs could be affecting bacteria in the gut, leading to weight changes.

However, they say more work is needed to confirm there is a link.

Bacteria living on people greatly outnumber the body’s own cells and there is a growing interest in how this “microbiome” affects human health. In extreme circumstances there are even examples of doctors transplanting faecal matter in order to introduce healthy bacteria into the gut, treating infections when other methods have failed.

In this study, children who had antibiotics between birth and the age of five months were slightly heavier between the age of 10 and 20 months. After 38 months they were 22% more likely to be overweight.

One of the researchers, Dr Leonardo Trasande from New York University School of Medicine, said: “We typically consider obesity an epidemic grounded in unhealthy diet and exercise, yet increasingly studies suggest it’s more complicated.”

“Microbes in our intestines may play critical roles in how we absorb calories, and exposure to antibiotics, especially early in life, may kill off healthy bacteria that influence how we absorb nutrients into our bodies, and would otherwise keep us lean.”

Microbiologist Dr Cormac Gahan, from University College Cork, said there was certainly a lot of interest in the area, “but it is very early stages for this type of work”.

He said changing gut bacteria could alter weight by “a direct effect on energy extraction” or by “influencing hormones”.

Extreme Exercise and Heart Disease

Extreme exercise such as marathons may permanently damage the heart and trigger rhythm abnormalities, warn researchers. They say the safe ‘upper limit’ for heart health is a maximum of an hour a day – after which there is little benefit to the individual.

A review of research evidence by US physicians says intensive training schedules and extreme endurance competitions can cause long-term harm to people’s hearts. Activities such as marathons, iron man distance triathlons, and very long distance bicycle races may cause structural changes to the heart and large arteries, leading to lasting injury.

Faecal Transplants restore Gut Health

Flatulence and defecation are perhaps what most of us associate with the stomach and intestines, which is not so surprising when you consider that the gastrointestinal tract is the body’s largest metabolic organ and gives everyone, sick or healthy, a daily reminder of its function. Less likely to occupy our minds is that the gut is the home to more than a thousand different species of bacteria, together weighing more than a kilo. A growing number of researchers, on the other hand, are now spending their days pondering the significance of this myriad of bacteria.

Medical Science met three researchers at the Karolinska Institute, Stockholm, Sweden, who are attempting in different ways to find out what our normal gut flora looks like, how it helps us to stay healthy, and what roles it plays in serious diseases. Elisabeth Norin, associate professor at the Department of Microbiology, Tumour and Cell Biology at Karolinska Institute, is studying faecal transplantation as a way of restoring gut health in people with diarrhoea caused by a bacterial imbalance.

Gut-Microbe swap changes Eating Habits

EATEN too many pies? Blame the microbes in your gut – they may be influencing how much you eat.

In 2006, biologists found that the types of bacteria in the guts of obese rats differed from those in non-obese rats. To find out more, Mihai Covasa and his colleagues at the French National Institute for Agricultural Research (INRA) in Paris swapped gut bacteria between obesity-prone and obesity-resistant rats.

The obesity-resistant rodents proceeded to eat more and pile on the pounds. They also developed gut hormone levels typical of obesity-prone rodents.

These rats are a good model for human obesity – people, too, are either resistant or vulnerable to the condition. Understanding the gut flora associated with it may offer ways to help control food intake, Covasa said this week at the Experimental Biology 2012 meeting in San Diego, California.