Tuesday, August 03, 2010

Junk food starts allergies? Western high-fat diets are blamed for surge in illnesses

Just another epidemiologically-based theory. That poor African villagers have different internal flora from us should be no surprise to anyone -- but moving on from there is pure speculation

The most amusing comment: They found that the African villagers had "a far lower proportion of microbes associated with obesity". Seeing that African villagers are never very far from starvation that has to be a VERY big non-surprise

The rise of junk food and high-fat diets could be behind the explosion of allergies sweeping Britain, scientists claimed last night. They have found evidence that 'industrialised' Western diets high in red meat, sugar and fat lowered the numbers of healthy bacteria in our guts.

Without these microbes to prime the immune system, children are more likely to grow up suffering from asthma, eczema and other allergies, they say.

The number of people with allergies has trebled in the past 20 years. One in three people now suffer at some point in their lives.

Many scientists blame the modern obsession with hygiene and children's indoor lifestyles. Some doctors say exposure to germs and dirt in the early years is essential for a healthy immune system. Others have linked the rise in allergies to traffic pollution, food additives and the increasingly exotic diets of children.

The new study compared gut bacteria of children living in Florence, Italy, with youngsters raised in a rural village in Burkina Faso, West Africa.

They found that African children - who were eating food similar to the diet of the earliest farmers thousands of years ago - had a far lower proportion of microbes associated with obesity in adults and far more fatty acids known to protect against inflammation.

The diet of the African children consisted mainly of cereals, black-eyed peas and vegetables. The Italians, by contrast, ate higher quantities of meat, fat and sugar.

Dr Paolo Lionetti, who led the study at the University of Florence, said the differences between the children's gut microbes could be explained by their diets, which dominated other factors such as ethnic background, sanitation, climate or geography.

'The Burkina Faso children were selected as representative consumers of a traditional rural African diet,' he said. 'The diet of Burkina Faso children is low in fat and animal protein and rich in starch, fibre and plant polysaccharides, and predominantly vegetarian.

'All food resources are completely produced locally, cultivated and harvested nearby the village by women. Although the intake of animal protein is very low, sometimes they eat a small amount of chicken and termites.'

The trillions of microbes that inhabit the human gut were an essential 'organ' that helped to digest food, protect against pathogens, and reduce the risk of inflammation, he said.

Lindsey McManus, of Allergy UK, said: 'There is some evidence that probiotics in the gut are effective at boosting the immune system, especially in children with eczema and that they can protect against allergies. 'However, it's very early days with this study and a lot more work needs to be done.'


Every now and again the most relevant fact about weight pops out: Scientists link obesity to DNA

It's one of the most infuriating things in the world. Your best friend devours cream cakes by the plateful without putting on weight, but you gain 3lb by glancing at a chocolate bar. Now scientists think they know why. A study suggests that the 'propensity for obesity' may be hardwired into the brain while we are in the womb.

Its findings will be welcomed by the millions of us who have struggled to lose weight despite sticking rigidly to calorie-controlled diets.

Dr Tamas Horvath, of Yale University School of Medicine in the U.S., said: 'It appears that this wiring of the brain is a determinant of one's vulnerability to develop obesity.

'These observations add to the argument that it is less about personal will that makes a difference in becoming obese, and, it is more related to the connections that emerge in our brain during development.'

Britain, like most Western countries, is in the grips of an obesity epidemic with the number of fat people rising sharply since the 1960s. [Pick your starting point. Pick the year 2000 and there has been NO rise]

Dr Horvath and colleagues studied a group of laboratory rats bred to be vulnerable to obesity. They found that these naturally greedy animals were born with a major difference in the 'feeding centre of the brain'.

Neurons in the brain that are supposed to signal when enough has been eaten and when the body needs to burn off calories are far more sluggish in obese rats because they are inhibited by other cells, the researchers report in the journal Proceedings of the National Academy of Sciences.

However, in animals resistant to obesity, these same neurons are far more active - and quickly tell the rest of the brain and the body when enough food has been consumed.

The way the brain develops and whether it is vulnerable to obesity is influenced by genes and conditions in the womb, the researchers say.

Dr Horvath added: 'Those who are vulnerable to diet-induced obesity also develop a brain inflammation, while those who are resistant, do not. 'This emerging inflammatory response in the brain may also explain why those who once developed obesity have a harder time losing weight.'

In 1980, six per cent of men and eight per cent of women in Britain were obese. Twenty years later, 22 per cent of men and 23 per cent of women are obese. At least 20million people in this country are thought to be overweight, while 12million are clinically obese. If the trends continue, one third of adults and half of all children will be obese by 2020.

Diet experts say the explanation for the wave of obesity is simple - that in an age of labour- saving devices and home entertainment, most people are doing too little exercise. At the same time, high-fat, high-sugar foods are more widely available.

The new finding doesn't explain why obesity is on the rise - but sheds light on why some people struggle to lose the extra pounds they get from a sedentary lifestyle.


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