Posts Tagged ‘Bacteria’

Bacteria and Obesity

December 22, 2012
Two mice; the mouse on the left has more fat s...

Guess which mouse has the bacteria inside it.

 

Here is a story that might make you feel better about eating too much at Christmas get togethers. According to a study in China, it isn’t how much we eat or how little we exercise that makes us fat, it is what bacteria we have in our colons. I found the article in the Financial Times through Instapundit.

 

Obesity in human beings could be caused by bacterial infection rather than eating too much, exercising too little or genetics, according to a groundbreaking study that could have profound implications for public health systems, the pharmaceutical industry and food manufacturers.

The discovery in China followed an eight-year search by scientists across the world to explain the link between gut bacteria and obesity.

Researchers in Shanghai identified a human bacteria linked with obesity, fed it to mice and compared their weight gain with rodents without the bacteria. The latter did not become obese despite being fed a high-fat diet and being prevented from exercising.

 

Personally, I think that diet and exercise might have a little to do with obesity. If this study proves to have merit than it might pave the way to more effective weight loss methods. This isn’t the only article I have read indicating that human intestinal bacteria might have a profound impact on our health and clearly a lot more research needs to be done in this field.

 

Here is a sentence in the middle of the article that ought to make anyone think for a minute.

 

Governments around the world are grappling with an obesity pandemic.

 

Do you know how truly weird it is that governments around the world have to deal with obesity. It wasn’t that long ago that the major preocupation of most governments was preventing their citizens from starving. The fact that a large portion of the population of the world may suffer from having too much food is simply unprecedented in human history and represents a triumph of man over nature, if not an entirely unprobematic one.

 

 

 

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No Man is an Island

August 20, 2012

As the poet John Donne put it,

No man is an island entire of itself; every man is a piece of the continent, a part of the main; if a clod be washed away by the sea, Europe is the less, as well as if a promontory were, as well as any manner of thy friends or of thine own were; any man’s death diminishes me, because I am involved in mankind. And therefore never send to know for whom the bell tolls; it tolls for thee.

Though he had it slightly wrong. If the latest research in biology is any indication, we are, each one of us, a continent, perhaps even a world in ourselves. That is the impression I got when I read this article in The Economist.

The traditional view is that a human body is a collection of 10 trillion cells which are themselves the products of 23,000 genes. If the revolutionaries are correct, these numbers radically underestimate the truth. For in the nooks and crannies of every human being, and especially in his or her guts, dwells the microbiome: 100 trillion bacteria of several hundred species bearing 3m non-human genes. The biological Robespierres believe these should count, too; that humans are not single organisms, but superorganisms made up of lots of smaller organisms working together.

It might sound perverse to claim bacterial cells and genes as part of the body, but the revolutionary case is a good one. For the bugs are neither parasites nor passengers. They are, rather, fully paid-up members of a community of which the human “host” is but a single (if dominating) member. This view is increasingly popular: the world’s leading scientific journals, Nature and Science, have both reviewed it extensively in recent months. It is also important: it will help the science and practice of medicine

The microbiome does many jobs in exchange for the raw materials and shelter its host provides. One is to feed people more than 10% of their daily calories. These are derived from plant carbohydrates that human enzymes are unable to break down. And not just plant carbohydrates. Mother’s milk contains carbohydrates called glycans which human enzymes cannot digest, but bacterial ones can.

This alone shows how closely host and microbiome have co-evolved over the years. But digestion is not the only nutritional service provided. The microbiome also makes vitamins, notably B2, B12 and folic acid. It is, moreover, capable of adjusting its output to its host’s needs and diet. The microbiomes of babies make more folic acid than do those of adults. And microbiomes in vitamin-hungry places like Malawi and rural Venezuela turn out more of these chemicals than do those in the guts of North Americans.

The microbiome also maintains the host’s health by keeping hostile interlopers at bay. An alien bug that causes diarrhoea, for instance, is as much an enemy of the microbiome as of the host. Both have an interest in zapping it. And both contribute to the task. Host and microbiome, then, are allies. But there is more to it than that. For the latest research shows their physiologies are linked in ways which make the idea of a human superorganism more than just a rhetorical flourish.

So, each one of us is not just a single entity, but a whole community of microbes. I’ll never feel lonely again. Meanwhile, we should all be good to our bacteria, they are our closest friends.


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