Ed Young has yet another great post, follow up to his last year Quaker Daily prizing winning post. Now that science has pretty much quantified the common sense, how many of us are willing to change our lifestyle? When will the (junk) food subsidies be downsized (or as they say in an utopian world "eradicated")? Your guess is as good as mine.
We depend on a special organ to digest the food we eat and you won’t find it in any anatomy textbook. It’s the ‘microbiome’ – a set of trillions of bacteria living inside your intestines that outnumber your own cells by ten to one. We depend on them. They wield genes that allow them to break down molecules in our food that we can’t digest ourselves. And we’re starting to realise that this secret society within our bowels has a membership roster that changes depending on what we eat.
These changes take place across both space and time. Different cultures around the world have starkly contrasting diets and their gut bacteria are different too. As we grow older, we eat increasingly diverse foods, from the milk of infancy to the complex menus of adulthood. As our palate changes, so do our gut bacteria.
Carlotta de Filippo compared the gut bacteria of 14 children from a village in Burkina Faso with those of 14 children in Florence, Italy. The African children came from families of subsistence farmers and their menus were mostly vegetarian. The eat little in the way of fat or animal protein and their diet is heavy in fibre, starch and plant carbohydrates. By contrast, the Italian kids ate a typical Western diet, high in animal protein, sugar, starch and fat and low in fibre. They ate about half as much fibre as their African peers and about 50% more calories.
These differences are reflected in their bowels. The bacterial community in the African guts were dominated by those plant-digesting specialists, the Bacteroidetes. They probably helped the children to break down the tough fibres that they eat and extract more energy from their meals. Meanwhile, the Italian bowels were dominated by another group, the Firmicutes, which are generally more common in obese people compared to lean ones.
We depend on a special organ to digest the food we eat and you won’t find it in any anatomy textbook. It’s the ‘microbiome’ – a set of trillions of bacteria living inside your intestines that outnumber your own cells by ten to one. We depend on them. They wield genes that allow them to break down molecules in our food that we can’t digest ourselves. And we’re starting to realise that this secret society within our bowels has a membership roster that changes depending on what we eat.
These changes take place across both space and time. Different cultures around the world have starkly contrasting diets and their gut bacteria are different too. As we grow older, we eat increasingly diverse foods, from the milk of infancy to the complex menus of adulthood. As our palate changes, so do our gut bacteria.
Carlotta de Filippo compared the gut bacteria of 14 children from a village in Burkina Faso with those of 14 children in Florence, Italy. The African children came from families of subsistence farmers and their menus were mostly vegetarian. The eat little in the way of fat or animal protein and their diet is heavy in fibre, starch and plant carbohydrates. By contrast, the Italian kids ate a typical Western diet, high in animal protein, sugar, starch and fat and low in fibre. They ate about half as much fibre as their African peers and about 50% more calories.
These differences are reflected in their bowels. The bacterial community in the African guts were dominated by those plant-digesting specialists, the Bacteroidetes. They probably helped the children to break down the tough fibres that they eat and extract more energy from their meals. Meanwhile, the Italian bowels were dominated by another group, the Firmicutes, which are generally more common in obese people compared to lean ones.
The African children also had a greater diversity of gut bacteria, which probably hitch a ride into their bodies via their food. In Europe, generic, uncontaminated food presents a blockade to bacteria from the outside world, which means that Western gut communities have become gentrified. They lack genetic diversity, and they have few ways of increasing it.
This is bad news, for bacteria from the outside world provide a reservoir of useful genes that could help the microbiome to adapt to unusual diets. The fibre-digesting abilities of the Burkina Faso children are probably one example of this. A more striking one was discovered just last year: Japanese gut bacteria have borrowed genes from an oceanic species, which allow them to digest carbohydrates in seaweed. Western diets hold back this evolutionary potential.
But De Filippo thinks that the problems are bigger. An unbalanced or simplified microbiome could be damaging the health of Westerners more directly, affecting the risk of a variety of other medical conditions, including allergies, inflammatory bowel disease, bowel cancer and obesity. A diverse microbiome could also prevent more harmful species from setting up shop – indeed, and somewhat unexpectedly, food poisoning bacteria like Shigella and Escherichia were less common in the Burkinabe children than the Dutch ones.
This is bad news, for bacteria from the outside world provide a reservoir of useful genes that could help the microbiome to adapt to unusual diets. The fibre-digesting abilities of the Burkina Faso children are probably one example of this. A more striking one was discovered just last year: Japanese gut bacteria have borrowed genes from an oceanic species, which allow them to digest carbohydrates in seaweed. Western diets hold back this evolutionary potential.
But De Filippo thinks that the problems are bigger. An unbalanced or simplified microbiome could be damaging the health of Westerners more directly, affecting the risk of a variety of other medical conditions, including allergies, inflammatory bowel disease, bowel cancer and obesity. A diverse microbiome could also prevent more harmful species from setting up shop – indeed, and somewhat unexpectedly, food poisoning bacteria like Shigella and Escherichia were less common in the Burkinabe children than the Dutch ones.
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