On The Hadza

The Food Programme - Hunting with the Hadza - from BBC Radio4.

What Lies Beneath

On gut flora extinction:

"Years ago, impelled in part by their oldest daughter’s constipation problems, the Sonnenburg family revamped its diet. They threw out all processed food-stuffs, and began eating plenty of veggies and whole grains. They bought a dog. Justin Sonnenburg began hand-milling his own wheat berries for bread. He took up gardening. And when he compared his archived microbes from years ago with recent ones, he discovered that his microbial diversity had increased by half. “That’s a huge difference,” he told me, “as big as the difference between Americans and Amerindians.”"

Moving Home and Microbes

An incredible finding from the Home Microbiome Study and featured in New Scientist:

• "You may forget your toothbrush next time you go away but you can't leave your microbes behind. Millions of bacteria hitch a ride with you, making themselves comfortable wherever you go. Within only a few hours, they will have colonised a hotel room; give them 24 hours and they can take over an entire house."

Gut flora and discussion about how microbial life impacts our health has long featured on these pages, but this really blows me away.

Allergies: Modern Life and Me

BBC2's Horizon aired last night, covering allergies.  Explicitly they looked at the gut mircrobiome and bacterial populations in and around humans and their principle habitats.

• Changes to the bacteria that live inside all of us are responsible for increasing the number of people with allergies, suggests new research. In this episode of Horizon, the show investigates this claim by conducting a unique experiment with two allergic families in order to find out just what it is in the modern world that is to blame. With a raft of mini cameras, GPS units and the very latest gene sequencing technology, the show discovers how the western lifestyle is impacting their bacteria. Why are these changes making people allergic? And what can be done to put a stop to the allergy epidemic?

Gut War

I've posted up loads about gut flora and ecology.  Your inner biome is critical to your health.  Whilst illness, injury and death by 'tooth and claw' has diminished, the threat posed by accident is ever present, and the danger posed by bacteria and virus is ever-changing. 

But with bacterial attack, the BBC reports that we should be equipped to fight back against some of the most lethal strains,

• The gut infection Clostridium difficile can be defeated by a cocktail of rival good bacteria, experiments in mice show.
  
  When C. difficile bacteria overwhelm the gut, it can be fatal and difficult to treat with antibiotics.
  
  A UK team showed a combination of six bacteria could clear the infection.
  
  The study, published in PLoS Pathogens, builds on faecal transplant procedures - which are used to introduce competing bacteria.
  
  C. difficile bacteria live in many people's guts alongside hundreds of other species - all fighting for space and food.

Think about that last line!

The Epigenetics Revolution: Nutrition

Some further extracts from Nessa Carey's excellent The Epigenetics Revolution. 

The Agouti mouse is no stranger to those who have spent any time in the paleosphere.  Epigeneticists have used these mice to uncover some pretty intriguing phenomena:

• [Emman Whitelaw changed the expression of epigenetic proteins]. No matter how tightly scientists control the environment for the [agouti] mice and especially their access to food, identical mice from inbred mouse strains don't all have exactly the same body weight. Experiments carried out over many years have shown that only about 20-30 per cent of the variations in body weights can be attibuted to the post natal environment. This leaves the question of what causes the other 70-80 per cent of variation in body weight. Since it isn't being caused by genetics (all the mice are identical) or by the environment, there has to be another source for the variation.

Gut Flora and Mood

Long time readers will be aware of the mounting evidence that the profile of your gut flora can change depending upon your diet.  Poor diets can enable 'bad' gut flora to flourish, causing a host of problems around chronic inflammation, nutrient absorption and so on.

Today I stumbled across this piece on how 'Microbes manipulate your mind' which goes in to how microbes in your gut might influence your brain and behaviour:

• The human gut contains a diverse community of bacteria that colonize the large intestine in the days following birth and vastly outnumber our own cells. These so-called gut microbiota constitute a virtual organ within an organ, and influence many bodily functions. Among other things, they aid in the uptake and metabolism of nutrients, modulate the inflammatory response to infection, and protect the gut from other, harmful micro-organisms. A study by researchers at McMaster University in Hamilton, Ontario now suggests that gut bacteria may also influence behaviour and cognitive processes such as memory by exerting an effect on gene activity during brain development.
  
  Jane Foster and her colleagues compared the performance of germ-free mice, which lack gut bacteria, with normal animals on the elevated plus maze, which is used to test anxiety-like behaviours. This consists of a plus-shaped apparatus with two open and two closed arms, with an open roof and raised up off the floor. Ordinarily, mice will avoid open spaces to minimize the risk of being seen by predators, and spend far more time in the closed than in the open arms when placed in the elevated plus maze.
  
  This is exactly what the researchers found when they placed the normal mice into the apparatus. The animals spent far more time in the closed arms of the maze and rarely ventured into the open ones. The germ-free mice, on the other hand, behaved quite differently – they entered the open arms more often, and continued to explore them throughout the duration of the test, spending significantly more time there than in the closed arms.
  
  The researchers then examined the animals' brains, and found that these differences in behaviour were accompanied by alterations in the expression levels of several genes in the germ-free mice. Brain-derived neurotrophic factor (BDNF) was significantly up-regulated, and the 5HT1A serotonin receptor sub-type down-regulated, in the dentate gyrus of the hippocampus. The gene encoding the NR2B subunit of the NMDA receptor was also down-regulated in the amygdala.

Many obese people describe themselves as 'emotional eaters' and the domian this approach to obeisty is the domain of psychologists.  This story makes me think that food quality may well play a pivotal role.  FEED YOUR MIND!

Guts: The Strange and Mysterious World of the Human Stomach

A heads up for viewers in the UK;  Guts: The Strange and Mysterious World of the Human Stomach on BBC Four at 21:00 BST on Thursday 12 July (or watch online afterwards via iPlayer):

• Now, you might think that just reducing the size of the stomach would be enough to sort out Bob's problems, because the smaller the stomach the less you eat.
  
  But that does not seem to be what happens according to his surgeon, Mr Ahmed Ahmed, at London's Charing Cross Hospital.
  
  "The modern thinking is that by doing the surgery you're producing changes in various hormones, chemical messengers which affect hunger levels and fullness levels, which in turn cause the weight loss.
  
  "Bob's gastric bypass surgery separated off and isolated the part of his stomach which produces most ghrelin, a hormone which appears to play a key role in making you feel hungry."
  
  The hope was that this would result in a permanent fall in production of ghrelin. His new shrunken stomach was then attached further down his small intestine, to a section known as the ileum which secretes a different gut hormone, PYY, which is responsible for making you feel full.
  
  When we eat, it normally takes 20 minutes for food to get from the stomach to the ileum, causing the release of PYY and the message to the brain, "I'm full".
  
  That is why it is better to eat slowly, to give the stomach a chance to tell the brain you have had enough before you overeat.

Inflammation and Gut Flora

New Scientist had an interesting piece called 'Milk fats clue to inflammatory bowel disease'.  Various gut flora can thrive on particular diets - and in terms of our own health, not all gut flora is created equal,

• Concentrated milk fats, a common ingredient of processed foods and confectionary, trigger blooms of otherwise rare gut bacteria in mice that may contribute to inflammatory gut diseases.

This comes hot on the heels of the Human Microbiome Project which seeks to map out the trillions of bactiera which inhabit the human body,

• "Knowing which microbes live in various ecological niches in healthy people allows us to better investigate what goes awry in diseases thought to have a microbial link, like Crohn's disease and obesity," says George Weinstock, associate director of the Genome Institute at Washington University in St Louis and one of the Human Microbiome Project's principal investigators.
  
  They found that microbial cells outnumber native human cells by 10 to one, and collectively have 8 million genes compared to just 22,000 in humans. Of the 10,000 species identified, the most diverse range lived on the skin. Bacteria that colonise the teeth are different from those in saliva, and the vagina hosts the simplest range of bugs. 

 Looks like you are what you eat, you are what your body does with what you eat, you are what your bacteria is and you are what bacteria does with what you eat. 

Trying to figure out first cause with the obese never looked so complicated.