leaky-gut syndrome confirmed at columbia university...,

columbia |  A new study may explain why people who do not have celiac disease or wheat allergy nevertheless experience a variety of gastrointestinal and extra-intestinal symptoms after ingesting wheat and related cereals. The findings suggest that these individuals have a weakened intestinal barrier, which leads to a body-wide inflammatory immune response.

Findings from the study, which was led by researchers from Columbia University Medical Center (CUMC), were reported in the journal Gut.

“Our study shows that the symptoms reported by individuals with this condition are not imagined, as some people have suggested,” said study co-author Peter H. Green, MD, the Phyllis and Ivan Seidenberg Professor of Medicine at CUMC and director of the Celiac Disease Center. “It demonstrates that there is a biological basis for these symptoms in a significant number of these patients.”

Celiac disease is an autoimmune disorder in which the immune system mistakenly attacks the lining of the small intestine after someone who is genetically susceptible to the disorder ingests gluten from wheat, rye, or barley. This leads to a range of gastrointestinal symptoms, including abdominal pain, diarrhea, and bloating.

Researchers have struggled to determine why some people, who lack the characteristic blood, tissue, or genetic markers of celiac disease, experience celiac-like GI symptoms, as well as certain extra-intestinal symptoms, such as fatigue, cognitive difficulties, or mood disturbance, after ingesting foods that contain wheat, rye, or barley. One explanation for this condition, known as non-celiac gluten or wheat sensitivity (NCWS), is that exposure to the offending grains somehow triggers acute systemic immune activation, rather than a strictly localized intestinal immune response. Because there are no biomarkers for NCWS, accurate figures for its prevalence are not available, but it is estimated to affect about 1 percent of the population, or 3 million Americans, roughly the same prevalence as celiac disease.

the poop gap

westhunt |  There’s a new article out in Science tracing the splits in gut flora. It looks as if the gut bacteria in chimpanzees split with those in humans 5.3 million years: doesn’t quite match our genetic estimates based on Human/chimp autosomal DNA differences, but it’s in the ball park. They estimate the human-gorilla split at 15.6 million year ago, but that can’t be right: we know that gorillas split off just a bit before the human-chimp split. Perhaps gorilla diet changed drastically, and maybe they picked up new bacteria from some other species.

Different populations of modern humans apparently have pretty different microbiomes. The gut bacteria from people in Malawi appear to have diverged 1.7 million years ago from those in Europeans (people from Connecticut). That is surely too old to be a consequence of modern humans’ trek out of Africa: it looks as if AMH, after leaving Africa, picked up gut flora from archaic sapiens like Neanderthals and Denisovans and dwarves.

Microbiomes are trendy. We know that fecal transplants can cure C difficile (pseudomembranous colitis) lickety-split: they might help with Crohn’s disease and ulcerative colitis. Some researchers think the microbiome has something to do with the initiation of multiple sclerosis. Others suspect that it may play a role regulating how people think and feel – in particular, mood disorders. Autism has been mentioned. 

So.. Poop matters: it certainly can affect health, and it may influence brain function. People from sub-Saharan have divergent poop, or you could say that Eurasians do. Are there differences in brain function between sub-Saharan Africans and Eurasians? Sure: Africans do poorly on IQ tests and in academic subjects. They have significant higher rates of schizophrenia, higher murder rates, etc.

Maybe it’s the poop. It’s worth checking out. Perhaps the fault lies not in our stars, or our genes, but in our stool. 

Already, eager experimenters – paleos on stilts – are trying to dramatically modulate their internal flora.

immune system controls social interactions

medicalxpress |  In a startling discovery that raises fundamental questions about human behavior, researchers at the University of Virginia School of Medicine have determined that the immune system directly affects - and even controls - creatures' social behavior, such as their desire to interact with others. So could immune system problems contribute to an inability to have normal social interactions? The answer appears to be yes, and that finding could have great implications for neurological conditions such as autism-spectrum disorders and schizophrenia. 

"The brain and the adaptive immune system were thought to be isolated from each other, and any immune activity in the brain was perceived as sign of a pathology. And now, not only are we showing that they are closely interacting, but some of our behavior traits might have evolved because of our immune response to pathogens," explained Jonathan Kipnis, PhD, chairman of UVA's Department of Neuroscience. "It's crazy, but maybe we are just multicellular battlefields for two ancient forces: pathogens and the immune system. Part of our personality may actually be dictated by the immune system."

gut bacteria spotted eating brain chemicals for the first time

newscientist |  Bacteria have been discovered in our guts that depend on one of our brain chemicals for survival. These bacteria consume GABA, a molecule crucial for calming the brain, and the fact that they gobble it up could help explain why the gut microbiome seems to affect mood.

Philip Strandwitz and his colleagues at Northeastern University in Boston discovered that they could only grow a species of recently discovered gut bacteria, called KLE1738, if they provide it with GABA molecules. “Nothing made it grow, except GABA,” Strandwitz said while announcing his findings at the annual meeting of the American Society for Microbiology in Boston last month.

GABA acts by inhibiting signals from nerve cells, calming down the activity of the brain, so it’s surprising to learn that a gut bacterium needs it to grow and reproduce. Having abnormally low levels of GABA is linked to depression and mood disorders, and this finding adds to growing evidence that our gut bacteria may affect our brains.

Treating depression 

An experiment in 2011 showed that a different type of gut bacteria, called Lactobacillus rhamnosus, can dramatically alter GABA activity in the brains of mice, as well as influencing how they respond to stress. In this study, the researchers found that this effect vanished when they surgically removed the vagus nerve – which links the gut to the brain – suggesting it somehow plays a role in the influence gut bacteria can have on the brain.  Fist tap Big Don