Gutsy bacteria

Missing MicrobesThe human microbiome is hot stuff these days. Hard to imagine we have only gained some understanding of its existence and importance since the Human Microbiome Project kicked off in 2008. Beneficial gut bacteria, it turns out, are very hard to study because they live an anaerobic (oxygen-free) life in our intestinal tract. It was only when their DNA could be studied (metagenomics) that we began to understand how big a deal they were in human health. A very big deal indeed, as they are thought to number in the trillions. Our understanding of their diverse identities can barely be described as sketchy.

I’ve been browsing my way through Missing Microbes. I love this book. Its author, Martin Blaser, is an MD who has been researching a much discussed bacterium, Heliobacter Pylori, for over 30 years. H. pylori, which has colonized the human gut for more than 50,000 years, was determined by the winners of the 2005 Nobel Prize in Physiology to be the cause of peptic ulcers which had previously been ascribed to stress. The bacterium has also been associated with stomach cancer.

But Blaser also believes H. pylori plays an important immunological role, and that our all-out antibiotic assault on it may be costing us in more ways than the increasing rates of antibiotic resistance which the Nobel winners had also predicted. Blaser and others speculate that since its loss in Western populations correlates to increases in autoimmune disorders, there may be more to this ancient bacterium that has for so long co-existed in the human gut. Adults who lack H. pylori may also be more susceptible to reflux (GERD) and heartburn that can themselves lead to esophageal cancers. And there is some evidence that it protects against allergies and asthma in childhood.

Blaser has a lot to say about antibiotic use in modern medicine as well as modern farming, and how these have contributed to making the modern microbiome a biological desert, and landed humans in a completely new and dangerous medical landscape.

As his book’s subtitle suggests, Blaser believes that antibiotic use has contributed to many of our modern ills.  His work on antibiotics and obesity suggested that antibiotics administered in childhood may have the same effect farmers look for in their meat animals: accelerated growth, making them taller and fatter.

North American children are typically exposed to around 17 courses of antibiotics by the time they are 20, and another 13 by the time they are in their 30s. This doesn’t include the antibiotics they may receive from their mother through the placenta or breast milk, nor those consumed in drinking water, milk and meat. Children born of C-sections are also deprived of protective maternal bacteria from vaginal birth, and subject to direct or indirect antibiotics.

We don’t know yet what will be the long term effects of so many antibiotics on a developing brain and immune system in children, nor on public health as a whole. There are a lot of troubling correlations: people who used antibiotics in the month before a salmonella outbreak in Chicago got sicker than those who didn’t. Exposure of children to broad-spectrum antibiotics in the first two years of life (notably –mycin drugs) is associated with lifetime obesity. A Swedish study found a clear association between celiac disease onset following antibiotic use. Antibiotics impair our ability to excrete estrogen, leading to the modern ills of estrogen dominance (which affects men and children as well as women). Even short courses of antibiotics may permanently change our unique, personal microbiome, and there is no known way to permanently reinstate what’s been lost – even if we knew what that was.

Not all beneficial bacteria – or, like H. pylori, those that demonstrate amphibiosis, being sometimes beneficial and other times not – can be re-colonized into the human gut over the long term. H. pylori, for example, which is not just one but a family of microbes, is acquired in infancy and childhood in conditions that typically no longer exist in the Western world. (Blaser stresses replacing the term “infection” with “colonization” when speaking of our microbes. Since we have co-existed with some – like H. pylori – for millennia, the only thing we know for sure is that we don’t fully understand our biological history with them.)

Meanwhile, says Blaser, we can start by avoiding antibiotics wherever possible, particularly broad-spectrum ones that cause too much collateral damage. Avoiding c-section births except in medical emergencies, and re-evaluating the prophylactic use of antibiotics where c-sections are required would help protect children. Discussing with a pediatrician whether antibiotics are the appropriate first course of treatment for childhood ailments  is crucial. Lobby for policies preventing the use of antibiotics in farming and meanwhile avoid conventionally raised meat and dairy. He’s lukewarm on probiotic supplements, prebiotics, and their hybrid synbiotics, mainly because we simply don’t know which bacteria are crucial, and there is little research and no standards for production. Fecal transplants are helpful for some conditions (but not DIY versions where the donor has not been screened for medical risks to the recipient).

Meanwhile, the research into this essential biological mystery is exploding in the scientific world. Let’s hope we can get enough scientific leverage on political will to reverse some of the excesses of antibiotics before we’ve killed off all that aids us.

Gluten problems? Don’t stop eating it!

17628204I happened to attend a talk recently, given by a registered dietician who’s worked closely with the Canadian Celiac Association, and wanted to share what she knew about gluten intolerance and allergy, and to warn those with a suspected sensitivity NOT to stop eating wheat.

This particular dietician holds in high regard a book, Gluten Freedom, by an author I’d been impressed with when I heard him speak last year: Alessio Fasano. He’s a pediatrician with a background in celiac research. He first sought and then delivered the research that disproved the popular medical wisdom of the 1990s which held that celiac disease was virtually unknown in North America. By testing existing Red Cross blood samples, he determined that 1 in 133 were undiagnosed celiacs; relatives of celiacs numbered 1:22, comparable to rates already known in Europe.

The fundamental problem for humans is that a class of gluten proteins found in wheat, rye and barley, the gliadins, are indigestible by humans. We lack the enzymes to break them down properly. For most of us this is not a problem, but it is for celiacs, those with wheat allergies, FODMAP sensitivities, or the real but so far undiagnosable (lack of a known biomarker) non-celiac gluten sensitivity.

Celiacs produce antibodies in the presence of gliadins, triggering an autoimmune response that destroys the villi which line the digestive tract and allow nutrient absorption. For this reason, celiacs often suffer weight loss, mineral depletion and associated problems such as osteoporosis or osteoarthritis. Often they have acid reflux, anemia, dental problems, skin conditions or other autoimmune disorders such as Hashimoto’s.

Such conditions and symptoms do not set celiac disease apart medically from many other conditions, and celiacs may be asymptomatic, so diagnosis takes on average about 12 years. And the autoimmune response to gluten may be triggered at any age. Some estimates are that 85% of celiacs are undiagnosed; the real number could be higher still. Medical researcher Joseph Murray MD from the Mayo Clinic tested blood samples from soldiers in the 1950s, compared them with 21st century samples and found a fourfold increase in celiac markers in 2009.

Diagnosing celiac disease, wheat allergy, non-celiac gluten sensitivity, or a FODMAP sensitivity (which may also feature gluten among the trigger foods) requires blood testing, to determine the presence or absence of antibodies (tTG-IgA in celiacs; IgE in wheat allergies), plus genetic markers (HLA DQ2 and DQ8 in celiacs) followed by a biopsy of the small intestine for celiacs.

So.. the dietician’s advice not to stop eating gluten had to do with the celiac screening process. If you have symptoms that are relieved by avoiding (gluten-containing) trigger foods, that solves one problem. But it doesn’t answer the question of whether you are one of the large number of undiagnosed celiacs. If you might be, you must eat gluten (3g/day, about 1.5 pieces of bread) for at least 3 weeks before having the blood tests and biopsy. If you have stopped, the inflammation dies down and healing will begin. So the test results will be off. Also, if you go off gluten and then return, you may trigger a more severe reaction leading to much worse symptoms. You may not be compensating for the nutrients you had lost if your villi were damaged, or which you previously obtained from gluten products (there are recommended supplements) such as fibre. Staying on gluten also reduces the number of tests and re-tests needed, and puts you firmly on biopsy waiting and cancellation lists, and means a speedier diagnosis = the better to make those long-term changes if needed.

Also, if you are found not to be celiac, you might fall into a luckier category and be needlessly depriving yourself by embarking too soon on a gluten-free diet. Wheat allergy might leave room for other gluten-containing foods; FODMAP-sensitive people tend to have episodic symptoms and may tolerate alternate forms of wheat such as spelt; and non-celiac gluten sensitive people may (or may not) be able to tolerate small amounts of good quality gluten products, given proper preparation methods and food enzymes. As anyone who’s tried it knows, going off gluten can be an expensive, isolating and frustrating experience, so here’s hoping it isn’t necessary.

Bottom line? Celiac disease is worth checking out if you have gluten issues, as it robs your body of important nutrients with a strong effect on future health, is curable (by diet), has a genetic aspect (family members need to know) and if left untreated gives you a much shorter lifespan with more chronic health conditions and susceptibility to autoimmune disorders and a couple of nasty forms of cancer.

I’ll have more to say about wheat allergy, FODMAP and non-celiac gluten sensitivity in a future post.