January 03, 2014

Gut Bacteria And The Brain

They’re called flora. Their name comes from the Roman goddess of plants, flowers and fertility, and refers to the plant life occurring in a particular region. The region in this case is the intestine, and the florae that occupy it are micro-organisms that total almost a hundred trillion, a number considerably larger than the number of cells in the human body. So phenomenal are the metabolic activities of these bacteria that they are considered an organ (O’Hara, 2006). Gut bacteria are so influential that they affect more than just a few bodily functions, from immunity to weight control to behavior and concentration (Bravo, 2011). And without them we couldn’t make biotin, vitamin K, or the short-chain fatty acids that energize intestinal cells. An absence of intestinal bacteria is associated with reduction in mucus cell turnover, muscle wall thickness, cytokine production (regulatory proteins), and of course, digestion. The micro-organism population begins in the mouth, where about two hundred different kinds live. They bypass the almost-sterile stomach and then increase on their way to the colon, where several hundred species thrive (Canny, 2008). For all that we know about the body, this area is not completely understood.

Gut diversity is more pronounced in adults than in children and, once developed, tends to remain stable unless dietary changes are dramatic. Generally, those who consume lots of vegetables and fiber have a different composition from those whose diets typify the Western regimens that are high in unwholesome fats and carbohydrates. Studies have demonstrated that what happens in the gut affects what happens in other areas of the body as well, including those that manage mood, anxiety, and possibly the onset of chronic and degenerative diseases (Tillisch, 2013). Suppose we could manipulate intestinal conditions to address health issues, either one at a time or as a group, by using probiotics.

Lactic acid bacteria and Bifidus bacteria are the most common ones used as probiotics, but others may also be employed. The WHO recognizes probiotics as living micro-organisms that confer a health benefit when taken in adequate amounts. The “health benefit,” however, is undefined. What is defined is that specific strains of a beneficent bacteria offer specific effects that cannot be ascribed to other strains, even in the same variety. Therefore, the probiotic used to treat irritable bowel syndrome will be different from the one used for pediatric diarrhea (Verna, 2010). What’s more, the optimal remedial number of colony forming units (CFU’s) for each bacterial strain is still uncertain; and the doses used in animal studies do not necessarily translate to humans. Then there’s the delivery system. Do we use yogurt, milk or a capsule? The gut environs make a difference, too. If too acidic or alkaline, some bacteria cannot survive.

One micro-organism has shown significant promise as a therapeutic agent in the matter of hypertension. It’s called Lactobacillus helveticus, a bacterium used to add a nutty flavor to American Swiss cheese and to prevent bitterness, although it lends character to other cheeses, including cheddar and various Italian varieties. The name helveticus derives from a Gallic tribe that occupied Switzerland in the first century B.C.

L. helvicus produces a compound called a tripeptide. A peptide consists of two or more amino acids linked end to end, sort of like joining batteries in series (That would be positive to negative in order to increase voltage.)  They always hook up between the oxygen-bearing carbon end of one amino and the nitrogen-bearing end of the other. When you get ten or more amino acids in this parade, it’s called a polypeptide; fifty or more give you a protein. That’s the stuff we’re made from. Some peptides, though, are hormones. The biological synthesis of protein depends on messenger RNA that lives on ribosomes; that of peptides doesn’t. A tripeptide has three amino acids. A familiar one is glutathione, an antioxidant made by the body to shield itself from reactive oxygen species. When L. helveticus is used to make a fermented milk product, it forms a tripeptide called IPP, or isoleucine-proline-proline, which acts like an ACE inhibitor.

Without getting too complicated, an ACE inhibitor deals with angiotensin-converting enzyme, a substance that makes angiotensin, which narrows blood vessels after the lub-dub and consequently raises blood pressure. Most of these drugs end in “-pril,” but have different brand names, such as Univasc, Altace or Vasotec. As with all pharmaceuticals, there are side effects, the most common being a bothersome cough. With L. helveticus there are none.  The Finns realized this after conducting a gold-standard clinical trial—randomized, double-blind, placebo-controlled—in which one hypertensive group received no intervention and the other received 150 milliliters (5 oz.) of L. helveticus fermented milk twice a day for ten weeks. There was a four-point difference in systolic pressure and a two-point difference in diastolic pressure between groups, indicating efficacy of the IPP tripeptide (Jauhiainen, 2005). Though these numbers don’t seem like much, they are, indeed, significant. If you prefer higher numbers, another, earlier, Finnish study reported six point and four point differences (Seppo, 2003). Contributing to this positive outcome is a reduction in the arterial stiffness that contributes to hypertension, particularly as we age. Additional study along these lines found that L. helveticus dairy wrought moderate changes in gene expression in the aorta, which you know to be the main artery leading away from the heart (Ehlers, 2011).

Finland is not the only venue enjoying the anti-hypertensive nature of fermented dairy. The Sant’Orsola-Malpighi University Hospital, in Bologna, Italy, noticed that subjects with high-normal blood pressure experienced a drop in numbers, while those with normal readings were unaffected, which is not a surprise (Cicero, 2010). To make this enterprise even more affable, the Japanese used powdered fermented milk to draw similar results, adding a kind of portability to the protocol (Aihara, 2005).

It’s almost hard to bridle one’s encouragement at the prospect of a hypertension management system based on functional food. A few probiotics already contain the strain: Dr. Stephen Langer’s, Garden of Life, and New Chapter are three. Spectra Probiotic by Integrative Therapeutics is another. Kefir, a probiotic drink available in the supermarket, contains L. helveticus, as well as other beneficent micro-organisms. Be advised not to stop any medications. Just know that any decrease in BP is welcome.

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