Thursday, March 10, 2011

Is Your Gut Well Armed?

The immune system is often likened to a castle whose moats, ramparts and battalions provide successive layers of defense. Barriers like skin and mucous membranes, as well as the cough reflex and enzymes in tears and sebum, provide “innate" immunity, a first line that acts without specificity against pathogens, antigens and other “non-self" substances. Phagocytes called natural killer (NK) cells also rove the bloodstream, indiscriminately scavenging what they identify as foreign. When the innate defenders fail, the next layer of immunity kicks in. This cell-based, or adaptive, response comprises the action of white blood cells known as B and T lymphocytes. The former produce antibodies that bind to antigens and ultimately destroy them, while the latter go after the antigens themselves, and also release cytokines that help control the immune response. In theory, this layered setup protects us from illness and infection. In practice, it often falls short or overreaches.

Any number of culprits cause the immune response to fail, including genetics, pollution, oxidizing free radicals, allergens, intolerants, aging and everyday stressors. Anything that stresses you stresses your immune system. Everybody deals with stress in a slightly different way. So every one of us has a personal immunity balance point. Diet is crucial to striking this balance because the gastrointestinal tract is a large immune organ. The gut mediates anywhere from 70% to 80% of immunity. Gastrointestinal mucosa, stomach acid and intestinal enzymes all participate in this interaction. Low gut mucosa, enzyme deficiencies, and overly alkaline gut environment can all be a factor in low immunity. Our natural gut flora—the beneficial bacteria adapted to inhabit our gastrointestinal (GI) tracts and aid in digestion—also plays a crucial role.

The microflora in your digestive system ‘talk’ to your immune system. The diet that you eat can change that microflora—the bacteria—in your digestive system. And if you change the population, then you change the conversation. Consuming beneficial probiotics, including lactic acid bacteria and bifidobacteria, appears to turn that conversation in an immuno-positive direction. Probiotics out-compete pathogens like Clostridium and E. coli for space and nutrition in the gut to grow. This lowers the incidence of illness—as does probiotics’ ability to alter gut pH to a level inhospitable to intruders. Probiotics also directly affect immune health—both innate and adaptive—by triggering proliferation of the cells that produce immunoglobulin A (IgA), an important mucosal antibody, and of T cells and natural killer cells.

Polyphenolic flavonoids such as quercetin have been shown to display a wide range of biochemical properties, including antioxidant and chemoprotective effects. Oxidation weakens the body’s natural defenses, so it’s no surprise that protecting against oxidation strengthens immunity. If you don’t have enough oxidative protection, then you deplete immune capacity and trigger inflammation, where cells are slowly going to give up their natural defense. Antioxidant vitamin stalwarts such as carotenoids, vitamin C, D, and E improve the capacity of innate immune cells to fight off infection and temper the proliferation of T-cells. Antioxidant minerals copper, zinc and selenium regulate redox-sensitive transcription factors, while also affecting cytokines. Physiological amounts of zinc have reduced morbidity and mortality associated with respiratory and diarrheal diseases in developing countries. Broad-spectrum coenyzmes such as lipoic acid and CoQ10 are also important.

Inflammation is a crucial step in the immune response. In the right place at the right time, inflammation is a good thing. It’s a sign that the immune system is bringing everything to bear on a problem. If you’ve got a cold or flu, you’re going to get inflammation in some of your nasal passages and your lungs, and this is the immune system doing what it’s supposed to do to fight off an infection. It’s when this inflammatory response goes into overdrive for no good reason that problems like allergies and autoimmune disorders result. Balance is key. Some foods and ingredients, and the compounds within them, help restore immunity’s balance by modulating the inflammatory response. What the right natural substance can do is not attack the symptoms, but attack the root cause, which is this imbalance in the immune system. One universally helpful substance for inflammation is omega-3s docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA).

Our gut is really the key to so many aspects of our health. An expert health professional should be able to discover a diet, lifestyle, and supplemental plan that is right for you.

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