Dr Alan C. Logan, ND, FRSH

Gut Health

By Dr. Alan C. Logan, ND, FRSH

For centuries humans have focused on the gastrointestinal tract (GI) as a foundation stone in health and vitality. The health of the GI tract is highly dependent upon the 100 trillion bacterial cells which set up camp in the human gut. There are somewhere between 500 and 1000 bacterial species in the GI tract which are collectively referred to as the microflora. Together, they have an untold effect on the structure and function of the human intestinal tract. However, the influence of gut bacteria goes way beyond the intestinal tract - the bacteria in our intestines plays a role in the immune system function, including a widespread influence on immune chemicals called cytokines and on oxidative stress.

Among the hundreds of bacterial species which make the human GI tract home, two are of critical importance to our health. Lactobacilli and Bifidobacteria, the so-called friendly bacteria, are involved in vitamin synthesis, the detoxification and metabolism of toxic substances, stimulation of the immune response, protection from pathogenic (bad) bacteria, and the defense of the intestinal lining. In addition, Lactobacilli and Bifidobacteria can lower levels of toxic compounds which can otherwise build up through digestive and other metabolic processes and they can lower oxidative stress in the gut and beyond.

Scientists now know that cytokines can influence human mood and cognitive function. Some of these cytokines can be elevated in healthy humans in laboratory settings via administering a bacterial coating. Controlled studies show that the end result of such administration is symptoms of depression, anxiety and difficulty in mental processing. A number of experimental and human studies have made connections between alterations in normal GI bacteria and subsequent mental and cognitive symptoms. Altered microflora has been associated with the following conditions:

Acute diarrhea
Allergies/eczema
Autism
Constipation
Chronic fatigue syndrome
Colic
Crohn’s disease
Fibromyalgia
Irritable bowel syndrome
Obesity
Ulcerative Colitis

Stress and over-use of antibiotics is associated with altered microbial flora in the gut.
Probiotics are viable bacteria which positively influence human health. There are three important parts to a probiotic name - genus, species, and strain. Examples of highly researched strains include Lactobacillus (genus) casei (species) Shirota (strain) and Bifidobacteriuminfantis (genus) infantis (species) 35624(strain). Researchers from Yale University, and the University of Connecticut identified 288 health-related outcomes in human clinical trials published from 1980 though August 2004 and found that about 83% of these studies documented the benefits of probiotics administered to humans. From Crohn’s disease to lactose intolerance, from allergies to irritable bowel syndrome, probiotics have shown benefit. However, not all probiotics are alike, and some commercial products marketed under the umbrella term ‘acidophilus’ are probably nothing more than pixie dust. In today’s natural product marketplace, it is buyer beware. One cannot extrapolate the benefits of one probiotic strain and apply them to all others. For example, Lactobacillus casei strain Shirota, found in the commercially available yogurt drink Yakult, has been shown to help with human constipation. This may not be the case, and is probably not the case with other products which contain unidentified strains of Lactobacillus casei or Lactobacillus acidophilus.