I asked Brenda Watson, author of the just released new book, The Skinny Gut Diet: Balance Your Digestive System for Permanent Weight Loss, to answer a few questions about bowel health and bowel flora.
Long before probiotics were a household word, Brenda was deeply involved in this world of restoring the bacterial species that co-exist with humans and, when managed properly, provide an unexpected and substantial list of health benefits to the host human. So here are some thoughts from Brenda that give you a sense of the conversations in her Skinny Gut book.
WB: Accepting that nobody knows all the bacterial species that should comprise healthy bowel flora, do you aim to provide several specific species you find crucial in probiotic choices?
BW: Human microbiome studies strongly suggest that the more diverse the microbiota, the healthier the host. Over 10,000 species of bacteria are known to inhabit the human digestive tract, with at least several hundred (up to several thousand) found in any one human. To improve gut bacterial diversity we turn to 1) diet, 2) supplementation, and 3) fecal transplants (in extreme medical circumstances).
Gut bacterial diversity is enhanced by eating foods that contain beneficial microbes (fermented foods) and foods that feed beneficial microbes (prebiotic fibers and resistant starches). Diversity is also enhanced by supplementing with a multi-strain probiotic formula or, in certain medical situations, receiving direct fecal implants under the care of a physician.
When supplementing with probiotics, the key is to choose microbes that are known to be beneficial. Virtually all species of Lactobacillus and Bifidobacterium have been found in human studies to be beneficial. These strains have the strongest record of safety and efficacy. Not only that, but they also exhibit excellent stability when packaged and stored under the right conditions. A probiotic formula containing a diverse array (at least 10) of different strains of Lactobacillus and Bifidoabcterium will best reflect the diversity found in a healthy human digestive tract. Potency is also important, since there are 100 trillion cells inside the digestive tract, outnumbering—by ten times—the number of cells that make up the entire body. Saccharomyces boulardii, a beneficial yeast, is also well known to be an effective probiotic, especially for cases of diarrhea, and is usually taken on its own.
While other beneficial species are found in the healthy human gut, the only way, at this time, to obtain many of these species, is by receiving a fecal transplant. Currently, fecal transplants are only being used in clinical trials and in select clinics for people with severe, refractory C. difficile infections.
WB: In Skinny Gut, you discuss the bowel flora distortions in overweight people at length and how correcting bowel flora can facilitate weight loss. But have you seen the opposite occur: People unable to maintain weight due to distortions of bowel flora? If so, have you approached this situation any differently?
BW: Good question. That could be the next thing we need to look at! I have more commonly been working with people who need to lose weight, so I have not yet had the opportunity to investigate gut imbalance in people who have difficulty gaining weight. It certainly makes sense that if you increased certain bacteria (such as the Firmicutes) in people who are underweight, that they would gain weight.
WB: Can you summarize some of the mental and emotional benefits that people may experience with positive changes in bowel flora?
BW: The gut-brain connection travels in two directions. When we are emotionally upset or under great mental stress, it affects our digestion. It’s fight-or-flight in full effect—digestion shuts down as the body readies itself for the worst. We might experience stomach aches, nausea, or changes in bowel habit (diarrhea, constipation). Also, under stress, our levels of beneficial bacteria go down. In the reverse, when our gut bacteria are out of balance, it can affect our mental and emotional health. With positive changes in bowel flora, improvements in our mental health can occur. Reductions in anxiety and improvements in anxiety-related digestive disturbances, in particular, are experienced.
WB: Thanks for the helpful thoughts, Brenda!