A current trend in alternative and holistic medicine is that of specialized diets to treat gut health, with the intent of improving immune function. With a focus on fostering the growth of healthy gut bacteria, many of these diets are quite restrictive, eliminating food groups entirely. Some diets (think AIP or GAPS) become increasingly restrictive if the patient doesn’t continue to get better. A new study to be published in Molecular Metabolism may call in to question this practice.
Many of the common illnesses of the 21st century, including type 2 diabetes, obesity and inflammatory bowel disease, are associated with reduced microbiotic richness. The study found that highly specialized diets will change the landscape of the gut microbiome over time. In fact, it takes only a few days of changing diet to alter the micro-biotic makeup of the human gut, they say. And if the dietary change involves elimination of one or more macronutrients, humans are essentially selecting for some micro-biotic species over others.
Gut microbiota function as an endocrine organ, metabolizing specific nutrients from the diet and producing specific substances that act as metabolic signals in the host. They produce an abundance of important molecules for the host and with increased variation comes increased adaptability and an increased range of physiological responses. “The greater the repertoire of signals, the more likely is the ability to maintain homeostasis when dietary intake is perturbed,” explain Heiman and Greenway. “Furthermore, because each particular macronutrient has the potential to be metabolized by microbiota into unique metabolic signals, the greater the variety in signals, the greater the variety of responses possible.”
The authors of the study suggest that additional research into how specific macronutrients impact the microbiome and how to increase gut microbial diversity may be the future of personalized medicine in metabolic disease. A stool sample, rather than a blood sample, may be enough for the doctor to prescribe individualized dietary changes that will treat metabolic disorders.
Before attempting to treat any intestinal, immune, or other disease through a restrictive dietary change, a stool test may be the best way to begin, to look at markers that indicate how well the gut is actually functioning, and to assess the diversity of the gut microbiota. Diets that claim to treat immune disease through restriction should be viewed with caution, as there may be individual genetic components, food allergies, and mineral deficiencies that are being overlooked.