Hippocrates recognized over two thousand years ago that the gut plays a major role in overall health—a view that modern scientific research has substantiated and solidified. With regard to GI health, there’s a lot of focus on advanced testing and intricate healing protocols. While some patients may benefit from precise analysis of the makeup of their gut flora or from specific food elimination and reintroduction strategies, let’s not overlook the fundamentals. Sometimes addressing the basics, such as general micronutrient repletion or supplementation with foundational nutrients for targeted therapeutic purposes, can go a long way for a patient’s healing.

The amino acid glutamine is a trusty workhorse for healthy gut function. It serves as an energy source for epithelial cells that make up the intestinal lining and while it’s not technically an essential amino acid, various circumstances (such as trauma, burns, or recovery from major operations or illnesses) increase the body’s demand for glutamine, making it conditionally essential. Looking beyond this reliable standby, the amino acid taurine may be beneficial for select patients, particularly those who need help with digestion of dietary fat. Taurine is unique in that it is not used in any structural protein but has other roles in the body. Taurine can be synthesized from cysteine but this process is relatively limited in humans, so it’s best obtained from foods—animal foods, specifically, as taurine is nearly nonexistent in plant foods. Bile acids secreted by the liver are bound to taurine (or glycine), making this compound critical for bile acid function and proper absorption of fat.

Potassium is a core nutrient that has a role in healthy GI function, especially with regard to intestinal motility. Beyond the fatigue and cardiac arrhythmias that may result from deficiency in this crucial mineral, inadequate potassium may lead to delayed gastric emptying and intestinal paralysis, potentially resulting in a cascade of unpleasant GI effects such as bloating, abdominal pain and constipation. Potassium is abundant in the food supply but certain medications (such as potassium-wasting diuretics) may reduce potassium levels, and behaviors that are unfortunately common, such as excessive alcohol consumption or strict chronic dieting for weight loss, may also result in inadequate potassium intake and body status.

Taking the GI tract to begin at the mouth, B vitamins help maintain a healthy mouth. Deficiency in B6 may cause a swollen or sore throat, pain in the tongue, or painful fissures and cracks at the angles of the mouth and on the lips (angular stomatitis or cheilosis). These signs and symptoms may also result from deficiency in niacin and/or riboflavin. Deficiency in thiamin may lead to gastrointestinal beri-beri, involving nausea, vomiting and abdominal pain mainly resulting from buildup of lactic acid.

If it seems strange to give a nod to these kinds of basic foundational micronutrients and amino acids for their roles in GI health, consider that it is not unheard of for patients to present with deficiencies in these critical compounds. The popularity of highly restrictive diets, emphasis on caloric restriction for weight loss, pickiness or rigid food preferences and other self-imposed factors mean that even individuals who are surrounded by abundant food and who have the means to obtain it may choose to limit intake of certain nutrient-dense foods, potentially leading to dietary shortfalls that seem like relics unearthed from middle school health textbooks. Take, for example, the case of a two-and-a-half year old boy who was diagnosed with scurvy—not on a British sailing ship three hundred years ago, but in the U.S. in 2016. Multiple doctors and specialists failed to identify this most basic of problems likely because they simply weren’t looking for it. Granted, odds are slim that practitioners will encounter a patient with a deficiency so severe that it’s become pellagra or beri-beri, but this possibility shouldn’t be dismissed out of hand.

Functional medicine practitioners and nutritionists should remain vigilant for what they’re more likely to see in their clinics: patients with subclinical deficiencies that aren’t manifesting as overt “deficiency diseases,” but rather as general malaise and lack of vitality that might be addressed easily and inexpensively through nutrient repletion and employing advanced testing and analysis only when warranted. Sometimes the art of a good old-fashioned physical exam can provide clear clues that obviate the need for more advanced or invasive assessment.