Xylitol is a sugar alcohol (a biochemical designation; it does not mean that it yields ethanol like that in wine or whiskey) that can be used as a sweetener, a replacement for the toxic effects of sucrose, fructose, and glucose. It’s among the more baking-friendly natural sweeteners, as it can be used for glazing, as well as sweetening. Interestingly, while xylitol itself does not possess anti-fungal properties, it is metabolized via some bowel flora microbial species to fatty acids with anti-fungal properties. Xylitol therefore represents a very user-friendly way to reduce fungal infestations of the gastrointestinal (GI) tract, from mouth on down. Recall that, along with small intestinal bacterial overgrowth (SIBO), small intestinal fungal overgrowth (SIFO), as well as fungal overgrowth confined to the colon, is occurring at epidemic levels. We are also witnessing increasing evidence of fungal translocation, i.e., infections of other parts of the body outside of the GI tract that result from fungi exiting the intestines and taking up residence in the skin, airways, sinuses, even brain. I label this phenomenon “saprophytica,” the human body succumbing to the natural process of fungal infestation and degradation, as occurs when a tree or animal dies in the forest, fungi “reclaiming” all the components of biological systems, part of the cycle of life and death on this planet. What is not clear is how much of this phenomenon in the human body is natural and inevitable, how much is accelerated by modern habits. My bet is that it’s both, but that modern dietary and lifestyle habits have made it much worse. It also means that adopting safe, accessible strategies that reduce fungal infestations can yield health–and youth-preserving—effects, thus my interest in the fatty acids that result from microbial metabolism of xylitol.

Abundant evidence has demonstrated that xylitol reduces populations of Streptococcus mutans, the main tooth decay-causing microbial species in the mouth, and thereby reduces the incidence of cavities (caries). Xylitol may also reduce the incidence of sinusitis and ear infections. But there is also evidence that xylitol possesses significant anti-fungal effects against species such as Candida albicans. Overgrowth of Candida species, in particular, in the colon and small intestine (small intestinal fungal overgrowth, SIFO) are growing problems, likely due in part to the proliferation of sugars in the modern diet, since fungi thrive on sugar. The CDC has issued warnings regarding the rise of fungal infections. We are not interested here so much in life-threatening fungal infections, but the low-grade infestations that can, over time, lead to serious infections, infestations of the GI tract and elsewhere that occur in seemingly healthy people who are unaware, for instance, that the gas, bloating and diarrhea, or the skin rash that responds poorly to steroid creams, are really evidence of widespread fungal infestation.

Xylitol has important prebiotic fiber effects, since it is metabolizable by a number of bacterial species. These microbes convert xylitol to the fatty acids, butyrate and propionate, major mediators of health benefits for the human host that help reduce insulin resistance, blood sugar, blood pressure, and triglycerides.. But here’s where it gets especially interesting: Microbes, especially fermenting species such as Lactobacillus plantarum, Lactobacillus pentosus, and Pediococcus acidilactici, also metabolize xylitol to fatty acids with anti-fungal effects. If we therefore add xylitol to our foods while also consuming plentiful fermented foods such as sauerkraut, kimchi, kefir, and fermented meats that provide these microbes, could this be sufficient to manage fungal overgrowth? To my knowledge, this strategy has not yet been tested in a real-world setting. Most of us following my conversations already include at least several servings of fermented foods every day in our diets. There is no harm in adding, say, a couple teaspoons of xylitol to your coffee, yogurts, or other foods. I would be interested in hearing from anyone trying this strategy to know whether a presumptive decrease in fungal-related phenomena results such as decreased anxiety, sugar cravings, or eczematous rashes.

Fungi also produce mycotoxins, i.e., metabolites with toxic effects. Over 600 mycotoxins have been identified, likely explaining why fungal infestations can yield varying symptom profiles and are increasingly being identified as contributors to metabolic derangements, even cancers. (By the way, one of the food sources with greatest burden of fungal contamination? Yup: wheat and grains. How much of the extraordinary improvements in overall health that derive from wheat/grain elimination are due to avoidance of fungal infestations? I don’t know, but it’s yet another reason to be wheat/grain-free.) The world of human fungal infestation remains inadequately studied, but it is increasingly looking like a major player in health. And perhaps the solution may include something as simple as obtaining some sugar alcohols like xylitol.

(Yes, the NOW brand xylitol shown in the photo is sourced from non-GMO corn. However, zein protein and sugar residues should be negligible.)

Mocha Mint Kefir

You’ll love this Mocha Mint Kefir recipe that I took from my Super Gut book. So simple and so tasty—it’s almost like drinking melted chocolate ice cream. It combines the beneficial microbes of kefir, species such as Lactobacillus plantarum, Leuconostoc mesenteroides, and various Bifidobacteria species, with the prebiotic and anti-fungal effects of xylitol.

Use either commercial kefir or a kefir you made yourself using a commercial kefir or kefir starter.

2 cups kefir
1 teaspoon instant coffee granules
1 tablespoon unsweetened cocoa powder
1/2 teaspoon mint extract
2 tablespoons xylitol or to taste

Makes 4 1/2-cup servings

In a shaker, combine kefir, coffee, cocoa, mint, and xylitol and shake vigorously until well mixed. Serve cold or at room temperature.