For years, many have struggled to understand why some nutritional supplements, components of foods, even drugs clearly exerted beneficial health effects—but were not absorbed by the gastrointestinal (GI) tract). Some compounds with substantial health benefits are completely inert in humans, ingested and then flushed down the toilet.
Take curcumin, for example. This component of the spice, turmeric, taken orally is almost entirely unabsorbed. If you took 100 mg of curcumin, 99 mg or so is undigested, unprocessed, unmetabolized by your GI digestive process and passed out in a bowel movement. Yet the evidence is clear: curcumin reduces measures of inflammation such as C-reactive protein, reduces arthritis pain, and exerts metabolic benefits such as reduced blood sugar and triglycerides. Many efforts have therefore been made to try to force absorption of curcumin to increase efficacy: combined with piperine, bioperine, nanoparticle emulsions, surfactants, chelating agents, and others. Absorption can indeed be increased, though no one has yet demonstrated an increase in beneficial effects with enhanced absorption.
Consider this: Curcumin has also been shown to increase intestinal mucus production and the intestinal immune response, explaining why curcumin, working within the GI tract, improves the intestinal barrier to entry of bacterial breakdown products. This may explain why curcumin has been shown to reduce endotoxemia, i.e., the entry of bacterial lipopolysaccharide toxin into the bloodstream, explaining why curcumin reduces body-wide inflammation, reduces measures of inflammation like C-reactive protein, reduces arthritis pain, and improves metabolic measures such as blood sugar and triglycerides. Curcumin also modifies bacterial species composition of gut flora, reducing fecal species of Proteobacteria (e.g., E. coli, Klebsiella, and other fecal microbes) and Enterococcus. Do you see where I am going with this? If curcumin is known to exert important effects within the GI tract, then maybe you do NOT want to force absorption and you want maximum concentration within the intestines, not in the bloodstream.
There are other compounds that have beneficial effects yet are poorly-absorbed or not absorbed at all, such as:
- Berberine—Exerting many of the same benefits as curcumin but with greater antibacterial and antifungal effects. It also boosts Akkermansia numbers in the GI tract, a major determinant of metabolic health.
- Green tea catechins—Associated with weight loss, reduction of anxiety, improved cognitive function, and other beneficial effects. Green tea catechins are known to crosslink mucin proteins within intestinal mucus, converting it to a less liquid to a more gel-like, less penetrable, consistency.
- Capsaicin—This is the component of peppers that is responsible for the hot feeling in the mouth. Capsaicin helps “mold” the microbial composition of bowel flora increasing, for instance, important species such as Faecalibacterium prausniztrii, the main producer of butyrate that mediates a long list of health benefits for humans.
- Quercetin—Quercetin is a flavonoid sourced from foods such as apples, onions, broccoli, and green tea. While a number of important health benefits have been documented, quercetin may be especially beneficial in improving insulin responses and reducing blood sugar, even though there is minimal absorption.
You can appreciate that there has been a lot of wasted effort in trying to devise ways to increase absorption, when the real benefits may derive from NOT being absorbed and exerting effects on the GI microbiome, the intestinal mucus and immune barriers, and endotoxemia. You can also appreciate that there is a lot of marketing going on to promote sales of versions of, say, curcumin, with enhanced absorption that may prove to be less effective than non-absorbable forms. It highlights the enormous role that the GI microbiome and GI tract play in numerous human health conditions. In a future DrDavisInfiniteHealth.com blog post, I shall discuss all the ways that you can easily, safely, inexpensively, effectively take advantage of strategies that improve your GI intestinal barrier and reduce endotoxemia to obtain huge health benefits and ignore a lot of pointless or misleading marketing efforts.