In 2018 it was popularly reported that the consumption of tequila was linked to (and may actually be good for) weight loss. Unfortunately this was just media generated hype. The key issue with the misrepresentation of this information involves a particular type of carbohydrate known as a fructan, more specifically agavin. A paper was presented at the 247th National Meeting of the American Chemical Society in 2014 (Santiago Garcia & Lopez 2014) in Dallas Texas. The paper discussed the effects of agavins sourced from A.angustifolia (a primary agave for aguamiel and pulque production) and A.potatorum (also known as Tobala – an agave used in mezcal production). Neither of these plants is used to produce tequila. Before the release of this paper the only physiological effects of agavins from A.tequilana (the ONLY permitted tequila agave) that have been reported was in a paper from 2007 (Urias-Silva etal) published in the British Journal of Nutrition. This paper also looked at the effects of fructans sourced from the Dasylirion species (which is used to produce another form of “mezcal” called sotol). There has since been some more information published (Huazano-Garcia & Lopez 2015) on agavins from the tequila agave, A.tequilana (Weber). The 2015 paper (Huazano-Garcia & Lopez) seems to be a more thorough presentation of the 2007 paper and even shares an author (Lopez). All of the studies referred to involved experimentation on mice.

Agavins are a type of non-digestible carbohydrate that are fermented to produce alcohol. Pulque, being a fermented low alcohol liquid (4-7%) still contains much of its agavin content while tequila, being a double distilled high alcohol liquid (up to 70%) will contain very little (if any) agavin content as it is these sugars that are converted into alcohol. The higher the alcohol content, the lower the agavin content.

Agavins are a many branched molecule and it is this characteristic that is advantageous for fermentation as these branches provide bacteria with multiple points for initiating fermentation. This fermentation can occur in aguamiel when it is converted into pulque or can be by bacteria in the gut of the host which is where the potential health benefits of agavins arise.

Bacteria in the bowel act on the agavins (and other fructans) and convert some of them into short chain fatty acids (SCFA’s). The fermentation of non-digestible carbohydrates into SCFA’s allows the promotion of pro-glucagon mRNA expression in intestinal L-cells which is a precursor to the production of glucagon like peptide 1 (GLP-1).

In the agavin fed mice the concentration of SCFA’s in the cecum and colon (particularly propionic and butyric acid) increased significantly. This increase in the production of total SCFA’s through bacterial fermentation resulted in a significant decrease in colonic pH. This drop in pH promoted the growth of probiotic bacteria and prevented the growth of pathogenic bacteria that were sensitive to changes in pH. It was also found that simply by changing the high fat diet to a more healthy diet the gut dysbiosis was not reversed. It required the supplementation of the fructans which then selectively modulated the gut microbiome through SCFA production along the large intestine. One thing to take into consideration is that the testing period was not even 3 months long. Dietary changes alone can be effective but they are generally slower acting and it may take many months (even years) to undo years of unhealthy dietary practices.

The increase of propionic concentration is also associated with beneficial effects on carbohydrate metabolism and has positive influences on metabolism by regulating intestinal gluconeogenisis. Propionate also inhibits the synthesis of lipids in hepatocytes and the incorporation of acetate during the synthesis of cholesterol which potentially explains a decrease in overall cholesterol levels. Decreases in both triglycerides and cholesterol were observed in test subjects that received both agavin and inulin. Butyrate however is utilised in the colon by L cells which are responsible for releasing GLP-1.

The effects of fructans (agavin, inulin) on satiety is linked to the production of GLP-1 by the bacterial fermentation of agavins and the SCFA’s they produce. GLP-1 is a hormone that reduces the release of glucagon and slows down gastric emptying. This increases the feeling of abdominal fullness (satiety) and helps in controlling food intake. GLP-1 plays an important role in lowering blood glucose levels because it increases the level of circulating insulin (and thus lowers the blood glucose concentration)by enhancing insulin secretion from pancreatic β-cells or it affects the blood glucose concentration by lowering glucagon secretion. It was also found that the production of ghrelin was decreased. This too is beneficial as it is ghrelin (the hunger hormone) that stimulates appetite. Agavins stimulate the growth of Bifidobacterium and Lactobacilli more efficiently than (commercial) inulins do.

The studies being referred to above involved the mice being fed a diet comprising of 10% agavins. The metabolic disorders (raised blood glucose, triglycerides and cholesterol) artificially induced by a high fat diet were reversed by both agavins and (to a lesser extent) inulin. A key point is that weight loss was observed in overweight mice that were shifted to a healthy diet but the metabolic effects caused by the high fat diet were not reverted.

If you want to take advantage of the health benefits of the agave then I recommend the use of aguamiel or pulque. If you want to get drunk then I recommend the use of tequila, mezcal or sotol. They are not the same thing and are not interchangeable (although, after drinking a couple of litres of pulque you may forget how to use your legs).