Medicinal Qualities of Pulque

Aguamiel and pulque are both highly nutritive liquids. Aguamiel in its raw state (prior to fermentation) contains essential amino acids, proteins, vitamins, gums and minerals and is a valuable water substitute in areas where water may be scarce or potentially contaminated and unsafe to drink. When aguamiel is dehydrated it is composed of around 90% sugars (mainly sucrose, glucose and fructose) and around 10% fructooligosaccharides (fructans – primarily agavin). These bulk of these sugars are bound within the starch of the plant and are released by cooking the piñas and then “juicing” them. This liquid can then be fermented and distilled to produce tequila and other mezcals.  During the fermentation of these sugars (from aguamiel to pulque) they are transformed into useful probiotic (1) substances while the fructans are retained and constitute an important prebiotic (2)  function. Aguamiel does not remain in its raw state for long as it can be difficult to prevent fermentation due to the nature of its collection (3). Fermentation can begin to occur in as little as a few hours and can actually begin while the aguamiel is still resting in the cavity created during the castration of the maguey.

  1. live microorganisms (usually bacteria) that are similar to beneficial microorganisms found in the human gut.
  2. a non-digestible food ingredient that promotes the growth of beneficial microorganisms in the intestines.
  3. aguamiel is collected (usually twice daily) from a cavity scooped out of the heart of the maguey/agave plant. It is (traditionally) sucked up into a dried out gourd and is exposed to the air (and potentially to various insects if the cavity is not securely covered)

Pulque itself has medicinal qualities. It can be effective in the treatment of gastritis and esophagitis due to the lactobacilli and mucilages (1) in the mixture which are known to repair the mucosa of the gastrointestinal tract. These same bacteria (and others) also prevent stomach infection as they help inhibit pathogenic intestinal microorganisms. Mazahua women are known to drink pulque as a galactagogue (2) and iron and calcium levels were found to be higher in women regularly consuming about 800ml/day of pulque (3). In addition, pulque is a source of the enzyme phytase which, when consumed with corn tortillas, results in an increased bioavailability of iron and zinc present in maize (Tovar etal). Newborn babies are often given a finger dipped in pulque to suckle on just after being born.  This is believed to make the baby stronger, it would certainly add several strains of probiotic into the babys system and potentially aid in strengthening the babys immune system and perhaps enhance the tolerance toward pathogenic bacteria in the GIT.

  1. a polysaccharide substance extracted as a viscous or gelatinous solution from plant
  2. something that can help a breastfeeding mother to increase her breast milk supply. “galact-” milk, and “-ogogue” leading to or promoting.
  3. although higher levels of pulque consumption are correlated with lower birth weights. (Backstrand etal 2001)
Parents feeding their baby with a little Pulque                      

The fermentation of aguamiel into pulque involves three main fermentation activities. There is the alcoholic fermentation (which gives pulque an alcohol content of up to 5-6%) and is carried out by yeasts such as Saccharomyces cerevisiae and the gram negative, facultative anaerobic, non-sporulating, polarly-flagellated, (pause for a breath) rod-shaped bacterium Zymomonas mobilis. Then there is the lactic acid fermentation which is carried out by the probiotic organisms in the lactobacillus species such as L.acidophilus, L.plantarum, L.buchneri, L.kefir and L.acetotolerans (among others) and finally a viscous fermentation which is the result of exopolysaccharide synthesis. These exopolysaccharides include dextran, levan and inulin from lactic acid bacteria.

Many therapeutic properties have been attributed to pulque particularly in relation to the digestive system. Dyspepsia (1), diarrhoea, anaemia, griping and gastrointestinal infections can all benefit from the probiotic organisms in the liquid as these organisms have an antagonistic activity against many pathogenic bacteria and fungi.  Lactobacilli are known to inhibit Clostridium difficile which causes watery diarrhoea, fever, nausea, and abdominal pain. C.difficile is also involved in diarrhoea caused by the use of antibiotic medications.

  1. A condition characterized by upper abdominal symptoms that may include pain or discomfort, bloating, feeling of fullness with very little intake of food , feeling of unusual fullness following meals, nausea, loss of appetite, heartburn, regurgitation of food or acid, and belching.

The beneficial microflora in the gut also benefit from the fructans which they feed upon to produce short chain fatty acids which can benefit their host (us) by optimising the absorption of nutrients such as iron and calcium and help prevent anaemia and osteoporosis (Garcia –Vieyra etal 2013) . These sugars are destroyed when converted into ethanol during the production of mezcal and tequila and won’t be found in either of these liquids. An important fructan called agavin found in the maguey may even benefit those suffering from diabetes as it can reduce glucose levels and increase glucagon-like peptide 1 (GLP-1) which can stimulate the production of insulin by slowing down the speed at which the stomach empties . Agavins don’t affect blood sugar in the same way as glucose (or other sugars) as they are configured in such a way that the body cannot effectively absorb them.

Agavin, like inulin, is an indigestible form of fibre known as a prebiotic. Dietary prebiotics pass undigested through the upper part of the gastrointestinal tract and stimulate the growth or activity of advantageous bacteria that colonize the large bowel by acting as substrate for them (1) (Slavin 2013). One source of prebiotics in humans is human breast milk, which contains oligosaccharides which are similar in structure to galactooligosaccharides.  These substances act as a substrate for intestinal probiotics, in particular bifidobacteria, and can aid in ensuring a healthy intestinal microbiome. This reduces the impact of colonization of pathogenic bacteria within the gut, reduces the risk of potentially dangerous intestinal infection and reduces the incidence of constipation (Le Doare etal 2018)

  1. the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached

For a substance to have a prebiotic effect they must have the following characteristics, be indigestible and resistant to breakdown by stomach acid and enzymes in the human gastrointestinal tract, be able to be selectively fermented by intestinal microorganisms and be able to selectively target and stimulate the growth and activity of beneficial bacteria (Hutkins etal 2016). Both Bifidobacterium and Lactobacillus have been shown to have differing prebiotic specificity and selectively to ferment prebiotic fibre based on the enzymes characteristic of the bacterial population; Lactobacilli prefer inulin and fructooligosaccharides, while the Bifidobacterium displays specificity for inulin, fructooligosaccharides, xylooligosaccahrides and galactooligosaccharides. Fermentation is the main mechanism of action by which prebiotics are used by beneficial bacteria in the colon. One of my favourite quelites, dandelion, is almost 25% prebiotic content by weight (dried green leaves)

In addition to the optimisation of calcium and iron absorption, ferritin and haemoglobin deficiencies may be avoided due to the superior abosorption of iron and its increased bioavailability due to pulques vitamin C (and to a lesser extent – ethanol) content (Backstrand 2001)

Preliminary research into pulque has demonstrated potential effects such as improving immune system effectiveness (Franco-Robles & Lopez 2015), improving bowel acidity, the reduction of colorectal cancer risks and inflammatory bowel disease (Crohn’s disease or ulcerative colitis) and the reduction of hypertension (Yeo etal 2009). Pulque has traditionally been used as a galactagogue to improve the production of breast milk in breastfeeding women and a previously noted was once the first liquid taken by newborn babies. (Backstrand etal 2001).

Some of these potential health benefits arise from the saponin (tigogenin and hecogenin) within the plant. Saponins are a class of chemical compounds which are sterols with hypocholesterolemic, anti-inflammatory and antibiotic activities. Precursors for the synthesis of steroidal hormones such as cortisone have been isolated from certain species of Agave (A.americana) (Peana etal 1997).

As a diuretic pulque was also traditionally used to treat urinary tract infections and other bacterially transmitted diseases that affected the urinary tract such as syhphilis (Ramirez-Rancaño 2000). Pulque fuerte (1) is also used to strengthen the excretion pathways of the kidneys (Montiel etal).

Its antibiotic/antimicrobial and anti-inflammatory qualities may also have benefit in the treatment of pityriasis (2) and for the treatment of wounds. For external wounds pulque sediments (xaxtle) are used in plasters, poultices and compresses. Aguamiel itself has been recommended by naturopathic doctors in Mexico for aiding in the recalcification of bones after suffering a fracture.

Pulque can be consumed hot to induce diaphoresis (3), relieve coughing, as an expectorant and to treat chronic respiratory asthenia (4).

It has also been noted that pulque can be an effective sleep aid in the treatment of insomnia as it has a low alcohol content which can aid in relaxation and that its melatonin content is effective at promoting sleep. Melatonin is a hormone produced by the body and is often called the “sleep hormone”. Melatonin can also be of assistance in resetting your internal body clock if it has been affected by jet lag (5). Melatonin is produced primarily in the pineal gland. Although there does seem to be plenty of talk about the melatonin content of pulque I have found no papers on the subject that definitively list its content and all references to it seem to be quoted word for word from the same (as yet unknown) source.

Pulque can be used internally both orally and as an enema.

  1. Young Pulque is somewhat sweet, and is called “Pulque Dulce” (sweet Pulque) or “Tlachique.” Its alcohol content is 2 to 4 %. Older Pulque is higher in alcohol, somewhat sour, and is called “Pulque Fuerte.” Its alcohol content is around 5 to 7 %.
  2. A skin disease characterised by the shedding of fine flaky scales
  3. Induce sweating
  4. Abnormal physical weakness or lack of energy
  5. Jet lag is the result of quickly crossing several time zones (as a result of airline travel). Your body’s natural sleep rhythms are disrupted so they are no longer aligned with the prevailing timezone. Jet lag can affect your mental performance, cause headaches, affect your digestion and change bowel habits by causing constipation or diarrhoea and cause a general feeling of malaise.

The modern industrialisation and production of pulque has had to overcome several hurdles. Pasteurisation of the product is necessary to prevent its continuing fermentation and potentially exploding the container that holds it and will also considerably extend its shelf life. Fresh pulque has a life of only a few days. The viscous nature of the liquid, which many people may find somewhat confronting, is addressed by eliminating L.mesenteroides from the inoculum. A lower viscosity liquid equates to a wider acceptance of the product in export markets and also with the younger generation of Mexican consumers. From the point of view of fresh pulque, the closer you get to the source of its production, the better it is. The actual fermentation processes of pulque are considered to be a “black box” and no detailed studies have addressed the complexities of the microbial ecological dynamics from inoculation to the end point of its fermentation. The industrial manufacturing of pulque is still in its youth. (Steinkraus 2004)


Colour change associated with the fermentation of aguamiel (left) to pulque (right) 

There can be potential problems for the first time drinker of pulque, one of which is that the first time you drink it you will get diarrhoea. This can potentially happen because of the high probiotic bacteria content of the liquid. Probiotics are typically given to prevent diarrhoea (1) but in some cases, when large amounts of a new probiotic is taken for the first time, it can cause an imbalance in the gut microbiome (2) which can cause mild diarrhoea. This usually corrects itself fairly quickly (1 or 2 days). Another potential problem espoused by the old timers is that pulque can continue to get you drunk after you have finished drinking as it “keeps cooking in your stomach” (3)

  1. The Saccharomyces cerevisiae (synonym S.boulardii) probiotic is a specific treatment (and prophylactic) for travellers diarrhoea (turista also known as Montezuma’s Revenge)
  2. Your gut microbiome is made up of trillions of bacteria, fungi and other microbes. The gut microbiome plays a very important role in your health by helping control digestion and benefiting your immune system and many other aspects of health (including mental health)
  3. Auto-brewery syndrome, also known as gut fermentation syndrome, is a rare medical condition in which intoxicating quantities of ethanol are produced through endogenous fermentation within the digestive system. Fermentation (and alcohol production) continues to occur in the gut after the ingestion of fermentable material.

Aside from its medicinal qualities pulque is said to have the following powers. It……(roughly translated)

Extinguishes guilt
Causes forgetting
Raises spirits
Raises your gun
Closes deals
Creates compadres
Opens doors
Eases the journey
Cures sadness
Makes you some children

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