undissolved solids

As much as I deeply love coffee, the prerequisite to a coffee is also a toilet nearby 😂😅 Coffee (almost) always just passes through both ends regardless if i’ve had food prior.

To seek answers, I turned to the trusty interwebs for the most reliable sources [mostly RESEARCH ARTICLES WITH DATA] and this is pretty much a loose analysis of what I’ve found over the last couple of weeks.

Coffee is very chemically complex. Throughout the growing, processing and roasting phases of its lifecycle, the acids, proteins, fats and sugars change. Below are the contributing chemical compounds of coffee that seem to be the cause of the increased urge to pee and poo. The research seems to be quite inconclusive but regardless, this is what’s been discovered so far.

Caffeine is a diuretic
Caffeine can be found in numerous beverages. In coffee, caffeine is very easily extracted as it is hydrophilic (drawn to water)- meaning, when water is poured over coffee, caffeine is easily drawn out of the coffee particles and into the coffee liquid regardless if the water is hot or not. According to Mayoclinic and Amaia et al. caffeine is not just a central nervous system stimulant that wakes you up, it is also a diuretic (1)(2).

A diuretic is a substance that increases urine production. Caffeine acts as a diuretic by:

↑ blood pressure
→ ↑ the Kidney function of blood filtration (called Glomerular Filtration Rate)
= ↑ urine produced in a directly proportional matter- meaning more caffeine = more urine (1).

Melanoidins
During the Maillard Phase in coffee roasting (green raw coffee becomes yellow and eventually brown), melanoidins (also known as browning products) are formed and make the coffee appear brown (this is similar to getting a nice sear on a steak). Melanoidins main purpose in coffee is to add body/texture to the drink as these are large and heavy molecules. However, these have low digestibility in the body and with their molecular weight, can act as dietary fibre in the colon (increase the mass of a stool)- which in turn, can signal your body to push the stool further down (3).

This could also possibly mean that darker roasts (containing more melanoidins) could have an increased effect on your urge to poop. 

Gastrin
Gastrin is a hormone stimulated by the ingestion of coffee through the volume of liquid ingested and the caffeine (4). When anything enters your stomach (liquid or solid), your stomach is stretches and prompts gastrin production. Gastrin then signals the stomach to release hydrochloric acids and digestive enzymes to start digestion, pushing old food/liquid out of the stomach and breaking down the new food/liquid. As a result, this signals the rest of the body to move everything else further along i.e. colon contractions (pushing the stool further down) (4).

Exorphins
Exorphins are opioid peptides that are naturally-occurring derivatives of proteins found in gluten, dairy, soy, and also coffee etc. These activate opiate receptors (found in the brain and gut-wall) and stimulate colonic motility through activation of the muscles in the colon. This speeds up digestion and boosts peristaltic movement in intestines (6).

Does coffee make everyone want to poop?
A study published in 1990 by Brown et al. conducted a questionnaire of ~99 volunteers regarding bowel habits from the effects of beverages in which only 29% claimed that coffee induced their desire to defecate (6).

In a separate study on the same paper, comparing normal coffee, decaf and hot water on 14 fasted subjects, they found that 8/14 claimed that drinking coffee induced the desire to defecate as well.

With the lack of statistical significance of this data, we cannot purely claim that coffee would make everyone go to the bathroom.

Circadian Rhythm?
A interesting study done in 2006 by Willemijntje A. Hoogerwerf suggested that in your body’s circadian rhythm colonic activity is reduced at night and increase in the following morning. Meaning, that your morning poo could also just be coincidentally wanting to happen after you drink your coffee (5). But this varies from person to person.

Thanks for reading #8
jos x