Astringent Stage of Digestion

When foodstuff reaches the ileocecal valve, apana vayu opens the valve with help from samana vayu, pushing food into the cecum. The cecum, sometimes called the second stomach because food lingers there, is where food becomes astringent. The elements of astringent are Earth and Air: Air helps further absorption while Earth gives bulk to the stools.

Astringent taste is necessary for the absorption of certain vitamins, minerals, and water, which occurs in the ascending colon and first half of the transverse colon. Kleda (liquid) is absorbed through the colon and eliminated via the kidneys and bladder as urine. In the second half of the transverse colon the food becomes solid and heavy, forming well-bound fecal matter in the descending and sigmoid colon.

This stage stimulates mass peristalsis, and apana vayu generates the urge to defecate — ideally once or twice a day depending on food quality and quantity. True appetite returns during this stage because the Air component of astringent taste stimulates prana in the hunger center of the brain. Astringent taste is yielded into rasa dhatu and nourishes asthayi shukra or artava dhatu.

Kashaya avastha paka is the astringent and final stage of the six stages of digestion. It occurs in the colon roughly six hours after a meal, when the food bolus has been fully processed and only dry residue remains.