I receive many queries related to premature aging. Reduced appetite, reduced sleep, grey hair, arthritis – All these issues manifest after 40. But you now see them even in age below 20.
In old age, we can understand, it is due to मन्दाग्नि (Mandagni – Low Fire) but how come they are now regular in young age?
Ama (आम) – Toxins – Something that is unripe. Unripe outcomes of biological process. it can be at the time of digestion, assimilation or purging. All three stages or any one of them, when not working as per laws of the body, accumulates toxins locally. That is आम.
These end products, being inadequately processed, have a macromolecular structure, which is bigger and grosser than those end products which might have produced if a complete processing would have taken place.
It happens naturally in old-age. It happens unnaturally in young age due to following habits:
Despite physically young and metabolically active, if you indulge in physical and mental activities just after having meal, you are disturbing active digestion process. This can result in Ama i.e. Toxins.
Irregular meal timings is another reason that disturbs fire-based processes in body.
Regular intake of food lacking hydration and fat (dry), cold food, stale food can also generate Ama.
Too many emotions out of balance. Extreme Kama, Krdha, Lobha, Moha, Irshya. Extreme lajja, shoka, abhimana, Udvega, Bhaya, Up-tapta (sad).
In many experimental studies, various types of physical and psychological stress are found to induce dysfunction of intestinal barrier, resulting in enhanced intake of potentially noxious material (e.g., antigens, toxins, and other proinflammatory molecule) from the gut lumen into the bloodstream  . This gives a very interesting proposition to see if these noxious materials play the role of ama as a progenitor to joint diseases as perceived in Ayurveda.
In short, Quality of the food + Intake method and timing + Mood + Compatibility with your nature and age play critical role in perfect digestion, assimilation and elimination.
Check your routine. Check life of avg urban teen-ager. You will realize reason behind early aging. If such habits continue for 3-4 generations, rapid aging becomes स्वभाव of the gene-pool.
Take care. Check your habits in mirror. Correct them. Whatever happened so far, cannot be reversed but you can certainly slow down further aging by eliminating toxins and not making their way again in the body.
 Stress and intestinal barrier function
The intestinal mucosa is continuously exposed to an immense load of antigens from ingested food, resident bacteria, invading viruses, etc. The single-cell epithelial layer lining the gut lumen (surface area ∼300 m2) has conflicting functions, playing a major role in the digestion and absorption of nutrients and at the same time constituting the organism’s most important barrier between the internal and external environments. Under normal circumstances, the epithelium allows only minute quantities of intact antigens to cross into the mucosa, where they interact with the mucosal immune system to downregulate inflammation (known as oral tolerance). On the other hand, it is necessary for enteric pathogens to activate immune cells and initiate the inflammatory response required to clear the infection. In some disease conditions, such as inflammatory bowel disease, excessive penetration of antigens through the epithelial layer may result in inappropriate immune stimulation, leading to chronic gastrointestinal inflammation. The ability of the epithelium to control uptake of molecules into the body is denoted as the intestinal barrier function.