A group of diseases in which abnormally folded proteins, called amyloid, deposit in organs and tissues, progressively impairing their function. Different precursor proteins define different forms: AL amyloidosis arises from antibody fragments in plasma cell disorders, AA from chronic inflammation, and transthyretin amyloidosis from a transport protein, each targeting characteristic organs such as the heart, kidneys, or nerves. Symptoms depend on where deposits accumulate, ranging from heart failure to kidney failure to numbness. Diagnosis requires biopsy with special staining that makes amyloid glow under polarized light. Treatment has advanced from merely supportive care to drugs that silence the faulty protein’s production or stabilize its shape. Nutrition support matters because the disease often causes weight loss and gut dysfunction that complicate already serious illness.