Peat Archive

Ray Peat identified parathyroid hormone (PTH) as one of the key harmful substances that increases with aging and metabolic dysfunction. PTH rises when calcium intake is low, when vitamin D is deficient, or when phosphorus intake is disproportionately high relative to calcium. Elevated PTH pulls calcium from bones and deposits it in soft tissues, contributing to osteoporosis, arterial calcification, and cellular stress.

Peat emphasized that keeping PTH low was essential for health, and his dietary recommendations — particularly his advocacy for dairy foods and adequate calcium intake — were partly aimed at suppressing PTH. He saw the age-related rise in PTH as both a cause and consequence of metabolic decline, creating a vicious cycle of bone loss, soft tissue calcification, and cellular stress.