Peat Archive

Ray Peat discussed vitamin A as an essential nutrient with important roles in immunity, thyroid function, and protection against estrogen excess. He noted that vitamin A (retinol) works synergistically with thyroid hormone and vitamin D, and that deficiency in any of these can mimic or worsen deficiency in the others. He recommended obtaining vitamin A from foods like liver, eggs, and dairy rather than from supplements, due to concerns about toxicity at high supplemental doses.

Peat was particularly interested in vitamin A's role in steroid hormone metabolism — it supports the conversion of cholesterol to pregnenolone and progesterone, and it helps the body clear excess estrogen. He saw vitamin A deficiency as contributing to estrogen dominance and associated health problems.