Ray Peat on Vitamins A, D and K

Short answer: Ray Peat gave each of the fat-soluble vitamins a job in his system. Vitamin A feeds the making of the protective steroid hormones, vitamin D with calcium keeps parathyroid hormone quiet, and vitamin K supports cell respiration and directs calcium into bone.

What Ray Peat wrote about vitamins a, d and k

Vitamin A is used heavily in steroid synthesis. He suspected it is needed for the step that turns cholesterol into pregnenolone, and noted that a progesterone supplement can prevent the symptoms of vitamin A deficiency. Source: Multiple Sclerosis and other hormone related brain syndromes

Vitamin A is needed for the proper differentiation of skin and other linings. A deficiency releases enzymes that break tissue down. Source: Blocking Tissue Destruction ↗

Thyroid hormone and vitamin A travel on the same carrier protein. Polyunsaturated fats compete for it and block the effects of both. Source: Fats, functions & malfunctions

He names thyroid, adequate animal protein, trace minerals and vitamin A as the first things to consider for preventing prostate enlargement. Source: Prostate Cancer

Vitamin D and vitamin K are both now known to prevent diabetes. Enough calcium and vitamin D keep parathyroid hormone suppressed, which he considered important against the degenerative diseases. Source: Glucose and sucrose for diabetes

Vitamin K is needed for the step in which carbon dioxide is built into osteocalcin so that it can bind calcium. Like aspirin, it supports cell respiration and inhibits lactic acid formation. Source: Osteoporosis, aging, tissue renewal, and product science

Antibiotics, and the natural antibiotics in raw carrot, can reduce the gut bacteria that make vitamin K, so he advised supplying it. Source: Rosacea, inflammation, and aging: The inefficiency of stress

Calcium, magnesium, vitamin A, vitamin B6, vitamin K and vitamin D are his list for developing and maintaining bone. Source: Bone Density: First Do No Harm

What he suggested in practice

• Liver about once a week as the food source of vitamin A.
• Not cod liver oil, because of its unsaturated fat.
• Calcium carbonate with vitamins D and K for a quick anti-stress effect.
• Vitamin K, or occasional liver or broccoli, when eating raw carrot daily or using antibiotics.

Where he wrote about it

This topic comes up in 40 of the articles on his site. These are the most relevant ones:

• Calcium and Disease: Hypertension, organ calcification, & shock, vs. respiratory energy · original on raypeat.com ↗
• Sugar issues · original on raypeat.com ↗
• Glucose and sucrose for diabetes · original on raypeat.com ↗
• Vitamin E: Estrogen antagonist, energy promoter, and anti-inflammatory · original on raypeat.com ↗
• Rosacea, inflammation, and aging: The inefficiency of stress · original on raypeat.com ↗
• Alzheimer's: The problem of Alzheimer's disease as a clue to immortality — part 2 · original on raypeat.com ↗
• Blocking Tissue Destruction ↗ · original on raypeat.com ↗
• Milk in context: allergies, ecology, and some myths · original on raypeat.com ↗

My take

In the studies I have covered, 2,000 IU of vitamin D3 lowered cortisol within two weeks, and D3 with K2 beat either one alone for bone density. I get most of my vitamin D from the sun.

Quick answers

What did Ray Peat say about vitamin A?

That it is consumed in making the steroid hormones, probably at the step from cholesterol to pregnenolone, and is needed for healthy skin and linings.

What did Ray Peat say about vitamin D?

That with calcium it keeps parathyroid hormone suppressed, protects bone and helps prevent diabetes.

What did Ray Peat say about vitamin K?

That it supports cell respiration, is needed for osteocalcin to bind calcium in bone, and should be supplied when antibiotics or daily raw carrot reduce the bacteria that make it.