Preformed vitamin A is one of the nutrients Weston Price suggested was responsible for the glowing health of the cultures he studied in his book Nutrition and Physical Degeneration. It's an essential nutrient, but it's different from most vitamins (except D) because it acts like a hormone, entering cells and altering gene transcription. Thus, it has its hand in many important bodily processes.
"Vitamin A" from plant sources such as carrots is actually a group of vitamin A precursors called carotenes, which the body inefficiently converts to actual vitamin A. The efficiency of conversion varies around 10%, depending on the carotene and how much fat is ingested along with it. Nutrition labels in the US do not reflect this. When a nutrition label on a plant-based product says "30% vitamin A", you can assume you will get about 3% of your RDA from it. This doesn't apply to eggs, dairy and liver, which contain preformed vitamin A.
I'm not sure how this happened, but somewhere along the line we decided in the US that muscle is the only proper animal tissue to eat. We are missing out on the most nutritious parts of the animal, and our health is suffering.
I recommend purchasing organic calf's liver, 100% grass-fed if possible. Chicken livers are also nutritious but ruminant livers are the most concentrated in vitamins by far.
Here is a recipe for a liver pate. I recognize that many people don't like the taste of liver, which is why I chose this recipe because it is very mild.
- 1/2 to 1 lb calf's liver, chopped into 1-in strips
- 3 eggs
- 1/2 stick butter
- 1/2 onion
- 1-2 carrots (optional)
- Sage and/or rosemary (optional)
- Salt to taste
- Saute the onions and carrots in 1 tbsp butter until they're soft.
- Add liver and herbs and cook until the liver is just done.
- Crack the eggs right into the pan and stir them until they're cooked.
- Turn off the heat, add the remaining butter.
- Blend until smooth.