The Vitamin D Problem, Part 2 (including the role of Vitamin A)

The big issue at the heart of the Vitamin D controversy, (see 12/15 post,) is how much we should take in supplement form.  But I wonder if we’re having the wrong conversation. It seems odd to me that we’re not discussing how human beings met their Vitamin D requirements before supplements were available, and by extension, how we can live and eat to maintain optimal levels without resorting to synthetic supplements.

Humans make Vitamin D from exposure to sunlight. It’s a pretty good system.  When the body has enough, it shuts down production until it needs more.  When there’s not enough sunlight to keep this system up and running, what then? Well, humans ate foods that were rich in Vitamin D, especially during the winter.  These foods included butterfat, eggs, organ meats, fish, shellfish, and cod liver oil.

Interestingly, these are the same foods that are rich in Vitamin A, which I consider to be Vitamin D’s partner. These two crucial nutrients work synergistically, even sharing receptor sites and preventing the uptake of one over the other. This ingenious system, compliments of mother nature, keeps these fat soluble nutrients in balance. No need to worry about dosage and toxicity, which are major concerns when taking synthetic versions of either one of these vitamins which are fat soluble, stored in the liver, and not easily eliminated.

Compared to it’s famous partner Vitamin D,  Vitamin A is usually either ignored or demonized. Studies have shown that large doses of Vitamin A can be toxic and cause birth defects. But these studies were done with a synthetic version, not the natural retinol found in foods, which has never been found to have toxic effects. We neglect this critical nutrient at our peril. It is a crucial catalyst for many biochemical functions.  According to Dr. Weston Price, neither protein, minerals, nor water-soluble vitamins can be utilized without Vitamin A from animal sources.  It stimulates the secretion of gastric juices, plays an important role in bone formation, and is necessary in the maintenance of healthy respiratory tissue and immune function.

When you ask most people to name some Vitamin A rich foods, they immediately think of carrots. But carrots don’t contain Vitamin A. They contain beta-carotene.  Though beta-carotene can be converted to Vitamin A in the upper intestine, this conversion is inefficient at best. Only about 1/6 of the beta carotene you ingest can be converted to real Vitamin A, and this is only if you have enough fat in your diet, and you’re not genetically limited in your ability to make the conversion. People of Celtic ancestry for instance, have very poor ability to convert beta-carotene to retinol, and people with diabetes or low thyroid function can’t make the conversion at all.   This is important because many vegetarians end up severely Vitamin A deficient thinking that eating plenty of brightly colored vegetables provides abundant Vitamin A.  They are mistaken. Real Vitamin A comes from animal sources just like its partner Vitamin D–butterfat, egg yolks, organ meats, fish, shell fish, and cod liver oil.

So as usual, the sensible approach to the supplement dilemma is to eat whole foods including plenty of the nutrient dense traditional foods that were part our ancestors’ diets.  Your Vitamin A & D needs can be met with a combination of adequate sunlight, along with abundant amounts of butter, eggs, organ meats, fish, shellfish, and grandmother’s reliable all-purpose superfood–cod liver oil.  And, best of all, you can stop worrying about dosage.

(Cod liver oils are not all the same. Many are highly processed and therefor poor sources of A & D. For the best cod liver oil available go to Their cod liver oil is traditionally made and is the finest on the market.)

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