By Stephen Byrnes, PhD, RNCP

This article is one part of a series of articles, which is a revision of an older article that we had previously posted on our site. You can find the original article here. Additionally, please see the rebuttal to this article, by Dr. Michael Janson.

Part 4 of 15 (Previous)

Myth #4: The body's needs for vitamin A can be entirely obtained from plant foods.

Vitamin A, or retinol and its associated esters, is only found in animal fats and organs like liver (26). Plants do contain beta-carotene, a substance that the body can convert into vitamin A if certain conditions are present (see below).

Beta-carotene, however, is not vitamin A. It is typical for vegans and vegetarians (as well as most popular nutrition writers) to say that plant foods like carrots and spinach contain vitamin A and that beta-carotene is just as good as vitamin A. These things are not true even though beta-carotene is an important nutritional factor for humans.

The conversion from carotene to vitamin A in the intestines can only take place in the presence of bile salts. This means that fat must be eaten with the carotenes to stimulate bile secretion. Additionally, infants and people with hypothyroidism, gall bladder problems or diabetes (altogether, a significant portion of the population) either cannot make the conversion, or do so very poorly.

Lastly, the body's conversion from carotene to vitamin A is not very efficient: it takes roughly 6 units of carotene to make one unit of vitamin A. What this means is that a sweet potato (containing about 25,000 units of beta-carotene) will only convert into about 4,000 units of vitamin A (assuming you ate it with fat, are not diabetic, are not an infant, and do not have a thyroid or gall bladder problem) [27].

Relying on plant sources for vitamin A, then, is not a very wise idea. This provides yet another reason to include animal foods and fats in our diets. Butter and full-fat dairy foods, especially from pastured cows, are good vitamin A sources, as is cod liver oil.

Vitamin A earned its name from the fact that it was the first vitamin discovered. Researchers in the 1930s described vitamin A as the "anti-infective vitamin" as it is intimately involved in the health of the mucous membranes and in fighting off infections.

Since its discovery, vitamin A has been shown to be pivotal in several bodily functions: formation of "visual purple" which allows us to see partially in low light; maintenance of healthy vision and proper eye function; repair and maintenance of epithelial tissues, especially those of the skin and mucous membranes; maintenance of the endocrine system, espeically the thyroid gland; proper utilization of dietary proteins; and stimulation of the thymus gland, a major part of the immune system.

Supplementation, then, of vitamin A could be of great help to someone who is facing vision problems, poor thyroid function, weakened immunity, and assorted infections, particularly those of the respiratory and urinary tract (these areas are lined with mucous membranes). When approaching supplementation, a couple of things need to be kept in mind:

1. Supplements of beta-carotene (or foods containing it such as orange and yellow plant foods) are NOT the same as those with vitamin A.

2. Beta-carotene is the metabolic precursor of vitamin A; it must be converted into real vitamin A in the intestines along with the help of bile salts, thyroid hormone, and dietary fat. Infants, and those with diabetes, alcoholism, hypothyroidism, and/or liver or gall bladder problems cannot make this conversion.

3. Additionally, the body's conversion of beta-carotene to active vitamin A is very poor: it takes roughly 6 units of beta-carotene to make just one unit of vitamin A. Be sure, then, that you pruchase supplements that very clearly state that they are REAL vitamin A and not beta-carotene.

4. Consumers are often warned that vitamin A can be toxic if taken to excess. Pregnant women are also warned that too much vitamin A can cause birth defects. Such warnings are overblown.

5. Though vitamin A can produce toxicity symptoms if taken to excess, it takes a huge and massive amount to generate them. There have been studies done of people who have taken 300,000 units of vitamin A a day for over a year with NO adverse effects.

6. One has little to fear of overdosing on this nutrient. Additionally, the toxicity symptoms of excess vitamin A disappear quickly once supplementation is stopped.Studies done on pregnant women with vitamin A were actually done with an acne medicine made from a synthetic derivative of synthetic vitamin A -- in other words, a drug, not real vitamin A.

Native peoples the world over take special care to feed vitamin A-rich foods to pregnant women: liver, fish roe, eggs, butter, and cream. One does not see birth defects in these people. As far as the amount to take, this is a matter of debate.

Obviously, children need to take less than adults. Also, the right amount for one person may not be the same as another. Consulting with a clinical nutritionist or orthomolecular physician would be a wise choice in determining the right amount for you.

A safe amount I've used with my adult HIV/AIDS clients is 25,000 IU's a day. In case of respiratory or urinary infections, I'll increase it to as much as 200,000 IU's a day for 5-10 days (along with other substances needed by the body to oversome the infection). Supplementing with vitamin A could be a wise choice for those facing immune system weakness, in combination with a nutrient-dense diet that eliminates refined sugars, vegetable oils, processed foods, and drugs. (28).

As with vitamin D, Dr. Price found that the diets of healthy primitive peoples supplied substantial amounts of vitamin A, again emphasizing the great need humans have for this nutrient in maintaining optimal health now and for future generations.

Please see the next issue of the newsletter for our continuation of this article. To read the rebuttal of the above article, please click here.