About 10% of our genes have shown to be directly influenced by vitamin D. This translates into everything from preventing colds and flu to inhibiting at least 16 different types of cancer. There is even a link to the process of detoxification, such as getting the heavy metals out of the brain. The lack of vitamin D has been strongly linked to issues such as autism, asthma and both types of diabetes. Sounds like something you would want plenty of in your system, doesn't it?

Vitamin A is also in cod liver oil. It is essential for your immune system, but also in your hormone regulation. But, there is tons of evidence that without the balancing power of vitamin D that vitamin A can be ineffective, or even toxic. Research is also showing that vitamin D protects against breast cancer, but only when there is enough vitamin A in the person's system. Sounds like cod liver oil may be a good thing.

But... the problem is that there is no guarantee of the ratio between the two in cod liver oil. Since it is a manufactured item (it can't be found naturally) the producers can put as much or as little of the vitamins in each bottle. The problem is the vitamin A. Remember I said it could be toxic? Studies are showing that too much vitamin A can cause increases in infections, and even death. Other studies show that it decreases infections. What is the difference? It seems to be the countries in which the studies are done. In less developed countries it has the more positive results. This can be because in those countries they are not getting enough of the vitamin from their diet, thus they are in a much greater deficit. In the US, as in most well developed countries they did studies to find out if the population was deficient in Vitamin A. They found about 5% had too much vitamin A. They compared this to underdeveloped countries and found the opposite was true, there was an actual deficiency. They key seems to be that enough is good, but too much is really bad. It will even interfere with the good attributes of vitamin D.

Depending on how much vitamin A you are getting from your diet even a small amount in cod liver oil can be too much., and most of them have more than just a little. One brand that was study had 3 to 60 units of vitamin D per tablespoon, but 150 to 12,000 times that much vitamin A. If you already had enough vitamin A in your system you can very easily enter the toxic realm.

There is a lot of information pointing out that Vitamin D is very good, and a small amount of vitamin A is important, so what are we supposed to do? Unless you feel the cold or flu coming on make sure you are getting a balanced amount of both nutrients, such as in the Complete Vitamins Plus by Enriching Gifts. Then when you do need a little extra boost find a good quality vitamin D supplement that does not contain a large amount of vitamin A, if any. Remember, unless your diet is devoid of fresh fruits, vegetables, butter, eggs, and other vitamin A rich foods you don't need supplemental vitamin A. Of course getting your extra vitamin D from sunlight is the best way, when it is available.

(This information is not intended to serve as a prescription, or to diagnose, treat or replace the advice of your medical doctor. If you have any medical conditions or are taking prescription or non-prescription medications, consult your physician before altering or discounting the use of them.)