Tuesday, March 16, 2010

Unexpected vitamin E supplement absorption

Population studies show those who eat foods high in vitamin E (green vege's, cold pressed oil's, milk cows feed of fresh grass) have lower risk of health disease. However when individual trials were carried out with supplements the results have been very variable.

Well reading today I found some amazing data. They feed a breakfast "meal" of 400 IU vitamin E tablet with glass of skim milk, or the same amount of milk with breakfast cereal. The breakfast cereal was fortified with either 30 IU or 400 IU of vitamin E. Staggeringly enough the lowest vitamin E blood levels were the 400 IU supplement as the graph below shows. The graph is vitamin E levels in blood after the breakfast. The triangles are the 400 IU supplement. The circles are the 30 IU breakfast cereal and squares are the 400 IU breakfast.
What this shows is that the same synthetic vitamin E ground into cereal is much better absorbed than a tablet with a glass of milk.Logically the scientists then asked the question - what happens if we give the same subjects 400 IU tablet with the breakfast cereal that has no vitamin E added. The results were again unexpected. The 400 IU tablet with breakfast gave highly variable results, as shown below. Some test subjects gave blood level rise that was no different between the two 400 IU test meals. However some fed the 400 IU tablet with cereal absorbed as little as the 400 IU tablet without the cereal !

Clearly there is something going on that we do not yet understand. My first thought was that this was different people in each test, hence the variation. However this was not the case. It was the same people spread out over time so after each test meal the vitamin E levels returned to baseline (normal) before the next test.

This really surprised me. So did a little digging around. Couldn't find a definitive answer, but found some more clues. Firstly that vitamin E uptake is very strongly dependent upon what food is in the meal. It is generally accepted that you need fat in a meal to absorb vitamin E. That makes sense as vitamin E is found in nature in fat. An example of this is vitamin E mixed with orange juice or full cream milk.  This is shown below, approximately twice level of vitamin E (solid diamonds) vs the orange juice (solid triangle). 
However this does not explain the difference between the cereal that has vitamin E added as a powder and taking a tablet with the meal. One such reason could be that they used synthetic vitamin E. Synthetic vitamin E is alpha-tocopheryl acetate. The body needs to turn this into alpha-tocopheryl. To do this enzyme needs access to the vitamin E. Hence the finely powdered vitamin E in the cereal would be more available for changing. This would make sense as to why people supplemented with synthetic E didn't see the same health benefits as diets high in natural vitamin E. The synthetic vitamin E might not have been absorbed!

What is the take home message:
  • Try to eat lots (6+)of green vege's, cold pressed oils, nuts and fats from animals feed a full grass diet, so you get maximum amount of vitamin E through your diet. 
  • Make sure you are supplementing with natural vitamin E 
  • Take you supplement with a meal, not with just a drink 
  • Take your supplement with a meal that contains fat 
  • Could indicate that powder supplement would be better. However I not seen a powdered form of vitamin E for sale (not that I was looking)
Scott W Leonard, Carolyn K Good, Eric T Gugger and Maret G Traber Vitamin E bioavailability from fortified breakfast cereal is greater than that from encapsulated supplements American Journal of Clinical Nutrition, Vol. 79, No. 1, 86-92, January 2004

KC Hayes Andrzej Pronczuk1 and Daniel Perlman Vitamin E in fortified cow milk uniquely enriches human plasma lipoproteins American Journal of Clinical Nutrition, Vol. 74, No. 2, 211-218, August 2001

No comments:

Post a Comment