vitamin a and infection i ve sent gordon r my posts on protein vitamin c and vitamin a prior to posting on internet as a professional courtesy somehow i ve managed to delete my vitamin a post from my text file gordon r had promised to send it back to me but he s pretty mad at me right now so i ll just retype it since digging through all my references is very time consuming took me all day for that pms post i m not going to cite any references gordon r has them i m going to include some of the material from weinsier and morgan s new nutrition textbook which was not in my original material to point out that what i m going to say has some support in the medical community diet has been know to affect the immune system of man for a very very long time protein has always had the biggest role in infection and i ve already covered the role of protein in protecting you against infection now i m going to hit what i consider to be the most important nutrient in the u s as far as infection is concerned vitamin a when vitamin a was originally discovered it was commonly referred to as the anti infection vitamin many people linus pauling being one have decided to take this title away from vitamin a and give it to vitamin c which i ve already covered big mistake in my opinion vitamin a is also getting a reputation as an anti cancer vitamin with good reason the nci currently has numerous clinical trials in progress to see if vitamin a can not only prevent cancer but cure it as well it s role in both cancer and infection is almost identical but not quite vitamin a comes in two completely different forms retinol and beta carotene retinol is the animal form and it s toxic beta carotene is the plant form and it s completely nontoxic both retinol and beta carotene display good absorption in the human gut if bile is present the liver stores all of your retinol and doles it out for other tissues to use by synthesizing retinol binding protein rbp a normal human adult liver should have iu to iu of retinol stored we are born with iu in our liver u s autopsy has shown that about of americans die with the same or less amount of vitamin a as they were born with if you don t believe that nutritional reserves like that of retinol in the liver are important then this low vitamin a reserve is not going to affect you but if you believe like i do that the nutrient reserves are important then there is a problem with vitamin a in the u s the u s rda for vitamin a in an adult male is re or iu of vitamin a for adult feamles its re or iu of vitamin a diet surveys show that most americans are getting this amount of vitamin a either retinol or beta carotene from their diet but the nrc national research council was going to release a new rda table in that had the rda for both vitamin a and vitamin c raised c to mg per day and a to iu per day for adult males that report and it s recommendations was killed why concern over the increasing supplementation was the main reason rdas are set to prevent clinical disease not to keep nutrient reserves full many scientist in the u s feel that the time has come to move away from the prevention of clinical pathology concept and move towards the promotion of optimum health concept especially since we have some very good data now that show that nutrient reserves are extremely important during periods of stress the nutritonal concervatives won that battle and a new group of scientist were collected to come out with the rda list which lowered the rda for several nutrients and moved the dietary guidelines back to where they were when we first started in the s get enough to prevent clinical pathology but not enough to fill the reserves we know from autopsy that only about of americans have a liver with a normal vitamin a reserve iu to iu i preach nutrient reserves to my students and tell them to measure them in their patients but for vitamin a only a liver biopsy or autopsy data will tell you how much somebody has stored we can tell very easily if someone has overfilled his or her liver with vitamin a by measuring the serium retinol level levels above ug dl are highly suggestive that you have filled your liver with vitamin a and it s time to stop taking retinol the normal range of serum retinol will be ug dl hypervitaminosis a is diagnosed with a serum retinol level of ug dl or higher interpretation of diagnostic test wallach m d a little brown series book this level of vitamin a in blood means that medical attention is necessary due to vitamin a toxicity weinsier and morgan take a much more conservative approach to vitamin a toxicity than does wallach as you will see later in this post between ug dl and ug dl you should have plenty of warning that it s time to eliminate the retinol from your diet headache redness of the skin hair loss joint pain i tell all my students that will use vitamin a in their practice that they had better monitor the serum retinol level and stop when there are clear signs that the liver is full you will never really know if the patient needs the vitamin a because you can not measure the pool in liver but you will always know when it s time to stop just like in those vitamin a for pms studies beta carotene can be taken to fill up your liver with retinol and you will never have to worry about toxicity because the conversion of beta carotene to retinol that occurs in both your gut and your liver will slow down stops in the liver and slows down in the gut when your liver is full of retinol but taking beta carotene as the source of retinol takes a very long time to fill the liver up i ve seen estimates of years if you are in the that only has as much as you were born with in your liver iu one other problem with beta carotene if you have a zinc deficit you will not convert as much beta carotene to retinol in the gut or the liver because the enxzyme that does this conversion requires zinc in addition the release of retinol from the liver is a zinc dependent process so a zinc deficit will cause a vitamin a deficit even if your liver has plenty of vitamin a now what does vitamin a do in cancer and infection protection the body uses vitamin a retinol for many different things vision the first to be nailed down and where you see overt clinical pathology uses the aldehyde retinal and alcohol retinol form of vitamin a reproduction uses the retinol form and some retinal infection and cancer protection uses retinoic acid how do you convert retinol which your white blood cells and the mucosal cells get from blood to retinoic acid you use enzymes one of which requires vitamin c this is why pauling has tried to pull the title of anti infection vitamin away from vitamin a vitamin c does play a role in infection interferon production for example but it s biggest role is the conversion of retinol to retinoic acid if you increase your intake of vitamin c you will increase your formation of retinoic acid but retinoic acid can not be converted back to retinol as retinal can and once it s formed it s used and then lost to the body this is why the nrc group wanted to increase both vitamin c and vitamin a rda s most people taking large amounts of vitamin c really think that they are helping themselves if they don t have much vitamin a in their liver and they are not also increasing their intake of vitamin a they actually do themselves more harm than good retinoic acid functions in white blood cells to promote antibody formation in the mucus membrane it is the main factor in promoting good mucus production and a good epithelial cell barrier to prevent infectious agents from entering the blood system the mucus membrane is referred to as the first line defense against infection for cancer retinoic acid has been shown to act as a cell brake it counteracts the effect of cell promoters which stimulate cells to divide cancer has two distinct steps dna alteration and cell promotion for cells that normally divide all the time promoters are not that important but for lung and breast tissue which does not normally divide promoters are real important in the malignant process this is the major reason why the nci has so many different clinical trials in progress using retinol and or beta carotene chronic infection irritation of the mucus membranes is a signal that vitamin a may not be adequate i tell my students that any patient who walks into their office with a complaint of chronic infection has to be worked up for vitamin a along with the other factors that medicine already has on it s list of causes for chronic infection i drive this home in my course at the osteopathic college in tulsa when i teach at the allopathic medical school in tulsa ou s branch campus and when i give cme lectures dark adaptation is the best clinical test for vitamin a status since night vision is impacted when liver reverves drop to iu of retinol the serum level of retinol can also be used but it does not drop until liver reserves drop below to iu asking a patient if they have trouble seeing at night is a good initial screen if cataracts are ruled out in one study done on u s spanish americans where serum retinol levels were measured of the sample population had a serum retinol level below ug dl as more studies are done on serum retinol levels in population groups of the u s that have had a history of high infection rates we will probably see a much stonger correlation between infection incidence rates and low serum retinol levels what do weinsier and morgan have to say about vitamin a here are excerpts from their book vitamin a functions in vision in the forrm of retinol it is necessay for growth and differentation of epithelial tissue and is required for reproduction embryonic development and bone growth protein calorie malnutrition and zinc deficiency may impair the absorption transport and metabolism of vitamin a retinaldehyde is converted to retinoic acid which has biological activity in growth and in cell diferentiation but not in reproduction or vision the most common procedure to evaluate vitamin a status is to measure the retinol level in plasma or serum the normal range for vitamin a content for a child is to ug dl lower values are indicators of deficiency or depleted body stores serum levels greater than ug dl are indicative of toxic levels of vitamin a dark adaptation tests and electroretinogram measurements are also useful but difficult to perform on young children rapidly proliferating tissues are sensitive to vitamin a deficiency and may revert to an undifferentiated state the bronchorespiratory tract skin genitourinary system gastrointestinal tract and sweat glands are adversely affected a daily intake of more than mg about iu of retinol is not advised and chronic use of amounts over mg iu can result in a dry and itching skin desquamation erythematous dermatitis hair loss joint pain chapped lips hyperostois bony depositis headaches anorexia edema and fatigue they recommend mg of retinol via im injection in children for vitamin a deficiency but do not discuss treatment for adults their toxic serum retinol level is very conservative i recommend that my students try iu in adults that are having problems with chronic infection they have to rule out a zinc deficit first by getting an rbc zinc run or if their clinical lab can t run it i tell them to do what weinsier and morgan suggest give them the zinc along with the vitamin a at iu per day toxicity should not be a problem and you will not have to worry about pulling the patient into the office on a regular basis to run a serum retinol both elaine and jon found doctors who used a much higher dose of vitamin a recall that the pms papers were using iu to iu of vitamin a i don t suggest that my students use these high doses if you wanted to fill the liver up fast as part of a clinical trial and were monitoring the serum retinol level then you would be okay but my knowledge of the vitamin a literature suggests to me that iu for patients with a demonstrated vitamin a deficit dark adapatation test or serum retinol will provide a good and steady improvement as long as zinc and vitamin c status are good without having to worry about toxicity if they want to get more agressive fine if they follow my advise to check the serum retinol but vitamin a retinol should never be given in high dose to women who could become pregnant since vitamin a shows teratogenicity towards the human fetus the dose needed to show this effect on the developing fetus is iu of retinol per day beta carotene will never have this effect on the human fetus could just taking beta carotene instead of retinol supplements help yes but the effect will take a long time to develop my advise is to use retinol to fill the liver up and then switch to beta carotene to keep it full vitamin a is probably one nutrient that is better off left to prescription by doctors but when we have the m d s in this newsgroup jumping all over me and other doctors that propose the use of vitamin a supplements for treating patients with chronic sinus and gi distress i think that the most prudent option is to keep vitamin a in the otc market but require manufactors to provide package inserts to educate the general public about the dangers of vitamin a supplementation marty b
