of the different micronutrients may be extremely important for optimum
health.  For example, it is well known that vitamin E can affect tissue levels  of vitamin A and that vitamin C can impact the active tissue form of vitamin  E (4,5). Therefore, to avoid imbalancing the vitamins it may be important, as
a long term supplement, to use a multivitamin supplement.

Vitamin A
  FORM - Both preformed vitamin A (retinol) and provitamin A (beta  carotene) are used in AMC to ensure a more complete intake of vitamin A as  it is found in nature.  Although beta carotene is considered to be converted to  vitamin A once ingested, beta carotene itself has strong antioxidant action  (6).
  FUNCTIONS - Vitamin A is essential for normal vision, growth, cellular differentiation, reproduction, and integrity of the immune system (7).  Vitamin A and especially beta carotene have antioxidant activity which may partly account for their anticancer and immune enhancing actions (8). Because vitamin A is essential for normal growth and differentation of cells which make up skin and tissue linings it may be helpful in the treatment of  lung, cervical and skin cancers (9, 10, 11).  A number of skin diseases (e.g. acne & pityriasis) have been shown to respond favorably to vitamin A supplementation (12).  Further, vitamin A can be extremely beneficial to promote good wound healing and tissue repair (13).
Not only does beta carotene have stronger antioxidant activty (please see the in depth discusion of the importance of antioxidants to health in the AntiOX 18 monogram or in lesser detail the discussion under botanicals in this monogram) but in may also have greater anticancer activity than vitamin A (14).  A number of studies have shown that beta carotene has good cytoprotective effects, especially for muscosal surface cells (15, 16).  A highly publicized, negative outcome study of a large clinical trial using � -carotene supplementation, in hopes of preventing lung cancer in smokers, actually reported slightly higher deaths due to lung cancer in the supplement compared to placebo groups (17).  This study has been heavily criticized for its methodological errors by the natural medicine community, but the medical community at large has apparently embraced these negative results (18).  The actual difference of deaths in the � -carotene group was 4.14% whereas the number of cancer deaths in the placebo group was 3.60%.  This difference is not realistically significant.  Another important consideration in interpreting the results of this study is to realize that vitamin E and vitamin A (beta-carotene) compete for absorption (19).  Both were used in the supplement group.  This would suggest that the actual amount of beta carotene absorbed by the subjects was far less than that ingested.  Furthermore, beta carotene should not be considered a chemotherapeutic drug.  Beta carotene was prescribed in this negative study like a drug even though the wealth of literature on its cancer prevention effects would suggest that it is effective as part of a whole complement of micronutrients which are found together in fruits and vegetables (20).  It is also clear that using a synthetic source of beta carotene may have been a mistake, since only naturally occurring beta carotene has high bioavailabity (21).                             
Vitamin B1 (Thiamine hydrochloride)
  FORM - Foods which are high in thiamine tend to be high in all the B vitamins.  When taking a B vitamin supplement it is prudent to take a whole B complex since that's how they are found in nature.  Also a variety of metabolic reactions, especially energy producing pathways,  require two to several B vitamins in order to work.
  FUNCTIONS -  The majority of B vitamins work as cofactors for enzymes which are part of energy producing pathways (22).  Thiamine is one of those B vitamins which is needed for normal burning (oxidation) of carbohydrates and fats.  This means that patients who have excessive fatigue may have a subclinical deficiency of the B vitamins.  Initial symptoms of thiamine deficiencies induced in animals is anorexia with subsequent weight loss (23).  In humans thiamine deficiency is associated with peripheral neuropathies and when severe beri-beri (24).   A variety of factors can lead to an increased use of the B vitamins thereby  necessitating a higher  B vitamin intake.  Those factors include; a high intake of refined sugar, high intake of alcohol, high intake of nicotine, and high physicial or emotional stress (25).  Because of the high metabolic activity of the brain and peripheral nervous system B vitamins can be supportive for the nervous system and mental functions (26).  People who are especially nervous or anxious may benefit from a B vitamin supplement .   
 
Vitamin B2 (Riboflavin)
  FUNCTIONS -  Vitamin B2 is another B vitamin that is crucial to overall energy metabolism.  This vitamin, once converted to its active form in the body is need as a cofactor for many different reactions.  There are studies suggesting that riboflavin may be helpful in diverse situations such as improved mental function in the elderly and hypothyroidism (27, 28).  People may have a relative deficiency of riboflavin for a variety of reasons including that riboflavin is destroyed by UV light, that poeple with chronic illness or following chemotherapy treatment have a high requirement for B2, that people who exercise alot or take lots of antibiotics may require extra amounts, and that women taking birth control pills may require more B2 (29, 30,28).  Clinical features of riboflavin deficiency include seborrheic dermatitis, soreness and burning of the lips, burning and itching of eyes, cheilosis, glossitis, anemia, and neuropathy (31).
        
Vitamin B3 (Niacin)
  FORM - Both niacin and niacinamide are use in AMC to ensure both dietarily active forms of vitamin B3 are included.  Another name for niacin is nicotinic acid (not related to nicotine) and for niacinamide, nicotinamide.  Although both forms of vitamin B3 are thought to be converted to the same biologically active form in the body niacin in large (greater than 75 mg/day) doses can cause flushing and other side effects, whereas niacinamide does not (32, 33).
  FUNCTIONS - Besides its role in energy production vitamin B3 is necessary for a healthy nervous system, normal blood sugar metabolism (i.e. insulin function), and red blood cell production (34,35). Use of some chemotherapeutic agents, isoniazid, alcohol are all known to lead to niacin deficiency (35).  Pellagra has been known for some time as a disease of vitamin B3 deficiency (36).  Niacin has been shown in numerous studies to be effective at lowering elevated blood cholesterol (37).  The doses required to acheive this effect are very high and with many adverse reactions reported (38).  Vitamin B3 may also be useful in preventing cancer and diabetes (39, 40).

Vitamin B5  (Pantothenic acid)   FORM - Vitamin B5 is added into AMC as d-calcium pantothenate and pantethine.  One of the biologically active forms of B5 is pantethine, which is much more expensive than pantothenate, and is added into AMC to ensure that conversion of pantothenate to pantotheine is not limiting to vitamin B5 nutrition.
  FUNCTIONS -  This B vitamin is notable for its role in oxidation of fats, carbohydrates and proteins (i.e. amino acids).  It play a crucial role in many metabolic pathways including synthesis of progesterone, testosterone, estrogens, cortisol and all other steroid hormones (41).  This means that vitamin B5 is supportive for adrenal gland, gonadal tissue, and liver health.  The fact that the