From: hnewstrom@hnewstrom.ess.harris.com (Harvey Newstrom)
Subject: Re: Vitamins:  How to Get the Right Mix?
Date: Wed, 7 Oct 1992 02:09:13 GMT
Organization: Harris Corporation

In article <1992Sep30.164358.2736@access.usask.ca>, skeeter@skatter.usask.ca writes:
> 
> From article <1992Sep21.135826.29196@mercury.cair.du.edu>, by kguinn@diana.cair.du.edu (Kip J. Guinn):
> > It's difficult to get a handle on how much of each vitamin you need,
> > and how to mix them so that you get the maximum effect.  For example,
> > some vitamins, when taken together, cancel each other out.  Is there
> > any good book I can buy that discusses vitamins and their use?  
> > Preferably a book that has some scientific authority...
> > 
> > Also--I have bad eyesight.  A common "urban legend" is that if I 
> > were to consume a megadose of Vitamin A every day for a long
> > period, my eyesight would improve.  But, large doses of A can be
> > toxic, I've heard...  How much A is toxic?  And would it help?
> > 
> > Kip
> > 
> 
> More than 25,000 IU per day of Vitamin A is asking for trouble.
> I'll have to check my copy of the 'Recommended Nutrient Intake
> Guide for Canadians' (something like that) to be sure.
> 
> The book (which is a ~100 page summary of research done around
> the world) gives the levels of Vitamin A in Retinol Equivalents
> (RE), since the absorbtion of Retinol and Beta-Carotene differ
> (therefore 5000 IU of beta-carotene is less effective than
> 5000 IU of retinol).

Vitamin A is toxic in amounts over 25000IU.  Beta carotene is not toxic at any levels, except
that high levels will turn your skin orange.  It also will aggravate liver or kidney damage if it
already exists.

One Retinol Equivalent equals five IU of vitamin A.  IU is a measurement of potency, as are the Retinol
Equivalents, so 5000IU beta-carotene is equivalent to 5000IU of retinol.  5000 micrograms of beta-
carotene would be less effective than 5000 micrograms of retinol.

Vitamin A will help night blindness.  It will not help nearsightedness, cataracts, or other causes of
seeing difficulty.  To tell if you need a vitamin, you need to check many of the symptoms that might
indicate a deficiency, not just one.  If you do decide to take any vitamin suppliment, you need to
start checking the symptoms of overdose to make sure you aren't taking too much.

Deficiency Symptoms for vitamin A:
night blindness, itchy eyes, dry eyes, deterioration of tear ducts, bloodshot eyes, sties, thickening 
of cornea, softening of cornea, acne, skin rashes, rough skin, dry skin, skin eczema, enlarged 
follicles, dry hair, brittle hair, appetite decreased, deterioration of gastrointestinal tract, 
deterioration of salivary glands, decreased sense of smell, fatigue, weight decreased, deterioration 
of growth, immunity decreased, infections, sterility, decreased vitamin C, decreased cancer 
resistance, slow healing, increased menstrual bleeding, birth defects, deterioration of lactation

The Toxicity Symptoms for vitamin A:
(Detoxified by vitamin C)
dry skin, itching, profuse sweating, peeling skin, scaling skin, thickening skin, rashes, sore lips,
sparse hair, coarse hair, hair decreased, brittle hair, brittle nails, eyebrow hair decreased, 
increase cranium pressure, blurred vision, protruding eyes, irregular menses, headache, emotional 
agitation, nausea, abdominal pain, appetite decreased, diarrhea, muscle weakness, fatigue, bone 
thickening, bone demineralization, aching bones, aching joints, enlarged spleen, enlarged liver, 
enlarged kidneys, retarded growth, decreased immunity, development of some cancers