Symptoms of Vitamin A Deficiency
 

Some of the symptoms of A deficiency include dry eyes and the inability to tear, rough itchy skin, night blindness, weak eyesight, poor bone growth, chronic diarrhea, weak tooth enamel and frequent respiratory infections.  In pregnant mothers, all sorts of birth defects can occur if there is a deficiency of vitamin A, such as cleft palate and harelip, abnormalities of the heart and blood vessels, eye defects and displaced kidneys.

Humans are able to store large quantities of vitamin A in the liver, as well as in other organs.   God made us this way because A is so important to our bodies!  So if we have a well-stocked supply, we can get by for quite a while on a low-fat diet before deficiency symptoms appear.  However, when we are under a lot of stress, even good stress like being pregnant or exercising, our A stores can become rapidly depleted, and some of the above symptoms can start appearing.  Traditional peoples left spaces between children, like 3 years, so as to give our bodies a chance to replenish our A stores.
 

Extra Vitamin A Requirements
 

Long term use of mineral oil laxatives seems to reduce A absorption, so people who have use these on a regular basis need more vitamin A.  Also vitamin A stores are depleted rapidly during periods of stress, including exercise and fever.  Those with diabetes and those suffering from thyroid problems seem to need more vitamin A.  Those with cancer, pneumonia, urinary tract infections, tuberculosis or chronic nephritis may also need more A.

In addition, researchers have found that inadequate fat in the diet, low enzyme status, poor production of bile salts, and compromised liver function can all get in the way of your body properly utilizing vitamin A, especially when taken in a synthetic form.  So if your body is not that healthy, you will probably need a higher level of vitamin A than others who are healthier.   Some researchers also believe that synthetic vitamin A can interfere with the utilization of real vitamin A from foods, and if this is the case, then ironically, someone eating margarine, pizza and breakfast food that are fortified with vitamin A might actually need higher levels of natural vitamin A in their diet.