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Vitamin A
Vitamin A represents a number of related compounds: retinol, retinal, retinoic acid, and a vitamin A precursor beta (b)-carotene. Vitamin A is important for night vision, for fighting infection (body immunity), and for regulating the genes to ensure their proper functioning.
Dietary sources
Orange and yellow vegetables such as carrots, cod liver oil, fortified cereal, cantaloupe, whole milk, spinach, and eggs are examples of vitamin A rich foods.
Vitamin A Deficiency aftermath
Early vitamin A deficiency leads to impaired night vision, and advanced vitamin A deficiency can lead to corneal ulcers and scarring and blindness. In developing countries, vitamin A deficiency is an important cause of blindness among children. These children are also more likely to develop diarrhea and respiratory infections
Why are supplements beneficial?
There is NO evidence that taking vitamin A supplements can prevent cancer or heart attacks. In the ATBC trial, subjects given beta-carotene had higher incidence of lung cancer than subjects not given beta-carotene.
Toxicity
Vitamin A can be toxic in high doses (Usually 10 times RDA). Symptoms of vitamin A toxicity include nausea, dry itchy skin, headache, and loss of appetite, bone and joint pain. High doses of vitamin A can also cause liver toxicity. Elderly people and people who drink alcohol heavily are more susceptible to vitamin A toxicity.
Tips for supplements
Eat a balanced diet and take one multivitamin daily. (Most multivitamins contain 5000 IU of vitamin A, generally in the form of beta-carotene). Additional vitamin A supplements are currently NOT recommended. Pregnant women should not take additional vitamin A supplements without medical supervision. Pregnant women should also avoid skin acne medications derived from natural and synthetic retinoids such as tretinoin (Retin-a), isotretinoin (Accutane), and psoriasis medications such as etretinate and acitretin.
Dietary sources
Orange and yellow vegetables such as carrots, cod liver oil, fortified cereal, cantaloupe, whole milk, spinach, and eggs are examples of vitamin A rich foods.
Vitamin A Deficiency aftermath
Early vitamin A deficiency leads to impaired night vision, and advanced vitamin A deficiency can lead to corneal ulcers and scarring and blindness. In developing countries, vitamin A deficiency is an important cause of blindness among children. These children are also more likely to develop diarrhea and respiratory infections
Why are supplements beneficial?
There is NO evidence that taking vitamin A supplements can prevent cancer or heart attacks. In the ATBC trial, subjects given beta-carotene had higher incidence of lung cancer than subjects not given beta-carotene.
Toxicity
Vitamin A can be toxic in high doses (Usually 10 times RDA). Symptoms of vitamin A toxicity include nausea, dry itchy skin, headache, and loss of appetite, bone and joint pain. High doses of vitamin A can also cause liver toxicity. Elderly people and people who drink alcohol heavily are more susceptible to vitamin A toxicity.
Tips for supplements
Eat a balanced diet and take one multivitamin daily. (Most multivitamins contain 5000 IU of vitamin A, generally in the form of beta-carotene). Additional vitamin A supplements are currently NOT recommended. Pregnant women should not take additional vitamin A supplements without medical supervision. Pregnant women should also avoid skin acne medications derived from natural and synthetic retinoids such as tretinoin (Retin-a), isotretinoin (Accutane), and psoriasis medications such as etretinate and acitretin.
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What is the ideal timing for getting exposed to sun for vitamin D benefit and how far long exposure especially for those with Osteoporosis ?
I'm not a doctor. I'd say long enough to maintain a healthy full-body tan. Skin tone is a mechanism that the body uses to prevent excess D production. Now it's likely that nobody is going to do this [I won't], which means we all need some degree of supplement in or with our diets. For osteoporosis? Remember that D pulls calcium into the blood, but it also pulls it out of the bone. You want both D and something to put that calcium where you want it (vit K2?).
I have had kidney stones since I was 14 years old. Now the doctor tells me that my body is making to much calcium and that is the reason I am getting kidney stones. Is there a doctor who I can see that can fix this problem? I am wanting someone who can treat the calcium problem not my kidney stone problem.