Vitamin A

Vitamin A and Miscarriage

Vitamin A and beta carotene lower in women with recurrent miscarriage

The levels of reduced glutathione, vitamin A, E and beta carotene were significantly lower in women with habitual miscarriage than in controls. However, the plasma levels of lipid peroxidation, alkaline phosphatase, glucose and blood haemoglobin were significantly higher in habitual miscarriage than in controls. In addition, plasma levels of glutathione peroxidase, AST, ALT, total bilirubin, total protein, albumin, sodium, potassium, calcium and number of white blood cells, red blood cells, platelet and values of packet cell volume showed no significant differences between habitual miscarriage and controls. According to the results of this study, we observed that the levels of lipid peroxidation were increased and plasma levels of vitamin A, E and beta carotene were decreased in habitual miscarriage.

http://www.ncbi.nlm.nih.gov/pubmed/9857484

Vitamin A and Hormones

Beta carotene increases progesterone and estrogen

Concentrations of plasma progesterone were higher between days 6 and 10 after ovulation in cats fed diets containing beta-carotene and continued to increase through day 14 after ovulation in cats fed a diet containing 10 mg of beta-carotene. Plasma concentration of estradiol-17beta also was higher between days 0 and 4 after ovulation in cats fed diets containing beta-carotene. Cats fed a diet containing 10 mg of beta-carotene had the highest plasma estradiol concentration. Total uterine protein concentration was higher in cats fed beta-carotene, compared with values for cats fed an unsupplemented diet.

http://www.ncbi.nlm.nih.gov/pubmed/11453481

Progesterone and Miscarriage

Estrogen and Miscarriage

Low vitamin A and E common in acne sufferers

Patients with severe acne had significantly lower plasma concentrations of vitamins A and E than did those with lower acne grade and the age-matched healthy controls.

http://www.ncbi.nlm.nih.gov/pubmed/16681594

Vitamin E and Miscarriage

Vitamin A and Birth Defects

Beta carotene safe, but preformed vitamin A causes birth defects

Toxic effects of vitamin A have been shown to significantly affect developing fetuses. The fetus is particularly sensitive to vitamin A toxicity during the period of organogenesis. These toxicities only occur with preformed (retinoid) vitamin A (such as from liver). The carotenoid forms (such as beta-carotene as found in carrots), give no such symptoms, but excessive dietary intake of beta-carotene can lead to carotenodermia, which causes orange-yellow discoloration of the skin.

http://en.wikipedia.org/wiki/Vitamin_A

Birth Defects

Vitamin A and Thyroid

Vitamin A deficiency exacerbates iodine deficiency related hypothyroidism

Recent vitamin A and iodine depletion studies in rats indicate moderate Vitamin A deficiency alone has no measurable effect on the pituitary-thyroid axis; however, concurrent iodine deficiency and vitamin A deficiency produce more severe primary hypothyroidism than ID alone.

http://www.ncbi.nlm.nih.gov/pubmed/18214025

Low beta carotene associated with hypothyroidism

The serum levels of vitamin A were significantly decreased in both hyperthyroidism and hypothyroidism, the serum levels of carotene in hypothyroidism only.

http://www.ncbi.nlm.nih.gov/pubmed/6880574

Thyroid and Miscarriage

Vitamin A Overdose

Vitamins A and D compete for the same receptors

It has been estimated that 75% of people may be ingesting more than the recommended daily allowance for vitamin A on a regular basis in developed nations. Intake of twice the RDA of preformed vitamin A chronically may be associated with osteoporosis and hip fractures. This interaction may occur because vitamins A and D may compete for the same receptor and then interact with parathyoid hormone which regulates calcium.