Vitamin A includes the powerful antioxidants alpha and beta carotene, and is absorbed by the body in the form of retinol. The Institute of Medicine (IOM) sets the RDA of vitamin A for healthy adults at 700 micrograms (mcg) (3,000 IU) for women and 900 for men. Children between the ages of 1 and 3 are recommended to have 300 mcg (1,000 IU), ages 4 to 8 400 mcg, and ages 9 to 13 600 units. Lactating women are recommended to have between 1,200 mcg (4,000 IU) for ages 14 to 18 and 1,300 for age 19 and above. (Source: NIH)

On the Other: Complications of Excess Levels

A lack of adequate vitamin A in the diet can lead to night blindness, skin changes and dry mouth. It can also have the effect of slow healing of wounds, skeletal development problems in children, and respiratory infections. Excess levels of vitamin A have been linked to hip fractures in men and menopausal women. High levels of vitamin A storage in the body have also been shown to have adverse effects such as birth defects, liver problems, osteoporosis and central nervous system disorders. Ingesting toxic levels of the vitamin at one time can cause nausea and vomiting, headache, dizziness, blurred vision and muscle weakness.

Bottom Line

Healthy vitamin A levels can be achieved through a diet rich in foods that supply it such as beef and chicken liver, carrots, leafy dark greens, pumpkins, mangoes, spinach, cantaloupe and apricots. A cautionary approach should be used when taking vitamin A supplements so that toxic levels do not develop.

Source:

Feinberg School of Nutrition

National Institute of Health