We interviewed Dr. Swati Maheshwari, Internal medicine specialist, this is all she has to say about vitamin A.
Types of Vitamin A
There are two different types of vitamin A – one that is preformed is found in meat, poultry, fish, and dairy products. The second type, provitamin A, is found in fruits, vegetables, plant-based products. The most common type of provitamin A is beta-carotene which a precursor to vitamin A.
Adequate intakes of carotenoids from fruits and vegetables are linked to a lower risk of certain types of cancer.
Retinoic acid, (derived from vitamin A) has been found to normalise blood sugar in mice with diabetes.
Vitamin A is important in the growth of all bodily tissues, including skin and hair.
It is also responsible for a healthy eyesight and vision.
Ready-made retinol, the active form of vitamin A, only comes from animal sources which are :
- meats, such as liver
- fatty fish, and fish oil
- butter, milk, and cheese
- eggs and poultry
Plant-based foods contain carotenoids (an orange pigment that contributes to the color of certain fruits and vegetables) antioxidant forms of vitamin A. These are converted to retinol in the body.
- orange-colored vegetables
- sweet potatoes
- orange-colored fruits (papayas, mangoes)
- Plant foods rich in beta-carotene include:
- broccoli, spinach, turnip greens, and other dark, leafy green vegetables
- up to 3 years: 600 mcg per day
- 4 to 8 years: 900 mcg per day
- 9 to 13 years: 1,700 mcg per day
- 14 to 18 years: 2,800 mcg per day
- 19 years and over: 3,000 mcg per day
- From 14 years, the requirement for males is 900 mcg per day, and for females, 700 mcg per day
- For women aged 19 to 50 years, the requirement is 770 mcg per day during pregnancy and 1,300 mcg per day while breastfeeding
However, overconsumption of vitamin A can be toxic. It can cause :
- skin changes, such as yellowing, cracking, itching, and heightened sensitivity to sunlight
- vision changes and, in younger children
- brittle nails
- hair changes, like hair loss and oily hair
- weak bones, bone pain/swelling
- vomiting, dizziness, headaches and nausea
- difficulty gaining weight
- decreased appetite
- gum diseases
- changes in alertness
- a bulging fontanelle, or the soft spot in the skull, in children
- liver disease, in cases of extremely excessive intake