Vitamin A

What is Vitamin A? A fat-soluble vitamin that exists in foods in two forms:

  • Preformed Vitamin A (retinol) – found in animal products
  • Provitamin A (beta carotene) – found in plant-based foods
To use these forms, the body must convert them to the active forms of the vitamin: retinal and retinoic acid. 
 

Function

Role of Vitamin A

Vision

Protects the surface of the eye and involved in a part of the retina that responds to light

Immunity

Supports mucous membranes and immune cells that protect against infections

Cell growth

Supports skin regeneration and tissue repair

Reproduction

Important for fetal development and fertility

Antioxidant

May reduce inflammation, lowering the risk of heart disease, lung cancer and diabetes

 

Too Little Vitamin A (rare in developed countries):
  • Night blindness
  • Dry eyes, skin/hair
  • Increased infection risk, especially from measles
  • Impaired fetal growth and child development
Groups At Risk for Deficiency:
  • Chronic alcoholism
  • Premature infants
  • Fat malabsorption disorders such as Cystic Fibrosis, Ulcerative Colitis, Chron’s Disease
  • Food insecure regions
Too Much Vitamin A:
  • Nausea
  • Headache, dizziness and coordination problems
  • Liver damage, coma, death
  • Birth defects if overconsumed in pregnancy
Just Right (adults):
  • Beta-carotene from plant foods – generally safe, excess may cause orange skin but not toxicity
  • Recommended Daily Allowance: 700-900 retinol activity equivalents (RAE)/day

 

Medication Interactions

(consult your doctor)

  • Orlistat (weight loss)
  • Retinoids (skin conditions)

 

Food Sources

Animal
  • Beef liver (consume sparingly)
  • Egg Yolks
  • Whole Milk, Cheese
  • Salmon, Trout
  • Cod-liver Oil
  • Butter
Plant Based (beta carotene)
  • Orange and yellow fruits and vegetables: sweet potatoes, carrots, pumpkin and butternut squash
  • Leafy greens: spinach and kale
  • Papaya
  • Red Bell Peppers

Cooking tips:

  • Vitamin A is fat soluble, so its absorption improves when consumed with a little fat (ex: roasting veggies in olive oil or adding nuts/seeds).
  • Some fruits and vegetables have significant amounts of nutrients in their skin, so don’t peel carrots or potatoes.
  • Heat improves availability of beta carotene in plants. It breaks down the plant’s cell walls, making the carotenoids easier to absorb.

Reference:  Vitamin A and Carotenoids – Health Professional Fact Sheet