Vitamin A is an essential nutrient that plays a vital role in vision, growth and development, immune function, and reproduction. Many fruits and vegetables contain provitamin A carotenoids, which the body converts into retinol, the active form of vitamin A.
Top sources of preformed vitamin A
Preformed vitamin A comes from animal sources and is called retinol. It is found naturally in foods such as:
- Beef liver
- Fish liver oils (cod liver oil)
- Butter
- Whole milk
- Cheese
- Egg yolks
Beef liver contains the highest concentration of preformed vitamin A. Just 3 ounces provides the full Recommended Dietary Allowance (RDA) for adult men and women, which is 900 micrograms (mcg) Retinol Activity Equivalents (RAE).
Top provitamin A carotenoid sources
Provitamin A carotenoids are found in many red, orange, and green fruits and vegetables. The body converts these plant pigments into retinol. Some of the top sources include:
- Sweet potatoes – 1 medium baked with skin provides over 700% DV
- Carrots – 1 cup raw provides over 400% DV
- Kale – 1 cup cooked provides over 300% DV
- Spinach – 1 cup cooked provides over 150% DV
- Cantaloupe – 1 cup cubes provides over 135% DV
- Broccoli – 1 cup cooked provides over 90% DV
- Red bell peppers – 1 cup chopped raw provides over 75% DV
- Apricots – 1 cup halves provides over 35% DV
Beta-carotene is the most common and efficient provitamin A carotenoid that the body can convert into vitamin A. Other carotenoids like alpha-carotene, beta-cryptoxanthin and gamma-carotene also have vitamin A activity, but at lower conversion rates.
Daily vitamin A needs
The recommended daily intake for vitamin A depends on your age and gender:
- Infants 0-6 months: 400 mcg RAE/day
- Infants 7-12 months: 500 mcg RAE/day
- Children 1-3 years: 300 mcg RAE/day
- Children 4-8 years: 400 mcg RAE/day
- Children 9-13 years: 600 mcg RAE/day
- Adolescents 14-18 years: 900 mcg RAE/day (males), 700 mcg RAE/day (females)
- Adults: 900 mcg RAE/day (males), 700 mcg RAE/day (females)
- Pregnant women: 770 mcg RAE/day
- Breastfeeding women: 1300 mcg RAE/day
As you can see, the RDA increases for teenagers, pregnant women, and breastfeeding mothers who have higher needs.
Top sources of vitamin A by food group
To meet your daily needs, aim to include vitamin A rich foods from these groups:
| Food group | Top sources of vitamin A |
|---|---|
| Fruits | Cantaloupe, apricots, mango, papaya, guava |
| Vegetables | Carrots, sweet potatoes, spinach, kale, butternut squash, red bell peppers |
| Dairy | Whole milk, cheddar cheese, yogurt |
| Meats | Beef liver, lamb liver, goat liver |
| Seafood | Salmon, trout, halibut, tuna, herring roe |
| Oils | Cod liver oil |
Benefits of vitamin A
Here are some of the key benefits vitamin A provides:
- Essential for eye health – Vitamin A is needed to form retinal, a molecule that is crucial for vision, especially in low light. Vitamin A deficiency can lead to poor night vision and blindness.
- Supports immune function – Vitamin A plays several roles in immune health. It enhances the differentiation and activity of white blood cells, maintains mucosal barriers, and supports the function of immune cells in the gut.
- Needed for growth and development – During development and childhood growth, vitamin A supports cell differentiation, immune function, and healthy bones and teeth.
- Important for reproduction and pregnancy – Vitamin A is involved in embryogenesis, the development of the embryo. It also plays a role in spermatogenesis, the formation of sperm.
- May lower risk of certain cancers – Observational studies link high vitamin A intake from food (not supplements) with a reduced risk of certain cancers like lung and prostate cancer.
Deficiency symptoms
Vitamin A deficiency is rare in developed countries, but remains common in developing parts of the world. Symptoms include:
- Night blindness
- Dry eyes (xerophthalmia)
- Retinopathy
- Impaired immunity
- Poor growth
- Reproductive issues
- Skin changes and lesions
Young children and pregnant women have the highest risk of vitamin A deficiency. Worldwide, an estimated 250 million preschool-aged children are deficient in vitamin A.
Toxicity concerns
While vitamin A from food sources is not toxic, excessive intake from supplements may cause side effects. Symptoms of vitamin A toxicity include:
- Headaches
- Nausea
- Liver damage
- Bone pain
- Skin changes
- Blurred vision
Upper intake levels have been set at 3000 mcg RAE/day for adults to prevent toxicity. Make sure not to exceed this amount from fortified foods and supplements.
Increasing vitamin A intake
Try these tips to get more vitamin A from whole food sources:
- Enjoy carrots, sweet potatoes, dark leafy greens, red peppers, cantaloupe, eggs, and liver a few times per week.
- Cook tomatoes and carrots with olive oil to increase carotenoid absorption.
- Choose full fat dairy instead of low fat to get more vitamin A.
- Eat fruits like apricots, mango, and melon as snacks or desserts.
- Check the vitamin A content of fortified breakfast cereals and look for ones providing at least 10% DV.
- Take a vitamin A supplement as recommended by your healthcare provider if deficient.
Conclusion
Vitamin A is an essential nutrient needed for vision, growth, immunity and reproductive health. Preformed vitamin A is found in animal foods like liver, fish oils, dairy and eggs. Provitamin A carotenoids that the body converts to retinol are abundant in orange and dark green vegetables, as well as red fruits. Aim for the RDA of vitamin A daily from whole food sources. Watch for deficiency symptoms like night blindness and consume a variety of vitamin A rich plant and animal foods. But avoid very high intakes from supplements that may cause toxicity.