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Vitamin A

Vitamin A is essential for maintaining healthy vision, particularly in low-light conditions, by supporting the function of the retina. It plays a key role in immune function, helping the body fight off infections and illnesses. This micronutrient is also important for skin health, promoting cell growth and repair. Additionally, Vitamin A supports reproductive health and normal fetal development during pregnancy. It acts as an antioxidant, protecting the body from oxidative stress and reducing the risk of chronic diseases.

Foods rich in Vitamin A includes :

1. Live(beef and chicken) – one of the highest sources.

2. Carrots– packed with beta-carotene, which the body converts to Vitamin A.

3. Sweet potatoes – another excellent source of beta-carotene.

4. Leafy greens – such as spinach, kale, and collard greens.

5. Fish – like salmon and mackerel contain Vitamin A in its active form.

6. Dairy products – such as milk, cheese, and eggs also provide Vitamin A.

The recommended daily intake of Vitamin A varies by age, gender, and life stage. 1. Infants (0-12 months): 400-500 micrograms (mcg) of retinol activity equivalents (RAE) per day.

2. Children (1-8 years): 300-400 mcg RAE/day.

3. Males (9-13 years): 600 mcg RAE/day; **Males (14 years and older)**: 900 mcg RAE/day.

4. Females (9-13 years): 600 mcg RAE/day; **Females (14 years and older)**: 700 mcg RAE/day.

5. Pregnant women: 750-770 mcg RAE/day.

6. Breastfeeding women: 1,200-1,300 mcg RAE/day.

Vitamin A deficiency

1. Night blindness – difficulty seeing in low light.

2. Xerophthalmia – a severe eye condition that can cause blindness.

3. Weakened immune system – increasing the risk of infections.

4. Dry skin– due to poor skin cell regeneration.

5. Stunted growth – especially in children.

Vitamin A toxicity

1. Nausea and vomiting – early signs of acute toxicity.

2. Dizziness and headaches – due to increased intracranial pressure.

3. Liver damage– from chronic excessive intake.

4. Bone weakening – increasing the risk of fractures.

5. Birth defects – in pregnant women, excessive Vitamin A can harm fetal development.

Here are some interesting facts you may not know about Vitamin A:

1. Preformed Vitamin A vs. Provitamin: Vitamin A comes in two forms—preformed Vitamin A (retinol), found in animal products like liver, and provitamin A carotenoids (like beta-carotene), found in plant-based foods, which the body converts to active Vitamin A.

2. Fat-soluble nutrient: Since Vitamin A is fat-soluble, it is better absorbed when consumed with healthy fats, making meals with a balance of fats and Vitamin A-rich foods more effective.

3. Stored in the liver : The body stores up to 90% of its Vitamin A in the liver, which allows it to maintain adequate levels even if dietary intake fluctuates.

4. Protects against measles : Vitamin A supplementation is used in children in developing countries to reduce the severity and mortality of measles, as it boosts the immune response.

5. Excess beta-carotene is not toxic : While too much preformed Vitamin A can cause toxicity, excess beta-carotene from plant foods is generally non-toxic, though it can turn the skin a yellowish-orange color (a harmless condition called carotenemia).

References

National Institutes of Health. (2021). Vitamin A: Fact sheet for health professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/

Ross, A. C., Taylor, C. L., Yaktine, A. L., & Valle, H. B. (Eds.). (2001). Dietary reference intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. National Academies Press. https://doi.org/10.17226/10026

Penniston, K. L., & Tanumihardjo, S. A. (2006). The acute and chronic toxic effects of vitamin A. The American Journal of Clinical Nutrition, 83(2), 191-201. https://doi.org/10.1093/ajcn/83.2.191

World Health Organization. (2009). Global prevalence of vitamin A deficiency in populations at risk 1995–2005: WHO global database on vitamin A deficiency. https://apps.who.int/iris/handle/10665/44110

Submitted by: Tanisha Joyce M. Abellanosa

Section:BSN2D