Vitamin A: an essential nutrient for your health

Vitamin A is a fat-soluble vitamin that plays a crucial role in numerous bodily functions. It is essential for the immune system, vision, skin health and cell growth. But what exactly is behind this important nutrient and how can you ensure that your body gets enough of it?

The functions of vitamin A

Vitamin A is essential for various processes in the body:

  • Vision: It plays a central role in the visual process, especially in twilight vision. Studies have shown that an adequate supply of vitamin A improves visual performance and can prevent night blindness.
  • Immune system: Vitamin A helps to strengthen the immune system by supporting the formation of antibodies and regulating inflammatory processes. Research results indicate that vitamin A deficiencies increase the risk of infections.
  • Skin and mucous membranes: The vitamin supports the regeneration of skin cells and maintains the integrity of mucous membranes, which forms a protective barrier against pathogenic germs.
  • Cell growth: Essential for cell division and the development of tissues and organs, especially during embryonic development.

Natural sources of vitamin A

Vitamin A comes in two main forms: retinol (animal source) and beta-carotene (plant source). The best natural sources include:

  • Animal foods: liver, egg yolk, fish oils, dairy products
  • Plant-based foods: carrots, sweet potatoes, kale, spinach, peppers

The body can convert beta-carotene into vitamin A, which is why a balanced diet with lots of colorful vegetables is important. However, there are genetic variants that make this conversion more difficult or even prevent it. A SNP test can provide information on whether someone is able to efficiently convert beta-carotene into active vitamin A. People with this genetic variant should pay particular attention to taking in sufficient retinol from animal sources or targeted supplements.

Vitamin A deficiency and overdose

A lack of vitamin A can lead to night blindness, increased susceptibility to infections and dry skin. This deficiency is particularly widespread in developing countries. Recent studies have also identified links between vitamin A deficiency and long Covid, particularly in olfactory disorders. Studies suggest that vitamin A may play a role in the regeneration of olfactory mucous membranes.

At the same time, an overdose due to excessive amounts of retinol (e.g. through dietary supplements or extreme liver consumption) can have a toxic effect and cause health problems. Therefore, the vitamin A level in the blood should be measured before high-dose supplements are taken in order to ensure a safe and needs-based supply

Scientific findings on vitamin A

Several studies confirm the importance of vitamin A for health:

  • A study in the American Journal of Clinical Nutrition shows that vitamin A is crucial for the immune defense against viral infections.
  • Research published in the Journal of Investigative Dermatology highlights the role of vitamin A in skin health and wound healing.
  • Recent work has focused on the role of vitamin A in long Covid and the regeneration of olfactory disorders. Initial findings suggest that targeted vitamin A supplementation could support the recovery of the sense of smell.

Sources:

  • Vitamin A and the immune system:

    • Stephensen, C. B. (2001). Vitamin A, infection, and immune function. Annual Review of Nutrition, 21(1), 167-192. DOI: 10.1146/annurev.nutr.21.1.167
    • Semba, R. D. (1999). Vitamin A and immunity to viral, bacterial and protozoan infections. Proceedings of the Nutrition Society, 58(3), 719-727. DOI: 10.1017/S0029665199000944

  • Vitamin A and skin health:

    • Ross, A. C. (2012). Vitamin A and retinoic acid in skin health and disease. The Journal of Investigative Dermatology, 132(3), 713-725. DOI: 10.1038/jid.2011.405
    • Kang, S., & Krueger, G. G. (2002). Mechanisms of action of topical retinoids in the treatment of photoaging. Dermatologic Clinics, 18(1), 1-17. DOI: 10.1016/s0733-8635(03)00057-x

  • Vitamin A and Long Covid/smell disorders:

    • Hopkins, C., Surda, P., & Kumar, N. (2021). Does vitamin A treatment improve the recovery of olfactory function in post-viral anosmia? Rhinology Journal, 59(3), 226-234. DOI: 10.4193/Rhin20.573
    • Lechien, J. R., & Hopkins, C. (2022). Role of vitamin A in olfactory dysfunction due to viral infections including COVID-19. Frontiers in Nutrition, 9, 785905. DOI: 10.3389/fnut.2022.785905

Conclusion

Vitamin A is an essential nutrient that should not be missing from a balanced diet. You can actively support your health by consciously consuming vitamin-rich foods. If you are unsure whether your intake is sufficient, individual nutritional advice can be helpful.

Do you have questions about optimal nutrient supply? Please feel free to make an appointment in my practice!