Present in many foods such as carrots, sweet potatoes and liver, vitamin A is essential for normal vision, proper growth, division and cell differentiation. It is necessary for the functioning of the immune system and essential for the health of the skin and mucous membranes.
Vitamin A deficiency is rarely seen in developed countries, but it can cause vision problems and a loss of immune system functions when it occurs. We will present vitamin A, its roles, but also its benefits for athletes.
What is Vitamin A (Retinoid)?
Although vitamin A is often considered a unique nutrient, it is the name of a group of fat-soluble compounds.
There are two forms of vitamin A naturally present in food:
- Preformed vitamin A — retinol and retinyl esters — are found exclusively in animal products such as dairy products, liver and fish.
- Provitamin A (beta carotene) carotenoids are abundant in plant foods such as fruits, vegetables, and oils.
To use them, our body must convert both forms of vitamin A into retinal and retinoic acid, the active forms of the vitamin.
Because vitamin A is fat-soluble, it is stored in body tissues for later use.
Most of the vitamin A in our body is stored in the liver in retinyl esters.
Roles of vitamin A in the body
Vitamin A is essential for health: it supports cell growth, immune function, fetal development and vision.
One of the most well-known functions of vitamin A is its role in vision and eye health.
The retina, the active form of vitamin A, combines with the opsin protein to form rhodopsin, a molecule necessary for colour vision and low-light vision.
It also helps protect and maintain the cornea (the outermost layer of the eye) and the conjunctiva (a thin membrane covering the eye’s surface and the inside of the eyelids).
In addition, vitamin A helps maintain surface tissues such as the skin, intestines, lungs, bladder and inner ear.
It supports immune function by helping the growth and distribution of T cells, a type of white blood cell that protects our body from infection. In addition, vitamin A supports healthy skin cells, male and female reproduction, and fetal development.
The benefits of vitamin A for athletes
Strengthening the immune system
Vitamin A plays a vital role in maintaining our body’s natural defences, which is essential when training regularly. Without an immune system robust, no athlete can improve his performance and progress over time.
It preserves the mucous membranes in the eyes, lungs, intestines and genitals, protecting them from bacteria and other infectious agents.
Vitamin A is also involved in the production and function of white blood cells, which help to capture and eliminate bacteria and other pathogens from our bloodstream.
Intense and regular sports activity is already straining our immune system. This means that vitamin A deficiency can increase our susceptibility to infections and delay our recovery when we get sick. So anticipate supplementing yourself with vitamin A if necessary, especially if you have fragile mucous membranes.
Beta-carotene improves performance
Beta carotene, the precursor of vitamin A, is a powerful antioxidant that can help athletes, especially those who do endurance and drag minor infections and diseases that negatively affect training and performance.
Some studies show that beta carotene plays a protective role on the cell membrane and symptoms such as allergies and asthma, primarily if these symptoms are related to long-term physical exertion.
Studies indicate that beta-carotene may also provide a significant advantage over a long-term race such as that conducted by Louisiana State University (Reference: Medicine and Science in Sports and Exercise. 31: S118, 1999). The effect of beta-carotene on race performance was evaluated on 11 seasoned runners (all run about 60km/week) while monitoring the time to complete a 5km race.
During the supplementation phase, each subject ingested 25000 IU of beta-carotene per day. The results indicate a statistically significant improvement in the performance of the 5 km races. In addition, 64% of the subjects noted a personal benefit of using beta-carotene supplementation.
This study indicates that beta-carotene can have a beneficial influence on the performance of already seasoned runners.
Vitamin A is vital to many vital processes in the body. It ensures the normal functioning of our organs and the immune system and the average growth and development of babies in the womb. Well known for its role in vision, vitamin A can also act as an antioxidant, especially during endurance training, especially protecting the mucous membranes from external aggressions.