Vitamin A:

Vitamin A is a fat-soluble vitamin known for its role in improving night vision. There are two main forms of vitamin A in the diet: retinol/retinyl esters obtained from animal sources, fortified foods, and dietary supplements, and precursor forms of vitamin A such as carotenoids and beta-carotene that are converted by the body into retinol. Carotenoids can be naturally obtained from plant products. Some carotenoids do not convert into vitamin A in the body, such as lycopene, lutein, and zeaxanthin, which play important roles in overall health.

Benefits of Vitamin A:

* One of the most common benefits of vitamin A is aiding in night vision. It is widely believed that consuming carrots can improve night vision, as beta-carotene (a precursor of vitamin A) helps the eyes adapt to low-light conditions.
* The activation of white Vitamin A also supports blood cells, bone remodeling, and maintaining epithelial cells.
* Vitamin A plays a role in promoting cell growth and regulating cell division.

Recommended daily amounts of Vitamin A globally:

The recommended amount of vitamin A varies based on age and gender:

1. From birth to 6 months: 400 micrograms/day.
2. Infants from 7 to 12 months: 500 micrograms/day.
3. Children aged 1-3 years: 300 micrograms/day.
4. Children aged 4-8 years: 400 micrograms/day.
5. Children aged 9-13 years: 600 micrograms/day.
6. Adolescent males 14-18 years: 900 micrograms/day.
7. Adolescent females 14-18 years: 700 micrograms/day.
8. Adult males: 900 micrograms/day.
9. Adult females: 700 micrograms/day.
10. Pregnant adolescents: 750 micrograms/day.
11. Pregnant adults: 770 micrograms/day.
12. Breastfeeding adolescents: 1200 micrograms/day.
13. Breastfeeding adults: 1300 micrograms/day.

Food Sources:

Vitamin A can be found in various natural food sources such as leafy vegetables (spinach, broccoli, turnips), yellow and orange vegetables (carrots, sweet potatoes, pumpkin), tomatoes, red peppers, mangoes, fish oils, milk, and eggs. Vitamin A is abundant in cod liver oil, so if consuming it in large amounts, ensure that your dietary supplements do not contain excessive levels of vitamin A.

Signs of Vitamin A Deficiency:

Vitamin A deficiency can sometimes occur due to poor absorption associated with digestive disorders such as Crohn's disease, chronic alcohol consumption, and cystic fibrosis. However, vitamin A deficiency is rare. Some poor dietary habits can lead to a deficiency in vitamin A. Vitamin A deficiency is associated with the following symptoms:

• Dry conjunctiva (severe cases may cause blindness).
• Bone pain.
• Digestive disorders like nausea and vomiting

Some studies have linked high intake of dietary supplements containing vitamin A to an increased risk of lung cancer among smokers.
As for Beta-Carotene (a precursor of Vitamin A), it is not toxic even at high levels since it converts to vitamin A only when needed.

Studies Linking Vitamin A to Skin Cancers:

Vitamin A is commonly used in creams for skin treatment, sunscreens, and moisturizers. It is advised to primarily use these creams at night and try to avoid sun exposure. A study conducted on mice showed that retinol metabolites increased oxidative stress in cancer cells exposed to ultraviolet radiation. However, these studies cannot be generalized to humans because mice are more susceptible to developing skin cancers after exposure to UV radiation.

Vitamin A and Lung & Prostate Cancer:

Studies have conflicting results regarding the benefits of vitamin A and carotenoids in reducing the risk of lung cancer. Clinical studies have shown that taking vitamin A (retinyl palmitate) and beta-carotene supplements increased the risk of lung cancer among participants. Therefore, it is globally recommended not to consume dietary supplements containing vitamin A for smokers and asbestos-exposed individuals. It is also advised not to use vitamin A supplements for cancer prevention as they may do more harm than good.

• Regarding prostate cancer: Several studies have shown that consuming lycopene, a carotenoid that colors fruits and vegetables red or pink, plays a role in preventing prostate cancer.
• Consuming different forms of Vitamin A may slow down the progression of macular degeneration in elderly patients.
• Consuming large amounts of alpha-carotene, a form of vitamin A that contains lutein and zeaxanthin, may improve cognitive functions such as memory and learning in individuals at risk of cognitive decline.