What is Vitamin A?

Vitamin A is synonymous with carrots, good eyesight, and (for kids of the ‘90’s) the episode of the magic school bus where Arnold turns orange. Fat-soluble Vitamin A is found in two forms in the human diet - preformed Vitamin A (from animal products) and provitamin A (from plant products). You may have also heard the name of active forms of Vitamin A – retinol, retinal, and retinoic acid – in a variety of products. Vitamin A is one of the most studied vitamins as it plays a wide role in normal physiological function. Be careful not to eat too much as Vitamin A can be toxic at high doses.

Why does it matter?

• Vitamin A deficiency can lead to intestinal issues causing severe medical distress including death, especially in young children. Vitamin A deficiency can also impair normal sight, proper wound healing, and skin function, and increase the risk of infections.
• Retinoic acid receptor, an enzyme that uses active forms of Vitamin A, is intricately linked with normal immune cell development. In other words, without Vitamin A, your immune system is altered which may lead to different responses if you get sick!
• Vitamin A is a critical component of rhodopsin in the rods of the eye. Normal functioning of the rods allows us to see in low light conditions and thus Vitamin A deficiency can lead to night blindness.

Where can I find Vitamin A?

Some of the highest sources of preformed Vitamin A such as beef liver (7744μg/100g) and tuna (655 μg/100g). While both animal sources and plant sources are good, many versions of Vitamin A from plants are also antioxidants. Some great plant sources include carrots (852 μg/100g), spinach (469 μg/100g), lettuce (370 μg/100g), and swiss chard (315 μg/100g).

Daily recommended intakes

Recommended daily intake can vary depending on the advising body, but here are some recommendations for healthy adults across the world (Numbers may vary for those with specific deficiencies, pregnant women, children, etc.):

• 900 μg (Men) or 700 μg(Women)/day (USA)
• 900 μg (Men) or 700 μg(Women)/day (Canada) 
• 850 μg (Men) or 700 μg(Women)/day (Japan)
• 750 μg (Men) or 650 μg(Women)/day (EU) 

To wrap it up

 

Vitamin A is a critical part of a healthy diet with several physiologically relevant uses. However, eating too much can lead to toxicity and interact with some medications. By eating a diverse diet that includes adequate Vitamin A, you are providing your eyes, skin, and immune system with an important building block for healthy function.

Fun Fact

Yes, eating too many carrots can turn you yellow-orange. But this is harmless and will reverse almost immediately once you decrease your intake of Vitamin A. Sounds like a good idea for a prank on a friend, we think.