THE ABCS OF VITAMINS: VITAMIN A

You might take a multivitamin that includes Vitamin A, but do you know the important role that vitamin A plays in your health? Your body can’t make vitamins on its own, so you must get them from your food (or supplements). Vitamin A is one of four fat-soluble vitamins (also including Vitamins D, E, and K) – which means you need to consume a source of fat along with Vitamin A for it be best absorbed.

WHY VITAMIN A?

Vitamin A is necessary for eye health, essential for normal vision and healthy skin. Adequate Vitamin A promotes normal healthy skin appearance and texture while it supports the normal renewal of skin cells. Topical retinol products are very popular ingredients for anti-aging skin care products. Beta-carotene is part of a larger family of antioxidants called carotenoids, which have strong antioxidant properties to help fight cell damage [2].

Vitamin A isn’t a new or novel supplement – in fact, ancient Egyptians would eat liver if they had trouble seeing after the sun went down. Liver is high in vitamin A, which we now know is essential for normal vision and overall eye health. Low levels of Vitamin A are still associated with night blindness. It wasn’t until 1931 that scientist Paul Karrer defined Vitamin A’s chemical structure by extracting it from cod liver oil [1].

HOW VITAMIN A IS USED IN THE BODY 

Vitamin A is used by our eyes to create specific molecules that help our eyes to see in the dark. Low levels of vitamin A interferes with this process and may result in poor vision at night or in low-light situations.

Vitamin A is available in our diet from two primary sources. One group of compounds called retinoids come from animal-based food sources and provide Vitamin A in the form of retinol. Another source of Vitamin A in our diet comes from beta-carotene, which is easily converted by the body into Vitamin A. Beta-carotene is part of a larger group of important antioxidants called carotenoids.

Most daily multivitamins contain Vitamin A – and for good reason. In addition to supporting eye health, Vitamin A can help keep your skin and hair healthy as these cells and tissues grow frequently. Vitamin A is a popular ingredient in beauty supplements, promoting normal healthy skin appearance and texture, and renewing skin cells. Vitamin A is important during pregnancy for the healthy growth of the fetus when new cells are dividing very quickly.

SIGNS OF A VITAMIN A DEFICIENCY

Vitamin A deficiency is uncommon in the United States, but can be more prominent in areas where there is limited access to fresh produce and high quality protein sources. An early sign of Vitamin A deficiency is the inability to see at night. Long term low levels of Vitamin A intake can also lead to poor lung health, respiratory conditions, and anemia [3]. Low levels of Vitamin A can also lead to reduced immune function [3]. 

If you have digestive conditions that limit your intake of foods that contain Vitamin A or need to follow a very low-fat diet for a long period of time, you may want to consider talking with your health care team about your Vitamin A intake.  

Related Reading: CAN YOU TAKE A MULTIVITAMIN AND FISH OIL TOGETHER?

FOODS CONTAINING VITAMIN A 

Who knew that bright colors could serve for more than just visual appeal? Orange- and yellow-colored fruits and vegetables get their color from carotenoids. These include beta-carotene (which is converted into vitamin A) and other important compounds for eye health like lutein and zeaxanthin. While it’s easy to remember that carrots are high in beta-carotene, there are other foods outside of the red and orange color families that are also high in Vitamin A. Plant based foods supply the beta-carotene needed for Vitamin A, while animal-based foods contain retinol. 

Plant based foods high in Vitamin A (beta-carotene) include:  

• Sweet Potato (with skin) 
• Spinach 
• Kale 
• Tomatoes 
• Pumpkin 
• Carrots 
• Cantaloupe 
• Sweet Red Peppers 
• Mangos 

Animal based foods high in Vitamin A (retinol) include: 

• Beef liver 
• Pickled Herring 
• Milk (fortified) 
• Ricotta cheese 
• Fish oils & high fat fish (like salmon) 

RECOMMENDED DAILY INTAKE OF VITAMIN A FOR ADULTS:

How can you be sure you’re getting enough Vitamin A in your diet? Make sure to include sources of Vitamin A along with sources of heart healthy fats to maximize absorption. If you consume well-balanced diet by focusing on colorful fruits and vegetables, whole grains, lean meats, beans, eggs, nuts, seeds and milk products, you will likely give your body plenty of the Vitamin A that it needs.

Because Vitamin A is such an essential nutrient, it is added to some widely consumed foods (like breads, cereals, and some milks). If you are concerned about your Vitamin A intake or typically avoid the foods that are high in Vitamin A, talk with your doctor about whether you need to consider a Vitamin A supplement.

The recommended intake of Vitamin A for adults by the USDA is measured in “retinol activity equivalents”, or RAE, which accounts for both the retinol and beta carotene sources of Vitamin A. Adult women have a recommended dietary allowance of 700 mcg RAE while men have a recommendation of 900 mcg RAE [4]. If you already taking a multivitamin or fish oil supplement for other reasons, check the levels of Vitamin A that are included. 

For Pregnant Women 

Women who are pregnant and breastfeeding have a slightly higher recommended intake of between 750-770 mcg RAE for pregnancy and 1200-1300 mcg RAE for breastfeeding [4]. During pregnancy, it is common to take a prenatal that includes fish oil. This is important because Vitamin A is essential for growth and development. However, low Vitamin A levels in pregnant women are uncommon thanks to the common fortification of everyday foods with added Vitamin A. Many grain products (like cereals and breads) have added Vitamin A as well as some dairy products. Pregnant women should only consider additional Vitamin A if it recommended by their health care team as too much Vitamin A can actual be harmful to their unborn baby [5].

References

1. Wolf, G. (1996). A history of vitamin A and retinoids. The FASEB Journal, 10(9), 1102-1107. Accessed 10 June 2024. 
2. Underwood, B. A., & Arthur, P. A. U. L. (1996). The contribution of vitamin A to public health. The FASEB journal, 10(9), 1040-1048. Accessed 10 June 2024. 
3. Wiseman, E. M., Bar-El Dadon, S., & Reifen, R. (2017). The vicious cycle of vitamin a deficiency: A review. Critical reviews in food science and nutrition, 57(17), 3703-3714. Accessed 10 June 2024. 
4. USDA National Institutes of Health (2023). Vitamin A and Carotenoids: Fact Sheet for Health Professionals. Accessed 10 June 2024. 
5. Bastos Maia, S., Rolland Souza, A. S., Costa Caminha, M. D. F., Lins da Silva, S., Callou Cruz, R. D. S. B. L., Carvalho dos Santos, C., & Batista Filho, M. (2019). Vitamin A and pregnancy: a narrative review. Nutrients, 11(3), 681. Accessed 12 June, 2024.