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November 15th, 2013 |

Two Facts and A Myth: Vitamin A

“Two Facts and A Myth” is a series of nutrition topics that you can share at the dinner table, around the water cooler, or in line at a coffee shop. This series will bust popular misconceptions about nutrition while highlighting little-known facts. For this week, we will focus on Vitamin A.

Fact Vitamin A is important to your eyesight.

Vitamin A takes part in several key steps that allow us to see. The retina (the inner part of the eye) uses vitamin A to convert light into visual signals that are sent to the brain. So, carrots may not make your vision better, but they (and other foods with vitamin A) are important to eyesight.

Fact Vitamin A deficiency causes night blindness.

Night blindness is when your eyes have difficulty adapting from bright light to darkness. To treat night blindness, clinicians have prescribed diets rich in vitamin A to patients. This practice has been used for centuries. The first known treatment dates back to Hippocrates’ advice to the ancient Egyptians and Greeks.

Myth Vitamin A supplementation is necessary for curing certain conditions.*

Because of the abundance of foods with vitamin A, supplementation is not necessary. Our Retinol Activity Equivalents (RAE), the Recommended Daily Allowance (RDA) for Vitamin A, is 900 mcg (micrograms) per day for males and 700 mcg per day for females. Since we do not look at food in terms of mcg, how much of each food do we need in order to get the recommended daily amount of vitamin A?

Food

Males

Females

Liver 0.96oz (almost 1   pound) 0.75oz
Fish (depends on   the fish) 1 pound 7.3oz 1 pound 2.4oz
Eggs 10 large 8 large
Fortified Milk (with Vitamin A and D) 6 cups 4.5 cups

Another way to get vitamin A is to eat foods with beta-carotene. Beta-carotene is converted to the active forms of vitamin A during digestion. Beta-carotene is orange, so foods with beta-carotene tend to have that color as well. Some dark green vegetables also contain beta-carotene (the green covers up the orange color).

Food

Males

Females

Carrots 1 ½ large 1 ¼ large
Sweet Potatoes (5   inch) 1 potato ¾ of a potato
Kale 2 ¾ cups chopped 2 cups chopped
Apricots 5 ¾ cups 4 ½ cups
Mangoes 10 cups 8 cups

Remember it is important to have a balanced diet. So, you do not need to get all of your vitamin A from one source.

Be mindful of the supplements you choose to take. Unless otherwise recommended, you should try to get your vitamins and minerals from food sources.

 

*Before deciding to start or stop taking Vitamin A supplements, consult your doctor, registered dietitian, or other health professional.

** When you consume over certain amount, the upper limit (UL), it can become dangerous. The UL for vitamin A is 3000mcg for males and females.

***For more information on the vitamin and minerals in your food, go to http://ndb.nal.usda.gov/.

 

By Stephanie Snell, guest blogger, Master’s Candidate at Tufts University’s Friedman School of Nutrition Science and Policy