Hi all! Did You Know? Fridays is back this week! I started Did You Know? Fridays in December as a way of putting my nutrition knowledge to use in providing you with short, easy to understand snapshots about different nutrition topics. In December, we talked about:
Today we are talking about a topic near and dear to my heart—Vitamin A! My Ph.D. research involves different food sources of vitamin A, so I thought I would give you a simplified explanation here. Vitamin A is a fat soluble vitamin and is easily stored, so we don’t see many cases of deficiencies here in the US. Vitamin A is crucial for our eyesight (especially seeing at night time), immune system function, and reproduction/growth.
Did you know….
That there are TWO types of main dietary sources of Vitamin A: Preformed VA and Provitamin A.
Preformed Vitamin A is mainly found in animal sources: mainly meats (especially liver) and dairy products.
Provitamin A is mainly found in fruits and vegetables. Another term for Provitamin A that you might have heard is carotenoids. Ever heard that carrots are a great source of vitamin A, primarly beta-carotene? Well, beta-carotene is a carotenoid! Other common carotenoids that you can consume are alpha-carotene (also high in carrots) and beta-cryptoxanthin (high in citrus fruits). For the typical consumer, you can use provitamin A and carotenoids interchangeably. 🙂
Now some of you may be asking, how do these differ? Why should I care?
When you digest your food, preformed vitamin A (from animal sources) is easily absorbed in your intestines, as long as you have adequate amount of fat in your diet (yes, you do need some fat to live). Most carotenoids though, have to be cut to smaller pieces (AKA “cleaved”) first to be absorbed during digestion, which takes an extra step.
Think of it like a toll bridge—preformed vitamin A can just pass right through in the express lane, but most provitamin A/carotenoids have to stop at the toll booth and their toll is to be cleaved before they can cross the bridge.
FYI- That was my first attempt at a nutrition analogy, bear with me here! 🙂
PS- Your Did you Know Friday? Fun fact about me is that my favorite food is chocolate. My second favorite food though? Broccoli. Not kidding. 🙂
Image source used for preformed vitamin A.
Now you tell me…what other nutrition topics are you curious about? What would YOU like to see on Did You Know? Fridays?