What is nutrient “bioavailability” and why is it important?
Have you ever heard someone say that you can get the same nutrients regardless of whether you’re following a plant-based or animal-based diet?
I know I have. I used to be that person! But let me tell you, that is a half truth, and I’ll explain what I mean below.
One of the key convincing factors for me to change from a plant-based diet years ago was learning about the topic of nutrient bioavailability.
In short- bioavailability is the idea that some forms of nutrients are more biologically available than others.
Nutrients found in animal foods are far more bioavailable when compared to plant foods, across the board. We see this in iron, vitamin A, vitamin D, omega 3 fatty acids, and more.
Let’s take vitamin A for example.
Nutrients from plant and animal foods are not created equal. Bioavailability is essential! And as you can see in the image above, there are so many factors that influence our body's ability to absorb and utilize the nutrients from our foods.
Why would it be important to utilize vitamin A in pregnancy?
It has effects in liver detoxification, immune health, and skin health- just to name a few! And get this, 80% of women of childbearing age are not getting enough vitamin A- including women who consume animal foods!
Another interested tidbit from the study I cited was: "The absorption of beta-carotene from plant sources ranges from 5% to 65% in humans." That's a wide range! Are you relying solely on plants for your vitamin A? What if you're only absorbing 5% of that?!!
In the image above, I demonstrate one way vitamin A is less bioavailable to some people- about 40% of the population has a defect in the BCMO gene responsible for converting beta-carotene into active vitamin A.
One thing to note is that there are multiple ways your body uses carotenoids after absorption, vitamin A production is just one of the roles.
Liver, on the other hand, provides vitamin A in a form where it doesn’t need to be converted to be used and doesn’t have genetic barriers to its absorption or utilization.
This is bioavailability.
Do you want to hear more of this topic of bioavailability? What questions come up for you? Tell me in the comments!
