There’s a common misconception that beta-carotene found
in fruits and vegetables is the same thing as vitamin A. It’s
not.
Beta-carotene is the precursor (inactive form) of retinol, the
active form of vitamin A. While beta-carotene is converted
into vitamin A in humans, only 3% gets converted in a
healthy adult. And that’s assuming you’re not one of the
45% of adults that don’t convert any beta-carotene into
vitamin A at all.
This means that – contrary to popular wisdom – vegetables
like carrots and red peppers are not adequate food sources
of vitamin A.
Vitamin A is found in significant amounts only in animal
products like liver and grass-fed dairy. You’d have to eat a
huge amount of beta-carotene from plants to meet vitamin
A requirements during pregnancy. For example, 3 ounces of
beef liver contains 27,000 IU of vitamin A. As the chart
below illustrates, to get the same amount of vitamin A from
plants (assuming a 3% conversion of beta-carotene to
vitamin A), you’d have to eat 4.4 pounds of cooked carrots,
40 pounds of raw carrots, and 50 cups of cooked kale!
And remember: that’s assuming you’re not one of the 45%
of people that don’t convert any beta-carotenes into retinol
at all!
Obviously, since we only eat 3-5 pounds of food per day on
average, vegetables aren’t a viable food source of vitamin
A.
Why does this matter? Because vitamin A plays several
crucial roles in reproductive health, and many women (and
men) don’t get enough of it because vitamin A rich foods
like liver and raw dairy aren’t commonly consumed
anymore.
I’ll cover the importance of vitamin A in more detail in a
future post about cod liver oil, which is one of the best
sources of naturally occurring vitamin A.