Best Ikea purchase ever
Best Ikea purchase ever

I always assumed that when we eat food, we can get all of the nutrients out of it, but in the first nutrition class I took, I learned that I was very wrong.

In this class, we talked about the concept of bioavailability, which essentially means that our bodies only get a certain amount of the nutrients in some foods.

Part of this is due to the fact that food goes through a lot before we can actually use the nutrients. In nutrition, we call this process ADME: absorption, distribution, metabolism, and excretion. I won’t go into detail about it but the take-home message is that the process of getting nutrients out of our food is complicated and our nutrient levels don’t necessarily match our nutrient intake.

One thing that can decrease the bioavailability of a food is its physical structure. If we can’t break a food down, we can’t get the nutrients out of it. As our professor pointed out, we can see this in our daily lives – some high fiber foods pass right through you in one piece (you get to talk a lot about poop in nutrition classes).

In fact, a lot of food processing is done to break down food structure so we can get to the nutrients. If you’ve ever seen a stick of sugarcane, you know that it basically looks like bamboo. You could chew on that for hours and get very little sugar out of. Once it has been refined into table sugar, you can get a whole lot of sugar very quickly and easily.

Okay, so all that is interesting but how does it apply to your average college student (who usually isn’t gnawing on sugar cane)?

You can use fun food chemistry facts to maximize your nutrient bioavailability! Yay! And yes, I realize this is super dorky but I think it’s actually really cool too.

One way that I do this in my own life is with iron absorption. As a vegetarian and a woman, I have to be really careful to makes sure I’m getting enough iron. Iron is in both plant and animal based foods but it’s more bioavailable in meat. We use iron in our blood cells to help carry oxygen throughout our bodies, which makes it super important. When we lose blood, we lose iron too, so women of menstruating age tend to have lower iron levels.

The good news is that having some Vitamin C with your iron makes the iron more bioavailable. They don’t have to be in the same food but should be eaten around the same time. So if you’re eating iron fortified breakfast cereal and have a glass of orange juice on the side, you can absorb more of the iron in the cereal.

Green veggies, like spinach, kale, and broccoli, are also high in iron and taste great with a squeeze of lemon juice, like in the roasted broccoli below.

You can check out a list of more iron rich foods from the American Red Cross here.

Of course, if you don’t like the more bioavailable form of a food, it is better to eat the less bioavailable form than not eat it at all but sometimes the more bioavailable form as as tasty, if not tastier, than the original.

Roasted Broccoli with Lemon

So simple and so delicious! The amounts given depend on how big your broccoli heads are so feel free to tweak them. 

Time: 30 minutes (5 minutes prep, 25 minutes baking)

Yield: about 6 cups


  • 2 heads of broccoli
  • 3-4 Tablespoons olive oil
  • salt
  • pepper
  • juice of 1/2 a lemon


  1. Preheat oven to 425° Fahrenheit.
  2. Clean and chop broccoli into bite sized pieces. I use the stalk too but I like to quickly peel off any tough skin.
  3. Toss the broccoli with olive oil and add salt and pepper to taste. You can do this in a bowl or directly on a baking sheet.
  4. Roast broccoli for about 20-25 minutes until it is starting to brown. I like mine on the crispier side so I tend to leave it in for a few more minutes.
  5. Remove from oven and toss with lemon juice.


  • add red pepper flakes along with the salt and pepper before roasting
  • chop up a couple cloves of garlic and mix them in with the broccoli before roasting
  • toss in a handful of slivered almonds in the last couple minutes of roasting
  • sprinkle with grated Parmesan after it comes out of the oven

3 thoughts on “Bioavailability

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