Bioavailability of Food

Bioavailability is the body’s ability to absorb and utilize the nutrients we obtain from food. Not all the nutrients in the foods we eat are equally accessible to our bodies. In fact, some food combinations enhance the absorption of certain nutrients, while others inhibit it. In this blog, we’ll tell you a bit more about this so you can improve nutrient absorption through your diet.

Potential nutritional value vs. actual nutritional value
Potential nutritional value is the total content of nutrients in a given food—proteins, vitamins, minerals, antioxidants, and so on.

Actual nutritional value, on the other hand, is only the portion your body actually manages to extract, use, and turn into benefits for your system.

When we talk about a food’s benefits, we usually refer to its potential nutritional value—that is, the total nutrients it contains: proteins, vitamins, minerals, antioxidants...

However, there is something called actual nutritional value, which is the amount of nutrients your body truly absorbs and utilizes. This is where bioavailability comes into play.

No matter how nutrient‑rich a food may be on paper, if our bodies can’t absorb it properly, its actual nutritional value will be much lower.

What determines bioavailability?
Many factors can influence a food’s bioavailability:

• Preparation method: Boiling, simmering, fermenting, grilling, etc., can alter nutrient structure.
  
• For example, the lycopene in tomatoes is better absorbed when the tomato is cooked.
  
• Conversely, boiling leafy greens can reduce their vitamin C content.
  
• Food combinations: Some pairings boost nutrient uptake, while others block it.
  
• Presence of antinutrients: Compounds like phytates, oxalates, or tannins can hinder absorption of minerals such as zinc, calcium, or iron.
  
• Gut health: An imbalanced microbiome, intestinal inflammation, or digestive enzyme deficiencies can impair absorption of certain nutrients, even if you’re consuming enough of them.
• Age, stress, medications: As we age, absorption of nutrients like vitamin B12, magnesium, or vitamin D often declines. Chronic stress and certain medications can also interfere with how well we utilize what we eat.

How to combine foods so that they are more bioavailable?

There are combinations that improve nutrient absorption and others that hinder it, even if the foods themselves are healthy.

Combinations that improve absorption:

• Vitamin C + Plant‑based Iron:
  Plant‑based iron (non‑heme iron) is not absorbed as easily as animal‑derived iron, but vitamin C improves its absorption.
  Examples: lentils with red bell pepper, spinach with tomato, hummus with lemon.
• Healthy Fats + Fat‑soluble Vitamins (A, D, E, K):
  Vitamins A, D, E, and K are fat‑soluble, meaning they need fat to dissolve and be absorbed properly by the body. If we don’t combine them with healthy fats, a portion of these vitamins passes through the intestine unutilized.
  Examples: cooked carrot with olive oil, salad with avocado, green smoothie with a handful of nuts.
• Black Pepper + Turmeric:
  Curcumin has very low bioavailability when consumed alone, and the body barely absorbs it. But when combined with piperine (present in black pepper), curcumin absorption increases by up to 2,000%.
  Example: golden milk or curry with turmeric and black pepper.
• Zinc + Animal Proteins:
  Zinc is better absorbed when it is found in animal proteins (lean meats, eggs, fish).
  Zinc is less bioavailable in plant sources (legumes, seeds, nuts) due to phytates.
• Calcium + Vitamin D:
  Vitamin D improves calcium absorption, facilitating its passage from the intestine to the blood.
  Opt for foods that naturally contain both nutrients, such as oily fish.
  Take advantage of products enriched with vitamin D and calcium, such as certain plant‑based beverages or yogurts.

Combinations that hinder absorption:

• Tannins (Tea, Coffee) + Plant‑based Iron:
  Tannins chemically bind to iron in the intestine, forming insoluble compounds that the body cannot absorb.
  Avoid drinking coffee or tea one hour before or after eating legumes, leafy greens, or whole grains.
• Phytates (Legumes, Grains) + Minerals (Zinc, Iron, Calcium):
  Phytates block the minerals in legumes and grains.
  Soaking, sprouting, or fermenting these foods before cooking makes most phytates disappear and facilitates nutrient absorption.
• Calcium + Iron:
  Calcium and iron compete for the same absorption receptors in the intestine, so if you supplement with iron or eat iron‑rich foods, calcium will block its absorption.
  Avoid taking both supplements at the same time.
  If you eat iron‑rich foods, try to avoid dairy products for a couple of hours.

Conclusion
We may be eating in an apparently healthy way, but if our body cannot access those nutrients, the effort is in vain.

The true value of a food is not only in what that food possesses, but also in what your body can take advantage of. Therefore, combining foods to improve the effectiveness of their nutrients is key.

 Written by Sara Montaner. We rely on AI technology. Translated by Irene Perea.