Why bioavailability is so important

1. what exactly does bioavailability mean?

The term bioavailability describes the proportion of an ingested nutrient that actually reaches the blood and can be used by cells, organs or the metabolism.

The higher the bioavailability, the more efficiently your body can utilize the substance. It is not only the quantity that is decisive, but also the form in which a substance is present - and which other nutrients it is combined with.

Example: Vitamin D3 is only optimally absorbed in combination with fat. Zinc competes with iron, magnesium with calcium.

2. why bioavailability determines effect

The idea is simple: only what your body can really absorb will have an effect. Everything else is either excreted unused - or in the worst case can even be harmful.

This applies not only to food supplements, but also to normal foods. Age, digestion, stress, illness or medication strongly influence how well nutrients are absorbed. With increasing age, for example, the absorption capacity for vitamin B12 or magnesium decreases noticeably. A study by the Journal of Nutrition (2017) shows: For certain vitamins, bioavailability can vary individually by up to 500 %!

3 What influences the bioavailability of nutrients?

The most important influencing factors:

• Form of the nutrient

  Organic compounds (e.g. magnesium citrate) are often more readily available than inorganic compounds (e.g. magnesium oxide).

• Accompanying substances

  Fat-soluble vitamins need fat - dietary fiber can inhibit the absorption of certain minerals.

• Intestinal health

  Healthy intestinal flora improves the absorption of many micronutrients. It can reduce inflammation or dysbiosis.

• Food matrix

  Nutrients in natural foods are often better embedded than isolated extracts.

  → An apple works differently than isolated vitamin C.

4. how you can improve your bioavailability

The good news is that you can do a lot yourself to increase the bioavailability of your diet:

• Combine foods

  Z.E.g. turmeric with black pepper (piperine improves absorption by up to 2000 %).

  Or an iron-rich plant-based diet with sources of vitamin C (e.g. peppers, citrus fruits).

• Take fat-soluble vitamins with a little oil

  (e.g. vitamins D, E, K, A - preferably with a meal containing healthy fats)

• Use fermented or cooked foods

  → e.g. cooked vegetables or fermented soy products such as tempeh - both improve utilization.

• Choose supplements consciously

  Look for bioavailable forms and tested combinations (e.g. chelated compounds, liposomal systems).

Conclusion

Bioavailability is a key, often underestimated factor in the effectiveness of your diet. It determines whether your body is supplied with what it needs - or whether potential is wasted. If you understand how nutrients are absorbed, you can make smarter decisions. Because health doesn't start with counting calories, but with the right understanding of them. Only what is available can work.

1. FAO/WHO Expert Consultation. Vitamin and mineral requirements in human nutrition. World Health Organization, 2004.
2. Institute of Medicine. Dietary Reference Intakes: The Essential Guide to Nutrient Requirements. National Academies Press, 2006.
3. Journal of Nutrition. Individual Variability in Nutrient Absorption and Bioavailability, 2017.
4. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific Opinion on the bioavailability of nutrients, EFSA Journal.
5. Winklhofer-Roob, B. et al. Micronutrient Absorption and Bioavailability, in Annals of Nutrition & Metabolism, 2003.
6. NIH Office of Dietary Supplements. Nutrient Interactions and Absorption Overview, 2021.
7. Frontiers in Nutrition. The Role of Food Matrix and Processing on Nutrient Bioavailability, 2020.