Bioavailability of natural foods and supplements

Bioavailability is a term that is mostly used in pharmacology. It indicates both how much fraction of an administered drug reaches the systemic circulation without undergoing modifications, and the speed with which it reaches it.

Increasingly often the term bioavailability is also used in relation to substances assimilated through foods or supplements.

Bioavailability of nutrients

Thebioavailability of nutrients, present within a food, indicates the fraction of nutrients that the organism is able to absorb and make precisely “available” to carry out the functions physiological.

This can vary due to many factors, which are divided into:

• Intrinsic, therefore linked to the characteristics of the individual who is consuming that given food such as age, sex, state of health etc...

• Extrinsic, linked to the characteristics of the food itself such as chemical structure, nutrient composition, cooking, pH and more.

Nutrition declaration

According to the European Regulation 1169/2011 relating to the provision of food information to consumers, one of the mandatory to be reported on the package is the nutritional declaration (except for some food categories).

The nutrition declaration, generally expressed in the form of table, indicates the energy value, the amount of macronutrients, such as fats, carbohydrates and proteins, and salt.

Furthermore, it can be integrated with the indication of micronutrients such as vitamins and minerals, if present in significant quantities.

Unfortunately, however, the nutritional declaration does not provide any information on the bioavailability of these micronutrients.

In fact, for a food, it is not sufficient just to contain a significant quantity of micronutrients, but they must also be present in a form that is bioavailable, therefore assimilable by the body.

Minerals, vitamins and other nutrients can have different chemical forms in food and this can affect their bioavailability.

To better understand this concept let's take iron for example, whose bioavailability changes considerably depending on the origin of the food.

The molecule eme is like a protective ring that protects iron from interaction with other food components, thanks to which it is absorbed intact. In contrast, non-heme iron is easily affected by other components of the diet and therefore only a small part is absorbed.

The bioavailability of macronutrients such as lipids, carbohydrates and proteins is generally good, almost 90%. While that of minerals, vitamins and other bioactive compounds such as polyphenols, carotenoids, phytosterols etc... varies from 1% to 90% depending on the way in which they are absorbed and used.

What influences the bioavailability of a food?

As we said previously, there are many factors that can influence and modify the bioavailability of nutrients.

The most important are certainly thestate of health of the individual who is consuming the food. In fact, there are some pathological conditions that can decrease or increase assimilation.

For example in case of diarrhea, food intolerances, chronic inflammatory bowel diseases, celiac disease or the intake of some drugs can modulate the bioavailability of the various micronutrients.

Even cooking can have a positive effect on the bioavailability of some nutrients such as starches and proteins, and a negative one as in the case of fats and vitamins.

refining and complex food processing have a negative impact on the bioavailability of nutrients, as a large part of the vitamin and mineral content is lost.

Finally, alsothe interaction of multiple nutrients, especially minerals, can influence their bioavailability by limiting or enhancing their absorption. For example, zinc reduces the absorption of copper or, a large amount of iron limits the absorption of zinc, etc.

How does it affect nutrition?

Knowing the bioavailability of nutrients and their interactions helps us balance our diet and make it healthier without giving up taste and traditions. Furthermore, it can help us make a diet effective.

Let's give some examples:

Carotenoids are antioxidant compounds present mainly in orange fruit and vegetables, being fat-soluble, their bioavailability will depend on the presence and quality of the lipids present in the diet. Then seasoning a good plate of pasta with tomato sauce with a teaspoon of raw EVO oil will promote the absorption of carotenoids!

Instead, vitamin C is able to increase the absorption of iron, this means that if we season the meat with lemon juice or accompany a bowl of cereals with orange juice, we will help the body absorb a greater quantity of iron contained in that meat or cereals.

Bioavailability of supplements

Choosing or cooking balanced dishes that allow us to optimize the intake of different nutrients is important, whether you choose adiet Mediterranean, but also and above all for those who follow aplant-based diet and who will therefore necessarily have to integrate certain nutrients contained in foods of animal origin.

Hence, the need to take some food supplements, in the form of capsules, tablets or powder, useful for integrating certain nutritional deficiencies.

When choosing a supplement it is always better to opt for a fruit-based food supplement, such as açai and rose hips, or plants, as in the case of moringa or of maca, rather than supplements artificially synthesized.

In fact, although technology now allows us to synthesize molecules that are almost completely similar to natural ones, they are not always identical copies and some differences can influence their biological activity and absorption capacity.

In general, the nutrients naturally present in plants (fruit, leaves, roots...) are found in a form more compatible with human physiology and are also associated with each other in a combination that favors the synergy of the active ingredients present in terms of bioavailability and physiological effects.