How much of the food you eat can your body actually use?

Why is it harder to make use of some things?

When you are eating not everything that you put in your mouth is going to be used up by your body. Bioavailability expresses how much of the consumed food is being utilized by the body. There are internal (eg. gender, age) and external factors (eg. preparation of food) that influence the absorption of the different nutrients. The nutrients can be put in 2 groups, micro- and micronutrients. Macronutrients are proteins, carbohydrates and lipids and they usually have a high bioavailability. Micronutrients are vitamins and minerals and their availability can be very different depending on the circumstances of consumption.

One of the factors that can affect the absorption of the nutrients are anti-nutrients. These substances can be found both in animals and plants and in the foods produced of them. As we don’t want to be eaten, plants either. They produce these chemicals that makes them less nutrious and for this reason animals are going to choose something else that will supply their bodies with the right food content.

The size of the molecule that has to be ingested also matters, the smaller the component is the easier it is for it to cross through the intestinal wall.

It is especially important to pay attention to the bioavailability of minerals and therefore food preparation when you are eating a mainly plant based diet. Cooking practices and ideal combination of components can improve the availability of.

You can make it easier!

There are household practices that many people do, but are not aware that helps nutrient absorption. Such are soaking, heat treatment, germination, sprouting and fermentation. These are a couple of examples and general information on how the mineral availability can be influenced by these methods as listing everything would be a novel.

SOAKING, GERMINATION, SPROUTING

Soaking is a part of the germination and sprouting process. These techniques can reduce the presence of chemicals that decrease absorption of micronutrients. Soaking grains overnight or longer can improve bioavailability already, but germination or sprouting can have an even more beneficial effect.

HEAT TREATMENT

During heating of the food, which can be boiling, frying, stir frying ect. the food becomes softer. The molecules loosen up therefore the enzymes can access them easier. For the same reason the minerals that are bound to protein can escape from the molecules easier, as they have an easier way to move.

Moreover, the heat can change the function of absorption inhibitors, like phytate and soluble dietary fibre, thus improving bioavailability of minerals.

As an example pressure-cooking and microwave-heating improved the bioaccessibility of iron from cereals and pulses. The same process on the other hand reduced the accessibility of zinc.

FERMENTATION

During this process the plants are producing organic acids that change the bonding of minerals. Moreover, during this process the anti-nutrients are lowered in the plant, therefore nutrients become more accessible.

SPICES AND CONDIMENTS

Pungent spices, such as red and black pepper and ginger, are known to stimulate digestion, which can improve uptake of nutrients.

Onion and garlic is both part of the Allium family. These spices can improve the absorption of iron and zinc. Turmeric contains curcumin, which can enhance the availability of iron. These spices and also acidulants (e.g. lime juice) can help the ingestion of b-carotene.

And some examples…

A short list of cases when bioavailability can be enhanced:

• iron absorption by citric, malic, tartaric, and ascorbic acid
• iron absorption by adding carrot or amaranth to meals
• b-carotene ingestion by acidulants (e.g. lime juice)
• iron uptake by vitamin C
• iron uptake from plant sources by meat and fish
• carotenoids by fat or oil