A number of mineral substances are essential for us. This means that we cannot synthesize them and we are therefore dependent on their intake from external sources. Whether we try to get the recommended intake of minerals from a varied diet or whether we support it with food supplements, we usually focus only on the mineral’s amount in a specific food or supplement. But the truth is, that the final amount of the mineral substance our body absorbs is influenced by a number of other factors.
In this article, we are introducing some of the factors affecting the degree of mineral utilization that we can (at least partially) influence and so support their absorbed amount.
Article at a glanc:
- What are mineral substances and what is their role in the human body?
- What is bioavailability?
- How to increase the utilization of minerals?
- a) choose a quality source of food
- b) digestive enzymes and hydrochloric acid in our gastrointestinal tract
- c) composition of the specific food and the antinutrients
- d) chemical structure of nutrients
- e) correct timing of mineral supplementation
What are mineral substances and what is their role in the human body?
Minerals are inorganic substances that represent around 5% of the total weight of the human body. Minerals that are needed in larger amounts (in milligrams) are called macrominerals or major minerals. Minerals needed in smaller amounts (in micrograms) are called microminerals or trace minerals. The amounts needed in the body are not an indication of their importance. Macrominerals include calcium, phosphorus, magnesium, sodium, potassium, chloride and sulfur. Microminerals include iron, zinc, copper, manganese, iodine, chromium, selenium, molybdenum, cobalt and boron.
Mineral substances are not a direct source of energy for us, but they significantly participate in its creation. They mostly act as enzyme cofactors enabling and facilitating the course of reactions. Minerals form part of our body structures such as bones, teeth and connective tissues. They are also part of some hormones (for example iodine is contained in thyroid hormones). By transmitting chemical and electrical signals, they mediate communication between cells and so enable the proper functioning of muscles and nerves. They manage fluid and electrolyte balance as well as stability of the body's internal environment. Since our body cannot create minerals by itself, our vital functions depend on their regular intake. We should not forget that their sufficient absorption from the digestive tract is also crucial.
What is bioavailability?
In pharmacology, bioavailability refers to the rate a substance or drug enters systemic circulation. If the substance penetrates directly into a vein, its bioavailability will be 100%. The bioavailability of food or other substances taken orally depends on various factors, such as chemical properties or pharmaceutical form of the substance.
The ingested substance must also go through a difficult journey through the digestive tract. The degree of mineral substance utilization and absorption differs individually depending on the age as well as on the overall health.
How to increase the utilization of minerals?
a) choose a quality source of food
Our primary sources of mineral substances are water, plant and animal food. The mineral content of food varies significantly and is influenced for example by geographical location, industrial and coolinary processing.
Regarding plant sources, the nutrient content of the soil, the use (or overuse?) of agrochemicals, climatic conditions, plant breeding and genetic modification play a big role. However, the stage of maturity at which the crop was harvested and then technologically processed, handled and stored before reaching our table also plays a significant role.
In the case of animal sources, the content of mineral substances is influenced by genetics, feeding, the use of drugs, the age of the animal as well as the overall method of breeding connected with ethics and respect for animals and nature.
Unfortunately, it is now generally known that the nutritional value of basic foods has a decreasing trend.
In order to obtain as many nutrients as possible, it is necessary to choose seasonal and local food, as fresh as possible, ideally organic with the least intervention from the industrial sector.
b) digestive enzymes and hydrochloric acid in our gastrointestinal tract
The ingested food must first pass through the digestive tract, where the individual nutrients are enzymatically split and unbound from the chemical structures so that they can be absorbed by the intestinal cells and further distributed throughout the body.
Mechanically, food digestion begins already in the mouth by chewing and mixing the bite of food with saliva, which breaks down the food enzymatically. Proper chewing and swallowing of food is therefore the first step to support digestion. The chewed food is further transported to the stomach, where strong hydrochloric acid is secreted.
Hydrochloric acid helps break down food, has antibactericidal effects and so provides protection against possible infection from ingested food. It is also necessary for the absorption of certain elements such as calcium, iron or vitamin B9 and B12. For this reason, insufficient production of hydrochloric acid (caused by stress or excessive use of antacids) can lead to poor digestion of mineral substances and their lower absorption.
We can easily increase stomach acid by drinking a glass of water with unpasteurized apple cider vinegar (ideally organic) before our meal.
Digested food continues from the stomach into the small intestine, where it’s mixed with bile and a number of enzymes coming from the pancreas. Most minerals are absorbed into the bloodstream in the upper part of the small intestine. They then pass to the liver and are (like other nutrients) distributed throughout the body. Our intestine is composed of a large number of villi and microvilli, which significantly increase the intestinal absorption surface. If the intestinal mucosa is disturbed or inflamed, the absorption surface is reduced and along with nutrients also a number of toxic substances could leak into the bloodstream. The body then uses the minerals to remove toxins instead of using them for the necessary physiological functions.
Since health begins in the gut, we should not forget to take special care of our intestinal tract.
c) composition of the specific food and the antinutrients
Each food contains a composition of different substances that influence each other. Some promote the absorption of other elements, while others inhibit them. Individual minerals also interact with each other, compete for a binding site and can displace each other.
There are various anti-nutritional substances or supporting factors in food.
Antinutritional substances, or inhibitory factors, are mostly part of the defense mechanism of plants against birds, insects, fungi etc. They are called antinutrients because they can interfere with our body's ability to absorb vitamins, minerals, proteins etc. by binding together and forming insoluble structures.
Antinutritional substances include:
- Phytic acid - phytates, which are found in grains and legumes, make it difficult to absorb calcium, iron, magnesium, zinc, phosphorus and copper by forming solid compounds that are difficult to break down. This prevents mineral absorption. It is therefore advisable to soak or even sprout foods containing phytates before cooking.
- Oxalates, or salts of oxalic acid - these acids, found for example in beetroot or spinach, form complexes with mineral substances such as calcium, iron or zinc that are difficult for the body to use.
- Tannins - are secondary metabolites created by plants as a protection against pests or fungi. The human body can take advantage of their antioxidant, anti-inflammatory and antiseptic effects. On the other hand, their excessive amount in the diet can negatively affect the utilization of mineral substances, because together they form insoluble compounds. A higher content of tannins can be found for example in legumes, coffee, tea or cocoa.
- Fiber - has the ability to bind harmful substances to itself and remove them from the body. However, it can have a similar effect on the necessary minerals. Fiber is undoubtedly important for our health, but it is recommended to regulate its amount and ideally not to consume it together with food supplements.
- Phosphates - phosphorus is important together with calcium for building and maintaining healthy bones and teeth. On the other hand, its excess negatively affects the absorption of calcium. The modern Western European diet contains large amounts of phosphates, which are widely used as leavening and emulsifying additives in processed foods. We can find them for example in meat, sausages, cheese, confectionery and bakery products or cola drinks. They are marked among ingredients as E 338, E 339 – 343 and E 450 – 452. Phosphates are also widely added to dietary supplements and fortified foods.
Supporting factors can be:
- Vitamin C in the diet, which promotes the absorption of iron.
- Vitamin D, which enables the absorption of calcium and improves the absorption of magnesium.
- Vitamin B6, which also increases the absorption of magnesium.
You can find out more about anti-nutritional substances in food and what they can cause in the body if consumed frequently in our podcast here (available only in czech language).
A more detailed overview of interactions between individual nutrients is shown in the below table.
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Factors influencing the bioavailability of minerals |
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INHIBITORS |
Phytic acid (beans, soybeans, grains) Tannins (tea, coffee, wine) Oxalic acid (spinach, cabbage, rhubarb) Fiber (cereals, legumes, fruits, vegetables) |
They form solid or insoluble structures with some minerals that prevent their proper absorption |
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ANTAGONISTS* |
Calcium and phosphate Calcium and zinc Calcium and iron Zinc and copper |
Some minerals use the same channels to enter the cell. At a high dose of one of the elements, they can compete for space, displace each other or affect absorption. That’s why it is better to consume them separately. For this reason, it is usually not recommended to consume minerals together with dairy products |
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SUPPORTING FACTORS |
Vitamin D, calcium, vitamin K2 Vitamin C, iron, magnesium Vitamin B6 and magnesium |
The acidic environment in the stomach affects absorption of vitamin C, B12 or iron. The presence of certain vitamins or sufficient amount of hydrochloric acid can improve the absorption of minerals |
*For clarification, it's important to mention that the antagonistic effect of some elements only applies under certain conditions. It is necessary to consider other factors such as for example saturation of the mineral substance in the organism, its received amount or the proportions of individual minerals if consumed at the same time.
For example, a long-term higher intake of zinc can cause a lack of copper in the body. Therefore, zinc is often supplemented in combination with copper in order to maintain the mineral balance. Another example is the combination of magnesium and calcium. These mineral substances are often bundled together in dietary supplements, as they both cooperate in regulating nerve impulses and muscle contraction. The recommended ratio of these two minerals is 2:1 in favor of calcium.
d) chemical structure of nutrients
It is simple chemistry. Certain forms of minerals are better absorbed than others.
Choosing the right form of the mineral substance is therefore essential for its optimal absorption. Mineral substances in inorganic form are minimally absorbable. They are formed by combining a metal with another chemical group, such as chlorides, sulfates, carbonates, hydroxides or oxides. Unfortunately, due to their lower price, mineral substances in inorganic forms are widely used in supplements. This may be one of the reasons why there is such a difference in supplement prices. It can often happen that supplemented mineral substances pass through the digestive tract almost unabsorbed and are excreted from the body without a significant "effect".
On the other hand, organic salts in so-called chelated forms are considered to be the most absorbable. The word "chelate" is derived from the Greek "chele", meaning "claw, clamp" and thus refers to the way in which metal ions are bound to other organic or synthetic compounds and are protected during passage through the digestive system. Commonly used chelating agents are amino acids, which give rise to an “amino acid-mineral-amino acid” structure. The most common organic forms of minerals are gluconate, lactate, citrate, fumarate and bisglycinate. For example, magnesium in the form of bisglycinate is much better absorbed than magnesium oxide. If you decide for dietary supplements containing minerals, invest in those containing well-absorbable chelated structures.
e) correct timing of mineral supplementation
Mineral supplements are recommended to be used on an empty stomach. This does not necessarily mean after waking up, but at least half an hour before eating and 2 hours after eating. If you supplement several minerals, it is better to use them separately, at a different time of the day.
It is best to drink the supplements with clean filtered water. If you cannot use supplements on an empty stomach and need to consume something, it is better to avoid coffee, tea, dairy products and foods high in fiber and phytic acid.
Let us mention that there are also specific supplement formulas designed in a way that potential inhibitory factors (such as coffee, milk or phytates) do not interact with the absorption of supplemented minerals. Such an example is our Magnesium, Zinc + B6 or Zinc + Copper, where chelating agents (glycine molecules) surround the mineral substance and protect it within the structure. This reduces the undesirable interaction with dietary inhibitors such as phytates, some forms of fiber, etc.