Magnesium in foods

Magnesium is an essential mineral and is found in numerous foods. It contributes, among other things, to a normal energy metabolism and a normal muscle function as well as to the maintenance of normal bones . Particularly nuts, seeds, legumes, and whole grain products can contribute to magnesium intake. But which foods contain particularly high levels of magnesium and what factors influence absorption? You will find out in this article.

In which foods is magnesium contained?

Magnesium is found in numerous foods. Particularly high magnesium levels are found in plant-based foods such as pumpkin seeds, nuts, legumes, and whole grain products . The actual levels can vary depending on the food and growing conditions.To give you a better overview, the following table shows the average magnesium content of various foods per 100 g:

How much magnesium do we need per day?

The recommended daily magnesium intake is approximately 350 mg for men and about 300 mg for women, as suggested by the German Nutrition Society (DGE).These figures serve as guidelines and may vary, as the metabolism of magnesium is influenced by various factors.

Can we obtain enough magnesium through food?

In principle, an adequate intake of magnesium can be achieved through diet. Numerous foods such as nuts, seeds, legumes, and whole grains contain significant amounts of magnesium. However, the actual magnesium intake depends on individual dietary habits. A study involving 463 participants from Western Austria examined dietary magnesium intake and showed that some participants did not reach the established reference values.

How does the body absorb magnesium? 

The absorption of magnesium in the human body is a complex process that is facilitated by various transport mechanisms in the intestine. Magnesium is primarily absorbed in the small intestine, with two main mechanisms involved: A portion of the magnesium "slips" passively between the cells into the blood – especially when a lot of magnesium is present in the intestine. However, when less magnesium is available, regulated mechanisms become important. Special proteins act like small doormen, helping to transport magnesium through the intestinal cells. This allows the body to adjust its magnesium absorption to the available supply.

It is important to note that the amount of magnesium absorbed does not only depend on how much magnesium we take in through food.Other components of our food can also influence how well magnesium is absorbed.
For those who find this presentation too superficial, we will explain the two transport mechanisms in a bit more detail below.

Passive Diffusion

At high concentrations in the intestine, magnesium can passively enter the blood through the intercellular spaces (paracellular space) of the intestinal wall along a concentration gradient. This process mainly occurs in the ileum and jejunum and is influenced by the permeability of the tight junctions between the enterocytes (intestinal cells). Passive absorption depends, among other things, on the magnesium concentration in the intestinal lumen and on factors that can affect the permeability of the intestinal wall.

Transcellular Magnesium Absorption

In addition to passive absorption between the intestinal cells, magnesium can also be absorbed through the intestinal cells.This regulated absorption pathway plays a role particularly at lower magnesium concentrations in the intestine. Among other things, the ion channels TRPM6 and TRPM7 are significant:

• TRPM6 (Transient Receptor Potential Melastatin 6): This channel plays an important role in magnesium absorption in the intestine. TRPM6 is also present in the cells of the renal tubules and is involved in the reabsorption of magnesium. Mutations in the TRPM6 gene can be associated with rare hereditary forms of hypomagnesemia.
• TRPM7 (Transient Receptor Potential Melastatin 7): TRPM7 is closely related to TRPM6 but is found in numerous different cell types. The channel is involved in the regulation of cellular magnesium homeostasis and also plays a role in magnesium metabolism.

What factors influence magnesium absorption?

How well we absorb magnesium depends on various factors. These include, among other things, the composition of our diet, other food components, and certain medications. Phytic acid, which is found in many plant-based foods, can for example reduce magnesium absorption. Vitamin D may also be involved in the regulation of magnesium absorption.

Another factor is the intake of certain medications. Proton pump inhibitors (PPIs) can impair magnesium absorption in the intestine. Certain diuretics, on the other hand, can affect the excretion of magnesium through the kidneys.

Why do we absorb magnesium so differently?

The amount of magnesium our body actually absorbs can vary significantly.Various factors play a role in this – including the composition of our food and the form in which magnesium is present.

The latter is particularly relevant for magnesium supplements. Different magnesium compounds such as magnesium oxide, magnesium citrate or magnesium bisglycinate can differ in their properties. For magnesium bisglycinate, for example, the magnesium is bound to the amino acid glycine.

The magnesium bisglycinate capsules from MOLEQLAR contain the branded raw material MagChel®. 

How does cooking affect the magnesium content of foods? 

Preparation can influence how much magnesium is actually contained in a food or meal at the end.Especially when cooking in water, some of the magnesium from the food can leach into the cooking water. If this is subsequently discarded, a portion of the contained magnesium is also lost.

The extent of this loss depends, among other factors, on the cooking method, cooking time, and the amount of water used. If the cooking water is reused, for example for a soup or sauce, the dissolved magnesium remains part of the meal.

How can the loss of magnesium during cooking be reduced? 

To keep the loss of magnesium during preparation as low as possible, some simple strategies can help you:

• Steam vegetables or prepare them in the microwave instead of boiling them in large amounts of water.
• Reuse the cooking water, for example for soups or sauces, to utilize the magnesium dissolved in it.
• When cooking, use as little water as possible and avoid unnecessarily long cooking times.

Why can a magnesium deficiency occur? 

Looking at the magnesium content of many foods, one might think that sufficient magnesium intake should not be a problem. However, it is not that simple. How well we are supplied with magnesium depends on various factors.

A possible factor is certain medications that can influence magnesium levels. As previously described, proton pump inhibitors (PPIs), for example, can impair magnesium absorption in the intestines, while certain diuretics can affect magnesium excretion through the kidneys.

Changes in the mineral content of soils and plants are also discussed in this context.Research indicates that the levels of certain minerals in agricultural soils can change. However, it cannot be directly inferred whether and to what extent this affects human magnesium supply.

Magnesium in Foods: The Most Important Points Summarized

Magnesium is found in numerous foods. Particularly nuts, seeds, legumes, and whole grain products can provide significant amounts of this mineral. However, how much magnesium our body actually absorbs depends on various factors – including the composition of our diet and individual influencing factors. A varied diet and magnesium-rich foods can fundamentally contribute to daily magnesium intake.