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Is magnesium stearate dangerous?

According to several "alternative" websites, magnesium stearate, a common additive (E572) is dangerous for your health. True or false ?

"Danger", "harmful": "alternative" sites like that of Mercola , taken up by a host of blogs on the net, claim that magnesium stearate is a potentially toxic substance, to be absolutely avoided. What should we think ?

What is Magnesium Stearate?

Magnesium stearate is a salt used as an anti-caking agent in foods, medicines and dietary supplements: it prevents ingredients from sticking together, and from sticking to the machines used to manufacture them. It is made up of 2 simple and harmless natural substances : magnesium (4%) and stearic acid (96%):

  • Magnesium is an essential mineral for health.
  • Stearic acid is a saturated fatty acid with 18 carbon atoms which is found for example in chocolate or coconut oil, but which the body also synthesizes. In the body, stearic acid is converted very efficiently into oleic acid , the majority monounsaturated fatty acid in olive oil and avocado, which is associated with numerous health benefits.

Magnesium Stearate and ImmunityMagnesium Stearate and Immunity

Mercola assures that stearic acid “  suppresses T lymphocytes  ”, white blood cells which intervene in the control of immune reactions, the destruction of infected cells and cancer cells.

It is based on a 1990 in vitro study in which mouse lymphocyte cells were incubated with stearic acid (not magnesium stearate), researchers found that damage was inflicted on cell membranes with a loss of cell immune function.

But Mercola fails to mention that, unlike human cells, mouse immune cells lack the enzymatic material that converts stearic acid to oleic acid. This is however specified in full and on several occasions by the authors of this 1990 study. Thus, in mice, stearic acid accumulates in the membranes of lymphocytes, but this is not the case in l man since this fatty acid is desaturated into oleic acid. The result of this experiment therefore has little meaning for human immune cells .

Moreover, other studies show that stearic acid stimulates resistance to infections.

100 times more stearic acid in a square of chocolate

In addition, the dose of magnesium stearate provided by a food, drug or dietary supplement is between 10 and 20 mg , of which 96% is stearic acid. By comparison, food provides about 7 grams of stearic acid per day:

  • A tablespoon of coconut oil provides between 100 and 200 mg
  • For its part, 10 g of 70-85% chocolate provide 1 g of stearic acid .

The Mercola site, the very one that advises against magnesium stearate because of the "  harmful " effects  of stearic acid, nevertheless strongly recommends chocolate and coconut oil because this oil "  inhibits a wide variety of pathogenic organisms  ” (sic).

The “biofilm” affair

We read on some sites that magnesium stearate tends to form a hydrophobic “ biofilm ” in the digestive tract, which would constitute “ an impassable barrier for vitamins B and C, etc …”

But a biofilm has nothing to do with mineral salts; in biology it is in particular an organization carried out by bacteria, welded together by a matrix secreted by the members of the bacterial community.

In fact, stearic acid tends to oppose the formation of biofilms , and no study has found that it interferes with the absorption of any molecule.

In practicemagnesium stearate poses no health

The claim that magnesium stearate is dangerous is not based on any scientific fact. In fact, magnesium stearate poses no health concerns; it was moreover deemed harmless by the editors of  The New Guide to Additives, based on careful review of toxicology studies, as long as, like other completely safe additives, it does not doesn't even appear there.