Is malic acid dangerous?

Malic acid is one of those compounds that we consume almost daily without really knowing about them. Its dual presence — in living things as well as in processed products — can lead to confusion. Is it the same molecule? Does it have the same effects on the body? And above all, is there a risk in consuming it regularly in additive form?

Malic acid is an organic acid naturally present in many fruits, to which it gives the tangy taste.

This organic acid represented on average 95% of the total organic acids measured in these fruits, and these are the most acidic apples – such as granny smith – which contain the most.
Chemically, it is a dicarboxylic acid, that is to say a molecule which has two carboxylic acid functions. Its chemical formula is C₄H₆O₅, and its scientific name is 2-hydroxybutanedioic acid. In other words, it is a small carbonaceous molecule, soluble in water, characterized by a clear acidity and by the presence of a hydroxyl group in addition to its two acid groups.

It exists in several biochemical forms, due to its structure which contains an asymmetric carbon. « There naturally occurring form in living organisms is mainly L-malic acid – which is also the best recognized by our enzymes and therefore the best metabolized – while its industrial form in additive form is a mixture of the L and D-malic forms » explains our expert.

In the European food domain, it is listed as an additive under the code E 296.

In its natural form, malic acid is above all a key molecule of cellular functioning.

In other words, it is a essential intermediate of cellular respiration. This role explains why it is often associated with good muscular functioning: « by participating in the production of energy, it can support effort and contribute to better recovery after exercise » continues the expert.

Another advantage, linked to its acidity : il stimulates saliva production. You can feel it when you bite into a sour apple; the salivary glands, located near the jaw, immediately go into action, sometimes with a slight tingling sensation. « That’s what makes it useful in situations of dry mouthlike the xerostomiaparticularly after certain medical treatments such as radiotherapy in the ENT area (mouth, throat, salivary glands), particularly during the treatment of head and neck cancers » explains the specialist.

Malic acid also has a so-called capacity “chelator”that is, it can bind to certain unwanted metals (such asaluminium) et promote their elimination by the bodywhich is a good thing!

In the form of additive E296, malic acid is used for reasons that are much more technological than physiological. This additive is both a acidifyingand flavor enhancer and a conservativebecause acidity limits the development of certain micro-organisms and the browning of foodstuffs. It is thus found in many processed products (drinks, sweets, jams, prepared meals, fruit yogurts), where it helps stabilize and standardize flavors.

Like many molecules naturally present in the body, malic acid has not escaped the interest of the food supplement market. We find it today in the form of capsules or powdersoften associated with promises of energy, performance or ‘detox’.

However, by supporting energy metabolism and muscle functioning, it can contribute to better exercise tolerance or recovery. « And therefore, indirectly, facilitate regular physical activitywhich is a real weight loss lever. But it’s a context effect and not a direct one!” explains Dr. Martinat.

Foods that naturally contain it, such as fruits and particularly applesmalic acid, on the other hand, is part of an interesting nutritional package: fiber, water, low energy density… all elements which promote satiety and nutritional balance.

Conversely, in additive form, it is often found in ultra-processed products — sweet drinks, confectionery — which are rather associated with weight gain if consumed regularly. So it is not the malic acid itself that is the problem, but the “vehicle” in which it is consumed.

Malic acid in the form of a dietary supplement (crystalline white powder) is often presented in speeches “detox”, with promises of liver cleansing.

As explained previously, this organic acid is an intermediate in the Krebs cycle (therefore cellular energy metabolism). It participates in the production of ATP and can also intervene in certain metabolic shuttles linked to glucose management. “It participates in hepatic gluconeogenesis since it helps prevent depletion of glycogenesis stores and to maintain stable fasting blood sugar levels » indicates the specialist. But this action of supporting the normal functioning of the liver, has not nothing to do with a “cleaning” mechanism or “detoxification” in the popular sense of the term.

There is also some data suggesting that certain organic acids – including malic acid – may have a mild effect on bile secretion (modest choleretic effect). But here again, we remain on weak physiological effectsnon-specific, and far from a clear pharmacological effect.

The last point concerns the ability of malic acid to bind to certain heavy metals, promoting their biliary and urinary excretion. « But if this effect is modestit may be interesting indirectly, but more in its natural form than in its synthetic form which is less well metabolized by the body » recalls our expert.

If malic acid has some modest roles in hepatobiliary functioning, they do not really justify the use of the term “liver detox” in the marketing sense.

Malic acid (E296) is a additive considered as on by the health authorities (status “GRAS”, that’s to say Generally Recognized As Safe), which means that at doses usually consumed in food, it is not associated with any particular risk.

The main precautions mainly concern the form and the dose. « Like all organic acids, it can contribute to the erosion of dental enamel when it is consumed in a concentrated or repeated manner, particularly in the form of additives in very acidic or sugary products (sour candies, certain drinks, cider vinegar) » recalls Dr. Martinat. The problem comes less from the molecule itself than from the frequent exposure of the teeth to an acidic environment.

In the form of a dietary supplement, high doses can cause digestive disordersincluding abdominal pain, bloating or diarrhea.

« Finally, in people with digestive sensitivity (gastroesophageal refluxgastritis, ulcer), malic acid can potentially increase irritation and feelings of heartburnespecially on an empty stomach or in large doses” adds the expert.

Malic acid can therefore present some mild side effects, but no real danger. “And in its natural form, it has many benefits!” concludes Dr. Martinat.