Malic acid, or malate, is an organic compound that occurs naturally in fruits and vegetables. It is responsible for the sourness of green apples and other unripe fruit. It was first isolated in the late 18th century from apples, which belong to the genus Malus. The food and beverage industries use malic acid extensively for its tart flavor, and it has found favor as a dietary supplement for increasing energy levels, decreasing pain and improving exercise tolerance.
Malic acid is frequently added to wines and other beverages, jellies and jams, sherbets, frozen milk products and candies. One noteworthy application is in so-called “extreme candies,” in which a pocket of malic acid is buried to impart a burst of tartness. Malate, usually listed as alpha-hydroxy acid, is added to cosmetics as a skin toner. It has been used by athletes to enhance exercise efficiency and by fibromyalgia and chronic fatigue patients to alleviate pain and improve energy levels. The use of malate as a supplement presumably derives from its participation in the citric acid cycle, where it serves as an intermediary in the production of cellular energy.
Fruits and Vegetables
Arguably, the safest sources of malic acid reside in natural repositories. Apples, cherries, apricots, cranberries, peaches, rhubarb, plums, tomatoes, pears, pineapple, gooseberries and raspberries are all good food sources of malic acid. However, the level of malate in fruits and vegetables varies significantly during ripening and shipping, and these foods may not furnish sufficient amounts to meet the needs of some individuals.
Apple Cider Vinegar
Undistilled, unfiltered apple cider vinegar contains the malic acid that persists following the fermentation of apple cider. For some people, vinegar represents a more concentrated and convenient source of malic acid than fresh fruits and vegetables, but daily consumption may require an adjustment in one’s palate. The adjustment might be worth the effort, though, as apple cider vinegar is reputed to confer a plethora of health benefits. Unfortunately, most of these claims are unsubstantiated.
Malic acid is available as a powder, which is the form used by some people who wish to take large doses. In nature, malate exists in only one form, L-malate. Commercial powders often contain both D- and L-malate as well as variable levels of impurities, but purified L-malate is also available. Food-grade malic acid powder is offered by a number of vitamin and supplement manufacturers.
Encapsulated malic acid powder is available in a range of strengths from 300 to 800 milligrams. It is often combined with magnesium, which may improve its effectiveness for certain conditions. Daily dosing recommendations vary, so users should follow the manufacturer’s directions or consult a health care provider.
Malic acid is supplied in liquid and tablet forms by several supplement manufacturers. Some of these preparations may contain other nutrients, such as B vitamins, magnesium or manganese. The form of malic acid used is a matter of personal preference, convenience and response.
Malic acid is generally regarded as safe, when it is used according to proper dosing guidelines. Large or frequent doses of powder can cause oral irritation, and gastrointestinal upset was reported by some test subjects in a study published in the "Journal of Nutritional Medicine." Until more information is available, pregnant women and growing children should avoid supplementation with malic acid. Individuals with sensitive skin should consider applying test patches of alpha hydroxy acid-containing products.