What is citric acid?
In 1784, Swedish researchers first extracted citric acid from lemon juice. This odorless and colorless compound was produced from lemon juice until the early 1900s when researchers discovered that it could also be made from a black mold (Aspergillus niger), which produces citric acid when it feeds on sugar. Due to its acidic and sour nature, citric acid is mainly used as a flavoring and preservative-especially in soft drinks and candies. It is also used to stabilize or preserve medicines, and as a disinfectant against viruses and bacteria.
Natural food sources
Citrus fruits and their juices are the best natural source of citric acid. In fact, the word citric originated from the Latin word citrus.
Examples of citrus fruits include:
Other fruits also contain citric acid, but the content is less. These include:
Beverages or foods that contain these fruits—such as the ketchup in tomatoes—also contain citric acid. Although not naturally occurring, citric acid is also a by-product of cheese, wine and sourdough bread production. The citric acid listed in food and supplement ingredients is manufactured, not a substance naturally found in citrus fruits. This is because the cost of producing this additive from citrus fruits is too high and the supply is in short supply.
Artificial sources and uses
The characteristics of citric acid make it an important additive in many industries. It is estimated that 70% of artificial citric acid is used in food and beverages, 20% is used in medicines and dietary supplements, and the remaining 10% is used in detergents.
Artificial citric acid is one of the most common food additives in the world. It is used to increase acidity, enhance flavor and preserve ingredients. Soda water, fruit juices, powdered beverages, candies, frozen foods, and some dairy products often contain artificial citric acid. It is also added to canned fruits and vegetables to prevent botulism, a rare but serious disease caused by the toxin-producing botulinum bacterium.
Medications and dietary supplements
Citric acid is an industrial staple food for medicines and dietary supplements. It is added to medicines to help stabilize and preserve the active ingredients, and is used to enhance or mask the taste of chewing and syrup medicines. Mineral supplements, such as magnesium and calcium, may contain citric acid—in the form of citrate—and enhance absorption.
Disinfection and cleaning
Citric acid is a useful disinfectant that can fight many bacteria and viruses. A test-tube study showed that it may be effective in treating or preventing human norovirus, which is the main cause of food-borne diseases. Citric acid is sold commercially as a general-purpose disinfectant and cleaner to remove soap scum, hard water stains, lime, and rust. It is regarded as a safer alternative to traditional disinfectants and cleaning products such as quaternary ammonium salts and chlorine bleach.
Health benefits and body uses
Citric acid has many impressive health benefits and functions.
Citrate-a closely related citric acid molecule-is the first molecule formed in a process called the citric acid cycle. Also known as the tricarboxylic acid (TCA) or tricarboxylic acid cycle, these chemical reactions in your body help convert food into usable energy. Most of the energy of humans and other organisms comes from this cycle.
Enhance nutrient absorption
There are many forms of mineral supplementation. But not all forms are created equal, because your body uses certain forms more effectively. Citric acid can increase the bioavailability of minerals, allowing your body to absorb them better. For example, calcium citrate does not require stomach acid for absorption. Compared with another form called calcium carbonate, it also has fewer side effects such as flatulence, bloating or constipation. Therefore, for people with less stomach acid, such as the elderly, calcium citrate is a better choice. Similarly, magnesium in the form of citrate is more completely absorbed and bioavailable than magnesium oxide and magnesium sulfate. Citric acid can also enhance the absorption of zinc supplements.
Can prevent kidney stones
Citric acid — in the form of potassium citrate — prevents the formation of new kidney stones and breaks down the ones that have already formed. Kidney stones are solid blocks made of crystals and usually originate in the kidneys. Citric acid prevents kidney stones by making your urine unfavorable for the formation of stones. Kidney stones are usually treated with citric acid as potassium citrate. However, eating foods high in natural acids—such as citrus fruits—can provide similar anti-calculus effects .
Safety and risk
The Food and Drug Administration (FDA) (5) generally consider the manufactured citric acid to be safe (GRAS). There is no scientific research investigating the safety of long-term consumption of artificial citric acid in large quantities. Despite this, there are still reports that the additive can cause illness and allergic reactions. A report found that four people experienced joint pain, swelling and stiffness, muscle and stomach pain, and shortness of breath after eating food containing artificial citric acid. These same symptoms are not observed in people who consume natural forms of acids such as lemons and limes. The researchers admitted that they could not prove that the citric acid produced was the cause of these symptoms, but suggested further research on its application in food and beverages. In either case, scientists believe that these symptoms are most likely to be related to the mold used to produce citric acid, rather than to the compound itself.
to sum up
Citric acid is naturally found in citrus fruits, but the synthetic version—produced by a mold—is usually added to foods, medicines, supplements, and detergents. Although mold residues from the manufacturing process may cause allergies in rare cases, citric acid is generally considered safe.