What Is Citric Acid?
Citric acid is a weak acid that is found naturally in all citrus fruits. Unlike strong acids, weak acids ionize only partially when in solution. If you’ve ever sunk your teeth into a lemon or any other citrus fruit, you've tasted citric acid. But it's not just sour citrus fruits that have citric acid. All plants and animals have small traces of it. One reason is that it's an important intermediate in metabolism, which is the pathway that allows your body to get energy from carbs, fats, and proteins.
Citric acid doesn't have any color. It doesn't smell like anything either. If you put some on your tongue, you'd taste the acid. You might find it tastes pleasantly sweet and tart.
By itself, citric acid is a solid. If you put it into a solution, the pH will depend on its concentration. The pH of lemon juice is about 2 or 3.
The molecular formula for citric acid is C6H8O7. That means it contains six carbon atoms, eight hydrogen atoms, and seven oxygen atoms. It dissolves easily in water.
Many packaged food and nonfood items, such as cosmetics and cleaning products, contain manufactured citric acid, not the natural kind. Manufacturers add a man-made version of citric acid to processed foods. Medicines with citric acid in them are used to treat health issues such as kidney stones and blood clots.
What is the citric acid cycle?
This is the metabolic pathway your body uses to convert food into energy. It happens mainly in your liver, muscle, and kidneys.
Natural Sources of Citric Acid
You can find citric acid in many natural sources. Foods that are high in natural citric acid are citrus fruits, especially the juice of lemons and limes. Other fruits and vegetables also contain some natural citric acid.
These foods have the highest amounts of naturally occurring citric acid:
- Lemons
- Limes
- Oranges
- Grapefruits
- Berries (except blueberries)
- Pineapples
Other fruits and veggies with citric acid include:
- Tomatoes
- Broccoli
- Carrots
- Some peppers
Artificial Sources of Citric Acid
While citric acid is a natural ingredient in many fruits and vegetables, most of what you find in processed foods is chemically manufactured. Around the world, more than 2 million tons of citric acid is made every year.
It's made by fermenting sugars such as molasses and corn starch by Aspergillus niger, which is a type of fungus or mold. Another name for Aspergillus niger is black mold. The mold turns sugars into citric acid that's safe to use in foods, cosmetics, and other products.
Citric Acid Uses
The citric acid that’s added to many food and drinks, medications, personal care products, and cleaning products is artificially manufactured. It's used as an antimicrobial, antioxidant, flavoring agent, and more.
This type of citric acid is used in:
The food industry. Citric acid is often added to packaged food and drinks. It helps keep canned and jarred foods fresh over long periods. It can prevent some kinds of fresh-cut produce, such as sliced apples, from turning brown. Citric acid can also help thicken foods or give them a slightly sour flavor. That's why you might see citric acid listed as an ingredient in some ice creams, sorbets, or sodas.
Alcohol production. Citric acid can balance out the acid in a food or drink. Winemakers sometimes add it to their products to improve the taste.
Drug manufacturing. Some creams include citric acid to help clear up skin infections. Other citric acid drugs that you take by mouth can lower the amount of acid in your urine. This can help prevent kidney stones. You might also take citric acid for metabolic acidosis, a buildup of acid inside your body.
Supplements. Some people take calcium citrate supplements, which can help prevent kidney stones.
Personal care products. When manufacturers mix citric acid with other ingredients, they can form a compound called "alpha hydroxy acid" that helps smooth your skin. It's also in some cosmetics and toiletries, such as lipstick, hair spray, and deodorant, to help them last longer.
Household cleaners. Because citric acid can eat away at hard water buildup, you'll often see it in dishwasher detergent. Other household cleaners also include it as an ingredient since it can help remove stains and odors.
Disinfectants and cleaning products. Since citric acid kills some types of bacteria and viruses, you'll find it in insect sprays, products that kill fungus or algae, hand sanitizers, and even some tissues you use to blow your nose. Citric acid can safely remove toxins from polluted soil and even clean up nuclear waste.
Health Benefits of Citric Acid
There are many reasons to add citric acid to food, medicine, or other products. It can:
Act as a preservative. It is used to keep food fresh for longer periods. In some cases, it may prevent food-borne botulism, an illness that can be caused by home-canned foods that are low in acid.
Improve digestion. Citric acid may lead to changes in your gut that help with digestion and the absorption of nutrients from the food you eat. Some studies also suggest it changes the makeup of the gut microbiome in beneficial ways.
Protect kidneys. A solution of citric acid and sodium citrate can prevent kidney stones. It may also help with gout. It works by making your blood and pee less acidic.
Prevent oxidative damage. Citric acid is a natural antioxidant and may offer protective benefits against disorders affecting the metabolism, nervous system, and heart.
Is Citric Acid Bad for You?
The FDA says citric acid is "generally recognized as safe" in food and skin products and can have health benefits. Still, some experts think that more research is needed.
Citric acid may cause:
Skin irritation. When it touches your skin for long periods, it can cause stinging, swelling, or hives.
Eye pain. It will burn if citric acid gets in your eyes. If this happens, flush them well with water for several minutes. If you wear contact lenses, take them out as soon as you can.
Tooth problems. Drinks and candies that contain citric acid can wear away the enamel (the outer layer) of your teeth. This can make your teeth more sensitive, turn them yellow, and make it more likely you'll get cavities.
Upset stomach. If you take a medicine with citric acid by mouth, you can have side effects such as nausea or vomiting.
Sometimes, drugs with citric acid can cause severe side effects, such as:
- Confusion
- Lightheadedness
- Chest pain
- Fast heartbeat
- Pain
- Tingling or numbness in your hands or feet
- Fatigue
If you notice any of these symptoms, contact your doctor right away.
Where to Buy Citric Acid
You can order citric acid online or buy it in the grocery store. Look for it with canning supplies or in the aisle where you'd find herbs, spices, and seasonings.
Citric Acid Substitutes
Instead of using pure citric acid crystals, you may be able to substitute lemon juice. For example, you can use citric acid or bottled lemon juice when canning tomatoes.
If you're using citric acid or other acids in canning, it's important to follow the directions. For food safety, canned goods need a pH of 4.6 or lower.
It's important not to get mixed up between citric acid and ascorbic acid. Ascorbic acid is less acidic and used mainly to preserve color.
Takeaways
Citric acid is a compound found naturally in citrus and many other foods. It's also a common ingredient in processed foods and cosmetics in which manufactured citric acid is used as an antimicrobial and preservative. Citric acid has some health benefits, but it may also hurt your skin, stomach, or teeth.
Citric Acid FAQs
What does citric acid do to your body?
Citric acid has many possible effects on the body. It can help your kidneys and act as an antioxidant. It may help your intestines absorb more nutrients and lower inflammation. Citric acid is a normal intermediate in your metabolism. But too much citric acid may hurt your teeth, stomach, or skin.
Is citric acid vitamin C?
No. Vitamin C is ascorbic acid not citric acid. Vitamin C and citric acid have similar chemical formulas. The only difference is that citric acid has seven oxygen atoms, while vitamin C has six. Citric acid is more acidic than ascorbic acid.
Who should not take citric acid?
Citric acid is generally considered safe. But some people think manufactured citric acid may play a role in inflammation and conditions ranging from asthma to fibromyalgia. If you're worried about citric acid in your foods, talk to your doctor about your concerns.
Is citric acid safe to use every day?
It's generally safe to consume foods with citric acid. However, too much citric acid can hurt your tooth enamel over time. It's best to consume citric acid in moderation. You can also rinse your mouth after eating or drinking, use a straw, and eat other foods with less acid in them.
Does citric acid raise blood sugar?
Citric acid may affect blood sugar levels; however, studies have found conflicting results, with some showing an increase in blood sugar and others a decrease. If you have high blood sugar and are worried about citric acid in your diet, talk to your doctor, nutritionist, or dietician about your concerns.
