Citric acid is a naturally occurring organic acid that is being studied for its anti-oxidative activity as well as its ability to treat high acid levels in the blood and urine (1).
Citric acid is found naturally in citrus fruits, including lemons, grapefruits, tangerines and oranges, with the riches sources in lemons and limes. It is frequently confused with ascorbic acid (vitamin C), but unlike ascorbic acid, citric acid is not a vitamin or an essential nutrient.
For the treatment of high acid levels in blood and urine, a sodium citrate/citric acid oral dosage is sometimes prescribed.
Citric acid reduces risk of developing kidney stones. According to the National Kidney Foundation, one in ten people will develop a kidney stone (2). Studies show that consuming foods and beverages high in citric acid, such as lemons and lemon and lime juice help to prevent stone formation and break up small stones that are beginning to form (3).
Citrate (a derivative of citric acid) helps to prevent stone formation in two ways: First, it binds with urinary calcium, thereby reducing the supersaturation of urine; second, it binds calcium oxalate crystals and prevents crystal growth.
According to the researchers, patients with low urinary citrate may increase their consumption of foods and beverages high in citric acid. Consuming as little as 4 ounces of lemon juice per day has been shown to significantly increase urine citrate levels without increasing oxalate levels (high levels of which can lead to the formation of calcium oxalate kidney stones).
A sodium citrate/citric acid oral dosage may also be prescribed.
Citric acid helps prevent gout. Gout is a form of arthritis that is characterized by acute or chronic pain, redness and inflammation of certain joints in the body due to excess levels of uric acid in the blood. When uric acid builds up, it can form sharp urate crystals in a joint or surrounding tissue causing troublesome symptoms (4).
Researchers of a 2010 study set out to evaluate the effects of urine alkalizers (agents that counteract or neutralize acidity) like citrate preparations on reducing elevated serum uric acid levels. Seventy participants with elevated levels were randomly enrolled into two study groups: an allopurinol group (a drug commonly used to prevent or treat high uric acid levels) or a combination treatment group with allopurinol and a citrate preparation.
The results of the study, published in Endocrine Research, reported that the combination citrate preparation reduced serum uric acid levels as well as significantly increased urine pH levels and urinary uric acid excretion (5). An increase in urine pH is important because at a low pH, uric acid crystals will form.
Citric acid decreases brain and liver oxidative stress in mice. Oxidative stress is defined as a disturbance in the balance between the production of damaging free radicals and the body’s ability to counteract the harmful effects of these enemies with antioxidants. Over time, oxidative stress can leave cells damage or unable to perform properly.
Oxidative stress leads to many chronic diseases such as Parkinson’s disease and Alzheimer’s disease, gene mutations and cancers, chronic fatigue syndrome, blood vessel disorders, atherosclerosis, heart failure and inflammatory diseases (6).
Researchers studying the effects of citric acid on oxidative stress of the brain and liver in mice were met with encouraging results. The 2014 study found that brain oxidative stress significantly decreased by 40.4 percent and 58 percent after treatment with 1 and 2 g/kg citric acid, respectively, compared to the group that did not receive treatment (7).
In contrast, no significant effect on liver oxidative stress was observed after treatment with citric acid (1–4 g/kg). Researchers noted, however, that citric acid could have a beneficial effect on the liver under toxic and inflammatory conditions.
Citric acid helps increase bone density and strength in chicks. In a study published in the Journal of Animal Physiology and Animal Nutrition, a total of 1720 broiler chicks were randomly assigned to four groups and reared for a period of 35 days. The diets of groups 1, 2, 3 and 4 were supplemented with 0 percent, 0.25 percent, 0.75 percent or 1.25 percent citric acid by weight respectively.
The addition of citric acid up to 0.75 percent significantly increased among other things, bone ash content, bone mineral density and bone strength of the broiler chicks (8).
Whether or not citric acid has an effect on bone density and strength in humans has yet to be studied.
Citric acid inhibits the development of cataracts in diabetic rats. Researchers studying the effects of citric acid on the development of diabetic complications on diabetic-induced rats stumbled upon an interesting discovery. While oral administration of citric acid given to diabetic rats did not affect blood glucose concentration, it did delay the development of cataracts and inhibited the accumulation of advanced glycation end products (AGEs) in lens proteins (9).
AGEs are believed to play a role in vision loss associated with macular degeneration, cataract formation, diabetic retinopathy and glaucoma (10).
Side effects of sodium citrate/citric acid may include nausea, vomiting, stomach pain or mild or occasional diarrhea.
It should be taken after meals to help prevent stomach or intestinal side effects.
Rare but serious side effects may include numbness or tingly feeling, swelling or rapid weight gain, muscle twitching or cramps, fast or slow heart rate, confusion or mood changes, bloody or tarry stools, severe stomach pain, ongoing diarrhea or seizure (11).
Sodium citrate/citric acid should not be taken by those with severe kidney disease, severe heart damage, Addison’s disease (an adrenal gland disorder), high levels of potassium in the blood, high levels of sodium in the blood or are severely dehydrated (12).
For the purpose of making urine less acidic or reducing high uric acid levels in the blood, the recommended dosage will be determined by a physician.
Citric acid is a naturally occurring organic acid that is found in citrus fruits. For the treatment of high acid in the urine and blood, a sodium citrate/citric acid is sometimes prescribed. Citric acid is also being researched for its ability to decrease brain and liver oxidative stress, increase bone density and strength and inhibit the development of cataracts.
More studies are needed to evaluate the efficacy of sodium citrate/citric acid in humans.