Why N-acetyl-cysteine can help dry eye

Dry eye syndrome occurs when there is inadequate lubrication of your cornea. This is due to decreased tear production or substandard quality of the tears, which results in abnormally fast or rapid destruction of the tear film.

The tear film normally has three constituents: a lipid (fat) outer layer secreted by the meibomian glands; an aqueous (water) middle layer secreted by the lacrimal glands; and an inner layer of mucous. A malfunction in any of these layers can cause dry eye syndrome.

Dry eye symptoms may also arise if you have underlying, but often undiagnosed, diseases such as blepharitis (inflammation of the eyelids), Sjögren’s syndrome (which induces dryness in the mouth and eyes), and others.

N-Acetyl-cysteine (NAC)

N-acetyl-cysteine is of value mainly because it is produced from cysteine, a sulphur-containing amino acid. Sulphur gives cysteine numerous capabilities in binding with other compounds in the body. glutathione, a highly versatile antioxidant.

Cysteine, with its sulphur component, is the central amino acid in glutathione, along with two other amino acids. Glutathione benefits the body in many ways. This potent antioxidant helps repair the tissues of the body after a stroke, fights cancer, prevents sharp fluctuations in blood sugar, and protects arterial walls from damage.

Because it is the most easily absorbed form of cysteine, NAC has become the most common source of cysteine for therapeutic purposes. NAC can be obtained from foods containing proteins such as fish, eggs, dairy, meat, poultry, and soybeans.

You are more vulnerable to disease and other ailments when glutathione levels in your blood are depleted. Higher NAC intake will lead to higher glutathione production in the liver. The body needs NAC as a primary ingredient for making the un-oxidised form of glutathione – reduced glutathione (GSH), an endogenous antioxidant.

Due to its ability to support the increased production of glutathione, NAC helps to protect your eye against oxidation and the toxic waste materials that come with it. Glutathione is the main antioxidant used in the eye, and although all tissues in the body contain glutathione, its highest concentration (aside from the liver, where it is produced) is in the eyes. Many research studies have directly linked low levels of glutathione with all types of eye diseases, so adequate levels of glutathione are essential to eye health.

As a drug, NAC is used to unclog clumps of mucous in the body, such as in the lungs of patients with chronic emphysema, chronic bronchitis, cystic fibrosis, and pneumonia. The antioxidant action of NAC inhibits oxidation of lipids, which makes it easier for mucous to flow.

Its ability to break up mucous, making it less thick and free-flowing, makes NAC useful in treating lipid-associated health conditions in the eyes. Several studies have shown that treatment with NAC is able to produce better results than artificial tears in relieving the discomforts associated with blepharitis. Blepharitis symptoms were reduced as tear film quality improved with 100mg of NAC taken three times a day.

Many research reports have documented the beneficial effects of NAC on the autoimmune disease Sjögren’s syndrome which also affects the eyes. NAC’s fast-acting ability to thin out mucosal secretions unclogs the cellular passageways, allowing moisture to flow more freely. In several trials on people with the Sjögren’s syndrome, it was found that 200mg of NAC taken three times a day helped improve the dry eye symptoms associated with the disease.