Dry mouth, medically known as xerostomia, is a subjective lack of saliva in the mouth or dryness of the mucosal membranes. The predominant cause of dry mouth is related to reduced saliva gland output, which is affected by diseases, trauma, medications and medical treatments. Certain vitamin deficiencies affect the mucosal membranes lining the mouth, which leads to sensations of dryness, although saliva production is often normal.
Symptoms and Causes of Dry Mouth
In addition to mouth dryness, sometimes described as “cotton mouth,” other symptoms of xerostomia include burning sensations in the mouth and throat, ulcerations, reduced taste and smell, bad breath, difficulty with pronouncing words, trouble swallowing food and issues retaining dentures, as cited in “Professional Guide to Diseases.” Saliva is needed to neutralize acids and protect against pathogenic microorganisms, so lack of it can lead to increased rates of dental cavities and gum infections. Reduced saliva production is caused by severe anxiety, dehydration, diseases such as Sjögren's syndrome and diabetes, medications, especially amphetamines, antihistamines and antidepressants, stimulants such as alcohol, marijuana and heroin, and radiation therapy. Certain vitamin deficiencies do lead to a variety of dry mouth, but are not considered a common cause, as cited in “Vitamins: Fundamental Aspects in Nutrition and Health.”
Vitamin A, as retinol, is required for the formation and maintenance of the delicate surface membranes lining the mouth, as well as the throat, eyes, sinuses and digestive tract. Mucous membranes provide lubrication and are also an effective barrier against pathogenic microorganisms, contaminants and debris. Vitamin A deficiency leads to dryness of mucous membranes, especially of the mouth and eyes, which is also known as xeropthalmia. According to the National Institutes of Health, the recommended daily amounts of retinol range from 300 micrograms for children, to 900 micrograms for men, to 1,300 micrograms for lactating women. Good sources of retinol include pig, beef and fish livers, eggs, some cheeses and fortified dairy products.
Vitamin B-12 and Folic Acid
The body requires iron, vitamin B-12 and folic acid to produce healthy red blood cells within bone marrow. A deficiency of vitamin B-12 or folic acid, also known as vitamin B-9, results in immature red blood cells and a condition called pernicious anemia. The first symptoms of pernicious anemia are severe tiredness, headache and heart palpitations, although dryness of the mouth can result also, as cited in “Human Biochemistry and Disease.” If a dry mouth is the result of a B-12 or B-9 deficiency, then soreness and redness of the tongue should also be present. B-vitamins are often found together in foods of animal origin, such as meat, fish, poultry, eggs and milk.
Vitamin B-2, or riboflavin, is primarily needed for the breakdown of fats, ketone bodies, carbohydrates and proteins. However, a riboflavin deficiency causes ariboflavinosis, which manifests as cracked lips, inflammation of the tongue and dryness or burning of the mouth, as cited in “Biochemical, Physiological and Molecular Aspects of Human Nutrition.” Burning mouth syndrome is characterized by a burning sensation and dryness in the mouth and on the tongue, and can be caused by deficiencies in vitamins B-2, B-9 and B-12.