You probably glance at your tongue only when something feels off. Most of us never think of it as a window on the rest of the body.
A quick look in the mirror, though, can tell a surprising amount.
Changes in the color, surface and coating of the tongue are long-used clinical cues. According to the NIH MedlinePlus guide to tongue problems, a smooth, glossy tongue can point to anemia or a vitamin B12 shortfall.
A bright red tongue, by the same guidance, is linked to folic acid or B12 deficiency and to pellagra, a niacin shortage. Shifts in tongue color can be early signs of specific nutritional deficiencies that are easy to miss elsewhere.
Also read: Your first back pain prescription could more than double your opioid addiction risk
A smooth and shiny tongue
A tongue that has lost its tiny bumps and looks polished is called atrophic glossitis. A review in American Family Physician ties it to nutritional shortages of iron, folic acid, vitamin B12, riboflavin and niacin.
Iron deficiency has its own tell. MedlinePlus lists a sore or inflamed tongue among the symptoms that show up as iron deficiency anemia worsens. Pale skin, brittle nails and shortness of breath often appear with it.
A thick white coating
A thick white film that wipes off and leaves raw tissue underneath is often oral thrush. MedlinePlus describes it as white, velvety sores on the tongue and inside the mouth that can bleed if they are scraped.
The yeast behind thrush, Candida, lives in small amounts in a healthy mouth. It can overgrow in people with weakened immunity, in babies and older adults, and in anyone on antibiotics, steroids or inhaled asthma medicine.
Also read: How eating fermented foods every day may change your gut and immune health
A bright red swollen tongue
A fiery red, swollen tongue can also point to riboflavin or niacin shortfalls. The NIH guide to tongue problems links a reddish-purple color to folic acid and B12 deficiency, pernicious anemia and pellagra.
A bluish or purple tongue
A tongue that turns a dusky blue or purple is a different story. MedlinePlus calls this cyanosis and describes it as a bluish color to the skin or mucous membrane usually due to a lack of oxygen in the blood.
If the color comes on with trouble breathing, chest pain or confusion, the NIH guidance says to call 911. In adults it can signal heart or lung trouble. In children it can appear with heart defects.
Patches and dark fur on the tongue
Not every change is a warning. A patchy, map-like tongue, known as geographic tongue, affects between 1 and 14 percent of the US population according to American Family Physician and is usually benign.
Also read: What your hair can reveal about your thyroid, iron and stress levels
Deep grooves on the surface, called a fissured tongue, often appear with aging and rarely cause problems unless food gets trapped. A dark, furry tongue is usually tied to smoking, poor oral hygiene or certain antibiotics. Gentle brushing or a tongue scraper often clears it.
When to see a doctor
The NIH guidance says to contact a doctor if a tongue problem makes it hard to eat or breathe, or if it will not clear up.
A white patch that cannot be wiped off is a separate reason to see a dentist, since persistent white or red patches can be precancerous and may need a biopsy.
Also read: Check your fridge: Popular butter brand recalled over e. coli contamination fears
Also read: 8 minutes of exercise can lower your blood pressure
This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.