What is it?
The lining of the mouth is one of the fastest renewing tissues in the body. When iron, vitamin B12 or folate falls, this renewal falters and the signs often show up in the mouth first. A tongue that becomes smooth and red, cracks at the corners of the mouth, recurrent ulcers, burning and a change in taste are the main ones.
As the papillae on the top of the tongue are lost, the surface takes on a shiny, flat, red look; hot and spicy food can be uncomfortable. These findings do not give a diagnosis on their own. The same appearance can also occur in dry mouth, in thrush and with irritation from a denture. The finding in the mouth is therefore not a conclusion but the start of the investigation.
Finding a deficiency is not the end of the road either. Why there is a shortfall, that is whether it is a matter of diet, of absorption or of a hidden loss, is looked into separately. Starting supplements on your own on the strength of the signs in your mouth can make that investigation harder; the decision is therefore left to a doctor.
Signs
You will not necessarily have all of these at once.
Why does it happen?
- 01
Not taking in enough
A limited, one-sided diet can lower iron intake. Because vitamin B12 is found mainly in foods of animal origin, a deficiency can develop over time in people who do not eat them.
- 02
Problems with absorption
Diseases of the stomach and small bowel, coeliac disease, stomach operations and long-term medicines that suppress stomach acid can interfere with absorption. In that case blood levels can fall even when the diet is adequate.
- 03
Blood loss
Long, heavy periods and silent losses from the digestive system can use up iron stores. Supplements taken without finding the source cover the deficiency for a while but do not remove the cause.
- 04
A greater need
During pregnancy, breastfeeding and periods of rapid growth the daily requirement rises. If intake stays the same, stores can run down more quickly at these times.
How does it progress?
- 1
The silent phase, as stores fall
Blood levels start to drop, but there are no signs in the mouth or in how you feel generally. This phase is only picked up on a test.
- 2
The first signs in the mouth
Burning of the tongue, sensitivity to hot and spicy food, redness at the corners of the mouth and frequent ulcers can appear. The appearance may not be obvious yet.
- 3
Visible changes in the lining
The top of the tongue becomes smooth and takes on a shiny red look, the cracks at the corners of the mouth become established, and the lining can look pale.
- 4
Signs elsewhere in the body
Tiredness, palpitations and breathlessness can be added. In B12 deficiency there can also be numbness and tingling in the hands and feet and problems with balance; these findings should not be left to wait.
How is it treated?
The doctor to see for this is your GP or a specialist in internal medicine. A deficiency is not diagnosed by looking in the mouth but with a blood test; the doctor usually assesses a full blood count together with iron, ferritin, B12 and folate levels. Depending on the results, gynaecology, gastroenterology or haematology may come into it.
The dental clinic's role here is not to treat but to notice and to refer. The dentist sees the finding in the mouth and assesses the local causes that could produce the same appearance; they put right a poorly fitting denture, deal with thrush if it is suspected, and sort out mouth care. It is not the dentist who decides on the medicine for the deficiency, its dose or how long it is taken.
It is important not to start iron or B12 supplements on your own. While a supplement corrects the blood levels, it can hide the reason behind the deficiency; besides, which deficiency is the dominant one needs to be known beforehand. Once treatment has started, the signs in the mouth are expected to settle, but this usually takes weeks rather than days.
- Tiredness, palpitations or breathlessness are affecting your daily life
- You have numbness, tingling or a problem with balance in your hands and feet
- Your stools are black or you have noticed bleeding
- You have a single sore in your mouth that has not healed in two to three weeks
How is it prevented?
- Make a note of the signs in your mouth and describe them to your doctor; how often they come and how long they last affect the decision to test.
- If you are pregnant, have heavy periods, eat a restricted diet or have had stomach surgery, do not miss your check-ups.
- Do not use over-the-counter supplements; if you are taking any, tell your doctor before the examination.
- Ask for your tongue and the corners of your mouth to be looked at during your dental check-ups as well.
Frequently asked questions
- Can a deficiency be diagnosed from the signs in my mouth?
- It cannot. A smooth tongue, cracked corners of the mouth and frequent ulcers can be seen in a deficiency; but the same findings also occur in dry mouth, in thrush and with irritation from a denture. The diagnosis is made with a blood test. What the dentist does is to notice the finding, assess the local causes and refer you to the right doctor.
- Can I start supplements myself?
- That is not advisable. A supplement can correct blood levels but it does not remove the cause of the deficiency, and it makes the investigation harder. Products taken without knowing which deficiency is the dominant one can complicate the picture. The choice of medicine, the dose and the length of treatment are for the doctor assessing you.
- Will my tongue go back to how it was once the deficiency is corrected?
- When there is a response to treatment, the lining is expected to recover; burning and sensitivity usually ease earlier, while the surface of the tongue can take longer to improve. If the findings continue despite treatment, there may be another cause inside the mouth that needs assessing separately.
This content is for general information and does not replace an in-person examination. Symptoms overlap between conditions, and a diagnosis can only be made clinically.