Health specialists are drawing attention to a lesser-known symptom inside the mouth that may signal a vitamin deficiency.
One possible cause is vitamin B12 or B9 deficiency anaemia, which happens when too little vitamin B12 or folate affects the production of red blood cells, causing them to become unusually large and less effective.
“Vitamin B12 and folate perform several important functions in the body, including keeping the nervous system healthy,” the NHS explains.
When levels of either vitamin drop too low, it can lead to a range of health issues affecting different parts of the body.
The NHS says symptoms can include severe tiredness, low energy, pins and needles, muscle weakness, vision problems, and psychological symptoms such as depression, anxiety, confusion, or memory problems.
An additional sign that may be easier to overlook can appear in the mouth, including a tongue that becomes sore and red, along with mouth ulcers. In some people, the tongue may also look smooth or inflamed, a condition known as glossitis.
Although mouth sores can have many causes, recurring ulcers, a burning tongue, or soreness that does not go away can be worth checking, especially if they happen alongside fatigue or tingling.
Bolt Pharmacy says vitamin B12 deficiency can cause “recurrent mouth ulcers by impairing DNA synthesis and cell division in the rapidly renewing oral mucosa, making tissues vulnerable to damage and slow to heal.”
There are several reasons someone might develop a vitamin deficiency, though the most frequent cause of vitamin B12 deficiency in the UK is pernicious anaemia, an autoimmune condition that affects the stomach and prevents the body from absorbing B12 properly.
Other causes can include a vegan or highly restrictive diet without enough fortified foods or supplements, problems absorbing nutrients due to digestive conditions or surgery, and some medicines, including proton pump inhibitors and anticonvulsants.
In the United States, vitamin B12 deficiency is less common than many people think, but it is still a real issue: estimates from the NIH suggest about 3.6 percent of adults have a deficiency, rising to around 3.7 percent in adults aged 60 and older.
Because vitamin B12 is stored in the liver, symptoms can take years to appear, which can make the problem easy to miss until it starts affecting the blood, nerves, or mouth.
Health professionals usually recommend a blood test if B12 or folate deficiency is suspected, especially if symptoms include fatigue, numbness, balance problems, or unexplained mouth pain.
In some cases, checking methylmalonic acid can help confirm true vitamin B12 deficiency when blood levels are borderline or unclear.
People who are not getting enough through food may also be advised to take supplements.
Vitamin B12 is found naturally in meat, fish, eggs, milk, and other dairy products, and it is also added to some fortified foods such as breakfast cereals.
For vitamin B12 deficiency anaemia specifically, treatment often involves vitamin B12 injections called hydroxocobalamin.
These injections are usually given every other day for around two weeks, or until symptoms begin to improve.
What happens after that will depend on what is behind the deficiency, including whether it is linked to diet, medication, or an absorption problem.
“If your vitamin B12 deficiency is not caused by a lack of vitamin B12 in your diet, you’ll usually need to have an injection of hydroxocobalamin every 2 to 3 months for the rest of your life.”
In cases where the deficiency is dietary, treatment may instead involve vitamin B12 tablets. Folate deficiency is usually treated with folic acid tablets, while the underlying cause is also addressed if possible.
Because some symptoms of vitamin B12 or folate deficiency can become permanent if treatment is delayed, experts say it is important to seek medical advice early rather than waiting for symptoms to get worse.
Healthline reports that more than 40 percent of Americans have some type of vitamin deficiency, and estimates suggest that 30 to 40 percent of the wider US population could be at risk of being low in at least one essential vitamin.