When the nerves sound the alarm - what does tingling in the hands and feet mean?

Do your hands feel clumsy when you button your shirt, or do your feet fall asleep more often than before when you sit still? Tingling and numbness in the hands and feet are often common symptoms, but they should not be dismissed as “poor circulation” without thinking. Sometimes it is a matter of temporary pressure on a nerve. In other cases, the problem is an early signal of a vitamin deficiency or the effects of diabetes.

Tingling and numbness in the hands and feet – could it be due to a vitamin deficiency?

Tingling, numbness and a burning or “crawling” sensation are often called paresthesias. This means that sensory nerves are sending incorrect signals or are functioning less well than they should. The problems often start far out in the body, for example in the toes, soles of the feet or fingertips.

When nerves are affected, it is not just noticeable as discomfort. Some people describe that they step strangely, drop things more easily or have difficulty feeling small injuries on their feet. In diabetes, reduced sensation in the feet can increase the risk of ulcers, as pressure and friction are not felt as clearly.

There are many causes of nerve symptoms, but vitamin deficiency and diabetes are among the most important to rule out because they are both common and treatable. The longer the nerve damage lasts, the greater the risk that the symptoms will not completely resolve. This is especially true in the case of vitamin B12 deficiency.

B12 deficiency: a common and often overlooked explanation

Vitamin B12 is needed for blood formation and for the nervous system to function normally. Deficiency can cause fatigue, pallor and shortness of breath, but also neurological symptoms such as tingling, numbness, balance problems and sometimes memory or concentration problems. You can therefore have nerve symptoms even if anemia is not the most noticeable.

You should not dismiss B12 deficiency just because blood counts or the size of the red blood cells do not clearly show anemia. This is an important clinical point, since many people expect that if you have B12 deficiency, it must appear as anemia first. Neurological problems can be one of the early or dominant findings.

Common causes of B12 deficiency are not only diet. The risk also increases with impaired absorption in the stomach or intestines, after certain gastrointestinal surgeries, with autoimmune diseases that affect absorption, and with long-term use of certain medications. Metformin, which is used for type 2 diabetes, is a clear example because long-term treatment can be linked to B12 deficiency.

For those who eat a completely plant-based diet without fortified foods or supplements, B12 is also a known risk factor. The body has large stores of B12, so symptoms can creep up over several years. This is precisely why many people do not connect increasing numbness or clumsiness with vitamin deficiency.

Folate deficiency: important to detect, but rarely the entire explanation for nerve symptoms

Folate, or vitamin B9, is needed for cell division and normal blood formation, among other things. Folate deficiency mainly causes a form of anemia in which the red blood cells become too large and function less well. Symptoms may include fatigue, decreased energy, shortness of breath and sometimes tingling, but isolated folate deficiency is less typical as the sole explanation for pronounced nerve symptoms than B12 deficiency.

The important thing in practice is that B12 and folate are diagnostically linked. Homocysteine is a substance that is broken down by these vitamins and can rise in both B12 and folate deficiency. Thus, for example, folic acid treatment can improve the blood picture so that a simultaneous B12 deficiency becomes less obvious. Then there is a risk that the nerve damage will continue silently if B12 has not also been checked.

That does not mean that folate is unimportant. On the contrary, folate deficiency should be investigated and treated, especially if blood tests show abnormal blood counts or if the diet is one-sided, alcohol intake is high or absorption in the intestine is impaired. But in the case of tingling and numbness, the question is often not “B12 or folate?”, but whether both need to be checked at the same time so as not to miss the whole picture.

Diabetes is one of the most common causes of numbness in the feet

In diabetes, prolonged elevated blood sugar can damage small blood vessels and nerves. The most common form is peripheral neuropathy, which usually begins in the feet and lower legs and sometimes later affects the hands. Many describe numbness, tingling, burning pain or that it feels like walking on cotton.

Symptoms and signs of neuropathy are regularly monitored in people with diabetes. In type 2 diabetes, the assessment should begin at diagnosis, since nerve damage may have developed before the disease is detected. In type 1 diabetes, screening usually begins five years after diagnosis and then at least annually.

This is also the reason why blood sugar levels are relevant when someone is looking for numbness in the feet, even if the person does not know that they have diabetes. An elevated fasting glucose or long-term blood sugar, HbA1c, can be the first clue. 

An additional clinical detail is that diabetes and B12 deficiency can coexist. A person with type 2 diabetes and metformin treatment can therefore have nerve symptoms that are not only due to diabetes but also to a concomitant B12 deficiency. Therefore, sometimes you need to look for two causes at the same time, not just the most obvious one.

When should you test B12, folate and blood sugar?

It is reasonable to check B12, folate and blood sugar if the tingling occurs without a clear explanation, if it recurs, or if it is symmetrical in both feet or hands. Testing is especially relevant if you also have fatigue, paleness, balance problems, reduced vibration sense, increased thirst, frequent urination or involuntary weight loss. Medications and dietary habits also play a role in the assessment.

Examples where testing is often justified:

• you have been treated with metformin for a long time
• you eat a vegan diet without regular B12 supplementation
• you have had stomach or intestinal surgery
• you have diabetes, prediabetes or risk factors for diabetes
• you feel unsteady, clumsy or get nightly tingling in your feet

In the investigation, blood status, B12, folate and glucose-related tests such as HbA1c are often used. In some cases, healthcare may also proceed with additional tests if the B12 value is in the borderline zone or if the symptoms are clear despite unclear test results.

Once the cause is found, it is often possible to do something concrete about it. B12 deficiency can be treated with supplements or injections depending on the cause, folate deficiency with folic acid after proper investigation, and diabetes-related nerve damage is best slowed down by good blood sugar control and regular follow-up by a diabetes nurse. The goal is not only to relieve symptoms, but to protect nerve function going forward.

The biggest benefit of testing yourself is often the timing. Tingling and numbness can easily be felt as diffuse discomfort, but in the right context, they can be one of the body's earliest warning systems. Catching abnormal values ​​before the nerve damage becomes long-lasting provides better conditions for recovery and safer decisions about the next step.

Seek immediate care if the numbness comes on suddenly, if you also become weak in an arm or leg, lose control of your bladder or bowel, have difficulty walking, or if the symptoms worsen rapidly. In this case, other more acute causes need to be ruled out. This applies even if you think the problem is "just" a vitamin deficiency.