Experts warn that persistently low B12 levels can lead to irreversible problems, so it's important to see your GP if you're concerned07:17, 18 Jun 2026Updated 09:52, 18 Jun 2026Vitamin B12 is an essential nutrient that supports a healthy nervous system, red blood cell formation, and DNA production. Yet, its importance often remains overlooked until a deficiency develops, triggering various concerning physical changes.‌When vitamin B12 levels drop slightly, you may not notice any symptoms or might dismiss them. However, if these levels stay consistently low, it could cause nerve damage, cautions PeaceHealth, a non-profit organisation.‌The deficiency happens when insufficient B12 prevents the body from creating properly functioning red blood cells, which are essential for transporting oxygen throughout the body. This can cause numbness or tingling in your toes, amongst other indicators.‌The NHS advises seeing a GP if you think you have a vitamin B12 deficiency, as it can typically be identified through a blood test.It's vital to quickly diagnose and address a vitamin B12 deficiency, as certain complications from the condition can become permanent, reports Surrey Live.Alzheimer’s beaten by magic mushrooms, long life down to one gene, flu shot could save your live in more ways than one, and why you shouldn't wear wireless headphones if you have a pacemaker - all this and more in our science newsletter‌What causes a B12 deficiency?Pernicious anaemia is an autoimmune disorder where the body attacks stomach cells, decreasing production of a crucial protein called intrinsic factor.Intrinsic factor is a protein needed to absorb vitamin B12, so without it, no matter how B12-rich your diet may be, the body cannot absorb the vitamin.‌When it comes to tackling low B12 levels, the course of treatment varies depending on the root cause. The majority of patients find relief through injections that restore depleted vitamin levels."To ensure your treatment is working, you may need to have further blood tests," the NHS advises.Symptoms of B12 deficiencyVitamin B12 or folate deficiency anaemia can trigger a broad range of symptoms, which typically develop gradually. However, without proper treatment, these symptoms may deteriorate over time.‌According to the NHS, symptoms of vitamin B12 and folate deficiency anaemia can include:rapid breathing or shortness of breathheadachesindigestionloss of appetitepalpitationsproblems with your visionfeeling weak or tireddiarrhoeaa sore or red tongue, sometimes with mouth ulcersproblems with memory, understanding and judgment (cognitive changes)The NHS also noted that those with vitamin B12 or folate deficiency who haven't yet developed anaemia may still experience these symptoms.Article continues belowVitamin B12 deficiency can additionally cause symptoms affecting the brain and nervous system (neurological symptoms), including muscle weakness, psychological issues such as mild depression or anxiety through to confusion and dementia; difficulties with balance and coordination, pins and needles, and incontinence.