Vitamin B12: The Deficiency Hiding in a Vegetarian Diet
2026-07-01 · 2 min read
Vitamin B12 comes almost entirely from animal foods — meat, fish, eggs, dairy. In a country with one of the world's largest vegetarian populations, that makes B12 deficiency quietly widespread, and it's one of the results people are most surprised to see flagged.
What B12 actually does
It keeps two systems running: your nerves and your red blood cells. When it runs low, both suffer — which is why the symptoms are such an odd mix.
The symptoms that don't seem connected
- Tingling or numbness in the hands and feet ("pins and needles")
- Fatigue and weakness — a form of anemia B12 causes
- Brain fog, poor concentration, forgetfulness
- A sore, smooth tongue or mouth ulcers
- Low mood or irritability
People often chase each symptom separately for months before a single blood test connects the dots.
Who's most at risk
- Long-term vegetarians and vegans — the classic group
- Adults over 50, whose absorption naturally drops
- People on long-term antacids or metformin (both reduce B12 absorption)
- Anyone with unexplained anemia or nerve symptoms
The test and the numbers
A simple blood sample measures serum B12; no fasting needed. Broadly:
- Below 200 pg/mL — deficient
- 200–300 pg/mL — borderline, worth acting on if you have symptoms
- Above 300 pg/mL — generally adequate
Because B12 and folate deficiencies look similar and often travel together, doctors sometimes test them alongside a CBC, which shows the enlarged red cells they cause.
The good news, with one caution
Correcting B12 is straightforward — a course of tablets or, if levels are very low, a short series of injections, then a diet or supplement plan to keep it up. The one caution: don't leave nerve symptoms too long, as prolonged deficiency can cause damage that's slower to reverse. If the tingling or fog sounds familiar, testing early is worth it. B12 is part of our Full Body packages or can be booked on its own with home collection.
This article is for general information and is not a substitute for medical advice. Always discuss your results with your doctor.