Plenty of patients tell us "I have no energy" or "my feet keep falling asleep" and blame age or long shifts. Sometimes the cause is more specific: the body is short on vitamin B12. A blood test settles the question, and a low level is treatable.
What B12 does
B12, also called cobalamin, is not made by the body; it has to come from food or a supplement. The NIH Office of Dietary Supplements puts an adult's daily need at about 2.4 micrograms, slightly more during pregnancy and breastfeeding. Its main jobs:
- Building healthy red blood cells. Without it, a type of anemia develops in which the cells are oversized and work poorly.
- Protecting nerves. It maintains their outer sheath, which is why a shortage shows up as tingling.
- Making DNA in every new cell.
It is found in beef, liver, fish, shellfish, eggs, milk and cheese, and in some fortified cereals. Fruit, vegetables and beans provide none.
Signs you may be running low
Deficiency builds slowly, over months or years, and the symptoms pass for ordinary tiredness:
- Fatigue that rest doesn't fix, weakness
- Pale skin, getting winded on the stairs
- Tingling, burning or numbness in the hands and feet
- Unsteady balance when walking
- Forgetfulness, trouble focusing, low mood
- A smooth, red or sore tongue
- Poor appetite and weight loss
None of these proves anything alone. Several together are a reason to ask for a blood test.
Who is at higher risk?
- People on metformin for diabetes over the long term. Many patients with diabetes are unaware of this link. If that's you, ask about B12 at your next diabetes checkup.
- Anyone taking heartburn medicine such as omeprazole every day.
- Adults over 50, because the stomach absorbs B12 from food less efficiently.
- People who had weight-loss or stomach surgery, or who have celiac or Crohn's disease.
- Strict vegans and vegetarians.
- People with pernicious anemia, an autoimmune condition that blocks absorption.
How it's diagnosed
A blood sample measures the B12 level, usually alongside a complete blood count to look at the red cells. If the number lands in a gray zone, the doctor may order extra tests. Most people don't need to fast, but ask when the test is ordered.
One caution: high doses of folic acid can hide the anemia caused by low B12 while nerve damage continues. That is why guessing with supplements is a bad idea.
Shots or pills?
It depends on why the level is low:
| Situation | Usual treatment |
|---|---|
| The stomach or gut can't absorb it (pernicious anemia, surgery) | Intramuscular shots, frequent at first and then for maintenance |
| A diet low in B12, or metformin | High-dose pills or shots, depending on the level and symptoms |
| Mild shortage with normal absorption | Pills plus diet changes |
Shots raise the level faster and bypass the stomach. High-dose pills work for many people because a small share is absorbed even when digestion isn't ideal. The doctor decides with your result in hand.
An honest note: if your B12 is already normal, an extra shot won't give you more energy. The benefit comes from correcting a real shortage.
What to do at Clínica Hispana Cruz 4
- Stop by Suite 240 at 10100 Beechnut St; there's no need to book.
- Tell the medical team your symptoms and the medications you take.
- If a test is appropriate, the blood sample is drawn right at the clinic.
- Once the result is back, we explain in Spanish or English what treatment you need and how often to recheck.
You don't need insurance; call (281) 588-0033 to ask the price of the test first. For general reading, see MedlinePlus.
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