What Is Vitamin B12?
Vitamin B12 ((cobalamin) is a water-soluble vitamin that your body can’t make on its own. It’s found naturally in animal-based foods and is added to some fortified foods. B12 is stored in the liver, so your body keeps a reserve, but you still need a regular supply from your diet or supplements.
Health Benefits of Vitamin B12
| Health Benefit | How Vitamin B12 Helps Kids & Adults |
|---|---|
| Red Blood Cell Formation | Helps make healthy red blood cells and prevents anemia (tiredness, weakness). |
| Nerve Health | Keeps nerves healthy and supports brain function and memory. |
| DNA Synthesis | Essential for making and repairing DNA, the blueprint for every cell. |
| Energy Production | Helps convert food into energy, keeping kids and adults active and alert. |
| Mood & Mental Health | Supports the production of mood-regulating chemicals; low B12 is linked to depression and memory problems. |
| Healthy Pregnancy & Growth | Prevents birth defects, supports baby’s brain and spinal cord development, and is vital for growing kids. |
| Bone Health | May help keep bones strong and reduce the risk of osteoporosis. |
| Eye Health | May lower the risk of age-related macular degeneration (an eye disease). |
How Much Vitamin B12 Do You Need?
| Age Group | Recommended Daily Amount (mcg) |
|---|---|
| 0–6 months | 0.4 |
| 7–12 months | 0.5 |
| 1–3 years | 0.9 |
| 4–8 years | 1.2 |
| 9–13 years | 1.8 |
| 14+ years (teens & adults) | 2.4 |
| Pregnant teens/women | 2.6 |
| Breastfeeding | 2.8 |
*mcg = micrograms
Best Food Sources of Vitamin B12
| Food Source | Serving Size | B12 Content (mcg) |
|---|---|---|
| Beef liver | 3 oz (cooked) | 70–80 |
| Clams | 3 oz (cooked) | 80–85 |
| Salmon, trout, tuna | 3 oz (cooked) | 4–6 |
| Milk, yogurt | 1 cup | 1–1.5 |
| Eggs | 1 large | 0.5 |
| Chicken, turkey | 3 oz (cooked) | 0.3–0.5 |
| Fortified breakfast cereal | 1 serving | 1–6+ (varies) |
| Fortified plant milks | 1 cup | 1–3 |
Tip: Plant foods (like fruits, veggies, grains, nuts, and seeds) do NOT naturally contain B12. Vegans and some vegetarians need fortified foods or supplements.
What Happens If You Don’t Get Enough Vitamin B12?
Vitamin B12 deficiency can develop slowly and cause a range of symptoms:
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Fatigue and weakness
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Pale or jaundiced skin
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Numbness or tingling in hands and feet
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Balance problems
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Memory loss or confusion
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Mood changes (like depression or irritability)
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Glossy, sore tongue
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Poor appetite and weight loss in children
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Megaloblastic anemia (large, abnormal red blood cells)
In kids and babies: Deficiency can affect growth, brain development, and nerve function.
Who Is at Risk for B12 Deficiency?
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Vegetarians and vegans (unless they eat fortified foods or take supplements)
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Breastfed infants of vegan mothers
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Older adults (reduced absorption)
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People with digestive conditions (like celiac, Crohn’s, or after stomach surgery)
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People taking certain medications (like metformin or acid reducers)
What Happens If You Get Too Much Vitamin B12?
Vitamin B12 is water-soluble, so extra amounts are usually excreted in urine. Toxicity is rare, even at high doses from supplements. However, extremely high blood levels have been linked to certain health risks in some studies, so more isn’t always better.
Possible Side Effects of Vitamin B12 Supplements
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Most people tolerate B12 supplements very well.
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Rarely, high doses may cause mild diarrhea, itching, or skin rash.
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Injections can cause soreness or redness at the site.
Fun Facts for Families
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The body can store several years’ worth of B12 in the liver.
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B12 absorption requires a special protein in the stomach called intrinsic factor.
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B12 is sometimes called the “energy vitamin” because of its role in metabolism.
Quick Reference Table: Vitamin B12 at a Glance
| Feature | Details |
|---|---|
| What is it? | Water-soluble vitamin for blood, nerves, DNA |
| Best sources | Animal foods, fortified cereals/plant milks |
| Deficiency risk | Fatigue, nerve issues, anemia, poor growth |
| Toxicity risk | Very rare; excess excreted in urine |
| Who needs supplements? | Vegans, some vegetarians, older adults, people with certain medical conditions |
| Safe for kids? | Yes, in recommended amounts |
In a nutshell:
Vitamin B12 is essential for healthy blood, nerves, energy, and brain power—for both kids and adults! Most people get enough from animal foods, but vegetarians, vegans, and some others may need fortified foods or supplements. Watch for signs of deficiency, and talk to your doctor if you have concerns. For most families, a balanced diet is the best way to get all the B12 you need to stay energized, focused, and healthy!