| Average Recommended Dietary Allowances (RDAs) of Vitamin B12 by Age | |
|---|---|
| Age | Daily RDA |
| Birth to 6 months | 0.4 micrograms (mcg) |
| 7 months to 12 months | 0.5 mcg |
| 1 year to 3 years | 0.9 mcg |
| 4 years to 8 years | 1.2 mcg |
| 9 years to 13 years | 1.8 mcg |
| 14 years to 18 years | 2.4 mcg |
| 18 years and older | 2.4 mcg |
| During pregnancy | 2.6 mcg |
| When breastfeeding | 2.8 mcg |
Can You Tell if You Have a Vitamin B12 Deficiency?
Symptoms of vitamin B12 deficiency can vary and are often nonspecific. While certain symptoms could suggest a deficiency, they might also be related to other medical conditions.
If you are experiencing symptoms, it’s important to undergo diagnostic tests. This will help your healthcare provider determine the cause.
Anemia (a low number of healthy red blood cells) causes many of the symptoms of vitamin B12 deficiency. Peripheral neuropathy, which is impaired function in nerves outside the brain and spinal cord, can result from vitamin B12 deficiency and may lead to early symptoms of this condition.
Vitamin B12 deficiency symptoms and effects may include:
- Fatigue due to anemia
- Feeling numb in your hands or feet due to peripheral neuropathy
- Feeling like your fingers or toes are cold due to anemia
- Pale skin due to anemia
- Rapid heart rate due to anemia
- Brain fog or trouble concentrating due to anemia
- Weakness of the hands, feet, arms, or legs due to advanced peripheral neuropathy
Long-term vitamin B12 deficiency can lead to additional health risks, such as increased chances of heart disease, stroke, spinal cord damage, or dementia.
Vitamin B12 deficiency can also cause infertility in people of any sex. Additionally, if a pregnant person is deficient in this vitamin, it can result in developmental problems for the fetus and baby.
Diagnostic Steps
When giving a physical examination, your healthcare provider can identify signs that could indicate you have a vitamin B12 deficiency. These signs include pale skin, a rapid heart rate, and decreased hand and foot sensations.
However, these signs are not specific to vitamin B12 deficiency and could also indicate health conditions unrelated to vitamin B12.
Several blood tests can help identify vitamin B12 deficiency:
- Vitamin B12 level: While this blood test not a common screening tool unless a deficiency is suspected, a serum vitamin B12 level can diagnose a B12 deficiency.
- Methylmalonic acid level: Methylmalonic acid is produced when the body breaks down protein, which relies on vitamin B12. An elevated methylmalonic acid level is diagnostic of vitamin B12 deficiency.
- Red blood cell size: Vitamin B12 is an important part of RBC production. When vitamin B12 is deficient, RBCs are enlarged, described as macrocytic anemia. This is measured by a CBC.
Other tests can examine the health consequences of vitamin B12 deficiency. For example, due to anemia, your heart rate can be faster than usual. Nerve conduction studies can be used to diagnose peripheral neuropathy, which may occur due to vitamin B12 deficiency.
Pernicious Anemia and Vitamin B12 Deficiency
Pernicious anemia is a condition that interferes with the body’s absorption of vitamin B12. This type of anemia causes vitamin B12 deficiency. Consequently, vitamin B12 deficiency causes macrocytic anemia due to impaired RBC production.
Do Older Adults Need More Vitamin B12?
Older adults do not need more vitamin B12 than anyone else over age 18, but certain health factors increase the risk of vitamin B12 deficiency in older adults. With age, it is more common for people to take medications or to have medical diseases that could interfere with vitamin B12 absorption.
According to the NIH, older age is associated with decreased intrinsic factor and hydrochloric acid production in the stomach. These substances are necessary for the absorption of vitamin B12 from the diet or from supplements that are taken by mouth. The natural decline some people experience with age can lead to vitamin B12 deficiency.
Additionally, having another underlying medical condition, such as peripheral neuropathy or dementia, could make the effects of vitamin B12 deficiency add up with these other underlying disorders, worsening your overall symptoms.
What Conditions Can Vitamin B12 Help?
Taking vitamin B12 supplements or getting injections of this vitamin can improve medical conditions caused by vitamin B12 deficiency. Additionally, if you are at risk of becoming deficient, you might be prescribed a supplement or recommended to take an injection of this vitamin, even if you aren’t deficient yet.
Conditions caused by a vitamin B12 deficiency include:
- Dementia
- Increased risk of heart disease
- Increased stroke risk
- Macrocytic anemia
- Peripheral neuropathy
- Spinal cord disease
Should You Supplement Every Day?
Usually, people do not need to take vitamin supplements if they aren’t deficient. If you are not deficient in vitamin B12, you are getting an adequate amount in your diet, absorbing it properly, and there’s no need to take a supplement.
However, vitamin B12 supplements are not harmful if taken in moderation, so taking them as part of a multivitamin is fine if that’s convenient for you.
If you are deficient in vitamin B12, you would need to discuss the cause of this deficiency with a healthcare provider. If you take vitamin B12 supplements, you should take supplements as recommended by your healthcare provider.
Some people have trouble absorbing this vitamin due to disease, gastric surgery, or medication. If this is the case with you, you may need intramuscular injections (injections through a muscle) rather than pills.
If prescribed an oral vitamin B12 supplement, you would need to take it daily (ideally at the same time every day), as directed by your healthcare provider. Food, drinks, and medications may interfere with the absorption of certain vitamins, so it’s important to follow instructions.
Timing of Vitamin B12
Some factors may interfere with the proper absorption of vitamin B12. An acidic environment may decrease your absorption of dietary vitamin B12 or supplements taken by mouth. There’s some evidence that vitamin C (found in citrus fruits, berries, and vegetables) may decrease absorption of vitamin B12.
Other Sources of B12
You can get vitamin B12 from many different foods and drinks, and most of the sources are either animal products or foods fortified with vitamin B12. If you follow a vegan diet, plan how to get enough vitamin B12 in your diet through food, or you may need to take a supplement.
Some foods that provide vitamin B12 include:
- Beef liver (3 ounces): 70.7 mcg
- Ground beef (3 ounces): 2.4 mcg
- Clams (3 ounces): 17 mcg
- Oysters (3 ounces): 14.9 mcg
- Salmon (3 ounces): 2.6 mcg
- Canned tuna (3 ounces): 2.5 mcg
- Milk (1 cup): 1.3 mcg
- One egg: 0.5 mcg
- Turkey breast (3 ounces): 0.3 mcg
Foods that don’t naturally contain vitamin B12, such as breakfast cereals and nutritional yeast, may be fortified with this vitamin. You don’t need to worry about getting too much vitamin B12 in your diet, as your body eliminates excess in the urine.
Supplement Safety
In the United States, the Food and Drug Administration (FDA) does not regulate dietary supplements the way it regulates prescription medications. As a result, some supplement products may not contain the ingredients listed on the label.
When choosing a supplement, look for products independently tested or certified by organizations such as the National Sanitation Foundation (NSF), United States Pharmacopeia (USP), or ConsumerLab. For personalized guidance, consult your healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.
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