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Those White Spots on Your Arm Could Explain Why You Feel So Tired All The Time: You’re Not Getting Enough Vitamin B12

A shortfall in the nutrient can lead to depression, fatigue, brain fog and even dementia if left unchecked

If you’ve ever noticed tiny white spots or discolorations on your skin, you may have brushed it off as a result of age or sun exposure. But this change in your skin may be a sign of a vitamin B12 deficiency. Here, discover the symptoms of a vitamin B12 shortfall — and how to treat it.

How a vitamin B12 deficiency affects your skin

Vitamin B12 causing small white spots on the skin is a relatively rare result of a deficiency in the vitamin. “It occurs in people whose B12 deficiency is caused by pernicious anemia,” explains vitamin B12 expert and researcher Ralph Green, MD, PhD, a Distinguished Professor at the UC Davis School of Medicine. Researchers estimate that up to 25% of older adults who have a B12 deficiency also have pernicious anemia, which is an autoimmune disorder that creates inflammation in the GI tract that inhibits one’s ability to absorb vitamin B12. Pernicious anemia is more common in people of European ancestry and in those over 60.

A small percentage of people with pernicious anemia also have vitiligo, the autoimmune disorder that causes white spots, most commonly on the forearm. “In vitiligo, the body makes antibodies against cells that make pigment,” Dr. Green explains. “This causes a blotchy distribution of a lack of pigmentation in the skin.”

There are other reasons that someone would develop vitiligo, but about half the people who have the disorder get it before they turn 20. So if you start to notice skin discolorations later in life — and especially if they are accompanied by some of the other signs below — it’s worth asking your doctor about doing bloodwork to assess your vitamin B12 levels.

Related: Study: This Energy-Draining Vitamin Shortfall Is 7 Times More Common Than Expected — Simple Ways to Outsmart It

White spots on skin, signs of a vitamin B12 deficiency

Other sneaky causes of vitamin B12 deficiency

In addition to pernicious anemia, any problem that causes inflammation of the GI tract, including Celiac and Crohn’s Disease, can disrupt the absorption of B12. Common antiacid medications like Prilosec, Prevacid, Tagemet and Zantac can reduce stomach acid to the extent that it disrupts B12 absorption. Those who have undergone a gastric bypass procedure may also absorb less B12 from food. Finally, the diabetes drug Metformin can also disrupt B12 absorption.

The importance of vitamin B12

Vitamin B12, or cobalamin, cannot be made by the body and plays a critical role in a number of processes. The body needs B12 to create red blood cells, which deliver oxygen throughout the body and transport out carbon dioxide. “If you don’t have enough B12 you can end up with [non-pernicious] anemia, a condition in which you don’t have a sufficient amount of red blood cells to deliver oxygen to the tissues,” explains Dr. Green. (Click through to our sister publication to discover how a smartphone app could help diagnose anemia.)

Anemia can be a sign of vitamin B12 deficiency

Anemia caused by a shortfall of vitamin B12 in the diet is quite common and treatable (as distinct from pernicious anemia, mentioned above, which is caused by an autoimmune disorder that blocks the absorption of B12).

There are also more serious problems that can occur if you don’t address a B12 deficiency. “The most serious is permanent neurological damage, including Alzheimer’s-like cognitive decline,” Dr. Green cautions. The relationship between B12 and the brain and nervous system is still being studied, but Dr. Green explains that researchers suspect this link to cognitive decline is related to the role vitamin B12 plays in the body’s ability to make methyl groups.

“There are neurological signaling pathways that require methyl groups. B12 is critical to supplying adequate amounts of those methyl groups,” he says. Another component of methyl groups is the amino acid methionine, which is made from another amino acid, homocysteine. If you’re deficient in B12, you will accumulate “a bad actor” called homocysteine, which Dr. Green. “There’s now good evidence that shows that people with higher levels of homocysteine in their blood are more likely with increasing age to develop cognitive decline and end up with dementia,” Dr. Green says. (Click through to see how a high fiber diet can reduce your dementia risk.)

Other signs of a vitamin B12 deficiency

Chronic tiredness: “B12 plays a vital role in metabolizing fat, protein, and carbs into energy,” explains Fred Pescatore, MD. And it works in tandem with the B vitamin folate to make healthy red blood cells that transport energizing oxygen through the body, so it makes sense that when you’re low on this vitamin, you’re low on power.

Lack of concentration or memory blips: “This can be partly because of pernicious anemia, but probably more likely a result of the effects of B12 on the brain and nervous system,” Dr. Green notes. Other cognitive issues people with a B12 deficiency might experience include difficulty recognizing people they know or recalling directions to places they’ve been.

Depression: Several studies have found an association between depressed mood in older adults and shortfalls in vitamin B12.

Sensory and balance disturbances: can also be a warning sign of a B12 deficiency. These both have to do with B12’s effect on the nervous system. The most common manifestations include feelings of pins and needles in the fingers and feet, not being able to feel vibrations when they are happening close to you, and a lack of balance (especially with your eyes closed).

Other symptoms of a B12 shortfall include constipation and soreness of the mouth and tongue. For more on unusual symptoms that can signal a deficiency in vitamin B12, check out this video:

What blood tests reveal a vitamin B12 deficiency

Your doctor may order either a blood test or a urine test to assess vitamin B12 levels. Research suggests that measuring MMA and holoTC may be more accurate at reading low B-12 levels because they pick up only active B-12, so you may want to mention those to your doctor when asking for testing.

How to cure a vitamin B12 deficiency

Since the body can’t make vitamin B12 on its own, we need to get it through either our diets or supplementation. “The body’s daily requirement for B12 is small, about 1 mcg. per day,” says Dr. Green. “So the recommended daily intake is around 2-3 mcg. because we don’t absorb all the B12 that we ingest. Older adults require more – up to 5 mcg.”

Indeed, our ability to absorb B12 decreases with age. “There are diseases of the stomach, including gastric atrophy, that contribute to B12 deficiency,” explains Dr. Green. “The stomach lining gets thinner with age, we make less acid and less enzymes, so it’s more difficult to extract the B12 from food. As many as 20% of older people have problems getting B12 from the diet.” And research shows that risk of developing gastric atrophy, and ensuing B12 deficiency, doubles between the ages of 50 and 70.

Fill up on vitamin B12-rich foods

Since your body doesn’t need much vitamin B12 on a daily basis, it’s also possible to get all you need each day from food sources. Seafood like clams, tuna, king crab and canned oysters are high in B12, as is red meat. In fact, all these foods will deliver more than your recommended daily intake in one serving. Milk, cheese and eggs also contain substantial amounts of B12, as do foods that are fortified with the vitamin, such as certain cereals, nondairy milks, and tofu.

Dr. Green notes that your body won’t absorb all of the B12 contained in the food you eat and the percentage it does absorb declines with age. That means if you’re trying to get all your B12 from food, make sure to aim to consume at least twice the recommended daily intake, or at least 6 mcg.

A cheeseburger can help reverse a deficiency in vitamin B12
Anna Denisova/Getty

Take a vitamin B12 supplement

Since your ability to absorb B12 decreases with age, older adults need to take more than 6 mcg. — but not that much more. “For a normal, healthy person who doesn’t have demonstrated malabsorption, a B12 supplement with 25-50 mcg. of B12 is plenty,” says Dr. Green.

Taking more than 50 mcg. is not dangerous. Indeed, many supplements that contain just vitamin B12 contain much more. But if you’re getting your B12 from a multivitamin, make sure the dose is at least 25 mcg.. And if you do have a condition that significantly inhibits your ability to absorb B12, like pernicious anemia, you likely need injected B12 supplements. These bypass the issue of the vitamin needing to be absorbed through the GI system.

When choosing a supplement, Dr. Green says not to worry about the form of B12 noted on the bottle. “There are different kinds that claim to be more efficacious, like methylcobalamin,” he explains. “That is an active form in the body, but your body will have no trouble converting cyanocobalamin.” If the latter is more reasonably priced, there’s no need to spend more on the former. One to try: Solgar Vitamin B12 100 mcg. (Buy from, $6.17).

Read on to discover how shortfalls in vital nutrients and hormones can impact your health — and how to fix them:

This content is not a substitute for professional medical advice or diagnosis. Always consult your physician before pursuing any treatment plan.

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