Approximately 5.8 million people in the United States suffer from Alzheimer’s disease and related dementias, giving these life-altering diseases a broad impact across the country. But although it can be devastating when a loved one shows signs of memory loss, doctors say you shouldn’t automatically assume they have dementia.
Several factors can cause the classic signs of dementia to appear, including a vitamin B12 deficiency. “Vitamin B12 deficiency can cause cognitive impairment, including thought disorders,” says Dr. Scott Kaiser, a geriatrician and director of Geriatric Cognitive Health for the Pacific Neuroscience Institute in Santa Monica, California. “This can definitely mimic the signs of dementia.”
Add to that the fact that older adults are more likely to have trouble fully absorbing vitamin B12, putting them at risk for a deficiency, doctors say vitamin B12 deficiency should at least be on the radar of people with elderly loved ones. Unlike dementia, this is a health problem that can be reversed.
But what does a vitamin B12 deficiency look like and how can you distinguish it from dementia? The doctors explain.
What is vitamin B12?
Vitamin B12 is a water-soluble vitamin naturally found in some foods, although it is also available as a dietary supplement and prescription medicine, according to the National Institutes of Health (NIH). This vitamin helps the body produce DNA and also plays a role in the development and functioning of the central nervous system, which includes the brain and spinal cord.
Your body can’t make vitamin B12, so you need to get it from outside sources such as meat, dairy, eggs, fortified foods, and supplements, the NIH says. Most adults need 2.4 micrograms of vitamin B12 per day, although amounts are slightly higher during pregnancy and breastfeeding.
Causes of vitamin B12 deficiency
There are a few reasons why someone might develop a vitamin B12 deficiency. Following a vegan diet for years is important, says Deborah Cohen, DCN, associate professor in the department of clinical and preventive nutrition sciences at Rutgers University School of Health Professions. “Humans can store a small amount of vitamin B12,” which is why it may take a while for a deficiency to appear, she says.
But Cohen says there are many other risk factors for vitamin B12 deficiency, including years of taking the anti-diabetic drug metformin and certain medications for gastroesophageal reflux disease (GERD), such as proton pump inhibitors. “These drugs reduce the secretion of intrinsic factor, a protein secreted by stomach cells that is vital for transporting vitamin B12 from the stomach to the last part of the small intestine, where it is absorbed,” explains Cohen.
People who have had stomach surgery to lose weight, older adults, and people with gastrointestinal conditions such as Crohn’s disease and celiac disease are also at risk for vitamin B12 deficiency, he says.
Symptoms of vitamin B12 deficiency
According to doctors, vitamin B12 deficiency has some characteristic symptoms:
- Lack of energy
- Mental tiredness
- Nausea, vomiting or diarrhea
- Lack of appetite
- Weight loss
- Yellowish skin
“B12 is essential for energy production,” says Dr. Amit Sachdev, medical director of the Department of Neurology at Michigan State University. “The most common manifestation of vitamin B12 deficiency is fatigue.” Fatigue and related symptoms can be confused with symptoms of depression and dementia, he says.
People with vitamin B12 deficiency may act forgetful and confused and have difficulty concentrating and completing tasks, Kaiser says. In more severe vitamin B12 deficiencies, a person may develop delusions and paranoia. “This could mimic dementia,” Kaiser says.
How to distinguish a vitamin B12 deficiency from the symptoms of dementia
Doctors say it’s difficult to tell from a physical exam whether a person has a vitamin B12 deficiency or dementia. “There’s no way to tell the difference based on [cognitive] symptoms,” says Parul M Goyal, MD, assistant professor of medicine at Vanderbilt University Medical Center and director of Elderly Medicine at Vanderbilt One Hundred Oaks.
However, having gastrointestinal symptoms that started around the same time as cognitive problems can raise a doctor’s suspicion of a vitamin B12 deficiency, Sachdev says. “The combination of physical and cognitive changes is an important clue that the problem may be a treatable cause such as vitamin B12 deficiency,” he says.
How vitamin B12 deficiency is detected
If a doctor suspects a vitamin B12 deficiency, he or she will usually order blood tests to check a patient’s levels, Kaiser says. But having lower levels of vitamin B12 doesn’t automatically mean someone’s symptoms are caused by the deficiency.
“Vitamin B12 deficiency is also more common in people with Alzheimer’s disease, so there may be two things going on,” Kaiser says. As a result, doctors usually recommend taking a vitamin B12 supplement and seeing what happens. “If you treat your B12 deficiency and your symptoms improve, that will help you know what’s causing them,” Kaiser says.
But Sachdev says if your loved one is regularly seen with blood tests, things should never get to this point. “Routine laboratory monitoring of vitamin B12 during well checks is the most common way to detect deficiency,” he says.
What to do if a loved one has dementia-like symptoms
If your loved one shows signs of dementia, doctors stress that it is important to see a healthcare provider for an evaluation. “Many people will avoid having an evaluation due to the mistaken belief that these memory changes are normal with increasing age, but this is not a helpful assumption,” says Kaiser. “There’s a misconception that there’s nothing we can do about it, that’s not true.”
Once an evaluation is obtained, a doctor will usually order a blood test to check for vitamin B12 deficiency, along with other potential factors that could cause dementia-like symptoms, Sachdev says. If your loved one does, in fact, have a vitamin B12 deficiency, he or she will likely be prescribed oral or intramuscular supplements, Sachdev says. If they are taking a medication that may be underlying the deficiency, such as a proton pump inhibitor or metformin, a doctor may recommend trying a different type of medication, Goyal says.
Ultimately, doctors emphasize that a vitamin B12 deficiency and the resulting symptoms are reversible. “The effects of supplements are often noticed within a few weeks,” says Sachdev.
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