If you’re over 60, feeling tired all the time, have tingling in your hands and feet, and a cold you just can’t shake, it’s easy to chalk it up to getting older. But there’s a good chance the real culprit is a vitamin you may not be absorbing: vitamin B12.
Deficiency symptoms can mimic signs of normal aging and, as a result, be easy to miss. New preclinical research is now exploring a possible reason why: B12’s role in keeping your mitochondria—the energy factories inside your cells—running properly.
B12 and the Aging Cell
Mitochondria play a major role in the body as the tiny power plants that produce energy inside cells. A decline in mitochondrial function is a hallmark of aging, and B12 plays a direct role in both energy production and mitochondrial health. Two recent preclinical studies help explain the connection.
Martha Field, a co-author of both studies and an associate professor at Cornell University with a doctoral degree in biochemistry, said earlier mouse research had already linked B12 deficiency to mitochondrial DNA damage and reduced energy production. That led her team to look more closely at tissues that rely heavily on mitochondria, such as muscle, heart, and brain.
The muscle connection is especially important for older adults, since B12 deficiency becomes more common with age, partly due to reduced absorption, at the same time that aging adults face elevated risk of sarcopenia, the loss of muscle mass and strength that erodes independence and quality of life. “We’ve sort of shown that B12 deficiency or insufficiency is kind of a second hit on the same type of tissue in this same vulnerable population,” Field told The Epoch Times.
“We’ve known that B12 absorption declines with age, and mitochondrial dysfunction is a hallmark of aging. Our thought was that if there is a link between B12 availability and mitochondria in older adults, supplementation might reverse the decline,” Thalacker-Mercer told The Epoch Times in an email. “We were surprised by how robust of a result we observed.”
“The exciting finding is that in mice, improving B12 status was associated with better mitochondrial function in muscle,” Field said. “This suggests that B12 may play a role not only in preventing deficiency diseases but also in supporting cellular energy systems that help maintain healthy aging.”
Both researchers noted that these studies are on animals, and not proof of an effect in humans. Randomized controlled trials in people, which Thalacker-Mercer’s team is now pursuing, will be needed to confirm whether B12 supplementation actually improves mitochondrial function or muscle health in aging humans.
Why B12 Deficiency Is Easy to Miss
B12 is stored by the liver, which can hold years’ worth of our needed supply. This is part of why a deficiency can develop slowly and go unnoticed for a long time.
Getting enough isn’t just about how much B12 is in your diet, but also about whether you can break it down and absorb it.
Deficiency Is Common
B12 deficiency is common worldwide, especially in populations facing nutritional and socioeconomic challenges and among people on a plant-based diet.
“Given that up to one in five elderly will suffer from B12 deficiency, everyone should be aware,” Warren said.
The good news is that we only need B12 in tiny amounts, which for adults is around 2.4 micrograms daily. The requirement goes up to 2.6 to 2.8 micrograms for pregnant and breastfeeding women, respectively. To put that in perspective, one grain of sand weighs about 11,000 micrograms, meaning the vitamin B12 adults require daily is about one four-thousand-five-hundredth of a single grain of sand.
Symptoms to Watch For
Many of the symptoms of B12 deficiency and insufficiency are similar to those of other micronutrient deficiencies and to those of aging, Warren said.
Symptoms can develop slowly, making their cause more ambiguous, and many people may chalk them up to normal signs of aging. A deficiency in B12 can cause physical, neurological, and psychological symptoms.
B12 is vital for making myelin—the protective covering around nerves. When we don’t get enough B12, myelin is compromised, and nerve fibers can become exposed, leading to numbness and tingling in the hands and feet. If it progresses, it can also lead to degeneration of the spinal cord, resulting in loss of balance, poor coordination, and difficulty walking, a condition called subacute combined degeneration.
“Fatigue and tiredness are probably the most common symptoms, brain fog and cognitive changes are also quite common (e.g., concentration span, sharpness, etc.), tingling or pins and needles or fuzzy tongue, coordination issues and walking, muscle strength, depression and mood changes,” he added.
Other possible symptoms include tiredness or exhaustion, shortness of breath, balance problems, poor memory, vision problems, and weight loss. These symptoms can be due to a variety of causes beyond B12 deficiency, so if you’re experiencing them, check with your healthcare provider to determine the cause.
Testing B12 Levels
B12 status can be checked with a standard blood test, but testing has limitations.
“The common blood tests for B12 deficiency are not very accurate—you can send the same blood sample to five different laboratories and get five different results,” Warren said.
More precise testing, which means looking for byproducts that build up in the blood as a result of deficiency, exists but remains expensive, he added, noting that clearer clinical definitions of “deficiency” versus “insufficiency” are still needed.
Individual responses to low B12 also vary widely. “It is likely that two people with the same level of B12 can result in one of them being insufficient, whilst the other will suffer with deficiency. Some people seem fine with relatively low levels of B12, whilst others seem to have symptoms of deficiency with relatively high levels of the nutrient. This likely reflects genetic backgrounds, but could also reflect something that we are unaware of,” he said.
If you are having symptoms you assumed were just part of getting older, you may want to consider testing B12 levels. Something as simple as a dietary change, an evaluation of your current medications, or supplementation may improve what had previously seemed inevitable—and enhance quality of life—especially as we age.
