Vitamin B12 Boosts Brain Health and Fights Fatigue—Here’s How To Know You’re Eating Enough of It

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Vitamin B12 is a key input to a well-functioning body. While there are many vitamins and minerals that are crucial to our daily wellbeing, B12 may stand out—after all, it's responsible for making DNA, keeping your body’s nerve cells healthy, and forming red blood cells. And as a result, your body will do its job in reminding you when you’re not quite living up to your vitamin B12 intake potential.

Here, we spoke with two top dietitians to better understand vitamin B12 benefits, how much your body needs, top food sources, and signs that your body will send when you’re not getting enough B12.

Experts In This Article

The key vitamin B12 benefits

Vitamin B12 is central to a wide range of your body’s critical functions. “Vitamin B12 is needed for nerve system functioning, blood cell formation, and DNA synthesis,” says Samantha Cassetty, MS, RDN. “B12 is also involved in producing neurotransmitters that affect your mood, which may be why some research suggests that vitamin B12 may be helpful for people prone to depression.” That said, Cassetty notes, these linkages haven’t been solidly established, so be sure to check with your doctor before trying any home remedies for depression or other psychological concerns. Below, find more details on vitamin B12 benefits from Jillian Kubala, MS, RD, who previously spoke with Well+Good on the matter.

1. It can boost brain health and improve cognitive functioning.

Upping your B12 intake has been shown to help protect your neurological health. “Studies show that having low levels of B12 may harm cognitive health by accelerating neuron loss and negatively affecting brain function,” Kubala says. “In fact, even low-normal B12 levels may lead to poor cognition.” One study of people with early-stage dementia also showed that a combination of vitamin B12 and omega-3 fatty acids helped slowed mental decline.

2. B12 can up your energy levels.

Vitamin B12 can also help reduce fatigue and increase your energy levels, Kubala says. But before you start popping them like candy in place of coffee, note that all B vitamins play an important role in your body’s energy production, though they don’t necessarily provide energy themselves. Vitamin B12's specific impact on energy has only been proven with folks who are deficient in the essential vitamin or have low levels of it—so if you’re good on B12, taking supplements likely won’t give you the added energy boost you’re looking for.

3. It could help with your mood and mental health.

Kubala agrees with Cassetty's take on B12 for mood-boosting benefits. “Research shows that having low to low-normal levels of B12 increases the risk for depression,” Kubala says. "B12 may improve symptoms of depression and other mood disorders such as anxiety, especially in those with B12 deficiency or who have low-normal B12 levels.”

4. B12 supports healthy fetal development.

If you’re pregnant (or trying to get pregnant), you especially need to watch your B12 levels. “B12 is critical for the development of the fetus's central nervous system,” Kubala says. “The rapid growth and development of the fetus during pregnancy increases vitamin B12 needs drastically.”

5. It's been shown to help with bone development and assist in the prevention of osteoporosis.

Maintaining a sufficient intake of vitamin B12-rich foods may support your bone health. One study of more than 2,500 adults found that those who were deficient also had lower than normal bone mineral density. Also, because bones with decreased mineral density are prone to becoming delicate and fragile over time—which leads to an increased risk of osteoporosis—several studies have also found a connection between low vitamin B12 levels and osteoporosis, especially in women.

How much vitamin B12 should I be consuming a day?

“The recommended dietary allowance—RDA—for B12 is 2.4 micrograms [mcg] per day,” says Keri Gans, RDN. Note that this is the average recommendation for adults, and there are some variations in recommendation based on gender and health status. For example, for those who are pregnant, Cassetty says that the RDA increases to 2.6 micrograms, and for those breastfeeding, it is 2.8 micrograms. You should check with a doctor or dietitian for your own recommended intake.

Symptoms of vitamin B12 deficiency and susceptible populations

When you’re not getting enough vitamin B12, your body will certainly let you know. “A common side effect of low vitamin B12 intake is megaloblastic anemia,” says Gans. “This type of anemia may produce symptoms such as fatigue, pale skin, numbness and tingling in the hands and feet, weight loss, and dementia.” However, as Cassetty notes, "You do not want to wait for signs of this to appear."

There are certain groups who may be more likely to have B12 deficiency, so knowing your risk factors is key to taking care of your body. “For example, vitamin B12 is found in animal foods, so vegans and vegetarians need to pay close attention to their B12 status and eat fortified foods or take supplements to meet their needs,” Cassetty explains. Moreover, because you need stomach acid in order to absorb vitamin B12 from food, Cassetty recommends that folks on medication to treat GERD specifically ask their doctors to monitor their B12 levels. “A good proportion of people over 50 don’t have sufficient stomach acid to absorb B12 from food, so a supplement is often suggested,” Cassetty adds. “And anyone living with a digestive condition, like Crohn’s disease, also puts you at risk for deficiency. If you fall into one of these higher-risk groups, talk to your healthcare provider to see if it makes sense to take a supplement.”

The top food sources of vitamin B12

The good news is that there are many delicious foods that are packed with vitamin B12. “Red meat happens to be a leading source of B12, and the healthiest way to eat red meat is to choose grass-fed, lean red meat from New Zealand,” says Cassetty. “A four-ounce serving of grass-fed ground beef has 93 percent of your daily B12 needs, and it’s richer in other nutrients compared to grain-fed meat. It’s also lower in saturated fat.”

For folks looking to reduce their red meat intake, however, there are more than enough other animal-based alternatives. “B12 is also found in seafood, poultry, eggs, and yogurt,” Cassetty adds.

If you’re a vegetarian or vegan, however, fret not—Cassetty recommends fortified nutritional yeast for those foregoing meat. “It has a cheesy flavor and it tastes great sprinkled over popcorn or sauteed or roasted veggies.” Gans adds that beans, tempeh, spinach, and fortified breakfast cereal are also excellent plant-based sources of vitamin B12.

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