If you're looking to get more B12 but don't eat meat or dairy — try algae

• Vitamin B12 is an essential micronutrient that helps red blood cell form and nerves function.
• You can't get it from plants, so many vegans and vegetarians have a B12 insufficiency.

Vegetarian and vegan diets are increasingly popular and have been found to have numerous health benefits, including lower glucose and cholesterol levels. One drawback however, is a lack of vitamin B12.

Vitamin B12 is an essential nutrient found in meat, eggs, and — in smaller quantities — dairy products. But it is not found in plants. As a result, people who are vegetarian and vegan might unknowingly be missing out on this key nutrient.

Now researchers think that algae could be the key to helping vegans and vegetarians meet this dietary need.

Many types of algae, it turns out, need B12 just like humans. "So if you eat algae, then you get the B12 that way," Alison Smith, a plant biochemist at the University of Cambridge, told Insider. Smith's research focuses on how to reap the B12 benefits of algae.

Smith is part of a group of researchers and doctors at CluB-12, an organization that aims to educate people on the importance of B12, and advocates that vegans and vegetarians need a more reliable source of B12.

"It shouldn't be difficult to get a reasonable amount of B12," Smith said, "but people don't know about it." As a result, she said, people are "at risk of being unwell or even suffering harm."

Vitamin B12 deficiency can lead to muscle weakness and tingling

In the United States, federal guidelines recommend that non-pregnant adults need 2.4 micrograms of vitamin B12 per day, and that pregnant teens and adults should up their daily allotment to 2.6 micrograms. It is estimated that roughly 6% of adults under 60 have a B12 deficiency, and vegetarians are one of the groups that are most at risk.

B12 is traditionally only found in meat and dairy products unless it's fortified into foods such as breakfast cereals, soy products, and yogurt. "If you just eat fruit and vegetables and grains and pasta," said Smith, "then you won't have enough B12."

A lack of vitamin B12 can lead people to develop either an insufficiency, in which "you could do with some more, but you're not ill," or a deficiency, in which you're showing symptoms, Smith said.

Symptoms of B12 deficiency can include weak muscles, nausea, trouble walking, and tingling in the heads and feet.

One woman with a severe vitamin B12 deficiency who recounted her experience for Insider experienced pins and needles radiate through her left arm, and eventually had tingling and weakness spread to both arms, hands, legs, and feet before seeking treatment at an urgent care center.

Other severe symptoms can include mental confusion and heart problems.

Algae to the rescue

Algae routinely contain B12, and could be an excellent source of vitamin B12 for anyone, especially vegans and vegetarians, said Smith. Algae take up vitamin B12 from their environment, she said, and when people ingest algae they too can benefit from B12. One particularly good source of vitamin B12 in algae comes from chlorella, which more reliably has B12 than other types of algae.

But Smith warns that "you have to be careful about the type of algae that you eat."

Spirulina, for example, is sometimes marketed as a source of B12 — but it isn't one.

"Chlorella supplements have the correct type of B12, known as cobalamin," said Smith, "whereas spirulina has only got what's called pseudo cobalamin — so in other words, it's not the same. It's not got the one that humans can use."

Nori, a seaweed popular in sushi, is a type of algae that is also known to contain B12, but the amount of B12 it contains are highly variable — so it's unclear if eating it will satisfy your daily B12 needs.

Although algae can certainly help boost B12 levels, Smith advises people to talk to their doctor. Other options for B12 include vitamin B12 injections on a regular basis, or eating foods fortified with B12.

The biggest thing, Smith says, is to "make sure that you have a source of B12 in your diet, even if it's supplements or pills."