A Close Look at Each of the B Vitamins: Benefits, Food Sources and More

When you think about vitamins that are essential to your health, you probably think about a lot of different letters. There’s vitamin C, vitamin D, vitamin E, vitamin K and so on and so forth. It’s like an alphabet soup of nutrients.

And then, you get to the B vitamins. And your soup gets a little heartier.

Because there are eight different B vitamins. And they’re all important for your body to go about its day-to-day business effectively and efficiently.

“The main thing that most B vitamins do is help turn our food into energy that your body can use. It helps initiate the processes that turn carbohydrates, fats and proteins into a usable form of energy,” explains registered dietitian Natalie Romito, RDN, LD.

“If you’re deficient in any of the B vitamins, your body will be much less efficient at getting the energy it needs from the foods you’re eating.”

Each B vitamin comes from different foods. They each do slightly different things for your body. You need different amounts of each. Some can have serious health consequences if you get too much of them. Others will do damage if you don’t have enough.

Oh, and in addition to their “B” name, they each have an alternative moniker as well.

Confusing? Perhaps. Important for your well-being? Absolutely.

So, let’s take a look at each of the B vitamins: What they do, how much you need and how to get them.

B vitamin benefits

If there’s one thing all the B vitamins have in common, it’s this: B vitamins are water-soluble vitamins that act as coenzymes.

What does that mean?

Water soluble means they aren’t stored by your body, so you need to eat them daily for the best effects. (One exception to this is vitamin B12. Excess B12 is stored in your liver.)

Coenzyme means they work to power enzymes. Enzymes are proteins that help speed up chemical reactions in your body. But they can’t work on their own. They need coenzymes, like B vitamins and others, to act as a switch that turns them on.

“Each type of vitamin B works on different enzymes. They make sure the enzymes get the power they need to metabolize food, build and repair DNA, grow healthy blood cells and more,” Romito explains. “So, B vitamins essentially ensure those enzymes are able to do their work.”

There are eight B vitamins:

• Thiamin (B1).
• Riboflavin (B2).
• Niacin (B3).
• Pantothenic acid (B5).
• Pyridoxine (B6).
• Biotin (B7).
• Folate and folic acid (B9).
• Cobalamin (B12).

Fun fact for those of you doing the math: There are no vitamins B4, B8, B10 or B11 — at least not anymore. Over time, those substances were found to not be vitamins at all.

Vitamins, by definition, are compounds that are essential for life and aren’t created by your body — you have to get them from foods or supplements.

And just like research has shown that Pluto is no longer considered a planet, B4, B8, B10 and B11 have been proven not to fit the criteria for vitamin status.

That leaves eight B vitamins that are essential for your health. Romito tells us about each of them.

Thiamin (B1)

What it does

Thiamin helps your body get energy from the food you eat by turning it into adenosine triphosphate (ATP), which is the energy your cells use. It’s also important for adequate nerve cell function.

“If you go think back to high school biology, you might remember that your cells’ mitochondria are the ‘powerhouses’ that produce energy,” Romito illustrates. “ATP is the energy the mitochondria in your cells use to power your cells. Thiamin helps to create that energy.”

How much you need

Recommended dietary allowances (RDAs) for thiamin are:

• Adult males: 1.2 milligrams (mg) per day.
• Adult females: 1.1 mg per day.
• People who are pregnant or breastfeeding (chestfeeding): 1.4 mg per day.

Thiamin doesn’t have an upper limit for toxicity. That means you don’t have to worry about getting too much of it.

Thiamin deficiency, on the other hand, can cause health concerns like swelling of the lower extremities, loss of muscle coordination, weight loss, lowered immunity and confusion.

Food sources

Some of the top sources of thiamin in your diet include:

Riboflavin (B2)

What it does

Riboflavin is a component of two coenzymes that are needed for energy production, cellular function and metabolism. It also helps to make sure the other B vitamins are doing their jobs.

How much you need

RDAs for riboflavin are:

• Adult males: 1.3 mg per day.
• Adult females: 1.1 mg per day.
• People who are pregnant: 1.4 mg per day.
• People who are breastfeeding: 1.6 mg per day.

Riboflavin doesn’t have an upper limit for toxicity. Riboflavin deficiency is rare in the United States.

Food sources

Riboflavin is commonly found in many animal products, like meat and dairy. People who don’t consume animal products or who eat them sparingly may be at a higher risk for deficiency, but it’s extremely rare in the U.S. That’s at least in part because some foods that don’t naturally contain riboflavin are commonly fortified with it.

Top sources of riboflavin include:

Niacin (B3)

What it does

Niacin is converted into a coenzyme that’s used throughout the body for several different processes. It helps transfer the energy found in food into ATP. It also helps with the creation and repair of DNA. Niacin is also an ingredient in some skin care products, where it’s touted for its anti-aging effects and for helping to clear up eczema and acne.

How much you need

RDAs for niacin are:

• Adult males: 16 mg per day.
• Adult females: 14 mg per day.
• People who are pregnant: 18 mg per day.
• People who are breastfeeding: 17 mg per day.

Niacin can be dangerous when taken in very large quantities. It can cause flushing, redness and itchiness throughout the skin. So, it’s advised to avoid supplements that contain high doses of niacin.

And while deficiency isn’t as common these days, it used to be a big problem in some cultures. There’s evidence that some indigenous cultures in North and Central America would process corn to make it better fit for consumption.

“Pellagra is a nutritional disease that was common in the first half of the 20th century among people with corn-based diets who consumed corn that wasn’t processed to allow niacin to be absorbed,” Romito shares. “Some indigenous cultures processed corn as early as 2000 BC to make niacin absorbable. Today, food manufacturers continue to fortify food so that pellagra isn’t a concern for most people.”

People who are undernourished may still be at an increased risk for niacin deficiency. That includes people who are living with:

• Alcohol use disorder.
• Anorexia nervosa.
• HIV and AIDS.
• Inflammatory bowel disease.
• Cirrhosis of the liver.

Food sources

Top sources of niacin include:

Pantothenic acid (B5)

What it does

Pantothenic acid is used to make coenzyme A, which helps enzymes to build and break down fatty acids. It also is a popular and helpful ingredient in some skin care and hair care products.

How much you need

Adequate intakes for pantothenic acid are:

• Adults: 5 mg per day.
• People who are pregnant: 6 mg per day.
• People who are breastfeeding: 7 mg per day.

There’s no upper limit for vitamin B5. And as long as you’re eating adequate calories, it’s very uncommon for people to be deficient in pantothenic acid.

Food sources

Pantothenic acid is common in many foods we eat every day.

“Pantothenic acid comes from the Greek word ‘pantos,’ which means ‘everywhere’ because it’s in so many foods and food groups,” Romito shares.

Some of the top sources of vitamin B5 include:

Pyridoxine (B6)

What it does

Vitamin B6 is probably one of the more famous B vitamins.

One of its jobs is to help maintain proper levels of the amino acid homocysteine. Your body naturally produces homocysteine. But too much of it can lead to things like blood clots, hardened arteries and heart attack.

Vitamin B6 targets homocysteine and breaks it down into other substances that your body needs. That keeps homocysteine from building up and causing damage.

Vitamin B6 also helps support your metabolism, immune system, brain health and many other functions. In all, it’s involved in more than 100 enzyme reactions in your body.

How much you need

RDAs for vitamin B6 are:

• Adults ages 18 to 50: 1.3 mg per day.
• Adult males age 51+: 1.7 mg per day.
• Adult females age 51+: 1.5 mg per day.
• People who are pregnant: 1.9 mg per day.
• People who are breastfeeding: 2 mg per day.

Excessive amounts of vitamin B6 from supplements can cause severe effects. So, the National Institutes of Health advises that the upper limit of vitamin B6 is 100 mg per day.

“Vitamin B6 can cause neuropathy (nerve damage) if you’re getting a very high dose for a long period of time,” Romito cautions. “That can lead to loss of control of body movements. So, you want to be very careful about taking supplements with vitamin B6. You can get too much of a good thing.”

Food sources

Some of the top sources of vitamin B6 include:

Remember, vitamin B6 is only dangerous in amounts over 100 mg per day. Given the vitamin B6 content in foods, you can rest assured you won’t go over that threshold in your diet. It’s when you take supplements with high levels of vitamin B6 that you can go over that limit. So, stick to food sources for your vitamin B6 intake.

Biotin (B7)

What it does

Biotin is perhaps most known as a nutrient for healthy hair, nails and skin. But whether biotin supplements and biotin-added beauty products actually give you a more luxurious mane or long, strong nails is still up for debate.

“Using biotin has been shown to improve brittle nail syndrome, but it’s believed that biotin deficiency may not actually be the cause,” Romito says. “It’s more likely another underlying issue, like iron deficiency, medications or hypothyroidism, cause brittle nails, but biotin can help improve the condition.”

What we do know is that eating foods with biotin assists the enzymes that break down fats, carbs and proteins in your food. It also helps ensure your cells work together effectively and that they carry out their assigned tasks based on the instructions set out by your genes.

How much you need

RDAs for biotin are:

• Adults and people who are pregnant: 30 micrograms (mcg) per day.
• People who are breastfeeding: 35 mcg per day.

There’s no upper limit to how much biotin is considered safe.

Food sources

Some of the top sources of biotin include:

Folate and folic acid (B9)

What it does

Vitamin B9, commonly called folate (in food form) and folic acid (in supplement form), is the B vitamin most associated with pregnancy and prenatal vitamins. That’s because folate is critical for proper formation of the neural tube in early pregnancy. That’s the structure that forms the early brain and spine in a developing fetus.

“Folate is very important for people who could become pregnant because often, the neural tube develops before you even know you’re pregnant,” Romito explains. “If you’re low in folate in those early days of pregnancy, it can raise a risk of the fetus having birth defects like spina bifida, a condition where the neural tube doesn't fully close.”

And even if you’re not pregnant, folate is an important component of your healthy eating plan. It helps your body to:

• Form DNA and RNA.
• Metabolize protein.
• Break down homocysteine.
• Keep your red blood cells healthy.

How much you need

RDAs for folate are:

• Adults: 400 mcg.
• People who are pregnant: 600 mcg.
• People who are breastfeeding: 500 mcg.

Romito advises that taking folate supplements for long periods can hide the effects of a vitamin B12 deficiency, which can be dangerous. So, supplements aren’t recommended except for people who are pregnant or may become pregnant or who are otherwise advised to by their healthcare provider.

Food sources

Some of the top sources of folate include:

Cobalamin (B12)

What it does

Vitamin B12 is another of the heavy hitters of the B vitamin empire. It helps form red blood cells and DNA. It also is important for organ and brain function.

How much you need

RDAs for vitamin B12 are:

• Adults: 2.4 mcg.
• People who are pregnant: 2.6 mcg.
• People who are breastfeeding: 2.8 mcg.

A vitamin B12 deficiency can cause irreversible brain damage. But it can be harder for some people to get adequate amounts of vitamin B12 in their diets. Risks for deficiency can include:

• People who follow a vegan or vegetarian diet.
• People who’ve had bariatric surgery.
• People who use the diabetes medication metformin.
• People who take proton pump inhibitor medication.
• People over the age of 65.

Food sources

Some of the top sources of vitamin B12 include:

Though vitamin B12 is found naturally in animal products, many other foods have been fortified with vitamin B12. People who don’t eat animal products are advised to seek out fortified foods and to talk with a healthcare provider about vitamin B12 supplements if they’re concerned about their intake.

“Vitamin B12 is a lot harder to come by for people who don’t eat animal products,” Romito relays. “People who are vegan or vegetarian are generally advised to take a vitamin B12 supplement rather than relying on fortified foods.”

Should you take B complex supplements?

In most cases, Romito says most people should seek to get their B vitamins from foods rather than from supplements.

“Ideally, you want to have a varied diet that provides all the vitamins you need,” she states. “Eating whole foods gives you so many nutrients your body needs, not just B vitamins, but also things like fiber and antioxidants that you’re not going to get in a supplement.”

Two exceptions to the “food-first” rule:

• People who are pregnant or may become pregnant should take a prenatal vitamin with folate.
• People who don’t eat animal products or vitamin B12-fortified products should take a vitamin B12 supplement.

For others who are at risk of deficiency or who want some assurance that they’re getting the B vitamins their body needs, Romito has some additional advice: “If somebody really wants to take a supplement, I encourage you to look for ones that have 100% of the recommended dietary allowance. Some of those products contain super high doses — 2,000% of the RDA and even higher. More is not always better. And in some cases, it can be harmful.”