A Comprehensive Guide to The B Vitamins

There are eight different types of B vitamins – together, they are called the vitamin B complex.

The B vitamins are:

• B1 (thiamine)
• B2 (riboflavin)
• B3 (niacin)
• B5 (pantothenic acid)
• B6 (pyridoxine)
• B7 (biotin)
• B9 (folate)
• B12 (cobalamin)

Some B vitamins are known by their names, while others are known by their numbers.

Each of the B vitamins has its unique functions, but, in general, they support metabolism and contribute to the body’s ability to produce energy. (1)

The B complex vitamins are water-soluble, meaning they dissolve quickly in the body. Unlike fat-soluble vitamins, water-soluble vitamins are carried to the body’s tissues, but the body cannot store them. Any excess amounts of water-soluble vitamins just pass through the body. For this reason, we need to make sure we intake these vitamins regularly. (2)

How much of the B vitamins do I need each day?

To maintain good health, it is recommended to get a certain amount of B vitamins each day. (3)

Many foods provide B vitamins. Eating a variety of nutrient-dense foods can help ensure you get enough of the B vitamins each day. However, if you struggle to meet your daily needs, you may need to use supplements. You can buy B vitamins as individual supplements if you are deficient in only one type, but some evidence suggests that a full B-complex vitamin may be a better choice. (4)

B vitamins and their benefits

Below we look at each of the B vitamins in more detail.

Vitamin B1

Also known as thiamine, vitamin B1 helps turn the food that you eat into energy. It’s also important for the growth, development, and function of the cells in your body. (5)

Thiamine is found naturally in many foods and is added to some fortified foods. Foods containing thiamine include: (6)

• Whole grains and fortified foods: oats, breakfast cereals, rice, pasta, and bread
• Meat and fish: pork, trout, mussels, tuna
• Beans and legumes: black beans and soybeans
• Nuts and seeds: sunflower seeds, chestnuts, pistachios, macadamia nuts, pecans, hazelnuts

A thiamine deficiency is rare as most people in the United States get enough from the foods they eat. However, certain groups of people are more likely to have trouble getting enough. These include people with alcohol dependence, older individuals, individuals with HIV/AIDS and people who have had bariatric surgery. (7)

Symptoms of thiamine deficiency include loss of appetite and weight, confusion, memory loss, muscle weakness, and heart problems. (7)

A common thiamine deficiency in the United States is Wernicke-Korsakoff syndrome, which primarily affects people with alcoholism. It leads to tingling and numbness in the hands and feet, memory loss, disorientation, and confusion. (7)

Vitamin B2

Another name for Vitamin B2 is riboflavin. It is important for the growth, development, and function of cells in your body. It also aids the release of energy from proteins and in the production of red blood cells. (8)

Foods that are rich in riboflavin include: (9)

• Green vegetables: asparagus, broccoli, spinach
• Fortified foods: cereals, bread, and grains
• Lean meats: chicken, turkey
• Dairy products: low-fat milk, cottage cheese, feta cheese
• Organ meats: kidney and liver

A riboflavin deficiency is rare, however, certain groups of people may have trouble getting enough. These include people who follow a plant-based diet, pregnant and breastfeeding women and their babies, people who do not eat dairy foods and those with genetic conditions that cause riboflavin deficiencies. (10)

A vitamin B2 deficiency can cause skin disorders, sores at the corner of your mouth, cracked and swollen lips, hair loss, sore throat, liver disorders and problems with your nervous and reproductive systems. (10)

A severe riboflavin deficiency can result in anemia, which makes you feel lethargic and weak. It can also result in cataracts, a clouding of the lens in your eye, which compromises your vision. (10)

Vitamin B3

Vitamin B3 is also called niacin. Just like the other B vitamins, it helps to convert the food you eat into energy. It also helps the digestive system, skin, and nerves to function optimally. (11)

Niacin is found in a variety of foods including: (12)

• Meat and poultry: liver, chicken, pork, beef, lamb, turkey
• Fish and seafood: anchovies, tuna, salmon, mackerel, rainbow trout
• Nuts and seeds: pumpkin seeds, peanuts
• Beans and legumes: kidney beans, navy beans, adzuki beans
• Soy products: tempeh and tofu
• Dairy products: cottage cheese, cheddar cheese, mozzarella cheese
• Whole grains and fortified foods: oats, breakfast cereals, rice, pasta, and bread

Undernourished people with AIDS, alcohol use disorder, anorexia, inflammatory bowel disease or liver cirrhosis are more likely than others to have trouble getting enough niacin. (13)

Severe niacin deficiency leads to a disease called pellagra. Symptoms include:

• Rough skin that turns red or brown in the sun
• A bright red tongue
• Vomiting, constipation or diarrhea
• Depression, headaches, extreme fatigue
• Aggressive, paranoid or suicidal behavior
• Hallucinations, apathy, and loss of memory

As the disease progresses, it leads to loss of appetite and eventually death. (13)

Vitamin B5

Also called pantothenic acid, vitamin B5 plays an important role in the production of hormones and cholesterol. It also plays a role in making and breaking down fats. And just like the other B vitamins, it helps turn the food you eat into the energy you need. (14)

Almost all plant and animal-based foods contain some amount of vitamin B5, however food processing can cause a significant loss of the vitamin from food. You can get the recommended daily amount of pantothenic acid by eating the following foods: (15)

• Meat and poultry: beef, chicken, organ meats (liver, kidney)
• Fish: tuna
• Vegetables: broccoli, kale, cabbage, Brussels sprouts, mushrooms
• Whole grains: cereals, bread, rice, oats
• Nuts and seeds: sunflower seeds, peanuts
• Beans and legumes: chickpeas, lentils
• Eggs
• Dairy products: milk, yogurt

A deficiency in vitamin B5 is rare, however, those with a rare inherited disorder called pantothenate kinase-associated neurodegeneration can’t use pantothenic acid properly. This disorder can lead to symptoms of pantothenic acid deficiency. (16)

Symptoms of pantothenic acid deficiency include numbness and burning of the hands and feet, headache, extreme fatigue, irritability, restlessness, stomach pain, digestive issues, and sleeping problems. (16)

Vitamin B6

Vitamin B6 is less commonly known as pyridoxine. It has many important functions in the body including maintaining normal nerve function, making antibodies (needed to fight diseases), making hemoglobin (which carries oxygen around the body), breaking down proteins and keeping blood sugar in normal ranges. (17)

Vitamin B6 is found in a wide variety of foods, including: (18)

• Meat and poultry: venison, pork, beef, chicken, turkey, organ meats (liver)
• Fish: tuna, salmon, herring, mackerel
• Beans and legumes: chickpeas, pinto beans, lentils, refried beans
• Fruits and vegetables: potato, sweet potato, banana, prunes, avocado
• Nuts and seeds: pistachios, sunflower seeds, chestnuts
• Whole grains: wheat bran, Bran cereal, rolled oats

Most people get enough vitamin B6 from the foods they eat, however, certain groups of people are more likely than others to have trouble getting enough of the vitamin. People whose kidneys do not work properly, people with alcohol dependence, and people with autoimmune disorders including rheumatoid arthritis, celiac disease, Crohn’s disease, ulcerative colitis, may have low vitamin B6 levels. (19)

Symptoms of vitamin B6 deficiency include anemia, skin rashes, scaly lips, cracks at the corner of the mouth, and a swollen tongue. Very low vitamin B6 levels lead to symptoms such as depression, confusion, and a weak immune system. (19)

Vitamin B7

Vitamin B7 is more commonly known as biotin. It helps turn the carbohydrates, fats, and protein in the food you eat into the energy that you need. It also works with pantothenic acid to make and break down fats. (20)

The biotin content of food can vary depending on the plant variety, the season and the processing technique. Food sources include: (15)

• Meat: pork, beef, organ meat (liver)
• Eggs
• Fish: salmon, tuna
• Nuts and seeds: almonds, sunflower seeds
• Vegetables: sweet potato, spinach, broccoli
• Dairy products: milk, cheddar cheese, plain yogurt
• Whole grains: bread, oatmeal

Certain groups of people may have trouble getting enough biotin, including people with alcohol dependence and women who are pregnant or breastfeeding. (21)

Biotin deficiency can cause thinning of the hair and loss of body hair, pinkeye, skin infection, brittle nails, nervous system troubles, high levels of acid in the blood and urine, and a rash around the eyes, nose, and mouth. (21)

Vitamin B9

Also known as folate, vitamin B9 helps the body make new healthy cells. For women who are pregnant, a form of folate, called folic acid, is really important. Getting enough folic acid before and during pregnancy can help to prevent neural tube defects, a major birth defects of the baby’s brain or spine. (22)

Folate is naturally present in: (23)

• Fruits and vegetables: spinach, asparagus, Brussels sprouts, lettuce, avocado, broccoli, green peas, oranges, papaya, banana
• Beans and legumes: black-eyed peas, kidney beans, lentils, chickpeas
• Whole grains: bread, wheat germ, rice
• Beef liver
• Yeast extract (vegemite or marmite)

Folic acid is added to the following foods: (23)

• Enriched bread, flour, cornmeal, pasta, rice
• Fortified breakfast cereals

Women of childbearing age, people with alcohol use disorder and people with celiac disease or inflammatory bowel disease may have trouble getting enough folate. (24)

Getting too little folate can result in megaloblastic anemia, a blood condition that results in weakness, fatigue, difficulty concentrating, irritability, headache, heart palpitations and shortness of breath. Folate deficiency can also result in open sore inside the mouth, changes in the color of the skin, hair, and fingernails. (24)

Vitamin B12

Vitamin B12 is less commonly known as cobalamin. Unlike other B vitamins, the body can store vitamin B12 in the liver for years. Like the other B vitamins, it is important for energy production. Vitamin B12 also helps in the formation of red blood cells and the maintenance of the central nervous system. (25)

Food sources of vitamin B12 include: (26)

• Fish and seafood: clams, trout, salmon, tuna, haddock
• Meat and poultry: beef, ham, chicken
• Eggs
• Dairy products: milk, yogurt
• Nutritional yeast
• Fortified breakfast cereals

Certain groups of people may not get enough vitamin B12 or may have trouble absorbing it: (27)

• Older adults who do not have enough hydrochloric acid in their stomachs to help absorb vitamin B12 in food
• People who have had weight-loss surgeries or have digestive issues such as celiac disease and Crohn’s disease
• Vegetarians and vegans

Symptoms of vitamin B12 deficiency include weakness, fatigue, constipation, loss of appetite, weight loss, and megaloblastic anemia. Nerve problems, including numbness and tingling in the hands and feet, can also occur. (27)

The bottom line

As a whole, B vitamins are important for the body’s ability to produce energy, however, they each have their unique functions.

Eating a wide variety of healthful foods will help you get all the B vitamins recommended for health. If a deficiency in any B vitamin exists, it is recommended to increase the intake of high-vitamin B foods. In some instances, a vitamin supplement may be needed. It’s important to check with a doctor or other healthcare professional before adding any supplements to your diet.

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