According to the Harvard School of Public Health, only a fraction of U.S. adults currently gets the recommended daily intake of all B vitamins from their diets alone. (1) What does vitamin B do to your body, and why is it risky to be deficient in one or more of them?
“Vitamin B” actually refers to more than one vitamin, since there are eight different B vitamins in total. If you take a supplement that contains all eight of the B vitamins, this is referred to as a “vitamin B complex” or “B complex” formula.
B vitamins are most valued for their ability to help turn other nutrients into energy, maintain a healthy metabolism, and for supporting nerve function, liver function, skin health, eye health and fetal growth/development during pregnancy.
What puts someone at risk for vitamin B deficiency? You’re more likely to lack B vitamins in your diet if you avoid eating foods that are high in protein (such as fish, poultry, meat, eggs and dairy products), leafy green vegetables, seeds and legumes/beans. If this sounds like you, it’s essential to up your vitamin B intake in order to prevent health problems, such as chronic fatigue, anemia, mood disorders, weakness, poor memory and more.
What Is Vitamin B?
B vitamins are a group of water-soluble vitamins that are considered “essential,” meaning we must get them from our diets because our bodies cannot make them on their own. The B vitamins that together make up the “vitamin B complex” include: (2)
- vitamin B1 (also called thiamine)
- vitamin B2 (also called riboflavin)
- vitamin B3 (also called niacin)
- vitamin B5 (also called pantothenic acid)
- vitamin B6
- vitamin B7 (also called biotin)
- vitamin B12
- and folate (also called vitamin B9 or folic acid if in synthetic form)
The eight B vitamins have similar roles and chemical properties, although each has unique functions. For example, vitamin B6 is important for facilitating movement, memory, energy expenditure and blood flow, while vitamin B12 is needed for adrenal health, multiple metabolic functions, enzyme production, DNA synthesis and hormonal balance. Our bodies use vitamin B throughout the day, and we cannot store extra vitamin B that we’ve consumed, so we must replenish our supply often by eating vitamin B-rich foods.
1. Helps Form Blood Cells and Nerves
B vitamins like vitamin B12 are essential in the production of blood cells in bone marrow and for forming nerve sheaths and proteins. (3) Vitamin B is also needed for neurotransmitter signaling, which helps your muscles contract and gives you energy to go about your day. Deficiency in B vitamins can contribute to various neurologic and psychiatric disturbances because a lack of B vitamins will impair formation of blood cells, nerve health, neurotransmitter functions and neurological processes, potentially leading to symptoms like anemia, numbness, weakness, dementia and confusion.
2. May Help Fight Heart Disease
Folate, vitamin B6 and vitamin B12 have been found to play a role in the prevention of heart disease, as well as other chronic diseases like certain types of cancer, such as colon and breast cancer. However, there’s still more to learn about the relationship between cancer and B vitamins, so if you have cancer, make sure to check with your doctor before beginning any vitamin B supplement.
What is the function of vitamin B when it comes to heart health? Folate, vitamin B6 and vitamin B12 help convert homocysteine into methionine, an amino acid that helps the body build new proteins. Homocysteine is an amino acid in the blood, and elevated levels have been linked to dementia, heart disease, stroke and osteoporosis. (4) Homocysteine is especially problematic because as a byproduct it can contribute to the artery-clogging disease known as atherosclerosis. People with low levels of folate, vitamin B6 and vitamin B12 are more prone to elevated homocysteine levels and thickening/hardening of the arteries, potentially causing a modest increase in the risk of heart disease and stroke.
Vitamin B5 also protects cardiovascular health by helping balance blood sugar, reduce bad cholesterol, lower high blood pressure and help to prevent heart failure. (5) Vitamin B7 and chromium together can also help improve cholesterol levels, especially in people with diabetes and who are susceptible to heart disease. (6)
3. Gives Us Energy and Supports Our Metabolism
B vitamins, including folate, play a key role in building DNA, the compound that forms our genetic blueprint and helps us develop from the time of conception. B vitamins are also needed for cellular metabolism and energy production, the repair of DNA and RNA throughout our lives, and for utilization of carbohydrates, proteins and fats, which fuel our bodily processes. Many serve as coenzymes that are needed in various metabolic processes, such as those involves in the synthesis of fatty acids and gluconeogenesis. (7, 8)
Deficiency in B vitamins can result in thyroid and adrenal complications — and thus create many negative symptoms, such as fatigue, weight gain or loss, trouble sleeping, irritability, and more. Additionally, low levels of vitamin B12, B2 and iron can all contribute to anemia and fatigue.
4. Aids in Development and Helps Prevent Birth Defects
Consuming enough folate during pregnancy helps protect against fetal development of birth defects, such as spina bifida and anencephaly. (9) For more than three decades researchers have known that mothers of children with spina bifida tend to have lower levels of folate and other vitamins; therefore today all pregnant women are encouraged to supplement with folate during pregnancy. Folate is most important for fetal development in the first few weeks after conception, often before a woman knows she is pregnant, which is why taking prenatal vitamins while trying to conceive is a good idea.
5. Helps Maintain a Healthy Brain and Nervous System
B vitamins are needed to helps to produce neurotransmitters in your brain, which carry chemical signals throughout our entire body, affecting your mood, energy, appetite and more. Vitamin B5 also plays a part in producing sex and stress-related hormones (like cortisol) that are produced in the adrenal glands.
Getting enough B vitamins from your diet and/or supplements can improve your ability to cope with stress. In fact, without B vitamins, the body could not survive due to how the B vitamins help with adrenal function. This is why people who are chronically stressed or dealing with adrenal fatigue symptoms are highly encouraged to take B vitamin complex supplements.
B vitamins like vitamin B7 may be able to boost a positive mindset, energy and increase concentration. B6 vitamin benefits also include helping with proper brain development and brain function and retaining cognitive health. Consuming adequate amounts has been linked to better memory function and protection against cognitive impairment, Alzheimer’s and dementia as someone ages. (10) Taking vitamin B6 might also have a beneficial effect on children with learning and behavior disorders, including ADHD. (11)
6. Supports Skin Health, Muscle Tone and Hair Growth
Do B vitamins help grow your hair? Yes. Because B vitamins support cellular rejuvenation, they can be beneficial for your skin, nails and hair. B vitamins can boost skin health by reducing redness, dryness, inflammation, dermatitis, eczema and acne blemishes. (12) They also help repair wounds and support your immune system, making it easier to fight off skin infections.
Vitamin B7/biotin is commonly added to hair and skin beauty products, although it’s believed to be most beneficial when ingested and obtained from foods.
Can lack of vitamin B12 cause hair loss, and is vitamin b12 good for gray hair? Consuming adequate B vitamins may help reduce hair breakage and hair loss and can help nails become stronger. When it comes to gray or white hair, this is due to a decline in your hair’s pigmentation and is associated with aging. However, being deficiency in vitamin B12 may accelerate signs of aging and potentially contribute to graying hair. Other contributing factors can include lack of iron, copper and iodine, as well as chronic stress and anemia. (13)
Uses in Traditional Medicine
Traditional systems of medicine, including Ayurveda and Traditional Chinese Medicine (TCM), recognized that the aging process causes changes in nutrient absorption and therefore a need to adjust someone’s diet to slow aging. In Ayurveda, the focus is commonly on boosting “digestive fire” (called Agni), which helps the ability to break down and absorb the foods and liquids we consume. Warming spices, such as ginger, cinnamon and turmeric, are encouraged to promote a healthy appetite and metabolism.
A similar concept exists in Chinese medicine, in which attention is paid to the spleen’s energy (qi), which helps facilitate digestion, especially after the age of 50 or 60. In Chinese medicine, dried orange peel, cumin, pepper, salt and sugar are said to support absorption of nutrients, including B vitamins. Drinking small amounts of green or black tea between meals may also be recommended to improve absorption and energy. (14)
Because animal-derived foods are major sources of several of the B vitamins, a varied diet that includes both plants and animal products is encouraged in many traditional systems of medicine. According to Ayurveda, when someone enters the later stages of life dominated by the dosha called Vatta, that person may be encouraged to get B vitamins from plant foods, such as greens and legumes, as opposed to more calorie-dense foods.
In TCM, to help supply the body with energy, foods that are rich in B vitamins like organ meats, seaweed, eggs, bone broth, bee pollen, beans, black rice and seeds are encouraged, especially for those with fatigue, frequent illnesses, trouble focusing and lack of purpose. Because TCM and Ayurveda are “holistic” medicinal systems, they also focus on improving energy and use of vitamins by avoiding lack of sleep and staying up late, anger, chronic stress, and drugs and alcohol abuse. (15)
Top Vitamin B Foods
What foods are rich in vitamin B? Different B vitamins are often found in the same foods. The top 13 vitamin B foods include:
- Organ meats, like liver, kidneys or giblets
- Grass-fed meat
- Wild-caught fish, like salmon, mackerel, halibut, sardines, etc.
- Free-range eggs
- Pastured chicken and turkey
- Raw milk
- Dairy products, like yogurt, cheese and kefir
- Leafy green vegetables
- Nuts and seeds, like sunflower seeds, macadamia nuts and more
- Sea vegetables, like spirulina
- Beans, legumes and peas
- Nutritional yeast
Many whole foods are excellent sources of B vitamins — such as vegetables, meat, eggs, fish, beans and 100 percent whole grain products. Rather than consuming processed foods that are heavily fortified with B vitamins, such as breads and breakfast cereals, it’s better to get the B vitamins you need from real foods. Today, the U.S. Food and Drug Administration requires that certain B vitamins be added to most enriched breads, flour, cornmeal, pastas, rice and other grain products, however eating fortified foods isn’t necessary (or some cases even beneficial at all) if you eat a balanced diet.
Instead, opt for the following foods to get each specific B vitamin:
- Vitamin B1 (thiamine) foods — Nutritional yeast, seaweed like spirulina, sunflower seeds, macadamia nut, black beans, lentils, navy beans, mung beans, green peas, liver, white beans and pinto beans.
- Vitamin B2 foods — liver, grass-fed beef, seaweed, feta cheese, almonds, tempeh, mackerel, eggs, sesame seeds and goat cheese.
- Vitamin B3 foods — liver, chicken, sunflower seeds, beef, salmon, green peas, turkey, tahini, mushrooms and sardines.
- Vitamin B5 foods — both plants and animals like meat, organ meats, beans and legumes, salmon, veal, certain nuts and seeds like sunflower seeds, avocado, portobello mushrooms, raw milk, and eggs.
- Vitamin B6 foods — beans, poultry and turkey, fish, grass-fed beef, nutritional yeast, pinto beans, sunflower seeds, chickpeas, and some vegetables and fruits, especially dark leafy greens, papayas, avocado, oranges, and cantaloupe.
- Vitamin B7 foods — meat, eggs, liver, whole grains, potatoes, beans and lentils, leafy greens, salmon, avocado, cauliflower, berries, and mushrooms.
- Vitamin B12 foods — animal products, such as fish, organ meats like liver, poultry, meat, eggs, dairy products, and the plant-based product called nutritional yeast. Vitamin B12 is mostly only found in animal products, which means those who avoid all animal foods (vegans) are at risk for deficiency.
- Folate foods — asparagus, beans, peas and lentils, eggs, leafy green, beets, citrus fruits, Brussels sprouts, papaya, spinach and broccoli.
Vitamin B Deficiency
What are the symptoms of lack of vitamin B? Deficiencies in B vitamins can cause many different symptoms and conditions, such as:
- Pernicious anemia.
- Fatigue and weakness.
- Depression and anxiety.
- Memory and cognitive impairment.
- Dry skin, acne or dermatitis, brittle nails, and hair loss.
- Poor dental health, including bleeding gums and mouth sores.
- Digestive problems like nausea, diarrhea or cramping.
- Shortness of breath.
- Birth defects in fetuses, such as spina bifida.
- Swelling of the tongue.
- The disease called beriberi (lack of vitamin B), which affects the nervous system and can cause weight loss, emotional disturbances, weakness, irregular heartbeats and more.
- Wernicke encephalopathy (impaired sensory perception), weakness and pain in the limbs, periods of irregular heartbeat, and edema (swelling of bodily tissues).
- Ariboflavinosis (lack of vitamin B2), which can cause cracks in the lips, high sensitivity to sunlight, inflammation of the tongue and seborrheic dermatitis.
Risk factors developing vitamin D deficiency can include:
- Being chronically stressed.
- Eating a poor-quality diet.
- Being a vegan/vegetarian.
- Poor absorption of nutrients due to impaired gut health (this is especially problematic for vitamin B12 deficiency).
- Being over the age of 50 or elderly, which is associated with impaired digestion and decreased production of stomach acid that is needed to convert vitamin B.
- Calorie restriction, eating disorders, malnutrition or extreme dieting.
- Regularly drinking alcohol, since alcohol interferes with the proper metabolism of B vitamins like folate and inactivates circulating vitamins.
- Smoking and using drugs. Both alcohol and nicotine, and even long-term antibiotic use, can reduce the ability of the stomach to absorb and use vitamin B.
- Sleep deprivation and working shift work.
- Intense training and exercise.
- Many different illnesses, especially those that impair absorption of nutrients due to use of medications or intestinal disorders.
- Taking anti-seizure medications, the anti-diabetic drug Metforman or oral antibiotics long term.
- Being on oral contraceptives/ birth control pills.
- Pregnancy, which increases the need for many B vitamins (especially folate).
- Life changes or events that may deplete energy and cause stress, like having a baby, traveling, moving, etc.
How to Overcome a Deficiency
Whenever possible, it’s best to get the level of B vitamins that you require each day through eating a nutrient-dense, whole-foods diet. However, taking a multivitamin that includes B vitamins (or a B complex supplement) can also be considered “added insurance.”
Multivitamins commonly contain the full spectrum of B vitamins — in other words the B vitamin complex. I recommend taking a food-based vitamin that includes the full spectrum of B vitamins, since they all work together within the body to carry out functions and balance one another. B vitamins are mostly eliminated in the urine if taken in excess, so taking high doses doesn’t always serve a purpose (unless someone is severely deficient).
One of the most common forms of vitamin B deficiency is B12 deficiency. The National Institutes of Health recommends that adults over 50 years take a daily vitamin B12 supplement or consume foods fortified with vitamin B12. The recommendation is to take between 25–100 micrograms per day, whether in tablet form, in drops that you place under on the tongue or in oral spray form. Another approach to managing vitamin B12 deficiency is by taking B12 injections, which may help improve moods, protect against cognitive decline, manage anemia and provide you with energy.
Vitamin B vs. Vitamin D vs. Vitamin C
- B vitamins are especially important for metabolic functions, while vitamin D is needed for bone health and immunity, and vitamin C serves as an antioxidant.
- Vitamin D is a fat-soluble vitamin that plays a central role in many components of health, including helping with calcium absorption, bone mineralization, weight management, brain health, cancer prevention and hormone production. We get vitamin D mostly through exposure to sunlight, which is why it’s often dubbed the “sunshine vitamin.”
- Because there is a limited selection of vitamin D foods available and many people don’t spend much time outdoors in the sun, a huge portion of the population at risk for deficiency. It’s generally recommended to squeeze in at least five to 30 minutes of sun exposure two times per week to help meet your vitamin D needs. Vitamin D foods include cod liver oil, salmon, mackerel, tuna, sardines, beef liver, eggs, caviar and certain mushrooms.
- Getting enough vitamin D and B vitamins may bump up brain power, improve mental performance, help with attention and focus, support heart health, and help prevent infections.
- Vitamin C, also known as ascorbic acid, is a water-soluble vitamin that is found in many types of fruits and vegetables. It acts as an antioxidant to neutralize free radicals and reduce the risk of inflammation and disease. Vitamin C has many benefits, including reversing skin aging, reducing cholesterol levels, preventing impaired immunity, treating gingivitis and gout, and helping ward off illnesses and infections. A higher intake of vitamin C-rich fruits and vegetables may be associated with a lower risk of many chronic conditions, such as anemia, stroke and coronary heart disease. Taking vitamin C and B vitamins together can help to combat stress and fatigue and improve mental functioning and immunity.
- The best vitamin C foods include kiwi, bell peppers, oranges, strawberries, papaya, grapefruit, pineapple, broccoli, tomatoes, mango and spinach.
Supplements and Dosage
How much vitamin B do you need to prevent vitamin B deficiency? Here’s what the the Institute of Medicine recommends for daily intake of B vitamins among adults: (16)
- Vitamin B1: 1.1 to 1.2 milligrams per day.
- Vitamin B2: 1.1 to 1.3 milligrams per day.
- Vitamin B3: 14 to 16 milligrams per day.
- Vitamin B5: 5 milligrams per day.
- Vitamin B6 (may be called pyridoxine): 1.3 to 1.7 milligrams per day.
- Vitamin B7: 30 micrograms per day.
- Vitamin B12 (may be called cobalamin): 2.4 micrograms per day.
- Folate: 400 micrograms per day.
Who should take vitamin B supplements? You might take a higher dose of one or more individual B vitamins if you know you have a deficiency, such as in vitamin B12 or B6. If you eat a healthy diet and have no known deficiencies, then you should generally avoid taking high doses of vitamin B supplements, since they will just be excreted from your body via urine and serve little purpose. Some instances in which supplementing with B vitamins can be beneficial include:
- You’re a vegan/vegetarian. Plant-based eaters are especially advised to take a daily vitamin B12 supplement.
- You’re an elderly adult or someone who lacks stomach acid.
- You’re pregnant.
- You’ve dealt with alcoholism.
- You have anemia.
- You struggle with a digestive disorder, like celiac or Crohn’s disease, that impairs nutrient absorption.
- You’ve been diagnosed with beriberi or Wernicke-Korsakoff syndrome.
- You’re experiencing neuropathy.
Note that you should always talk to your doctor about whether it’s a good idea to take high doses of B vitamins, depending on your current levels, health history and risk factors.
You can prevent a vitamin B deficiency and get the most vitamin B benefits naturally by adding more vitamin B-rich foods to your diet. Try increasing your intake by making some of these recipes:
- Teriyaki Baked Salmon or Cilantro Salmon Burgers
- Turkey Meatloaf with Goat Cheese
- Crockpot Beef and Broccoli
- Garlic Lamb Roast
- Egg Recipes including this one for Turmeric Eggs
- Avocado Bison Burgers or 50 Amazing Avocado Recipes
- Pea Salad
B vitamins were discovered over the course of several decades, beginning in the 1920s. The first B vitamins to be identified were studied when researchers were trying to uncover the connection between certain nutrients and diseases caused by deficiencies. Vitamin B1 (thiamine) was the first B vitamin to be identified, known as the “the anti-beriberi factor.” (17) Vitamin B2 (riboflavin) was then discovered in 1922, followed by vitamin B6 (pyridoxine) in 1934 and vitamin B5 (pantothenic acid) in 1940. Scientists became more and more interested in creating vitamin-enriched foods, especially those made with processed wheat flour, as a means to reinstate the vitamins that are lost in grain processing.
Vitamin B12 was the last B vitamin to be discovered. In 1926, a team of physicians from Harvard University discovered that eating half a pound of liver every day would prevent pernicious anemia, a disorder that results in too few red blood cells being produced in the body. In 1947, vitamin B12 (cobalamin) was identified and tested on a patient who suffered from pernicious anemia, curing her. It was then determined that vitamin B12 was also a key growth factor in animals, leading to enrichment of animal diets with synthetically created vitamins and substantial increases in yields for livestock farmers.
Risks and Side Effects
Taking very high-dose vitamin B supplements should be avoided by most people, since this can potentially lead to side effects, including nerve damage, numbness, tingling, elevated levels of homocysteine — which may contribute to issues like atherosclerosis — nausea, jaundice, elevated liver enzymes and potentially increased risk for certain types of cancer. If you’re taking medications to control a health condition or antibiotics for an infection, make sure to mention any supplements you take to your doctor to check for interactions.
If you are concerned about getting too vitamin B from a combination of your diet and supplements, then the first thing to do is cut out fortified foods. Most experts recommend taking a daily multivitamin and skipping fortified foods like cereals, energy bars or drinks, processed grain products, milk substitutes, etc.
- “Vitamin B” refers to more than one vitamin, since there are eight different B vitamins in total that together make up the “vitamin B complex.”
- B vitamins have benefits including helping to turn other nutrients into energy, preventing fatigue, maintaining a healthy metabolism, and supporting nerve function, heart health, skin health and fetal growth/development during pregnancy.
- You can obtain vitamin B by eating foods like meat, eggs, organ meats, legumes/beans, seeds, nuts, sea vegetables, nutritional yeast, certain whole grains and green leafy vegetables.
- You’re more prone to vitamin B deficiency if you’re a vegan/vegetarian, an elderly adult, someone who lacks stomach acid, pregnant, have dealt with alcoholism, have anemia, or you struggle with a digestive disorder like celiac or Crohn’s disease that impairs nutrient absorption. In this case, you may benefit from taking a B complex supplement, food-based multivitamin, or a high dose of one or more B vitamins.