B Vitamins: What Are Their Health Benefits?
A registered dietitian nutritionist explains.
Medically reviewed by Allison Herries, RDN
B vitamins are water-soluble nutrients that are essential for countless bodily processes. In particular, B vitamins act as coenzymes in nutrient metabolism, DNA synthesis and repair, energy production, and pathways that help your body get enough of the other vital molecules it needs.
Some people may need more B vitamins than others. Notably, the following conditions require higher B vitamin intake to avoid the risk of a B vitamin deficiency:
Hyperemesis gravidarum (severe nausea and vomiting during pregnancy)
Issues affecting the gastrointestinal tract
Certain medications, such as metformin and proton pump inhibitors, also decrease B vitamin levels.
The following article covers the health benefits of taking B vitamins, B vitamin sources, and other considerations.
Explainer
Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian nutritionist (RD or RDN), pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.
How Many B Vitamins Are There?
Although B vitamins support energy production, they do not provide energy for the body. Instead, they allow the body to extract energy from carbohydrates, fats, and proteins—nutrient sources the body uses for fuel.
There are eight B vitamins. Because B vitamins are water-soluble, the body cannot store them. Therefore, you must obtain B vitamins from your food. Deficiency for some is pretty rare unless you are experiencing malnutrition or other underlying health issues.
Vitamin B1 (Thiamin)
How Much Thiamin Do I Need?
The Recommended Dietary Allowance (RDA) for thiamin is as follows:
Females 19 and older: 1.1 milligrams (mg) per day
During pregnancy and lactation: 1.4 mg per day
Males 19 and older: 1.2 mg per day
What Thiamin Does
Thiamin is an essential nutrient for energy and carbohydrate metabolism. Thiamin is also involved in neurotransmitter synthesis.
Emerging evidence suggests a role for thiamin in alleviating premenstrual syndrome (PMS) symptoms.
What Foods Have Thiamin?
Sources of thiamin include the following:
English muffin, enriched: 0.3 mg per muffin (30% of Daily Value (DV))
Ready-to-eat cereals: 0.3 mg per ⅔ cup serving (30% of DV)
Pasta, enriched: 0.3 mg per cup of cooked penne (30% of DV)
Pork loin: 0.6 mg per 3-ounce (oz) cooked serving (55% of DV)
Deficiency Symptoms
Symptoms of low thiamin include the following:
Thiamin deficiency causes beriberi, which can be either wet or dry.
Severe thiamin deficiency affects the brain, resulting in Wernicke-Korsakoff syndrome.
People with alcoholism have the greatest risk of thiamin deficiency because excessive alcohol intake prevents the body from absorbing thiamin from food.
Oleksandra Yagello / Getty Images
Supplements in a brown glass bottleVitamin B2 (Riboflavin)
How Much Riboflavin Do I Need?
The RDA for riboflavin is as follows:
Females 19 and older: 1.1 mg daily
During pregnancy: 1.4 mg daily
During lactation: 1.6 mg daily
Males 19 and older: 1.3 mg daily
What Riboflavin Does
Riboflavin is an essential part of coenzymes required for the following processes:
Energy production
Metabolism of fats, drugs, steroids, and other B vitamins
Cell function, growth, and development
Antibody production
Immune function
What Foods Have Riboflavin?
Most plant and animal-based foods have riboflavin. Some sources of riboflavin include the following:
Ready-to-eat cereals: 0.22 mg per ⅔ cup serving (20% of your daily value, or DV)
Pasta, enriched: 0.1 mg per cup of cooked penne (9% DV)
Pork loin: 0.2 mg per 3 oz cooked serving (18% DV)
Whole milk: 0.34 mg per cup of whole milk (31% DV)
Purchase milk stored in opaque containers or cardboard cartons because milk stored in clear containers under light loses its riboflavin content.
Deficiency Symptoms
Riboflavin deficiency symptoms include the following:
Skin issues
Swelling of mucous membranes
Vitamin B3 (Niacin)
How Much Niacin Do I Need?
The RDA for niacin is the following:
Females 19 and older: 14 mg daily
During pregnancy: 18 mg daily
During lactation: 17 mg per day
Males 19 and older: 16 mg per day
What Niacin Does
The term niacin includes nicotinic acid and its derivatives, such as nicotinamide.
All niacin is converted into its active form, nicotinamide adenine dinucleotide (NAD+), an essential enzyme for energy production.
Other bodily processes need niacin, including DNA repair and cholesterol production. Additionally, niacin has antioxidant-like properties that help support overall health and cognitive function.
One form of vitamin B3 (nicotinamide riboside (NR)) has recently garnered attention for potential anti-aging benefits. However, additional research in humans remains necessary.
What Foods Have Niacin?
Chicken: 10 mg per 3 oz serving of cooked boneless, skinless chicken breast (74% DV)
Enriched grains, such as English muffins: 2 mg per muffin (14% DV)
Ready-to-eat cereals: 1 mg per ⅔ cup serving (7% DV)
Pasta, enriched: 2 mg per cup of cooked penne (14% DV)
Pork loin: 7.8 mg per 3 oz cooked serving (56% DV)
Deficiency Symptoms
Symptoms of a niacin deficiency include the following:
Reduced mental function
A niacin deficiency results in pellagra, often referred to as “the three Ds” (dementia, diarrhea, and dermatitis).
Vitamin B5 (Pantothenic Acid)
How Much Pantothenic Acid Do I Need?
There is no RDA for pantothenic acid. Instead, we rely on adequate intake (AI), which reflects the estimated nutrient amount for nutritional adequacy.
The AI for pantothenic acid is as follows:
Males and females 19 and older: 5 mg per day
During pregnancy: 6 mg daily
During lactation: 7 mg daily
What Pantothenic Acid Does
Reactions in the body that support metabolism require pantothenic acid. Pantothenic acid is part of two essential enzymes: coenzyme A (CoA) and acyl carrier protein (ACP).
CoA is essential for the breakdown of fats, carbohydrates, and proteins. ACP helps with fatty acid synthesis.
What Foods Have Pantothenic Acid?
Common foods that contain pantothenic acid include the following:
English muffin, enriched: 0.2 mg per muffin (4% DV)
Pork loin: 1.1 mg per 3 oz cooked serving (22% DV)
Whole milk: 0.9 mg per cup of whole milk (18% DV)
Chicken: 1.5 mg per 3 oz serving of cooked boneless, skinless chicken breast (29% DV)
Lentils: 1.3 mg per cup of cooked lentils (26% DV)
Deficiency Symptoms
Pantothenic acid deficiency is extremely rare, especially without other nutrient deficiencies. Therefore, there is limited information about symptoms related explicitly to pantothenic acid deficiency.
However, symptoms of pantothenic acid deficiency likely include the following:
Fatigue, irritability, restlessness, and disturbed sleep
Vitamin B6 (Pyridoxine)
How Much Pyridoxine Do I Need?
The RDA for pyridoxine is the following:
Females and males 19 to 50: 1.3 mg daily
Males 51 and older: 1.7 mg per day
Females 51 and older: 1.5 mg per day
During pregnancy: 1.9 mg per day
During lactation: 2 mg daily
What Pyridoxine Does
Pyridoxine is important for producing and breaking down amino acids. Vitamin B6 also helps create glucose for energy from noncarbohydrate sources.
Pyridoxine is essential for neurotransmitter synthesis. Low vitamin B6 negatively affects mood-related neurotransmitters.
Vitamin B6 also alleviates pregnancy-related nausea and vomiting.
What Foods Have Pyridoxine?
Pyridoxine is in the following foods:
Fortified, ready-to-eat cereals: 0.15 mg per ⅔ cup serving (12% DV)
Pork loin: 0.5 mg per 3 oz cooked serving (38% DV)
Chicken: 1 mg per 3 oz serving of cooked boneless, skinless chicken breast (77% DV)
Lentils: 0.4 mg per cup of cooked lentils (27% DV)
White potatoes: 0.5 mg per cooked potato (36% DV)
Deficiency Symptoms
Pyridoxine deficiency symptoms include the following:
Swollen tongue (glossitis)
Depression or confusion
Symptoms often don’t appear until severe deficiency. Pyridoxine deficiency typically occurs with other B vitamin deficiencies.
Vitamin B7 (Biotin)
How Much Biotin Do I Need?
AI is used to estimate biotin needs because no RDA exists.
The AI for biotin is the following:
Males and females 19 and older: 30 micrograms (mcg) daily
During pregnancy: 30 mcg daily
During lactation: 35 mcg daily
What Biotin Does
Like other B vitamins, biotin plays an integral role in energy metabolism. Specifically, biotin is essential for glucose metabolism and maintaining adequate glucose levels in the bloodstream.
Biotin also aids gene expression and immune function.
What Foods Have Biotin?
Food sources of biotin include the following:
Egg yolks: 7.8 mcg per egg yolk (26% of DV)
Sunflower seeds: 2.6 mcg per ¼ cup of roasted sunflower seeds (9% of DV)
Sweet potato: 2.4 mcg per ½ cup of cooked sweet potato (8% of DV)
Deficiency Symptoms
Symptoms of biotin deficiency include thinning hair and a scaly, red rash around the eyes, nose, and mouth.
Consuming two or more raw egg whites daily for several months can result in a biotin deficiency. Uncooked egg whites bind to biotin and prevent its absorption in the body.
Vitamin B9 (Folate or Folic Acid)
How Much Folate Do I Need?
Folate needs are as follows:
Adults 19 and older: 400 mcg per day
During pregnancy: 600 mcg daily
During lactation: 500 mcg daily
Correct DNA synthesis is important because it helps avoid mutations leading to disease. Folate plays a vital role in this process of DNA synthesis, which is especially important during the early stages of pregnancy. Getting enough folate before pregnancy and during the earliest stages of pregnancy helps prevent neural tube defects (significant birth defects in a baby’s brain and spinal cord).
For this reason, current guidelines recommend that anyone who might become pregnant should consume 400 mcg of folic acid daily. This can come from supplements, fortified foods, or both, in addition to the folate they get from food. However, pregnancy increases folate needs, and in that case, 600 mcg daily is the recommended amount.
What Folate Does
Folate is essential for DNA and RNA production and cell division. Moreover, folate protects and repairs DNA from damage.
Folic acid is a form of folate used in supplements and to fortify food. The body more readily absorbs folic acid than it does folate.
What Foods Have Folate?
Food sources of folate include the following:
Ready-to-eat cereals: 17 mcg per ⅔ cup serving (4% DV)
English muffin, enriched: 54 mcg per muffin (14% DV)
Pasta, enriched: 78 mcg per cup of cooked penne (20% DV)
Leafy green vegetables: 58 mcg per cup of raw spinach (15% DV)
Lentils: 358 mcg per cup of cooked lentils (90% DV)
Peanuts: 67.8 mcg per ounce (17% DV)
Deficiency Symptoms
Symptoms of a folate deficiency include the following:
Fatigue or irritability
A smooth and tender tongue
Inadequate growth
Many folate deficiency symptoms overlap with symptoms of vitamin B12 deficiency. People with a folate deficiency should also get evaluated for insufficient vitamin B12.
Vitamin B12 (Cobalamin)
How Much Vitamin B12 Do I Need?
The RDA for vitamin B12 across the lifespan is as follows:
For males and females 19 and older: 2.4 mcg daily
During pregnancy: 2.6 mcg daily
During lactation: 2.8 mcg per day
What Vitamin B12 Does
Vitamin B12 is necessary for central nervous system function, red blood cell formation, and DNA synthesis. It is also a required nutrient for protein metabolism.
What Foods Have Vitamin B12?
Meat, particularly organ meat, contains the most vitamin B12. Other sources of vitamin B12 include the following:
Pork loin: 0.7 mcg per 3 oz cooked serving (29% DV)
Whole milk: 1.3 mcg per cup of whole milk (56% DV)
Shrimp: 1.4 mcg per 4 oz cooked shrimp (58% DV)
Nutritional yeast: 24 mcg per 3 tablespoons of fortified nutritional yeast (1,000% DV) (yeast is not a natural source of B12)
Deficiency Symptoms
Vitamin B12 deficiency symptoms include the following:
Fatigue
Heart palpitations
Dementia
Glossitis
Numbness and tingling in the hands and feet
Because animal products are the primary food sources of vitamin B12, deficiencies are more common among individuals who are vegan or vegetarian.
Vitamin B12 deficiency is more common in elderly adults. With aging, it becomes harder for the body to obtain vitamin B12 from food.
How Much Vitamin B Is Too Much?
Because B vitamins are water-soluble, excess B vitamins are often excreted in urine. Therefore, most B vitamins are not associated with harmful limits.
However, three of the eight B vitamins have an upper limit (UL) for daily intake. Taking too much (usually via supplements and not food) of niacin, folate, and pyridoxine can negatively impact health.
The UL for niacin is 35 mg daily for individuals 19 and older. Too much niacin leads to the following issues:
Increased blood sugar (glucose)
Skin rashes (niacin flush)
The UL for pyridoxine for individuals 19 and older is 100 mg daily. Excessive pyridoxine can result in:
Difficulty with movement coordination
Numbness
Sensory changes
In addition to masking a vitamin B12 deficiency, excessive folate supplementation is associated with an increased risk of certain cancers, specifically prostate cancer. Moreover, high folate supplementation may increase cancer progression.
Are B Vitamins Safe for Everyone?
Avoid B vitamins if you're allergic to them or their components (parts). Seek immediate medical attention if you have a severe allergic reaction (itching, hives, shortness of breath).
For most people, B vitamins are considered safe and well-tolerated. However, B vitamins may not be safe for some individuals with specific health conditions or on certain medications.
B vitamins interact with anti-epilepsy medications, reducing the effectiveness of the drug.
People taking diabetes medication may need their dose altered if they concurrently take niacin because niacin increases blood glucose levels.
Explainer
In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says.
When choosing a supplement, look for third-party tested products and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.
Summary
B vitamins are essential for health because they’re involved in numerous vital pathways, including energy metabolism, DNA synthesis, and red blood cell formation.
Many food sources contain B vitamins, but remedying deficiencies or meeting increased needs can sometimes warrant supplementation.
Before starting a B vitamin supplement, please consult your healthcare provider to ensure it is safe and effective for you. While B vitamin supplements are generally safe and well-tolerated, there are instances when too much can do more harm than good.
Read the original article on Verywell Health.
