What to Know About Vitamin B

B vitamins or B-complex vitamins is the name given to a group of eight nutrients that are involved in important processes within the body, including metabolism, energy production, and red blood cell production and development.

These vitamins are essential to health, and you need B vitamins on a daily basis to feel your best and prevent deficiency and certain health issues. Several foods are naturally rich in B vitamins, like meat, eggs, and grains, and B vitamins can also be taken in supplement form.

Supplements may be beneficial for people at risk for vitamin B deficiency, such as people with conditions that prevent nutrient absorption or who have diets that restrict vitamin B intake.

Types of Vitamin B

There are eight nutrients that are considered B vitamins or B-complex vitamins. These nutrients are water-soluble, meaning they are excreted in the urine. The body has a limited ability to store B vitamins, so they must be consumed on a daily basis in order to maintain optimal levels. 

Here are the eight types of B vitamins and their main functions within the body.

• B1 (Thiamine): Thiamine is used in the body to break down nutrients for energy production and the production of neurotransmitters, which are chemicals that bring "messages" from one nerve cell to another.
• B2 (Riboflavin): Riboflavin plays an essential role in energy production and also functions as an antioxidant in the body. Antioxidants prevent or slow oxidative stress, or cell damage.
• B3 (Niacin): Niacin is involved in the production and repair of DNA and is a precursor for nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), which are coenzymes—molecules that help enzymes function—that are necessary for cellular function, energy production, and many other critical processes. 
• B5 (Pantothenic acid): Pantothenic acid is involved in the production of cholesterol, neurotransmitters, and coenzymes. It also helps the body obtain energy from food.
• B6 (Pyridoxine): Pyridoxine is needed for immune function, hemoglobin—the protein in red blood cells—formation, and the production of neurotransmitters. It also helps regulate the amount of the amino acid homocysteine in the blood, which could harm health if levels get too high.
• B7 (Biotin): Biotin is essential for metabolism, gene regulation, and cellular signaling, 
• B9 (Folate): Folate is needed for DNA and RNA synthesis, the formation of red blood cells, cell division, cell growth, and amino acid metabolism. It’s also essential for the regulation of homocysteine in the blood. Folate in the form of folic acid is especially important during pregnancy to prevent birth defects of the brain and spine.
• B12 (Cobalamin): B12 is necessary for neurological function, DNA and RNA synthesis, and red blood cell production. It’s also needed for the production of myelin, a protective layer that surrounds nerve cells.

Benefits of Vitamin B

B vitamins are involved in vital processes within the body. They allow your body to derive energy from the foods you eat, produce neurotransmitters that regulate mood, and synthesize RNA and DNA.

Some studies show taking B vitamins in supplement form may offer several health benefits, especially in people with low B vitamin levels. In addition to treating low B vitamin levels and preventing deficiency, supplementing with B vitamins may positively impact mental health, enhance cognitive function, and reduce levels of homocysteine.

For example, a review of 18 studies found 11 of the 18 included studies reported a positive effect for B vitamin supplements on overall mood compared to placebo treatments. The researchers also found B vitamin supplementation helped improve stress in both healthy and overly stressed people.

B vitamin supplements have been shown to enhance performance on cognitive tests and reduce mental fatigue. Also, B vitamin supplements may help protect against cognitive decline in older adults.

Additionally, B vitamin supplements may help reduce blood levels of the amino acid homocysteine, which can help protect heart health. Elevated levels of homocysteine increase inflammation and oxidative stress, which leads to cellular damage. High homocysteine, or hyperhomocysteinemia, is linked to an increased risk of several health conditions, including heart disease, cognitive decline, and depression.

Recommended Amounts of Vitamin B

Daily needs for each B vitamin vary depending on gender, age, and pregnancy status.

Here are the recommended daily intakes (RDI) for the eight B vitamins:

People who are low or deficient in B vitamins may require higher doses than what’s recommended for the average person. If you have a deficiency in one or more B vitamins, your healthcare provider will recommend an appropriate daily dose depending on your specific health needs. 

How To Get Vitamin B

B vitamins are concentrated in a number of foods, including plant and animal-based products. People who don’t consume enough B vitamins through their diet or require higher daily doses of B vitamins may need supplements to meet their needs.

Diet

B vitamins can be found in many foods. Here are the best sources of B vitamins:

• B1 (Thiamine): Pork, whole grains, yeast, sunflower seeds, and wheat germ
• B2 (Riboflavin): Organ meats, eggs, almonds, beef, and mushrooms
• B3 (Niacin): Soy, nuts, seeds, grains, chicken, tuna and lentils 
• B5 (Pantothenic acid): Liver, mushrooms, eggs, lentils, fish, yogurt, and avocado 
• B6 (Pyridoxine): Beef, potatoes, chicken, fruit, and fortified cereal 
• B7 (Biotin): Yeast, eggs, soybeans, fish, seeds, and organ meats
• B9 (Folate): Dark leafy greens, beans, nuts, grains, and organ meats
• B12 (Cobalamin): Meat, seafood, dairy, and fortified foods.

There are many other foods that contain different amounts of B vitamins. Eating a balanced diet consisting of both plant and animal foods is the best way to ensure you’re taking in optimal amounts of each B vitamin on a daily basis. 

People who follow restricted diets, like vegan diets, are more likely to be low or deficient in B vitamins, such as B12, and might require a B-complex supplement in order to meet their needs. 

Supplements

People who are unable to meet their B vitamin needs through diet alone may require a B vitamin supplement. This might include people whose diets are low in B vitamin-rich foods, people who are on B vitamin-depleting medications, and people who have medical conditions that interfere with the absorption of B vitamins.

While some people may only require supplementation with one B vitamin, such as vitamin B12, others may benefit from taking a B-complex supplement that provides all eight B vitamins. 

Signs and Risks of Vitamin B Deficiency

If you develop low or deficient levels of one or more B vitamins, you may experience certain symptoms and health issues. If a B vitamin deficiency becomes severe, it can significantly harm health and may even be fatal.

Here are the symptoms and risks associated with B vitamin deficiencies as well as who’s most at risk for developing low B vitamin levels:

Can You Get Too Much Vitamin B?

B vitamins are water-soluble, meaning the body doesn’t store them in large amounts. Instead, extra B vitamins the body doesn’t use are excreted through the urine. Because of this, B vitamin supplements are safe and are not associated with many adverse health effects, even when consumed in very large doses.

For example, B12 supplements commonly contain over 10,000% of the daily intake recommendation for B12. However, because B12 has such a low level of toxicity, high-dose B12 supplements are generally safe for consumption.

However, consuming excessive quantities of certain B vitamins when it's not necessary could harm health. Very high doses of supplemental B3 (niacin) may lead to skin flushing, vomiting, high blood sugar levels, low blood pressure, and potentially liver damage.

Since some B vitamins can cause side effects and may be harmful when consumed in large amounts, it’s important to consult your healthcare provider before taking a B vitamin supplement. They can help you determine whether a B vitamin supplement may be beneficial for your health and can recommend appropriate dosing. 

A Quick Review

B vitamins refer to eight nutrients that play important roles in health, such as supporting cellular function, metabolism, energy production, red blood cell development, and neurotransmitter production.

B vitamins are found in a number of foods, including both plant and animal foods. Most people following well-rounded diets are able to meet their needs through food alone. However, B vitamin supplements may be necessary for certain populations, such as people with medical conditions that interfere with B vitamin absorption, pregnant and breastfeeding women, and people following restrictive diets. 

If you’re concerned you’re not getting optimal amounts of B vitamins, talk to a healthcare provider—like your primary care physician or a registered dietitian—for tips on how to increase your dietary intake of B vitamins.