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Get excited about nutrition, and learn as you go with these information-packed resources on a wide variety of nutrition-centric topics! Our bistroMD experts review the importance of the macronutrients protein, fat, and carbohydrates, as well as how to make them work most efficiently for you.

How Much Vitamin B Do You Really Need?

You may have noticed that vitamin B is commonly called out on food packaging, but what does this vitamin do, and how much of it do you really need?


Vitamins and minerals, known as micronutrients, are extremely vital to our health. Although vitamins do not provide energy the way macronutrients (carbohydrates, protein, and fat) do, their intake allows the body to use energy along with other functions. In total, there are eight critical B vitamins and commonly known as the "vitamin B complex." The B vitamins include: B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), and B12 (cobalamin). Although B vitamins are implied as a cohesive unit, each vitamin has their own individual functions, effects, and recommendations.

Vitamin B1

Thiamin is involved in the metabolism of carbohydrates, branched-chain amino acids, and fatty acids. Severe vitamin B1 deficiency can result in Beriberi, a condition in which the cardiovascular, nervous, muscular, gastrointestinal, and nervous systems can be affected.

Recommended Intake: 1.2 mg per day for males and 1.1 mg per day for females

Food Sources: whole grain cereals, legumes, nuts, pork, pecans

Vitamin B2

Along with the participation of the metabolism of carbs, lipids (fats), and proteins, riboflavin also functions as an antioxidant. Simply put, antioxidants protect the body's cells against damage. Furthermore, riboflavin may maintain proper eyesight.

Recommended Intake: 1.3 mg per day for males and 1.1 mg per day for females

Food Sources: milk, beef, asparagus, spinach, whole-wheat bread, halibut

Vitamin B3

Like riboflavin, niacin also has the functional capabilities of an antioxidant. Along with participating in carbohydrate, fat, and protein reactions, B3 also helps in alcohol metabolism.

Recommended Intake: 16 mg per day for males and 14 mg per day for females

Food Sources: tuna, chicken, fortified and enriched pastas and cereals, coffee

Vitamin B5

Pantothenic acid participates in multiple life-sustaining reactions and is essential to all forms of life. Additionally, B5 may improve the healing process of skin wounds.

Recommended Intake: Evidence lacks on a known dietary requirement for B5. Instead, an Adequate Intake (AI) was established based on observation of determined nutrient estimates by a group of health people that are assumed to be adequate. For pantothenic acid, the AI is 5 mg per day for males and females

Food Sources: found in a wide variety of foods; fish, sweet potatoes, eggs, legumes, mushrooms, yogurt, sunflower seeds, oranges

Vitamin B6

Also known as pyridoxine, vitamin B6 is involved in over 100 essential chemical reactions in the body. B6 works in part with hemoglobin and amino acid synthesis as well as fatty acid metabolism. Furthermore, it plays a vital role in hormone function, specifically with estrogen and testosterone.

Recommended Intake: 1.3 mg per day for males and females

Food Sources: fortified breakfast cereal, salmon, chicken, bananas, russet potato with skin, avocado

Vitamin B7

Biotin is required by all living organisms but actually be created by certain types of bacteria, yeast, algae, mold, and plants. B7 is involved in several processes, including participation in the formation of glucose and breaking down a branched-chain amino acid.

Recommended Intake: Like B5, evidence also lacks on a known dietary requirement for biotin. The AI is 30 micrograms per day for males and females

Food Sources: yeast, cheese, cauliflower, pork, raspberries

Vitamin B9

Folate and folic acid are often used interchangeably. However, folate occurs naturally in foods while folic acid is the synthetic form found in fortified foods and supplements. Vitamin B9 is critical in the the metabolism of nucleic acids (DNA and RNA) and amino acids (the building blocks of protein). It is extremely important in the prevention of neural tube defects. Furthermore, a deficiency may lead to pernicious anemia.

Recommended Intake: 400 micrograms per day for males and females

Food Sources: green leafy vegetables such as spinach, lentils, spaghetti, lima and garbanzo beans

Vitamin B12

Cobalamin is unique because it contains a metal ion, cobalt, and is essential in the role of folate metabolism. B12 contributes to DNA and RNA regulation and red blood cell growth and development. If deficient, pernicious anemia may arise just as in a folate deficiency. Pernicious anemia as an autoimmune inflammation of the stomach and results in the destruction of cells in the stomach's lining.

Recommended Intake: 2.4 micrograms per day for males and females

Food Sources: present in animal products such as meat, poultry, fish and shellfish, with lesser amounts in dairy products and eggs; deficiency common in vegetarians and vegans and the elderly population

All recommended intakes, unless otherwise specified, are based on healthy adults ages 19 to 50. In general, lower requirements are needed during infancy and childhood while higher intakes are needed during adulthood and in women who are pregnant or breastfeeding. Normally, vitamin B toxicities are rare. Whatever the body does not use for reactions and processes, the body rids via urine. A well-balanced diet can help achieve all recommended B vitamin requirements. If needed, a vitamin B complex can be supplemented to fill in nutritional gaps.

Reference: Micronutrient Information Center. Linus Pauling Institute. Available at:

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