You’ve seen vitamin B complex advertised, sold in the stores, online, and in the gym. You know that they’re important, but what exactly are they and why are they so important?
Let’s start with the basics…
What is a vitamin?
A vitamin is a set of molecules that a living organism needs for its cells to function properly.
When an organism can’t sufficiently produce a needed set of molecules on its own, it must be obtained from the diet and is called an essential nutrient.
Along with minerals, essential amino acids, and essential fatty acids, vitamins make up one of the four classes of essential nutrients.
Humans require 13 vitamins for metabolism, each of them with specialty functions: vitamins A, C, D, E, K, and a group of 8 vitamins referred to as the vitamin B complex.
Four of these vitamins are fat-soluble (vitamins D, E, A and K) and nine of them are water-soluble (the eight B complex vitamins and vitamin C). It’s an important distinction, since fat-soluble vitamins accumulate more easily in the body, and water-soluble vitamins can be more easily diluted if taken in excess.
The Vitamins of the Vitamin B complex
The individual, chemically distinct vitamins of the Vitamin B Complex are typically found in the same foods as well as in the same supplement, which is why they share a common name.
Also known as thiamine, Vitamin B1 acts as a coenzyme — an assistant to the enzymes that help the body metabolize nutrients. Vitamin B1 is particularly important for the body’s energy-releasing breakdown of sugar and amino acids and is found in foods like whole grains, legumes, pork, edible seeds, rice, and breakfast cereals.
The National Academy of Medicine (NAM) has set recommended thiamine intake at about 1.0 mg/day for teenage girls and women and 1.2 mg/day for adolescent boys and men, due to biological differences in the fat/water ratio of men and women. Due to the added demands of fetal metabolism, pregnant women require 1.4 mg of thiamine per day.
In fact, Vitamin B1 is so crucial for fetal and infant development that it’s secreted in breast milk even if the mother is low in thiamine.
Riboflavin, or vitamin B2, eventually becomes a cofactor — another type of assistant to enzymes that speed up the reactions that release energy the body can use. Riboflavin, which can be found in eggs, dairy, green vegetables, mushrooms, and almonds, is responsible for a wide variety of helper functions. It even helps the body convert other vitamins into more usable forms.
The NAM has recommended riboflavin intake at similar levels as thiamine: 1.0 mg/day for teenage girls and women, 1.2 mg/day for teenage boys and men, 1.4 mg/day for pregnant women, and 1.6 mg/day for lactating women. Its importance has led many countries, including the United States, to require riboflavin to be added to grains.
Niacin and nicotinic acid are two of several common names for this vitamin, which is found in breakfast cereals, meats and spices like ginger and tarragon. Like riboflavin, niacin is required to be added to grains in developed countries. Its primary functions are to assist in various areas of metabolism and in DNA repair.
In high amounts, niacin can be used to reduce cholesterol due to its ability to alter the body’s lipid metabolism. The NAM recommends niacin intake of 14 -18 mg/day, depending on age, sex, and pregnancy/lactation status.
This vitamin is also called pantothenic acid and is a necessary molecule to create coenzyme A, a compound that helps the body produce energy and synthesize fatty acids, cholesterol, hormones, antibodies, and neurotransmitters. The word “pantothenic” is Greek for “from everywhere,” as vitamin B5 can be found in a wide variety of foods.
Also known as pyridoxine, Vitamin B6 is an important molecule the body uses to synthesize amino acids, carbohydrates, and lipids for its structural and energy needs. It is found in a variety of fruits, vegetables, and is often added to grains.
Biotin is a cofactor that is involved in several components of metabolism. It is found in liver, avocado, eggs, and peanuts. Biotin is best known for being an essential component of carbon dioxide transport and for the proper functioning of hair and skin.
Known as folate or folic acid, vitamin B9 helps with the processes of DNA repair and cell reproduction. It is required by the body to make DNA, RNA, and several types of amino acids. Like several other B vitamins, it is so important that many countries have required it to be added to everyday foods like cereal grains.
Folic acid is recognized for its role in helping to reduce the incidence of neurological birth defects when taken as a supplement by pregnant women. “Folic” comes from the Latin word for “leaf” (like “foliage”); accordingly, vitamin B9 is found in leafy green vegetables like spinach and kale.
The NAM recommends 400 micrograms of folic acid per day, and at least 1 mg (milligram)/day for pregnant women.
Perhaps the most well known of the B vitamins, cobalamin is a large, complex molecule involved in the DNA synthesis for every cell in the human body. Among its most essential functions are the production of the nerve cell signal accelerator myelin and the maturation of red blood cells from bone marrow.
Since most sources of B12 are animal products, those who follow a vegan diet must get B12 supplementation or risk serious health consequences. For this reason, cobalamin is often added to foods that tend to be staples of vegan diets (e.g., soy and grain products).
There are no B4, B8, B10, or B11 vitamins, because these compounds were once thought to be essential to human metabolism until research proved otherwise.
Formulations of the Vitamin B Complex
Vitamin B complex is the name for the multivitamin combination containing all eight of the B vitamins. Some formulations are designed and marketed to meet the needs of special populations (seniors, pregnant women, etc.).
Consumers in these populations are encouraged to check with a health care provider to ensure that multivitamins like vitamin B complex will meet their needs.
- Semba R. The discovery of the vitamins. International Journal for Vitamin and Nutritional Research. 2012;82(5):310-5.
- Manzetti S, Zhang J and van der Spoel D. Thiamin Function, Metabolism, Uptake, and Transport. Biochemistry. 2014;53(5), 821-835
- Institute of Medicine (US) Standing Committee on the Scientific Evaluation of Dietary Reference Intakes and its Panel on Folate, Other B Vitamins, and Choline. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington (DC): National Academies Press (US); 1998.
- Czeizel AE, Dudás I, Vereczkey A, Bánhidy F. Folate deficiency and folic acid supplementation: the prevention of neural-tube defects and congenital heart defects. Nutrients. 2013;5(11):4760–4775.