By Daphne Baldwin Kornrich, MS, RDN, CSOWM

There are eight water-soluble B vitamins that do not provide energy, thus do not have calories, but act as cofactors and coenzymes in the release of energy from food. The B vitamins are: Thiamine (B1), Riboflavin (B2), Niacin (B3), Pantothenic Acid (B5), Pyridoxine (B6), Biotin (B7), Folate/Folic acid (B9) and Cobalamin (B12).

These B vitamins are essential for health and energy production and each has a unique purpose (1,2). The term “water-soluble” means that any excess will be excreted in the urine as opposed to being stored in the body. However, just because a vitamin is water-soluble does not mean that it passes through our bodies without any effect (1,2). Here is some important information on four of the B vitamins:

Thiamine (B1)

  • What it does: Thiamine is an important cofactor in breaking down carbohydrates. It helps with protein synthesis and the production of neurotransmitters. Thiamine is only stored in small amounts in the liver and a deficiency can occur in as little as 10 days (1,2).
  • Deficiency concerns: Thiamin deficiency in the U.S. is rare. Deficiency can occur from a low intake of foods containing thiamin, decreased absorption in the gut or increased losses in urine, such as with alcohol abuse or certain medications such as diuretics. (1,2)
  • Where to get it: Good sources of thiamine are fortified cereals, pork, beans and sunflower seeds. An Upper Intake level (UL) indicates the maximum daily dose unlikely to cause harm or adverse side effects in the general population. There is currently no UL for thiamine (1,2).

Biotin (B7)

  • What it does: Biotin is involved in assisting enzymes in the break down of fats, carbohydrates, and protein. Supplements and shampoos containing biotin are very popular. It’s perceived that taking biotin will make our hair fuller and nails stronger, but the benefit of supplementation in the absence of deficiency is inconclusive (1,2).
  • Deficiency concerns: Biotin deficiency is rare in the U.S., but it can lead to hair loss and/or nail problems (1,2). The U.S. Food and Drug Administration (FDA) issued a warning in 2017 that biotin supplements may interfere with certain blood work by causing a falsely elevated or decreased lab value for Vitamin D, certain hormones, such as thyroid-stimulating hormone, and troponin, a heart attack biomarker (3).
  • Where to get it: Some food sources are beef liver, eggs, sweet potato and nuts. There is no UL for biotin. (1,2).

Folate (B9)

  • What it does: Folate is needed to form DNA and RNA and is involved in protein metabolism. Folate is necessary for red blood cell development and needs are increased during times of rapid growth. Folate is critical for the development of the neural tube during the first six months of pregnancy and may help prevent neural tube defects such as spina bifida and anencephaly (1,2). Since 1998, the FDA has required the addition of folic acid to most enriched breads, flour cornmeal, pastas, rice and other grains to reduce risk of these birth defects. (1,2,4).
  • Deficiency concerns: Others at risk for folate deficiency include those with alcoholism, intestinal surgeries and digestive disorders that can decrease absorption, such as inflammatory bowel disease and celiac disease. There is also a genetic variant of a gene MTHFR which prevents conversion of folate to the active form used by the body (1,2). Folate deficiency can result in anemia, fatigue, irregular heartbeat, shortness of breath, hair loss and pale skin with mouth sores (1,2).
  • Where to get it: Good sources of folate include fortified cereal, broccoli, black and pinto beans, orange juice and potatoes. Heat can destroy ~90% of folate in foods so try to eat some fruits and vegetables raw. An UL for folate is 1,000 mcg/day. Taking higher amounts can mask symptoms of a B12 deficiency, which is much more common.

Cobalamin (B12)

  • What it does: B12 is necessary to produce red blood cells, DNA and is crucial in the development of brain and nerve cells.  It is also important for the metabolism of carbohydrates, fats and protein. B12 relies on hydrochloric acid in our stomach and a protein called intrinsic factor to unlock B12 from food to be absorbed in the small intestines (1,2).
  • Deficiency concerns: Populations at increased risk of a B12 deficiency include vegetarians and vegans who do not consume any animal products, a lack of intrinsic factor as seen in the autoimmune disease pernicious anemia, intestinal and bariatric surgeries that remove or bypass part of the stomach where acid and intrinsic factor is secreted and digestive disorders such as celiac and crohns disease. Signs of deficiency include anemia, fatigue, weakness, nerve damage with tingling in hands and legs, dementia, memory loss and confusion. Untreated deficiency can lead to irreversible nerve damage. It’s important to monitor your B12 status, especially if you are at increased risk (1,2).
  • Where to get it: Animal products such as meat, poultry, fish, eggs, dairy, fortified nutritional yeast and fortified breakfast cereals and enriched soy or rice milk. No UL has been set for B12 (2).

B vitamins are a powerful group that work synergistically with each other and are involved in many metabolic processes. It is important to discuss supplementation of any vitamin or mineral with your health care provided to prevent any harmful effects.



  1. Anding, R. (2009). Nutrition made clear. Chantilly, VA: Great Courses.
  2. B Vitamins. (2019, September 16). Retrieved from
  3. The FDA warns that biotin may interfere with labs tests: FDA safety communication. Issued November 28, 2017. Retrieved from
  4. Food Standards: Amendment of Standards of Identity for Enriched Grain Products to Require Addition of Folic Acid; Correction. (1996, August 5). Retrieved from


Daphne Baldwin Kornrich, MS, RDN, CSOWM has been a registered dietitian nutritionist for 30 years, working in a wide variety of clinical and outpatient settings. Daphne currently specializes in bariatrics and weight management.