biotin vitamin B7

What is biotin?

Biotin is one of the B vitamins (vitamin B7), which are primarily involved in metabolism, along with other functions.  It is an essential vitamin, which means that it is not synthesized in the body and it must be obtained through the diet.  It is also a water-soluble vitamin, which means that it is not readily stored in the body and it must be consumed on a regular basis to ensure optimal health. 

Where is biotin found?

Biotin is found in small amounts in many foods.  Some plant-based foods that are particularly rich in biotin are nuts, seeds, and sweet potatoes.  Some animal-derived sources of biotin include organ meats, fish, and meat.  Eggs also contain biotin, however, avidin, a protein found in raw egg whites, prevents the absorption of biotin in the digestive tract. For this reason, it is a good idea to cook eggs to optimize biotin absorption.

Biotin is also found in biotin supplements, B-complex vitamins, and some multivitamin supplements. Supplements marketed for hair, skin, and nail growth often contain biotin.

Why is it important?

Biotin is important because it performs many functions in the body. Being a B vitamin that supports metabolism, it helps many different enzymes work that catalyze the breakdown of fatty acids, amino acids, and glucose into energy for the body. 

Biotin also helps regulate the reading of genetic material because it alters the activity of proteins called transcription factors.  Finally, it regulates communication between and within cells, also known as cell signalling. 

What is the RDA for biotin?

The RDA for biotin (vitamin B7) was unable to be established, so the Food and Nutrition Board (FNB) determined the adequate intake (AI) values instead.  The AI is 30 micrograms (mcg) for men and women, and 30mcg and 35mcg for pregnant and lactating women, respectively.  The AI for biotin is 25mcg for teenagers between 14 and 18 years of age. 

The AI for biotin is 20mcg for children between nine and thirteen years of age, 12mcg for children between four and eight years of age, 8mcg for toddlers between one and three years, 6mcg for infants between seven and twelve months, and 5mcg for infants six months and below.  Biotin is transferred to infants through breast milk, and it is added to infant formulas. 

These values are given by the National Institutes of Health, and the AI represents the daily intake that is assumed to be nutritionally adequate when an RDA cannot be developed.  The AI for biotin can be met through food or supplements; one cooked egg contains 33 percent of the AI, and a half cup of cooked sweet potato contains eight percent of the AI.

How much is too much?

The Upper Limit (UL) represents the maximum daily intake of a vitamin or mineral that is unlikely to cause negative health effects.  There is no established UL for biotin because there is no current evidence of high doses of biotin being toxic. 

However, there is evidence that a high intake of biotin could potentially interfere with certain types of laboratory tests according to the FDA, causing falsely high or falsely low test results.  This could result in misdiagnosis and treatment plans that could potentially be harmful.  For this reason, it is important to tell your doctor about any supplements you are taking, especially ones marketed for hair, skin, and nails. 

What are the benefits of biotin?

Biotin (vitamin B7) is commonly marketed as a hair, skin, and nails vitamin because the side effects of biotin deficiency include hair loss, brittle nails, and a skin rash.  However, the evidence of excess biotin promoting hair growth is inconclusive and only supported by case studies and personal anecdotes in children with dermatitis, alopecia, and hair shaft disorders.  More research is needed to determine whether biotin induces hair growth in healthy people.

However, biotin could potentially have some other interesting benefits.  One study found that a combination of chromium picolinate and biotin could be helpful for type two diabetes, as it improved blood sugar control in type two diabetes patients when compared to a placebo. 

Biotin deficiency

Biotin deficiency in people with balanced diets is rare, however some groups are at a higher risk of deficiency than others.  For example, people with biotinidase deficiency cannot release biotin as easily, so they can quickly become deficient despite having a normal biotin intake.  Babies born in the United States are screened for this condition so they can start treatment early on, and treatment usually consists of oral biotin supplements.

In addition, some pregnant and lactating women develop a temporary biotin deficiency despite consuming adequate amounts of biotin.  More research is needed to determine why this occurs and how to prevent it. 

Finally, people with chronic alcohol exposure have a limited absorption rate of biotin, which often results in lower blood levels of biotin.

Biotin deficiency can lead to a variety of adverse side effects, including hair loss and thinning, skin rashes, conjunctivitis, seizures, brittle nails, neurologic problems, and developmental delays in infants, among others.

Biotin (vitamin B7) supplementation

Biotin deficiency can be treated by taking high-dose oral biotin supplements, generally 5mg daily.  Biotin deficiency can also be prevented by taking biotin supplements or eating a balanced, healthy diet that meets your nutritional needs.

If you think you have a biotin deficiency or are at an increased risk, consider getting your blood levels tested.  As always, consult your doctor before you begin taking any vitamin or mineral supplement, to make sure your medications or health conditions don’t make it a serious risk.

References:

Biotin. (2020, January 01). Retrieved August 23, 2020, from https://lpi.oregonstate.edu/mic/vitamins/biotin

Center for Devices and Radiological Health. (2017, November 28). The FDA Warns that Biotin May Interfere with Lab Tests. Retrieved August 23, 2020, from https://www.fda.gov/medical-devices/safety-communications/fda-warns-biotin-may-interfere-lab-tests-fda-safety-communication

Fuhr, J. P., He, H., Goldfarb, N., & Nash, D. B. (2005). Use of Chromium Picolinate and Biotin in the Management of Type 2 Diabetes: An Economic Analysis. Disease Management, 8(4). doi:10.1089/dis.2005.8.265

Office of Dietary Supplements – Biotin. (2020, June 3). Retrieved August 23, 2020, from https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/

Saleem, F., & Soos, M. P. (2020). Biotin deficiency. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK547751/

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