Vitamin B7; Deficiency Symptoms, Food Source, Health Benefit

Vitamin B7; Deficiency Symptoms, Food Source, Health Benefit

Vitamin B7 also known as biotin, vitamin H or vitamin B8, is a water-soluble vitamin, required by all organisms and is classified as a B-complex vitamin. There are eight different stereoisomers of biotin, but only one of them, D-biotin, occurs naturally and has full vitamin activity (essential cofactor for carboxylases in the intermediary metabolism) . Biotin can only be synthesized by some strains of bacteria, mold, yeast, algae, and by certain plant species.

Deficiency Symptoms of Vitamin B7

Biotin supplements are widely available but rarely necessary

A deficiency can lead to

  • Hair loss
  • A scaly red rash around the eyes, nose, mouth, and genitals
  • Cracks in the corner of the mouth
  • Sore tongue that may be magenta in color
  • Dry eyes
  • Loss of appetite
  • Brittle and thin fingernails
  • Hair loss (alopecia)
  • Conjunctivitis
  • Dermatitis in the form of a scaly, red rash around the eyes, nose, mouth, and genital area.
  • Neurological symptoms in adults, such as depression, lethargy, hallucination, and numbness and tingling of the extremities
  • conjunctivitis
  • hair loss will generally occur only when deficiency becomes more severe.
  • Depression
  • Lethargy and fatigue
  • Hallucinations
  • Insomnia
  • Numbness and tingling in the hands and feet
  • Impaired immune function and increased susceptibility to infections

Pregnant women appear to break down biotin more quickly, and this may lead to a marginal deficiency. Symptoms have not been observed, but such a deficiency could lead to developmental problems for the fetus.

Other groups who may benefit from supplements include

  • Those on anticonvulsant medications
  • People with some types of liver disease
  • People who are fed intravenously for a long time

Biotinidase deficiency is a rare, hereditary disorder that impairs biotin absorption, resulting in a deficiency of biotin. Biotin supplements can help people with this condition.

Daily Requirement/ Intake of Vitamin B7

Intake recommendations for biotin and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the National Academies of Sciences, Engineering, and Medicine . DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and sex, include:

  • Recommended Dietary Allowance (RDA) – Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
  • Adequate Intake (AI) – Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA.
  • Estimated Average Requirement (EAR) – Average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.
  • Tolerable Upper Intake Level (UL) – Maximum daily intake unlikely to cause adverse health effects.
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The FNB found the available data to be insufficient to derive an EAR and RDA for biotin. For this reason, the FNB established only AIs for biotin. The FNB based its determination of AIs for all populations on the amount of biotin in human milk consumed by infants and then used body weight to extrapolate AIs for other groups

 Adequate Intakes (AIs) for Biotin 
Age Male Female Pregnancy Lactation
Birth to 6 months 5 mcg 5 mcg
7–12 months 6 mcg 6 mcg
1–3 years 8 mcg 8 mcg
4–8 years 12 mcg 12 mcg
9–13 years 20 mcg 20 mcg
14–18 years 25 mcg 25 mcg 30 mcg 35 mcg
19+ years 30 mcg 30 mcg 30 mcg 35 mcg

According to the National Academy of Science’s Institute of Medicine, in order to receive biotin benefits, the daily recommended value of biotin is

  • 5 micrograms daily for infants
  • 6–8 micrograms daily for infants ages 7 months to 3 years old
  • 12–20 micrograms daily for children ages 4–13 years old
  • 25 micrograms for adolescents
  • 30 micrograms for male and female adults over 19 years old
  • 30 milligrams for pregnant women and 35 milligrams for women who are breast-feeding

Sources of Vitamin B7

Biotin is synthesized by intestinal bacteria, but there is a lack of good quality studies about how much biotin they provide.

Biotin is stable at room temperature and is not destroyed by cooking. Sources with appreciable content are

  • Beef or pork liver, cooked: up to 35 μg per 3 ounce serving
  • Egg, cooked: up to 25 μg per large egg
  • Yeast, baker’s, dried: up to 14 μg per 7 gram packet
  • Whole wheat bread: up to 6 μg per slice
  • Avocado: up to 6 μg per avocado
  • Salmon, cooked: up to 5 μg per 3 ounce serving
  • Cauliflower, raw: up to 4 μg per cup
  • Cheese, cheddar: up to 2 μg per ounce
  • Peanuts
  • Whole-wheat bread
  • Cheddar cheese
  • Pork
  • Salmon
  • Sardines
  • Raspberries
  • Bananas
  • Mushrooms
  • Cauliflower
  • Egg yolk
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Raw egg whites contain a protein (avidin) that blocks the absorption of biotin, so people who regularly consume a large number of raw eggs may become biotin-deficient. The dietary biotin intake in Western populations has been estimated to be as high as 60 μg per day. Biotin is also available in dietary supplements, individually or as an ingredient in multivitamins.

Health Benefit of Vitamin B7

Likely Effective for

  • Biotin deficiency. Taking biotin can help treat low blood levels of biotin. It can also prevent blood levels of biotin from becoming too low. Low blood levels of biotin can cause thinning of the hair and rash around the eyes, nose, and mouth. Other symptoms include depression, lack of interest, hallucinations, and tingling in the arms and legs. Low biotin levels can occur in people who are pregnant, who have had long-term tube feeding, who are malnourished, who have undergone rapid weight loss, or who have a specific inherited condition. Cigarette smoking might also cause low blood levels of biotin.
  • Skin rash in infants (seborrheic dermatitis). Taking biotin does not seem to help improve rash in infants.
  • Hair loss. Taking biotin and zinc by mouth in addition to applying a steroid cream to the skin might help reduce hair loss.
  • An inherited disorder called biotin-thiamine-responsive basal ganglia disease. People with this condition experience episodes of altered mental state and muscle problems. Early research shows that taking biotin plus thiamine does not prevent these episodes better than taking thiamine alone. But the combination might shorten how long the episodes last when they do occur.
  • Brittle fingernails and toenails. Taking biotin by mouth for up to a year might increase the thickness of fingernails and toenails in people with brittle nails.
  • Diabetes. Some early research shows that taking biotin along with chromium might lower blood sugar in people with diabetes. However, taking biotin alone doesn’t seem to improve blood sugar levels in people with diabetes.
  • Diabetic nerve pain. Early research shows that taking biotin by mouth or receiving it as a shot might reduce nerve pain in the legs of people with diabetes.
  • Muscle cramps related to dialysis. People receiving dialysis tend to have muscle cramps. Early research shows that taking biotin by mouth might reduce muscle cramps in these people.
  • Multiple sclerosis. Early research shows that taking high-dose biotin might improve vision and reduce partial paralysis in some people with multiple sclerosis.
  • Seizures caused by a high fever (seizures) – Early research suggests that taking pyridoxine daily for 12 months does not reduce the recurrence of seizures caused by a high fever.
  • Nerve damage caused by chemotherapy – Early research suggests that pyridoxine might help reverse nerve damage caused by the chemotherapy drug vincristine.
  • Metabolism of nutrients
  • Energy-producing metabolism
  • Maintaining hair, skin and mucous membranes
  • Nervous system function
  • Psychological function
  • Boosting the immune system.
  • Muscle cramps.
  • Eye problems.
  • Kidney problems.
  • Night leg cramps.
  • Arthritis.
  • Allergies.
  • Lyme disease.
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  1.  “Biotin – Fact Sheet for Health Professionals”. Office of Dietary Supplements, US National Institutes of Health. 8 December 2017. Retrieved 25 February 2018.
  3. “Vitamin H (Biotin)”University of Maryland Medical Center.
  5. National Health and Medical Research Council: Nutrient Reference Values for Australia and New Zealand
  6. “Biotin and biotinidase deficiency”Expert Rev Endocrinol Metab3 (6): 715–724. doi:10.1586/17446651.3.6.715PMC 2726758PMID 19727438.


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