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Biotin is a B vitamin also known as vitamin H or B-7. It helps the body convert carbohydrates into glucose, which it needs to make energy.
Biotin also helps metabolize fat and amino acids, which the body uses to build protein. Protein is needed to repair and maintain cells.
It is rare for a healthy person eating a balanced diet to suffer from biotin deficiency.
B vitamins help convert carbohydrates into glucose, which the body uses for energy.
B vitamins also help the body process fats and protein, and the nervous system to function. Sometimes referred to as B complex vitamins, they are needed for healthy skin, hair, eyes, and for liver functioning.
Biotin is available in small amounts in some foods. Additionally, the microbiome, which is the bacterial population living in the intestines, makes biotin
Similarly to all B vitamins, biotin is water-soluble. That means it dissolves in the water inside the body and cannot be stored.
People with health conditions that impact how the body absorbs nutrients, or who are on certain medications, can be at risk of developing biotin deficiency.
Biotinidase deficiency (BTD) is the most common cause of biotin deficiency. BTD is a rare inherited disorder where the body is not able to use biotin and leads to biotin deficiency. It is caused by a mutation in the BTD gene. This gene instructs the body on how to make the enzyme biotinidase, which the body needs to extract biotin from food.
BTD affects approximately one in 60,000 newborn babies.
Babies with BTD tend to start showing symptoms of the condition in the first weeks or months of life. The most common symptoms include:
Between 25 and 50 percent of babies born with BTD exhibit one or more of the following:
- ataxia or poor coordination
- conjunctivitis or red eye
- hearing loss
- lethargy and drowsiness
Between 10 to 25 percent of babies with BTD experience:
- periods of unconsciousness
- fungal infections
In fewer than 10 percent of cases, children with BTD suffer:
- hepatomegaly or enlarged liver
- splenomegaly or (enlarged spleen)
- speech problems
Without treatment, BTD can lead to a coma or be fatal.
All newborns in the United States are screened for BTD. A doctor usually diagnoses BTD by taking a family history and a blood test. Prenatal testing of sample fluid from the womb for biotinidase activity is also available.
Though symptoms of biotin deficiency typically appear in the first few months of life, symptoms can also appear later in childhood.
Conditions and medications
Other factors that put people at risk of developing biotin deficiency include:
- Being on parenteral nutrition, which means being fed intravenously, for long periods.
- Taking anti-seizure medication over a long period, which can lower the body’s biotin levels.
- Taking antibiotics over a long period, as these can destroy the biotin-producing bacteria in the gut.
- Having a condition, such as Crohn’s disease, that makes it hard for the gut to absorb nutrients.
- Having excessive exposure to alcohol, which inhibits biotin absorption.
Symptoms of biotin deficiency start gradually and can build up over time.
Symptoms can include thinning hair, progressing to loss of hair across the body, and a scaly, red rash around body openings, including the eyes, nose, mouth, and anus. Conjunctivitis can also develop.
Adults with biotin deficiency may suffer:
- skin infections
- brittle nails
- neurological problems, such as depression, lethargy, hallucinations, and paresthesias (pins and needles) in the extremities
While symptoms of BTD may disappear with medical assistance, a person may need to take biotin for the rest of their life.
Biotin multivitamins and supplements are available over-the-counter or online. However, a balanced diet is considered the best source of B vitamins.
An adult’s recommended daily intake is 30 micrograms (mcg), while a child’s recommended intake is 5 mcg per day. Pregnant women should aim for 35 mcg per day.
People should talk to their doctor before taking a biotin supplement. Biotin may be present in adult or prenatal vitamins, and there may be dangers in taking high doses.
Anyone who suspects they may have a deficiency is advised to speak to their healthcare team.
Good sources of biotin include:
- brewer’s yeast
- cooked eggs, the yolk in particular
- nuts, particularly almonds, peanuts, pecans, and walnuts
- nut butters
- legumes, including soybeans, beans, blackeye peas
- whole grains
It is important to bear in mind that some food processing techniques can destroy biotin. It is also worth noting that raw egg whites contain a protein called avidin that interferes with how the body absorbs biotin.
Biotin supplements are often promoted for hair, skin, and nail health, but there is little evidence to show that they are effective.
Biotin deficiency is reversible. People with BTD will be prescribed biotin supplements, which will stop the symptoms, but they will usually need to take the supplements long-term. The FDA does not monitor supplements as closely as they monitor food and drugs so a person should choose from a reputable source.
They should also talk to their doctor about all supplements, vitamins, herbs, and medications before beginning new courses.
A range of biotin supplements are available for purchase online.
Most of the other causes of biotin deficiency can be treated with dietary changes, though a short period of taking supplements may be recommended at diagnosis.
Anyone who suspects they have biotin deficiency should speak to a healthcare professional about what to do next.