What Is Biotin Deficiency?

Introduction to biotin deficiency

Vitamins are needed for basic body processes. Many of us know Vitamins A, B, C, D, E, and K. We may also be aware that Vitamin B has several types. Deficiency of any vitamin in the body manifests with certain characteristic features. But, just how many of us know a vitamin called Biotin? What can it look like to be biotin deficient?

Definition of biotin deficiency

Biotin deficiency is a disease caused by the lack of adequate amounts of a nutrient called Biotin in the body. Biotin is a type of Vitamin B that is required for vital processes in the body to occur, such as those that produce glucose, fatty acids and amino acids. It is also known as Vitamin B7 and in the past, it was called Vitamin H or Coenzyme R.¹

The symptoms include alopecia (hair loss), red and scaly skin reactions around the body openings, hearing and visual problems, delay in the development of the body (especially in children), and an increased acid content in the blood and urine. These are due to a relative lack of biotin, which is required to generate nutrients in forms that may be readily used by the body.¹

Biotin deficiency has been documented to cause irreversible damage in infants if diagnosis and treatment are not instituted early.

The importance of biotin for the body's functions

Biotin is required for vital metabolic processes such as gluconeogenesis (production of glucose from protein), fatty acid production and amino acid production. Furthermore, it plays a role in controlling inflammation.

Causes of biotin deficiency

Several factors may cause Biotin deficiency:

1. Inadequate dietary intake: The daily requirement of Biotin is 30-100 micrograms in adults and 30 micrograms in children. Most Western diets contain at least 35 micrograms of Biotin daily. There is evidence that clinical and laboratory parameters improve in both infants and adults after supplementation of biotin-deficient feeds with Biotin. This was observed in a study among adults who were initially fed on total parenteral nutrition lacking Biotin and infants fed on formulas devoid of Biotin.^1,3

Low biotin levels have been reported in mice fed on ketogenic diets.² This is because ketogenic diets increase Biotin use. In addition, children suffering from protein-energy malnutrition are also at a higher risk of being deficient in Biotin. The intake of up to six raw eggs per day can cause Biotin deficiency. Although eggs are biotin-rich, the presence of avidin (a protein that blocks the absorption of biotin) in raw eggs causes biotin deficiency unless they are cooked, which breaks the bond between avidin and biotin.³ Therefore, one may need to reconsider taking mayonnaise and egg nog.

2. Genetic predisposition: Biotin deficiency may result from Biotinidase deficiency. Biotinidase is an enzyme (a special chemical agent which functions to hasten chemical processes in the body) that releases biotin from biocytin. However, it is rare in the world to have 1:40,000 - 1:60,000 births. In the US (2006), profound Biotinidase deficiency (BTD) was as common as 1:80,000, while the partial deficiency occurs at a rate of 1:31,000 - 1:40,000. The incidence in Brazil is 1:10,000, while that of Turkey is as high as 1:7,116. The occurrence of BTD is highest in Turkey and Saudi Arabia due to high rates of marriages between relatives. It is inherited in an autosomal recessive manner: Two defective genes, one from the father and one from the mother, allow the disease to manifest. BTD is one of the inborn errors of Metabolism.⁴

Figure 1. Biotin deficiency in children.⁵

Factors affecting biotin levels

Medical conditions

Liver disease 

The liver is the largest source of Biotinidase in the body. Hence, conditions that affect the liver may affect the production of Biotinidase. Biotin deficiency has been reported in patients suffering from chronic liver disease.¹

Pregnancy

Pregnancy causes a decrease in Biotin levels as a result of the rapid growth of the foetus, which requires an extra consumption of biotin. However, it is usually mild and does not lead to clinical diseases. It has not been observed to cause any foetal anomalies in humans, unlike in the case of mice.⁶

Inflammatory bowel disease

Biotin is deficient in this condition. Furthermore, low levels of biotin have been found to increase inflammatory reactions, which are thought to contribute to skin and neurological manifestations of biotin deficiency.¹

Lifestyle factors

Chronic alcohol consumption

Chronic alcohol consumption inhibits biotin absorption in the rats’ intestines. Furthermore, alcoholics tend to suffer from both macro and micronutrient deficiencies, including biotin deficiency.⁷

Smoking

Cigarette smoke increases the breakdown of biotin and other vitamins and antioxidants. Biotin insufficiency was observed in female smokers.⁸

Long-term use of certain medications

Antibiotics: prolonged use of antibiotics can cause Biotin deficiency because antibiotics alter the gut flora, which is responsible for the production of biotin in the body.

Anticonvulsants (a medication for seizures) such as Carbamazepine, Phenytoin and Phenobarbitone may also cause Biotin deficiency by reducing the level of serum biotin.⁹

Symptoms of biotin deficiency 

The clinical findings of biotin deficiency are similar in infants, older children and adults. They are divided into two main categories: 

Hair and skin issues

Biotin deficiency causes thinning of hair, changes in hair colour and eventually, hair loss (alopecia). Most of the time, hair loss affects the scalp however, it could also affect the eyebrows and the lashes. A condition called Seborrheic dermatitis may occur in the skin of most patients. It is a scaly rash that appears red in White-skinned populations and darker or lighter in Black-skinned populations. The rash is usually distributed around the mouth, nose, eyes and perineal orifices in several individuals. The combination of skin manifestations and the peculiar spread of facial fat in biotin deficiency has given rise to the name "biotin deficiency facies".^3,4

Neurological symptoms

The neurological findings differ in infants and adults. In infants and children, the most salient features include generalised body weakness, hypotonia (low muscle tone), hearing and visual problems, and delay in development. On the other hand, adults may suffer from generalised muscle pain and weakness, hallucinations and tingling in the limbs.⁴

Diagnosis of biotin deficiency

Clinical assessment

This involves examination of the skin, neurological and musculoskeletal systems. The features previously mentioned may be found in frank biotin deficiency. However, a subclinical form may exist which does not manifest with clinical symptoms.⁴

Blood tests for biotin level measurement 

Laboratory tests are needed to measure biotin levels in the blood. They tell objectively if there are any changes in biotin levels after supplementation. There are a few markers for biotin, and each has its limitations. Hence, a combination of tests could be applied to obtain a more accurate measurement of biotin levels. The tests are not 100% reliable because certain factors could affect the results. Therefore, it would be appropriate for new studies to be carried out using better methods that yield more accurate results.¹⁰

Groups at risk of biotin deficiency

1. Pregnant and breastfeeding women.
2. People with certain medical conditions: chronic liver diseases, inflammatory bowel disease, alcoholics, smokers, patients on prolonged antibiotics (such as Amoxicillin and Levofloxacin), anticonvulsants such as Phenytoin, Primidone, Phenobarbitone, Carbamazepine, and Valproic acid which are used in the treatment of seizure disorders (epilepsy). Lipoic Acid also competes with biotin for binding sites, thereby causing biotin deficiency.³
3. Individuals on restrictive diets such as total parenteral nutrition, infant formulae that do not contain Biotin and ketogenic diets.
4. Children born into families with a history of BTD.⁹

Treatment and prevention

Biotin-rich foods

Foods rich in Biotin include beef liver, pork, salmon and cooked eggs. Others include avocados, sweet potatoes, nuts and seeds. Vegetarians and vegans may also receive more biotin from coffee, yeast, pumpkin, oats, tofu and mushrooms.

Biotin supplements

Biotin supplements are available for use in the prevention and treatment of biotin deficiency. However, this should not replace a varied diet. It is available as capsules or tablets including chewable tablets. It may be obtained without a prescription, and the daily recommended intake increases with age.

Biotin is available alone in several different doses, but several contain 5000 micrograms (5mg). It can also be found with other B vitamins.¹¹

Biotin supplements have been widely marketed by the cosmetics industry as hair and nail beautifying agents. Even though a few studies appear to be in line with this claim, it has not been verified appropriately due to a lack of evidence.⁶

Addressing underlying medical conditions

It is pertinent that underlying medical conditions be treated or eliminated to address biotin deficiency. 

Potential complications of biotin deficiency

Impact on general health 

Biotin deficiency has been linked to recurrent vulvar Candida infections due to impaired immunity.³

Neuropsychiatric symptoms

Depression, hallucinations (seeing things that are not there) and neurological deficits (such as hearing or visual losses) can affect the overall quality of life of affected individuals.

Long-term consequences if left untreated

Biotinidase deficiency if not diagnosed and treated early in infants, may cause long-term and irreversible neurological damage, which results in developmental delay and autistic behaviour.¹²

Summary

In summary, biotin deficiency is a rare micronutrient deficiency that is caused by either poor intake, heredity, or prolonged use of some medications. It manifests with skin and neurological features and it is preventable by nutrient supplementation. Biotin deficiency caused by BTD is an inherited disorder of metabolism and can result in cerebral palsy. To avoid biotin deficiency caused by prolonged consumption of raw eggs, cook eggs thoroughly. Most people with a varied dietary intake will not suffer from biotin deficiency. If you’re on biotin supplements, you must mention it at every visit to the doctor because it can alter the results of some laboratory tests, such as thyroid tests.¹²

FAQs

Can I have excess Biotin? 

Biotin is water soluble, and hence, it is excreted in the urine. The toxicity of biotin has not been known but signs of excess biotin may include insomnia, frequent urination and excess thirst.¹³

Can biotin improve my hair and nails?

There are case reports of improvement of the hair and nails after biotin use in certain conditions. However, more and better-designed trials are needed to confirm the claims.⁶