More Than Skin and Hair: The Real Role of Vitamin B7 in Metabolism
Biotin is best known as a beauty vitamin. Its fundamental role, however, goes much deeper: vitamin B7 supports enzymes involved in energy and macronutrient metabolism.
Summary
Vitamin B7, better known as biotin, is a cofactor for several enzymes. These carboxylases are involved in the metabolism of fatty acids, amino acids and glucose, among other processes.
The European Union recognises several health claims for biotin. Biotin contributes to normal energy-yielding and macronutrient metabolism, the normal functioning of the nervous system and normal psychological function. It also supports the maintenance of normal skin, hair and mucous membranes.
Severe biotin deficiency is rare in healthy people who eat a balanced diet. However, certain medical conditions, the long-term use of some medicines or the regular consumption of large quantities of raw egg white may increase the risk.
What Is Biotin?
Biotin is a water-soluble vitamin in the B-vitamin group. It is also known as vitamin B7 and occasionally as vitamin H.
The body cannot produce enough biotin on its own and therefore depends on a regular supply. Biotin is found in numerous animal- and plant-based foods.
Certain gut bacteria can also produce biotin. However, it has not yet been conclusively established how much of it is actually absorbed in the human intestine and made available to the body.
What Biotin Does in Metabolism
Biotin acts as a cofactor for several enzymes. Without this cofactor, certain metabolic reactions cannot proceed normally.
Five biotin-dependent carboxylases are known in humans. They perform functions in fat, amino acid and carbohydrate metabolism.
Fatty Acid Metabolism
Biotin-dependent enzymes are involved in the production and processing of fatty acids.
Amino Acid Metabolism
Certain amino acids can only be fully metabolised with the help of biotin-dependent enzymes.
Glucose Metabolism
Biotin is involved in reactions that enable the body to provide metabolic precursors for glucose production.
Energy Production
Through its role in processing macronutrients, biotin contributes to normal energy-yielding metabolism.
Biotin does not provide energy itself. However, it enables enzyme reactions required for the normal utilisation of energy-providing nutrients.
The Five Biotin-Dependent Carboxylases
- Pyruvate carboxylase: involved in the provision of glucose and metabolic intermediates
- Acetyl-CoA carboxylase 1: involved in fatty acid synthesis
- Acetyl-CoA carboxylase 2: involved in regulating fatty acid metabolism
- Propionyl-CoA carboxylase: involved in breaking down certain amino acids and fatty acids
- 3-Methylcrotonyl-CoA carboxylase: involved in breaking down the amino acid leucine
These functions explain why biotin is much more than a nutrient for outward appearance.
Why Biotin Is Associated with Skin and Hair
Biotin has been shown to contribute to the maintenance of normal skin and hair. These authorised claims refer to the vitamin’s contribution to normal bodily functions.
Severe biotin deficiency may be associated with skin changes and hair loss, among other symptoms. Such a deficiency is rare with a balanced diet.
Important Context
The fact that biotin contributes to the maintenance of normal hair and skin does not automatically mean that additional high doses accelerate hair growth or further improve healthy skin. Such a beauty effect has not been sufficiently demonstrated scientifically in people without a biotin deficiency.
Authorised Claims for Biotin
Based on the scientific assessment, the following health claims may be used for biotin in the European Union:
- Biotin contributes to normal energy-yielding metabolism.
- Biotin contributes to normal macronutrient metabolism.
- Biotin contributes to the normal functioning of the nervous system.
- Biotin contributes to normal psychological function.
- Biotin contributes to the maintenance of normal hair.
- Biotin contributes to the maintenance of normal skin.
- Biotin contributes to the maintenance of normal mucous membranes.
There is no separate authorised health claim for “normal fat metabolism.” This area is already covered by the authorised term “macronutrient metabolism.”
Which Foods Contain Biotin?
Eggs
Cooked egg yolk is a natural source of biotin. Heating also deactivates the avidin found in egg white.
Nuts and Seeds
Almonds, peanuts, sunflower seeds and other nuts and seeds can contribute to biotin intake.
Organ Meats and Other Animal-Based Foods
Liver, meat, fish and certain dairy products contain varying amounts of biotin.
Plant-Based Foods
Legumes, whole grains, mushrooms and some vegetables also provide biotin.
When Can Biotin Deficiency Develop?
Clinically relevant biotin deficiency is rare. However, certain circumstances can increase the risk.
Large Amounts of Raw Egg White
Raw egg white contains avidin, a protein that binds biotin and can reduce its absorption. This is mainly relevant when large quantities are consumed regularly over a prolonged period.
Certain Medicines
Long-term use of certain anticonvulsants may be associated with lower biotin status. Medicines should only be changed under medical supervision.
Chronic Alcohol Consumption
Long-term heavy alcohol consumption can impair the absorption and utilisation of various nutrients, possibly including biotin.
Rare Metabolic Disorders
Inherited disorders such as biotinidase deficiency can impair the recycling of biotin and require medical treatment.
Antibiotic treatment alters the composition of the gut microbiota. However, there is insufficient evidence that this can cause a relevant biotin deficiency in otherwise healthy people.
Potential Importance with Age
Biotin-dependent enzymes remain essential for normal energy-yielding and macronutrient metabolism at every stage of life.
Diet, appetite, digestion and medication use can change with age. This may make it more difficult to obtain all necessary nutrients reliably.
However, there is no evidence that additional biotin improves metabolic flexibility, slows ageing or extends lifespan when biotin status is already adequate.
Who Needs a Reliable Supply?
An adequate supply of biotin is relevant for everyone. Most healthy adults can meet their needs through a varied diet.
People whose diets are very restricted, who take certain medicines over the long term or who have a condition that affects nutrient absorption should pay particular attention.
Exercise, occasional alcohol consumption or a previous course of antibiotics do not, by themselves, demonstrate an increased need for biotin.
What Vitamin B7 Does Not Replace
A Balanced Diet
Alongside biotin, a varied diet provides many other nutrients that are important for the skin, hair, nervous system and metabolism.
Medical Investigation of Underlying Causes
Hair loss, skin changes or persistent fatigue can have many causes and should be medically assessed if pronounced.
A Healthy Lifestyle
Sleep, physical activity, stress management and an energy intake tailored to individual needs remain important foundations for well-being and normal bodily functions.
Important Information About Laboratory Tests
Higher doses of biotin can interfere with certain laboratory tests.
Tests for thyroid values, hormones and troponin may be affected, among others. Troponin is measured when a heart attack is suspected.
Before a blood test, tell your doctor and the laboratory that you are taking a supplement containing biotin. Do not stop taking a supplement on your own; discuss the necessary steps with a healthcare professional.
Safety Information
- Biotin is generally well tolerated in commonly used amounts.
- The product’s recommended daily intake should not be exceeded.
- Healthcare professionals must be informed of biotin use before blood tests.
- If you have an existing medical condition or take medication, seek medical advice if in doubt.
- The use of higher-dose products during pregnancy and breastfeeding should be discussed with a healthcare professional.
Conclusion
Biotin is much more than a beauty nutrient. As a cofactor for five carboxylases, it is involved in fundamental reactions in energy-yielding and macronutrient metabolism.
Vitamin B7 also contributes to the normal functioning of the nervous system, normal psychological function, and the maintenance of normal skin, hair and mucous membranes.
Severe deficiency is rare with a balanced diet. Additional high doses do not automatically produce more beautiful hair or better skin in people whose biotin status is already adequate.
It is especially important always to disclose the use of biotin-containing supplements before medical laboratory tests.
Vitamin B7 in Unlock Tomorrow
Unlock Tomorrow combines vitamin B7 with six other carefully selected nutrients.
Unlock Tomorrow – Formula OverviewNote: Replace href="#" with the URL of the overview article.
Sources
- EFSA: Scientific Opinion on the Substantiation of Health Claims Related to Biotin
- Commission Regulation (EU) No 432/2012 – Authorised Health Claims
- FDA: Biotin May Interfere with Laboratory Tests
Food supplements should not be used as a substitute for a balanced and varied diet and a healthy lifestyle. Do not exceed the recommended daily intake. Keep out of reach of young children.
This article is for informational purposes only and does not constitute medical advice. If you have any health concerns, please consult a qualified healthcare professional.
