Vitamin B8: benefits, dosage, contraindications
Other name(s)
Biotin, vitamin B7, vitamin H
Family or group:
Vitamins
Indications
Scoring methodology
EFSA approval.
Vitamin B8 deficiency ✪✪✪✪✪
Biotin deficiency is found in generalized hypovitaminoses, where all B vitamins are lacking, and often others as well, such as after antibiotic therapy or during aberrant diets (for example, where only egg whites are consumed). Non-specific clinical signs may be observed such as scaly dermatitis with atrophy of sebaceous glands and hair follicles, anorexia, nausea, and even neurological signs. In cases of biotin deficiency, a dose of up to 10 mg per day has been used.
Posologie
By mouth
10 mg
Adults
Type 2 diabetes ✪✪✪✪✪
Clinical research shows that taking 2 mg of biotin in combination with 600 mcg of chromium (as chromium picolinate) can lower blood glucose and hemoglobin A1C (glycated hemoglobin) levels in patients with type 2 diabetes who are poorly controlled on oral antidiabetic therapy. However, taking biotin alone does not appear to affect glucose levels in patients with type 2 diabetes.
Posologie
Oral
2 mg
Adults
Synergies
Chromium picolinate and biotin combination improves glucose metabolism in treated, uncontrolled overweight to obese patients with type 2 diabetes.
The effect of chromium picolinate and biotin supplementation on glycemic control in poorly controlled patients with type 2 diabetes mellitus: a placebo-controlled, double-blinded, randomized trial.
Multiple sclerosis ✪✪✪✪✪
Clinical research shows that daily intake of biotin at 100 to 300 mg can improve visual acuity and paraparesis (mild paralysis of the lower limbs) in some patients with progressive multiple sclerosis. A dose of 300 mg per day appears to be more effective. Treatment may take up to 8 months before a clinical improvement is seen. Furthermore, biotin does not seem to prevent disease relapse.
Posologie
Oral
100 - 300 mg
8 - months
Adults
Hair loss ✪✪✪✪✪
Some clinical evidence has shown that biotin promotes hair regrowth in children with alopecia areata. It is a sudden, non-scarring loss of scalp and body hair in circumscribed areas, affecting genetically susceptible individuals exposed to poorly defined triggering environmental factors. nnA dose of 20 mg per day of biotin was used orally in combination with zinc aspartate 100 mg/day and topical clobetasol propionate 0.025% for one year in children aged 9 years.nn
Posologie
Oral
20 mg
1 - years
Children
Synergies
Brittle nails ✪✪✪✪✪
Clinical evidence shows that taking 2.5 mg of biotin per day orally for 1.5 to 15 months increases nail thickness by 25% and reduces their splitting in women with brittle nails or onychoschizia (nail fissuring and splitting).nn
Posologie
Oral
2.5 mg
15 - months
Women
Properties
Essential
Biotin is an essential vitamin, found in foods bound to proteins and cleaved by the enzyme biotinidase. Biotin is stored in mitochondria and acts as a coenzyme in bicarbonate-dependent carboxylation reactions. Biotin-containing enzymes are involved in gluconeogenesis, fatty acid synthesis, propionate metabolism, and leucine catabolism in mammals. Furthermore, pyruvate carboxylase, a key enzyme of gluconeogenesis, is a biotin-dependent enzyme. A decrease in the activity of this enzyme during biotin deficiency can lead to an accumulation of pyruvate or a decrease in aspartate concentration. European health authorities (EFSA, European Food Safety Authority and the European Commission) consider that products containing vitamin B8 may claim to contribute to normal energy-yielding metabolism, the normal functioning of the nervous system, the maintenance of normal hair, skin and mucous membranes, normal metabolism of food and normal mental function.
Usages associés
Hypoglycemic
In both diabetic and non-diabetic subjects, blood glucose decreases when plasma and tissue concentrations of biotin increase. This effect is greater in diabetic subjects. Animal research suggests that biotin reduces blood glucose levels by stimulating the expression of hypoglycemic enzymes such as insulin, pancreatic glucokinase and hepatic glucokinase, and by inhibiting the expression of hepatic phosphoenolpyruvate carboxykinase (an enzyme that promotes glucose production).
Usages associés
Hypolipidemic
In animals, some evidence suggests that biotin can affect lipid metabolism by decreasing the activity of acetyl-CoA carboxylase 2 (ACC2), an enzyme that regulates fatty acid oxidation. The decreased activity of ACC2 appears to increase fatty acid oxidation by lowering malonyl-CoA levels.
Effect on fertility
Biotin deficiency appears to be associated with a disorder of spermatogenesis and a decrease in sperm count. In animals, biotin deficiency is associated with decreased testicular and serum testosterone levels. Treatment with biotin in combination with testosterone appears to normalize spermatogenesis in these animals.
Neurological
High doses of biotin seem to improve multiple sclerosis symptoms by activating the Krebs cycle in demyelinated nerve cells and by stimulating the synthesis of fatty acids necessary for myelin production.
Usages associés
Safe dosage
Infant up to 12 months: 6 µg
Child from 1 to 3 years: 20 µg
Child from 4 to 10 years: 25 µg
Child from 11 to 17 years: 35 µg
Adult 18 years and older: 40 µg
Lactating woman 18 years and older: 45 µg
Pregnant woman 18 years and older: 40 µg
Interactions
Médicaments
Cytochrome P450 substrate: moderate interaction
In vitro, biotin supplementation induces the activity of cytochrome P450 1B1 (CYP1B1). Theoretically, biotin may decrease the levels of drugs metabolized by this enzyme.
