By Barbara E. Amsler, MD
Biotin, a recently discovered B vitamin, is generally referred to by its name rather than B7. It is very stable and primarily produced in our intestinal tract by Lactobacillus. It was discovered when symptoms of deficiency developed in those consuming large quantities of raw eggs (about 30% of the diet). Egg white contains a protein called “avidin” which can bind to biotin and inhibit its absorption. If the egg is cooked, the avidin is destroyed and biotin is absorbed.
Biotin forms a coenzyme used to make the components of DNA and RNA and therefore plays a role in gene expression. It is also important in the production of fatty acids, the metabolism of fat and the incorporation of amino acids into proteins.
No toxicity of biotin is known, even at high amounts of supplementation. Excesses of this vitamin are readily excreted in the urine.
Although rare, deficiency states can develop in people treated for prolonged periods with antibiotics or on raw egg diets. It can be diagnosed by measuring the urinary excretion of 3-hydroxyisovaleric acid after a leucine challenge.
Deficiency states are common in infants under 6 months of age because they initially lack the bacteria to make it. The symptoms manifest as “cradle cap”, a dermatitis of the scalp characterized by excessive oiliness and white-yellow scales. This is also accompanied by muscle weakness, hair loss and fatigue. Supplementing 2-10 micrograms of biotin daily is usually sufficient to return levels to normal and improve symptoms.
Adults develop similar symptoms with biotin deficiency. Dermatitis, dry, scaly skin, hair loss, muscle weakness, irritated eyes, numbness, depression, hallucinations, nausea and lack of appetite are common symptoms. With prolonged deficiency, there may be an increase in cholesterol, a decrease in the blood count (anemia) and changes in the EKG.
Although biotin is found in our food, it is usually in very small amounts. The best food sources of biotin include liver, soybeans, brewer’s yeast, nuts (peanuts, walnuts, pecans, and almonds), oatmeal, cauliflower and mushrooms.
The daily recommended intake of biotin is 30 micrograms for both men and women. However, higher doses have been previously recommended. Healthy levels are likely somewhere between 30 – 100 micrograms daily.
Healthy Habits for Biotin:
1) Those taking antibiotics, especially for prolonged times, should supplement Biotin and take a probiotic to restore the normal bacteria of the bowel. Sulfa drugs are particularly prone to affecting the biotin producing bacteria.
2) Those on anti-seizure medications (valproic acid, phenobarbital, gabapentin) should take supplemental biotin. These medications interfere with biotin absorption.
3) Studies suggest that diabetics may benefit from additional biotin (200 – 400 micrograms daily), as it appears to help reduce blood sugar.