Main functions

• Synthesis of fatty acids, amino acids and glucose
• Energy metabolism
• Excretion of by-products from protein metabolism
• Maintenance of healthy hair, toenails and fingernails

Biotin plays a key role in the metabolism of lipids, proteins and carbohydrates. It acts as a critical coenzyme of four enzymes. Biotin plays a special role in enabling the body to use blood glucose as a major source of energy for body fluids, in DNA replication and transcription arising from its interaction with nuclear proteins. It owes its reputation as the “beauty vitamin” to the fact it activates protein/amino acid metabolism in the hair roots and fingernail cells.

Sources

Biotin is widely available in most foods but at very low levels. Its richest sources are yeast, liver and kidney. Egg yolk, soybeans, nuts and cereals are also good sources. 100 g of liver contains approximately 100 µg biotin, whereas most other meats, vegetables and fruits only contain approximately 1 µg biotin /100 g. In experiments, biotin bioavailability has been shown to vary considerably, 5%-62%, and lowest in cereals.

Biotin is absorbed unchanged in the upper part of the small intestine. The colon is also able to absorb biotin via an analogue transport mechanism. Once absorbed, biotin is distributed to all tissues. The liver and retinal tissues are the main storage places. Human biotin deficiency is rare. This is probably due to biotin being synthesized by beneficial bacteria in the human intestinal tract.

Deficiency symptoms

• anorexia
• nausea
• vomiting
• glossitis
• depression
• dry scaly dermatitis
• conjunctivitis and ataxia
• loss of hair color and hair loss (alopecia)

Signs of biotin deficiency have been demonstrated in volunteers consuming a biotin-deficient diet together with large amounts of raw egg whites. After 3-4 weeks they developed a fine dry scaly desquamating dermatitis, frequently around the eyes, nose, and mouth. After ten weeks on the diet, they were fatigued, depressed and sleepy, with nausea and loss of appetite. Muscular pains, hyperesthesia and paresthesia occurred, without reflex changes or other objective signs of neuropathy. Volunteers also developed anaemia and hypercholesterolaemia. Liver biopsies in sudden infant death syndrome babies reveal low biotin levels. Most of the affected infants were bottle-fed.

At risk

• patients maintained on total parenteral nutrition
• people who eat large amounts of raw egg white
• haemodialysis patients
• diabetes mellitus
• long-term anticonvulsant therapy
• biotinidase deficiency or holocarboxylase synthetase (HCS) deficiency (genetic defects)
• malabsorption, including short-gut syndrome
• pregnancy
• birth control pills/ synthetic HRT therapy
• obesity
• cradle cap/Uncomable hair syndrome in childeren

Large doses of biotin may be given to babies with a condition called infantile seborrhea or to patients with genetic abnormalities in biotin metabolism. A large number of reports have shown a beneficial effect of biotin in infant seborrheic dermatitis and Leiner’s disease .

Substances that Interfere with biotin

• Caffeine
• Sucrose
• estrogens
• Pharmaceutical Antibiotics (especially sulfonamides) and other Sulfur-containing pharmaceutical drugs – destroy the beneficial intestinal bacteria that produce endogenous biotin.
• Antiepileptic Drugs
• Proteins
• Avidin (a Glycoprotein found in raw egg whites) binds with biotin in the stomach, decreasing the absorption of biotin.
• Alcohol (ethanol) may deplete the body’s reserves of biotin.

Well we have reached the end of known B vitamins; I hope you now are taking a good B-complex to combat stress, hair loss, birth defects, heart disease and more… To your good health.

Tammera Karr has a private practice in Douglas County Oregon. You can read other articles written by Tammera in the reading room of her website or contact her at www.yourwholenutrition.com