Biotin deficiency is rare because biotin is found widely in foods and synthesized by gut bacteria. Deficiencies can be caused by antagonists or inadequate intake from mother's milk or intravenous nutrition. Symptoms include skin rashes, tongue inflammation, loss of appetite, nausea, depression, and lipid metabolism issues. One case was caused by a child eating raw eggs for six years, as the protein avidin in raw eggs binds biotin and prevents absorption. Marginal biotin levels may play a role in sudden infant death syndrome. While biotin toxicity is very low, excess biotin may help reduce diabetes symptoms.

1. Biotin deficiency and
toxicity
Domina Petric, MD

2. Biotin deficiency
I.
April 19, 2018
Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
2

3. Introduction
• Because biotin is widespread
among foods and is synthesized
by the intestinal microflora,
simple deficiencies of biotin are
rare.
• Biotin deficiency can be induced
by certain antagonists.
April 19, 2018
Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
3

4. Clinical deficiency
• Few cases of biotin deficiency have
been reported.
• Most of these have involved
nursing infants whose mothers’
milk contained inadequate
supplies of the vitamin or
patients receiving incomplete
parenteral nutrition.
April 19, 2018
Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
4

5. Clinical deficiency
• One case involved a child fed with
raw eggs for 6 years.
• The signs and symptoms included
dermatitis, glossitis, anorexia,
nausea, depression, hepatic
steatosis and hypercholesterolemia.
• The impairments of lipid metabolism
respond to biotin therapy.
April 19, 2018
Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
5

6. Raw eggs
Raw eggs contain AVIDIN.
Avidin antagonizes biotin by forming with the vitamin
a noncovalent complex that is resistant to pancreatic
proteases, thus preventing the absorption of biotin.
The avidin-biotin complex is
unstable to heat.
Heating to at least 100°C denatures the protein
and releases biotin available for absorption.
April 19, 2018
Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
6

7. Clinical deficiency
Marginal biotin status may play a
role in the etiology of sudden infant
death syndrome (SIDS), which
occurs in human infants at 2-4
months of age.
Studies have shown that infants
who died of SIDS had significantly
lower hepatic concentrations of
biotin than did infants who died of
unrelated causes.
April 19, 2018
Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
7

8. Subclinical deficiency
Incidence of low circulating biotin
levels has been found to be
substantially greater among
alcoholics than the general
population.
Relatively low levels of biotin (versus
healthy controls) have also been reported
in the plasma or urine of patients with
partial gastrectomy or other causes of
achlorhydria, burn patients, epileptics,
elderly individuals and athletes.
April 19, 2018
Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
8

9. Subclinical deficiency
Pregnant women may
experience marginal
biotin deficiency due to
increased catabolism of
the vitamin.
April 19, 2018
Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
9

10. Biotin toxicity
II.
April 19, 2018
Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
10

11. Biotin toxicity
• The toxicity of biotin appears to be
very low.
• No cases have been reported of adverse
reactions by humans to high levels (doses
as high as 200 mg orally or 20 mg iv.) of
the vitamin, as are used in treating
seborrheic dermatitis in infants or inborn
errors of metabolism.
April 19, 2018
Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
11

12. Biotin toxicity
Biotin excess appears to
provide effective therapy to
reduce the diabetic state,
lowering postprandial
glucose and improving
glucose tolerance.
April 19, 2018
Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
12

13. Literature
• Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
April 19, 2018 13