Medical Nutrition Therapy Nutrient
1. What is the nutrient?
Biotin is a B vitamin that is a co-enzyme involved in gluconeogenesis (formation of glucose
from excess amino acids, fats or other non-carbohydrate sources) and fat synthesis (used for
energy production). It is commonly found in egg yolk, peanut butter, liver, kidney, cauliflower,
and yeast.
2. What is the RDA/DRI for the nutrient?
There is no recommended dietary allowance (RDA) established for biotin, instead Adequate
Intake values are used, which are summarized in the table below.
Life-Stage
Infants
0-6 months
7-12 months
Children
1-3 years
4-8 years
Males
9-13 years
14-18 years
19-70+ years
Females
9-13 years
14-18 years
19-70+ years
Pregnancy
18+
Lactation
18+ years
AIs
micro g/d
5
6
8
12
20
25
30
20
25
30
30
35
3. How is the nutrient metabolized?
About half of biotin undergoes metabolism before excretion from the body. There are two
principal pathways of biotin catabolism that have been identified in mammals. The first being
that side chain of biotin is degraded by oxidation leading to the formation of bisboiotin methyl
ketones and tetranorbiotin methyl ketones, which appear in the urine.
The second pathway, the sulfur in biotin is oxidized leading to the formation of biotin Lsulfoxide, biotin D-sulfoxide, and biotin sulfone.
4. What are food sources of the nutrient?
The ultimate source of biotin appears to be de novo synthesis by bacteria, primitive eukaryotic
organisms such as yeast, molds, and algae and some plant species. Biotin is widely distributed in
natural foods, but the absolute content of even the richest sources is low when compared with the
content of most other water-soluble vitamins. Foods relatively rich in biotin include egg yolk,
liver and some vegetables.
5. What disease states alter the nutrients metabolism?
Although not considered a disease state, biotin has been shown to break down more rapidly
during pregnancy, resulting in a decline of an individual’s nutritional status.
It has also been shown in a few studies that biotin levels were significantly lower in patients with
non-insulin dependent diabetes mellitus than in non-diabetic subjects, and lower fasting blood
glucose levels were associated with higher blood biotin levels.
6. What are the tests or procedures to assess the nutrient level in the body?
Biotin levels may be assayed and the individuals’ blood and urine will be tested to check biotin
levels. In cases with confusing findings, laboratory studies including: serum ammonia levels,
urine ketones levels, quantitative plasma amino acid levels, plasma carnitine levels and a routine
serum chemistry panel may be run.
7. What is the drug –nutrient interactions?
There is no current evidence that biotin interacts with any medication, but there are some
medications, which may lower biotin levels, including antibiotics and anti-seizure medications.
Antibiotics used long-term my lower biotin levels by destroying the bacteria in the gut that
produces biotin. Anti-seizure medications may lower levels of biotin, causing a deficiency. In
many cases it is important to consult a doctor about supplements being used in accompaniment
with anticonvulsant medications.
8. How is the nutrient measured?
Biotin levels are measured in the units of micrograms.
9. What is the Upper Tolerable Limits?
Due to the lack of research on biotin, there is not sufficient data on which to base a Tolerable
Upper Intake Level for biotin.
10. What are the physical signs of deficiency?
Although it is rare for a deficiency to occur, it has been shown to result in cases of prolonged
intravenous feeding (parenteral feeds) without biotin supplementation and consumption of raw
egg white for a prolonged period.
Signs of a deficiency include:
 Hair loss
 Scaly red rash around eyes, nose, mouth and genital area
 Depression
 Lethargy
 Hallucination
 Numbness & Tingling of the extremities
11.What are physical signs of toxicity?
There are currently no reported incidents of biotin toxicity.
Resources:
http://www.ncbi.nlm.nih.gov/books/NBK114297/
http://umm.edu/health/medical/altmed/supplement/vitamin-h-biotin
http://lpi.oregonstate.edu/infocenter/vitamins/biotin/
http://www.nlm.nih.gov/medlineplus/druginfo/natural/313.html
Modern Nutrition in Health and Disease
Tabor’s Cyclopedic Medical Dictionary