Biotin (Vitamin B8)

Biotin is the most stable of B vitamins. It is commonly found in two forms: the free vitamin and the protein-bound coenzyme form called biocytin. Biotin is absorbed in the small intestine, and it requires digestion by enzyme biotinidase, which is present in the small intestine. Biotin is synthesized by bacteria in the large intestine, but its absorption is questionable. Biotin containing coenzymes participate in key reactions that produce energy from carbohydrate and synthesize fatty acids and protein.

Biotin deficiency was first recognized because of the effects of a protein called avidin, which is found in raw egg white. Avidin binds and inactivates biotin. Therefore, consumption of raw whites is of concern due to the risk of becoming biotin deficient. Cooking the egg white, however, destroys avidin.

Biotin can be made by gut bacteria and absorbed from the large bowel, so that not all biotin needs to be obtained from food. Theoretically, antibiotics that affect gut bacteria could reduce the amount of biotin available.

Infants may be at risk from biotin deficiency, which shows up as a 'seborrhoeic dermatitis' that responds to biotin. Also, some infants have a metabolic disorder requiring extra biotin. There has been some suggestion that 'cot deaths' or the sudden infant death syndrome may be due, in some cases, to an inadequate intake of biotin.

The biotin in human milk averages about 10 micrograms per 1000 kilocalories (4200 kilojoules) and in infant formulae is usually at least 15 micrograms per 1000 kilocalories. However, a higher concentration of biotin may be preferable for infant formulae because nutrients can be more biologically available to the infant from human milk than from infant formulae.

Common food sources	Liver, kidney, egg yolk, milk, whole grains, nuts and seeds, most fresh vegetables, also made by intestinal bacteria.
Major functions	Helps release energy from carbohydrates; aids in fat synthesis.
Recommended daily intake	Infants: 5 - 6 microg Children: 8 - 12 microg Adolescents: 20 - 25 microg Men & Women: 30 microg Pregnant Women: 30 microg Lactating Women: 35 microg
Deficiency symptoms	Uncommon under normal circumstances; Dermatitis, fatigue; loss of appetite, hair loss (alopecia), nausea, vomiting; depression; muscle pains; anemia, neurological disorders, impaired growth.
Overconsumption symptoms	None
Stability in foods	Biotin is sensitive to air and oxygen and also to alkaline conditions.

Vitamin B8 Food Chart

Cereals, Cakes, Biscuits, Desserts	Content(milligram per 100 grams)
Yeast, dried	200
Bran, wheat	14
Bread, brown	3
Crispbread, rye	7
Bread, white	1
Cake, fruit	4
Chapati	2
Cake, sponge	8
Pancake	5
Rice, boiled	1
Pizza, Cheese & Tomato	3
Custard	2
Custard tart	4
Jam tart	1
Milk pudding	0.1
Porridge	2
Triffle	3

Egg And Chesse Dishes	Content(milligram per 100 grams)
Egg,boiled	25
Egg,fried	25
Omelette	22
Poached	25
Raw	25
Scrambled	20
Macaroni cheese	1
Cauliflower cheese	2
Cheese soufflé	10

Fish and Seafoods	Content(milligram per 100grams)
Roe, Cod, fried	15
Salmon, canned	5
Sardine, canned	4
Tuna, canned in oil	3
Oysters, raw	10
Lobster, boiled	5
Cod, baked	3
Cod, poached	3
Cod, steamed	3

Meat and Meat Products	Content(milligram per 100 grams)
Chicken, boiled	4
Chicken livers, fried	170
Ham, canned	1
Beef, canned	2
Beefburger	2
Backon, fried	2
Lamb, brain, boiled	3
Lamb, heart, roast	8
Lamb, kidney, fried	42
Lamb, Liver, fried	41
Pork, chop	2
Pork, Leg roast	2
Sausage, liver	7
Salami slices	3
Pork, fried/grilled	3

Milk and Milk Products	Content(milligram per 100 grams)
Milk, cow's,cond,skim,sweet	4
Dried,skimmed	16
Dried,whole	10
Goat's	2
Human	0.7
Ice-cream	0.2
Cheese, Camembert	5
Cheddar	2
Parmesan	2

Vegetables	Content(milligram per 100 grams)
Broccoli	0.3
Cauliflower, raw	2
Cauliflower, boiled	1
Cabbage, raw	0.1
Carrots, raw	0.6
Carrots, boiled	0.4
Beans, French, boiled	1
Asparagus, boiled	0.2
Celery Raw	0.1
Cucumber slices	0.4
Lettuce raw, leaves	0.7
Onions, raw	0.9
Onions, boiled	0.6
Parsley, spring	0.4
Peas, canned	0.4
Pumpkin	0.04
Radish	0.4
Spinach leaves	0.1

Fruits	Content(milligram per 100 grams)
Apple	0.2
Avocado pear	3
Blackberries	0.4
Cherries	0.3
Currants, black	2
Grapes	0.2
Grapefruit	0.5
Lemon slices	0.5
Juice	0.3
Orange	0.8
Peach	0.2
Pear	0.1
Plums	0.1
Raspberries	2

Nuts	Content(milligram per 100 grams)
Almond	0.4
Chestnuts	1
Walnut	2

Sauces and condiments	Content(milligram per 100 grams)
Chutney, tomato	1
Mayonnaise	12
Tomato sauce	2

Beverages	Content(milligram per 100 grams)
Beer	0.5

---

Audio