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Biotin

life science Maturity 11-13 Next article →

Biotin is a vital micronutrient belonging to the B vitamin group. It is also known by the names vitamin B7 or vitamin H. This substance is found within every living cell. When scientists isolate biotin, it appears as a white, needle-like crystalline solid. It is a heterocyclic compound, which means it has a ring structure. Specifically, it contains a sulfur-containing tetrahydrothiophene ring fused to a ureido group. A C5-carboxylic acid side chain is also attached to this ring. This unique chemical structure allows biotin to perform essential tasks in living organisms.

Biotin
Biotin

In the human body, biotin acts as a cofactor for several enzymes. A cofactor is a molecule that helps an enzyme function correctly. Biotin specifically serves as a coenzyme for five different carboxylase enzymes. These enzymes are responsible for carboxylation reactions, which involve carrying carbon dioxide. Biotin helps with the catabolism of amino acids and fatty acids. It also aids in the synthesis of fatty acids and a process called gluconeogenesis. This is how the body creates glucose. Furthermore, biotinylation of histone proteins helps maintain chromatin stability and gene expression.

Biotin
Biotin

To use biotin, the body must first absorb it from food. Biotin in food is usually bound to proteins. Digestive enzymes break these proteins down into smaller pieces called peptides. An intestinal enzyme called biotinidase then frees the biotin in the small intestine. Once free, it is absorbed. The transport across the jejunum is faster than across the ileum. A transporter called the sodium-dependent multivitamin transporter, or SMVT, moves biotin into the liver. Interestingly, the microbiota in the large intestine can also synthesize biotin. This bacteria-made biotin is often in a free form that the body can absorb.

Biotin
Biotin

Humans require different amounts of biotin depending on their age and life stage. The US National Academy of Medicine sets adequate intakes, or AIs, for these needs. For infants aged 0 to 6 months, the AI is 5 μg/day. For children aged 4 to 8 years, it is 12 μg/day. Adults aged 19 and older require 30 μg/day. Pregnant females also need 30 μg/day, while lactating females need 35 μg/day. In Europe, the EFSA sets slightly different values. They recommend 40 μg/day for adults and 45 μg/day for those who are breastfeeding.

Biotin
Biotin

We obtain biotin from many different types of food. Beef liver is a very rich source, providing 31 μg per 100 g. Whole eggs provide 10 μg per 100 g. Pink salmon canned in water provides 5 μg per 100 g. Pork chops and hamburger patties each provide 4 μg per 100 g. Even roasted sunflower seeds provide 3 μg per 100 g. Biotin is very stable at room temperature. It is not destroyed by the process of cooking. Most people in Western populations consume between 35 and 70 μg/day.

Biotin
Biotin

While biotin deficiency from diet is rare, some people have genetic disorders. One common disorder is biotinidase deficiency. This occurs when a person lacks the enzyme needed to recycle biotin from biocytin. Without this recycling, the body cannot use its biotin stores effectively. Another condition is multiple carboxylase deficiency, which involves defects in enzymes like holocarboxylase synthetase. These defects prevent cells from using biotin for chemical reactions. In the United States, doctors began screening newborns for biotinidase deficiency in 1984. This testing is vital because untreated deficiency can be fatal.

Biotin
Biotin

Managing biotin levels involves both natural processes and medical care. When we eat biotin, the body absorbs what it needs. Any extra is eventually excreted into the urine. Biotin can be broken down through two different metabolic pathways. One path creates bisnorbiotin, while the other creates biotin sulfoxide. For those with genetic deficiencies, lifelong dietary supplements are necessary. For profound biotinidase deficiency, doctors may prescribe 5 to 20 mg of biotin per day. This treatment can help resolve symptoms like seizures within hours or days.

Biotin
Biotin
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