If you've like many adults, you've probably taken a multivitamin every single day of your life. Think back to your childhood. Who can forget those days of fighting off other siblings just so you could get your favorite flavor of Flintstones Chewables?
As the years passed, you inevitably graduated to "big boy" vitamins, the non-chewable kind you have to swallow, because you were too "cool" for a kiddie
vitamin. But did you ever think about why you took a multivitamin
or what those vitamins do?
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Sure, you probably know what some of the more popular ones like Vitamin C, D, or B12 do in the body, but that's not why we're here today. We're here to champion the lesser known, "little guy" vitamins.
There's one in particular long overdue for its chance in the spotlight. This vitamin is not only good for your hair, skin, and nails, it's also a powerful ally in the war against diabetes.
We're talking about biotin.
If you've never heard of this vitamin before, don't worry, we've got everything you need to know about the essential nutrient.
What is Biotin?
Biotin (Vitamin B7) is an essential, water-soluble vitamin belonging to the B-Complex family of vitamins. Researchers first became aware of Biotin in 1927 when they isolated a growth factor in yeast, alongside the rest of the B vitamins, and thus was lumped in with the rest of the B-Complex family.
Biotin is synthesized from bacteria in the intestines and can also be found in a number of common foods, including egg yolks, liver, soybean and yeast. Grains, legumes and nuts also contain moderate amounts of biotin, while fruits and vegetables (except mushrooms and cauliflower) are considered poor sources of biotin. 
Biotin has an elimination half-life slightly less than 2 hours, which means your body can't build a massive store of it like it can with fat-soluble vitamins (A, D, E, & K). So, you need to make sure you're getting a regular dose of biotin from your diet (or multi) daily.
As far as risk for deficiencies of the vitamin go, biotin deficiency in exceptionally humans is rare. Infants with a genetic disorder known as congenital biotinidase enzyme deficiency can be more prone to biotin deficiencies, as are people who eat large quantities of raw eggs.
Raw egg whites contain avidin, a protein which binds to biotin and inhibits its absorption. However, cooking eggs renders avidin inactive, which means you're free and clear to continue pounding those eggs each morning, provided they're cooked in some form.
Should an adult present with a biotin deficiency, they may experience thinning of the hair, loss of hair color, and scaly, red rashes around the mouth, nose, and eyes. Extreme deficiencies of biotin can lead to lethargy, hallucination, depression, and even paresthesias (burning or prickling sensations) of the extremities.
What Does Biotin Do?
Biotin primarily is the coenzyme for various carboxylases in the body (Acetyl CoA carboxylase, pyruvate carboxylase, propionyl CoA carboxylase, B methylcrotonyl CoA carboxylase), essentially making it a "CO2 carrier" of sorts. These biotin-containing enzymes play an essential role in the body's metabolic pathways, including gluconeogenesis, fatty acid biosynthesis, and the catabolism (breakdown) of some BCAAs. 
Basically, without biotin, your body's metabolism is going to come to a grinding halt.
OK, so Biotin is needed for basic survival, but are there any other tangible benefits to supplementing with biotin (i.e. in the form of a multivitamin)?
You bet, and that's what we're covering next!
Benefits of Biotin
As stated up top, biotin is required for carbohydrate metabolism, but it's also important to your body's ability to utilize the glucose derived from those tasty carbs you crush post workout.
Specifically, biotin supports glucose utilization by restoring glucokinase activity. Glucokinase is a crucial enzyme in utilizing glucose, and its actions are depressed in biotin deficient individuals, diabetics, those who fast. Research has shown that biotin supplementation can promote glucokinase activity via a cGMP-mediated mechanism. 
Research has shown that biotin deficient mice have defective insulin sensitivity. However, supplementation with biotin resulted in improved insulin response to a fasted oral glucose tolerance test, as well as a 70% increase in glucokinase. 
Type II Diabetes
Type II Diabetics have been shown to have reduced biotin concentrations in the body, which can impair glucose metabolism, utilization, and insulin sensitivty. Clinical trials using only biotin have shown mixed results with diabetics; however, when biotin is combined with chromium, the combination has been shown to be more effective in lowering blood sugar levels. 
Biotin has also been found to relieve diabetic neuropathy, and is recommended for the prevention and management of peripheral neuropathy. 
Type I Diabetes
Most studies regarding Diabetes are typically done on Type II Diabetics, especially in regards to controlling blood glucose levels and insulin sensitivity. However, one piece of research conducted on Type I Diabetics found that howed biotin supplementation in conjunction with insulin improved glycemic control and decreased plasma lipids concentrations compared to the insulin group receiving placebo. 
Biotin's role in promoting healthy skin isn't clearly understood, but researchers seem to point to the vitamin's role in fat metabolism in promoting healthy skin. Additionally, since biotin deficiency is known to lead to scaly rashes, supplementing with biotin may help support a clear complexion. 
Biotin is often promoted as a worthwhile supplement to increase hair growth and support a luscious, thick head of hair. However, little evidence supports these marketing claims. While it is true that a biotin deficiency can lead to thinning of the hair, research has shown that only people truly deficient in the vitamin benefit from its hair growth promoting properties. 
Not only is biotin promoted as helping hair grow, but it's also touted as a cure-all for brittle, nasty nails. It turns out research supports this claim, as oral supplementation of 2.5mg biotin over the course of at least six months increased nail thickness in test subjects by 25%. 
Multiple Sclerosis (MS) is an autoimmune disease that destroy the myelin sheath, the protective covering of nerve fibers in the brain, spinal cord and eyes. One pilot study found that high doses of biotin showed improvement in over 90% of patients.
More research on biotin's role in treating MS, and currently there are two other trials underway whose results are awaiting publication.
How Much Biotin is Needed?
The Institute of Medicine has set the daily Adequate Intake (AI) for biotin men, women and children of all ages. For men and women between the ages of 19 - 70, the recommended daily intake of biotin is 30mcg. 
Any Potential Side Effects?
Biotin is generally regarded as nontoxic since it is water-soluble, doesn't accumulate in the body, and is easily removed from the system via urine. There is no stated maximum daily dose for biotin, and does not have any known side effects.
Biotin is a little known but might B-Vitamin that plays a vital role in protein, carb, and fat metabolism. Due to its key interactions with glucose and insulin, biotin represents a possible source of treatment for those with Type II Diabetes or blood sugar problems. However, most of the potential health benefits (longer hair, better skin, etc.) are based on weak evidence at best.
Still though, biotin is essential for your skin, hair and nails, as well as your overall health. If you're not going to supplement with a multivitamin, just make sure you're eating a well-rounded, nutrient dense diet, to ensure your biotin levels are always topped off.
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