By Hrefna Palsdottir
Biotin is a water-soluble B-vitamin that helps your body convert food into energy.
It is especially important during pregnancy and breastfeeding.
Biotin is one of the B-vitamins, also known as vitamin B7.Shutterstock
This article explains everything you need to know about biotin, including its seven main health benefits.
What Is Biotin?
Biotin is one of the B-vitamins, also known as vitamin B7.
It was once called coenzyme R and vitamin H. The H stands for Haar und Haut, which is German for hair and skin.
Biotin is water-soluble, which means the body doesn't store it. It has many important functions in the body.
It's necessary for the function of several enzymes known as carboxylases. These biotin-containing enzymes participate in important metabolic pathways, such as the production of glucose and fatty acids (1).
A commonly recommended intake is 5 mcg (micrograms) per day in infants and 30 mcg in adults. This goes up to 35 mcg per day in breastfeeding women.
Biotin deficiency is fairly rare. However, some groups—such as pregnant women—may experience it in mild forms (2).
Eating raw eggs may also cause a deficiency, but you would need to eat a lot of eggs for a very long time. Raw egg whites contain a protein called avidin, which binds to biotin and prevents its absorption. Avidin is inactivated during cooking.
Summary: Biotin is a water-soluble B-vitamin that's important for energy metabolism. Deficiency is quite rare, although it has been associated with the long-term consumption of raw eggs.
1. Plays a Key Role in Macronutrient Metabolism
Biotin is important for energy production. For example, several enzymes need it to function properly (1).
These enzymes are involved in carb, fat and protein metabolism. They initiate critical steps in the metabolic processes of these nutrients.
Biotin plays a role in:
- Gluconeogenesis: This metabolic pathway enables glucose production from sources other than carbs, such as amino acids. Biotin-containing enzymes help initiate this process (3).
- Fatty acid synthesis: Biotin assists enzymes that activate reactions important for the production of fatty acids (4).
- The breakdown of amino acids: Biotin-containing enzymes are involved in the metabolism of several important amino acids, including leucine (5).
Summary: Biotin assists in energy production. It supports a number of enzymes involved in the metabolism of carbs, fats and protein.
2. May Help Brittle Nails
Brittle nails are weak and easily become chipped, split or cracked.
It's a common condition, estimated to affect around 20 percent of the world's population (6).
Biotin may benefit brittle nails (7).
In one study, 8 people with brittle nails were given 2.5 mg of biotin per day for 6 to 15 months. Nail thickness improved by 25 percent in all 8 participants. Nail splitting was also reduced (8).
Another study of 35 people with brittle nails found 2.5 mg of biotin per day for 1.5 to 7 months improved symptoms in 67 percent of participants (9).
However, these studies were small and more research is needed.
Summary: Brittle nails are fragile and easily become split or cracked. Biotin supplements may help strengthen the nails.
3. Good for Your Hair
Biotin is often associated with increased hair growth and healthier, stronger hair.
Surprisingly, there is very little evidence to support this.
While it is often marketed as an alternative treatment for hair loss, only people with an actual biotin deficiency get significant benefit from supplementing (11).
Whether it improves hair growth in healthy people has yet to be determined.
Summary: Biotin is claimed to promote hair growth and healthy hair, but the evidence is weak. However, deficiency has been linked to hair loss and those who are actually deficient may benefit from supplementing.
4. Plays a Role During Pregnancy and Breastfeeding
In fact, it has been estimated that up to 50 percent of pregnant women may develop a mild biotin deficiency. This means that it may start to affect their well-being slightly, but isn't severe enough to cause noticeable symptoms (14, 15, 16).
Deficiencies are thought to occur due to the faster biotin breakdown within the body during pregnancy (17).
Nevertheless, remember to always consult your doctor or dietitian/nutritionist before taking supplements during pregnancy and while breastfeeding.
Summary: If you're pregnant or breastfeeding, your biotin requirements may go up. Up to 50 percent of women may get less of this vitamin than they need during pregnancy.
5. May Lower Blood Sugar Levels in Diabetics
Type 2 diabetes is a metabolic disease. It's characterized by high blood sugar levels and impaired insulin function.
Researchers have studied how biotin supplements affect blood sugar levels in type 2 diabetics.
Some evidence shows biotin concentrations in blood may be lower in people with diabetes, compared to healthy individuals (21).
Summary: When combined with chromium, biotin may help lower blood sugar levels in people with type 2 diabetes.
6. May Benefit the Skin
Biotin's role in skin health may be related to its effect on fat metabolism, which is important for the skin and may be impaired when biotin is lacking (27).
There is no evidence showing that biotin improves skin health in people who aren't deficient in the vitamin.
Summary: People with a biotin deficiency may experience skin problems. However, there is no evidence that the vitamin has benefits for skin in people who aren't deficient.
7. Affects Multiple Sclerosis
Multiple sclerosis (MS) is an autoimmune disease. In MS, the protective covering of nerve fibers in the brain, spinal cord and eyes is damaged or destroyed (31).
This protective sheath is called myelin and biotin is thought to be an important factor in producing it (32).
A pilot study in 23 people with progressive MS tested the use of high doses of biotin. More than 90 percent of participants had some degree of clinical improvement (33).
While this finding needs much more study, at least two randomized controlled trials have been carried out in people with progressive MS. The final results have not been published, but the preliminary results are promising (34, 35, 36).
Summary: High biotin doses hold promise for treating multiple sclerosis, a serious disease that affects the central nervous system.
Which Foods Contain Biotin?
Biotin is found in a wide variety of foods, so an actual deficiency is rare.
Foods that are particularly good sources include:
- Organ meats, such as liver and kidney
- Egg yolks
- Legumes, such as soybeans and peanuts
- Leafy greens
- Nuts and nut butters
In addition, your gut bacteria produce some amount of biotin. It's also available as a supplement, either on its own or as a component of mixed vitamin supplements.
Summary: Many foods contain significant amounts of biotin and it is also available as a supplement. Your gut bacteria can also produce it.
Safety and Side Effects
Biotin is considered very safe. Even mega doses of up to 300 milligrams daily to treat multiple sclerosis have not led to adverse side effects (33).
To put this in perspective, 300 milligrams is 10,000 times the commonly recommended 30 microgram dose for adults.
Because it's a water-soluble vitamin, excess amounts are excreted in urine.
However, there have been some reports of high-dose biotin causing strange results on thyroid tests, so check with a doctor before using if you are currently taking thyroid medication (37).
Summary: Biotin appears very safe, even at extremely high doses. There are no known side effects of supplementing with biotin.
The Bottom Line
Biotin is a B-vitamin that plays a crucial role in carb, fat and protein metabolism.
Many of its potential health benefits are based on weak evidence. Nonetheless, it may be important for your skin, hair and nails.
Additionally, pregnant or breastfeeding women may require more biotin. High doses are also being investigated as a potential treatment for multiple sclerosis.
You can find biotin in a wide variety of foods, so actual deficiency is very rare.
For this reason, supplements probably have no significant benefits for healthy people who eat a balanced diet based on real food.
Reposted with permission from our media associate Authority Nutrition.
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By Ana Maldonado-Contreras
- Your gut is home to trillions of bacteria that are vital for keeping you healthy.
- Some of these microbes help to regulate the immune system.
- New research, which has not yet been peer-reviewed, shows the presence of certain bacteria in the gut may reveal which people are more vulnerable to a more severe case of COVID-19.
You may not know it, but you have an army of microbes living inside of you that are essential for fighting off threats, including the virus that causes COVID-19.
How Do Resident Bacteria Keep You Healthy?<p>Our immune defense is part of a complex biological response against harmful pathogens, such as viruses or bacteria. However, because our bodies are inhabited by trillions of mostly beneficial bacteria, virus and fungi, activation of our immune response is tightly regulated to distinguish between harmful and helpful microbes.</p><p>Our bacteria are spectacular companions diligently helping prime our immune system defenses to combat infections. A seminal study found that mice treated with antibiotics that eliminate bacteria in the gut exhibited an impaired immune response. These animals had low counts of virus-fighting white blood cells, weak antibody responses and poor production of a protein that is vital for <a href="https://doi.org/10.1073/pnas.1019378108" target="_blank">combating viral infection and modulating the immune response</a>.</p><p><a href="https://doi.org/10.1371/journal.pone.0184976" target="_blank" rel="noopener noreferrer">In another study</a>, mice were fed <em>Lactobacillus</em> bacteria, commonly used as probiotic in fermented food. These microbes reduced the severity of influenza infection. The <em>Lactobacillus</em>-treated mice did not lose weight and had only mild lung damage compared with untreated mice. Similarly, others have found that treatment of mice with <em>Lactobacillus</em> protects against different <a href="https://doi.org/10.1038/srep04638" target="_blank" rel="noopener noreferrer">subtypes of</a> <a href="https://doi.org/10.1038/s41598-017-17487-8" target="_blank" rel="noopener noreferrer">influenza</a> <a href="https://doi.org/10.1371/journal.ppat.1008072" target="_blank" rel="noopener noreferrer">virus</a> and human respiratory syncytial virus – the <a href="https://doi.org/10.1038/s41598-019-39602-7" target="_blank" rel="noopener noreferrer">major cause of viral bronchiolitis and pneumonia in children</a>.</p>
Chronic Disease and Microbes<p>Patients with chronic illnesses including Type 2 diabetes, obesity and cardiovascular disease exhibit a hyperactive immune system that fails to recognize a harmless stimulus and is linked to an altered gut microbiome.</p><p>In these chronic diseases, the gut microbiome lacks bacteria that activate <a href="https://doi.org/10.1126/science.1198469" target="_blank" rel="noopener noreferrer">immune cells</a> that block the response against harmless bacteria in our guts. Such alteration of the gut microbiome is also observed in <a href="https://doi.org/10.1073/pnas.1002601107" target="_blank" rel="noopener noreferrer">babies delivered by cesarean section</a>, individuals consuming a poor <a href="https://doi.org/10.1038/nature12820" target="_blank" rel="noopener noreferrer">diet</a> and the <a href="https://doi.org/10.1038/nature11053" target="_blank" rel="noopener noreferrer">elderly</a>.</p><p>In the U.S., 117 million individuals – about half the adult population – <a href="https://health.gov/our-work/food-nutrition/2015-2020-dietary-guidelines/guidelines/" target="_blank" rel="noopener noreferrer">suffer from Type 2 diabetes, obesity, cardiovascular disease or a combination of them</a>. That suggests that half of American adults carry a faulty microbiome army.</p><p>Research in my laboratory focuses on identifying gut bacteria that are critical for creating a balanced immune system, which fights life-threatening bacterial and viral infections, while tolerating the beneficial bacteria in and on us.</p><p>Given that diet affects the diversity of bacteria in the gut, <a href="https://www.umassmed.edu/nutrition/melody-trial-info/" target="_blank" rel="noopener noreferrer">my lab studies show how diet can be used</a> as a therapy for chronic diseases. Using different foods, people can shift their gut microbiome to one that boosts a healthy immune response.</p><p>A fraction of patients infected with SARS-CoV-2, the virus that causes COVID-19 disease, develop severe complications that require hospitalization in intensive care units. What do many of those patients have in common? <a href="https://www.cdc.gov/mmwr/volumes/69/wr/mm6912e2.htm" target="_blank" rel="noopener noreferrer">Old age</a> and chronic diet-related diseases like obesity, Type 2 diabetes and cardiovascular disease.</p><p><a href="http://doi.org/10.1016/j.jada.2008.12.019" target="_blank" rel="noopener noreferrer">Black and Latinx people are disproportionately affected by obesity, Type 2 diabetes and cardiovascular disease</a>, all of which are linked to poor nutrition. Thus, it is not a coincidence that <a href="https://www.cdc.gov/mmwr/volumes/69/wr/mm6933e1.htm" target="_blank" rel="noopener noreferrer">these groups have suffered more deaths from COVID-19</a> compared with whites. This is the case not only in the U.S. but also <a href="https://www.washingtonpost.com/world/europe/blacks-in-britain-are-four-times-as-likely-to-die-of-coronavirus-as-whites-data-show/2020/05/07/2dc76710-9067-11ea-9322-a29e75effc93_story.html" target="_blank" rel="noopener noreferrer">in Britain</a>.</p>
Discovering Microbes That Predict COVID-19 Severity<p>The COVID-19 pandemic has inspired me to shift my research and explore the role of the gut microbiome in the overly aggressive immune response against SARS-CoV-2 infection.</p><p>My colleagues and I have hypothesized that critically ill SARS-CoV-2 patients with conditions like obesity, Type 2 diabetes and cardiovascular disease exhibit an altered gut microbiome that aggravates <a href="https://theconversation.com/exercise-may-help-reduce-risk-of-deadly-covid-19-complication-ards-136922" target="_blank" rel="noopener noreferrer">acute respiratory distress syndrome</a>.</p><p>Acute respiratory distress syndrome, a life-threatening lung injury, in SARS-CoV-2 patients is thought to develop from a <a href="http://doi.org/10.1016/j.cytogfr.2020.05.003" target="_blank" rel="noopener noreferrer">fatal overreaction of the immune response</a> called a <a href="https://theconversation.com/blocking-the-deadly-cytokine-storm-is-a-vital-weapon-for-treating-covid-19-137690" target="_blank" rel="noopener noreferrer">cytokine storm</a> <a href="http://doi.org/10.1016/S2213-2600(20)30216-2" target="_blank" rel="noopener noreferrer">that causes an uncontrolled flood</a> <a href="http://doi.org/10.1016/S2213-2600(20)30216-2" target="_blank" rel="noopener noreferrer">of immune cells into the lungs</a>. In these patients, their own uncontrolled inflammatory immune response, rather than the virus itself, causes the <a href="http://doi.org/10.1007/s00134-020-05991-x" target="_blank" rel="noopener noreferrer">severe lung injury and multiorgan failures</a> that lead to death.</p><p>Several studies <a href="https://doi.org/10.1016/j.trsl.2020.08.004" target="_blank" rel="noopener noreferrer">described in one recent review</a> have identified an altered gut microbiome in patients with COVID-19. However, identification of specific bacteria within the microbiome that could predict COVID-19 severity is lacking.</p><p>To address this question, my colleagues and I recruited COVID-19 hospitalized patients with severe and moderate symptoms. We collected stool and saliva samples to determine whether bacteria within the gut and oral microbiome could predict COVID-19 severity. The identification of microbiome markers that can predict the clinical outcomes of COVID-19 disease is key to help prioritize patients needing urgent treatment.</p><p><a href="https://doi.org/10.1101/2021.01.05.20249061" target="_blank" rel="noopener noreferrer">We demonstrated</a>, in a paper which has not yet been peer reviewed, that the composition of the gut microbiome is the strongest predictor of COVID-19 severity compared to patient's clinical characteristics commonly used to do so. Specifically, we identified that the presence of a bacterium in the stool – called <em>Enterococcus faecalis</em>– was a robust predictor of COVID-19 severity. Not surprisingly, <em>Enterococcus faecalis</em> has been associated with <a href="https://doi.org/10.1053/j.gastro.2011.05.035" target="_blank" rel="noopener noreferrer">chronic</a> <a href="https://doi.org/10.1016/S0002-9440(10)61172-8" target="_blank" rel="noopener noreferrer">inflammation</a>.</p><p><em>Enterococcus faecalis</em> collected from feces can be grown outside of the body in clinical laboratories. Thus, an <em>E. faecalis</em> test might be a cost-effective, rapid and relatively easy way to identify patients who are likely to require more supportive care and therapeutic interventions to improve their chances of survival.</p><p>But it is not yet clear from our research what is the contribution of the altered microbiome in the immune response to SARS-CoV-2 infection. A recent study has shown that <a href="https://doi.org/10.1101/2020.12.11.416180" target="_blank" rel="noopener noreferrer">SARS-CoV-2 infection triggers an imbalance in immune cells</a> called <a href="https://doi.org/10.1111/imr.12170" target="_blank" rel="noopener noreferrer">T regulatory cells that are critical to immune balance</a>.</p><p>Bacteria from the gut microbiome are responsible for the <a href="https://doi.org/10.7554/eLife.30916.001" target="_blank" rel="noopener noreferrer">proper activation</a> <a href="https://doi.org/10.1126/science.1198469" target="_blank" rel="noopener noreferrer">of those T-regulatory</a> <a href="https://doi.org/10.1038/nri.2016.36" target="_blank" rel="noopener noreferrer">cells</a>. Thus, researchers like me need to take repeated patient stool, saliva and blood samples over a longer time frame to learn how the altered microbiome observed in COVID-19 patients can modulate COVID-19 disease severity, perhaps by altering the development of the T-regulatory cells.</p><p>As a Latina scientist investigating interactions between diet, microbiome and immunity, I must stress the importance of better policies to improve access to healthy foods, which lead to a healthier microbiome. It is also important to design culturally sensitive dietary interventions for Black and Latinx communities. While a good-quality diet might not prevent SARS-CoV-2 infection, it can treat the underlying conditions related to its severity.</p><p><em><a href="https://theconversation.com/profiles/ana-maldonado-contreras-1152969" target="_blank">Ana Maldonado-Contreras</a> is an assistant professor of Microbiology and Physiological Systems at the University of Massachusetts Medical School.</em></p><p><em>Disclosure statement: Ana Maldonado-Contreras receives funding from The Helmsley Charitable Trust and her work has been supported by the American Gastroenterological Association. She received The Charles A. King Trust Postdoctoral Research Fellowship. She is also member of the Diversity Committee of the American Gastroenterological Association.</em></p><p><em style="">Reposted with permission from <a href="https://theconversation.com/a-healthy-microbiome-builds-a-strong-immune-system-that-could-help-defeat-covid-19-145668" target="_blank" rel="noopener noreferrer" style="">The Conversation</a>. </em></p>
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