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Your immune system consists of a complex collection of cells, processes, and chemicals that constantly defends your body against invading pathogens, including viruses, toxins, and bacteria.
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Winter is upon us and so is the risk of vitamin D deficiency and infections. Vitamin D, which is made in our skin following sunlight exposure and also found in oily fish (mackerel, tuna and sardines), mushrooms and fortified dairy and nondairy substitutes, is essential for good health. Humans need vitamin D to keep healthy and to fight infections. The irony is that in winter, when people need vitamin D the most, most of us are not getting enough. So how much should we take? Should we take supplements? How do we get more? And, who needs it most?
By Gavin Van De Walle, MS, RD
While everyone has specific life stressors, factors related to job pressure, money, health, and relationships tend to be the most common.
Stress can be acute or chronic and lead to fatigue, headaches, upset stomach, nervousness, and irritability or anger.
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.
Researchers from the Linus Pauling Institute at Oregon State University (OSU) and three other institutions have taken issue with recent claims that “the case is closed” on whether or not a multivitamin/mineral supplement should be taken by most people to help obtain needed micronutrients.
In a correspondence to be published Tuesday in the Annals of Internal Medicine, the researchers reasoned that this type of dietary supplement helps fill nutritional gaps, improves general health, might help prevent chronic disease, will cause no harm and is easily worth the few cents a day that it costs.
To “call the case closed” is wrong and “misinforms the public and the medical community,” the researchers wrote. Their statements were a response to an editorial in the same publication last year that argued that such supplements are unnecessary and received widespread publicity.
While most nutrition experts agree that a balanced and nutritious diet is the best way to obtain needed nutrients, the researchers in this commentary point out that many Americans have a less-than-perfect diet—long on calories and short on nutrients—and the vast majority are not getting enough of several important vitamins and minerals.
“It’s naïve to ignore the fact that most people have micronutrient inadequacies, and wrong to condemn a daily supplement that could cover these nutritional gaps safely and at low cost,” said Balz Frei, professor and director of the Linus Pauling Institute, and a biochemist in the OSU College of Science.
“There’s strong evidence that a multivitamin/mineral supplement supports normal functioning of the body and helps improve overall health, and may even help lower chronic disease risk,” Frei said. “It’s irresponsible to ignore decades of nutrition research and tell the people of the United States they have no need for a supplement that could be so helpful, and costs as little as $1 a month.
“And if they have a poor diet, people should try to improve that as well,” he said. “The two are not mutually exclusive.”
Among the points the researchers made in their commentary:
The vast majority of people in the U.S. do not meet all of the guidelines for dietary intake of vitamins and minerals.
More than 93 percent of adults in the U.S. do not get the estimated average requirement of vitamins D and E from their diet; 61 percent not enough magnesium; and 50 percent not enough vitamin A and calcium.
Many subpopulations have even more critical needs for micronutrients, including older adults, African Americans, obese persons and some people who are ill or injured.
Concerns about “increased mortality” from supplements of vitamins A and E have been based on extremely high use through supplements far beyond the amount available in a multivitamin, and in the case of vitamin E largely refuted by comprehensive meta-analyses.
The value of proper nutrition, on the other hand, is wide-ranging and positive. Micronutrients maintain normal cell and tissue function, metabolism, growth and development. A supplement that helps a person “cover all the bases” can help protect daily, routine health.
Overt deficiency diseases such as scurvy or rickets are increasingly rare in the U.S. due to improved diet and fortified foods. However, certain vitamin and mineral deficiencies are still a major issue in the developing world, especially vitamin A, iron, iodine and zinc. According to the World Health Organization, more than 650,000 children under the age of five die around the world every year from deficiency in vitamin A.
And the potential for vitamins and other micronutrients to help reduce or prevent chronic disease continues to show promise. One of the longest, largest controlled studies ever done, the Physicians’ Health Study II, found a significant eight percent reduction in total cancer incidence in male physicians—people who, through their education, income and lifestyle, probably had diets much closer to optimal than the average American.
“There are many issues that have helped to mislead people when it comes to the study of micronutrients,” Frei said. “For instance, most research is done without first checking to see if a person is inadequate in a nutrient, and you won’t find much effect from a supplement if it isn’t needed.
“In similar fashion, too much research has been done with groups such as doctors and nurses who are probably not representative of the general population,” he said. “Whatever has been shown to be useful in such research probably would be even more effective in people who have poor diets or clear nutritional inadequacies.”
The researchers wrote in their conclusion that to “label multivitamin and mineral supplements useless, harmful and a waste of money is wrong.”
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