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Vitamin B7 Biotin — Great for Metabolism, Not Hair, Maybe Nails

We use biotin, also known as vitamin B7 or vitamin H, to convert fats, carbs, and proteins into energy. We also need it for gene expression and regulation, and for cell signaling.

Ironically, we don’t usually think of this nutrient when it comes to any of these body functions. Biotin has a reputation of being helpful in the prevention and treatment of hair loss, brittle nails, or skin problems. This is mostly because deficiency of this vitamin can cause these problems, so there is an assumption that treating the deficiency would eliminate them. But, what happens if the cause isn’t a biotin deficiency? 

Deficiency is rare in healthy individuals who follow a balanced diet. Vitamin B7 is present in both animal-based and plant-based foods. While the amounts are typically low, their presence in various food options makes it easy for us to get all we need. Plus, our healthy gut bacteria also produce it. This could explain why a study back in 1989 showed that the vegan population had the highest levels of biotin, versus the vegetarian population and the meat eating population.

Missing Information

There is a giant question mark when it comes to amounts of this vitamin in our foods, though. Unfortunately, the U.S. Department of Agriculture FoodData Central has not included biotin in most of their food reports. When we look up biotin content for certain foods on other publications, we get very different amounts depending on the source. This problem was called out in this report over twenty years ago, but it hasn’t been fully addressed yet. Furthermore, the Dietary Guidelines for Americans, 2020-2025 do not offer an intake recommendation for this nutrient, or even mention this vitamin at all.

Scroll down to learn more about vitamin b7, how much you or your loved ones need, some of its top plant-based sources, more details on how our gut bacteria synthesize it, concerns about high levels of supplementation, and whether it can actually help with hair, nails, and skin issues or not.

Top Whole-Food, Plant-Based Sources

Unfortunately, the U.S. Department of Agriculture does not offer vitamin B7 amounts in their food database. The foods shown below do offer the highest amounts, consistent to multiple sources.

Click on each food’s picture to visit its interactive page with a personalized calculator of all other nutrition you can get from one serving, more information about how it supports our body, tips to choose and prepare it, interesting facts, and more!

Nutritional Yeast

Nutritional Yeast

Link
Peanuts

Peanuts

Link
Mushrooms

Mushrooms

Link
Soybeans

Soybeans

Link
Sweet Potatoes

Sweet Potatoes

Link
Sunflower Seeds

Sunflower Seeds

Link

Vitamin B7 Biotin Personalized Calculator

See how much you and your family members need, according to the Food and Nutrition Board (FNB) at the National Academies of Sciences, Engineering, and Medicine.

Terminology:

  • Daily Value (DV): The recommended amount of nutrients to consume each day for individuals who are 4 years old or older.
  • Adequate Intake (AI): This is an approximation of nutrient intake by a group or groups of healthy people, based on age, sex, and whether a woman is pregnant, lactating, or none. This is used when a Recommended Daily Allowance (RDA) cannot be determined.
  • Upper Intake Level (UL): The highest amount of nutrient intake that will not pose adverse health effects on most individuals.

Important Things to Know

Hover over each of the interesting facts below to flip the tiles and learn more details.

Check out the interesting facts below! Tap on the red triangles to flip the tiles and learn more details.

Our gut flora has a key role in maintaining proper biotin levels.

Back in 1989 this study showed that vegans had higher vitamin b7 levels than vegetarians and meat eaters. While there are plant-based foods high in biotin, another explanation could be that we have more of the gut flora that produces this and other b vitamins, such as bacillus subtilis, which comes from the soil and plants. Plus, a plant-based diet is packed with prebiotics that help this flora thrive.

According to ScienceDirect, most people can satisfy their needs from the synthesis of this vitamin by their own gut flora. At the same time, a prolonged use of antibiotics can lead to a biotin deficiency. So, be sure to talk to your doctor about testing your vitamin B7 levels after taking antibiotics for a long time.

About 50% of pregnant women in the U.S. have a marginal biotin deficiency.

Despite having a normal biotin intake, about half of the pregnant women in the U.S. are marginally deficient. The reason is unknown as well as its clinical relevance. Women lactating also have a mild deficiency. Talk to your doctor about getting your vitamin b7 levels tested. If you are deficient, ask him about supplementation and about increasing your dietary sources.

Eating raw eggs could cause a biotin deficiency. See why.

Egg whites have avidin, a protein that binds to biotin from our dietary sources or to the biotin produced by our gut bacteria. This keeps us from absorbing this nutrient, leading to deficiency, known as “egg white injury.” Cooked egg whites do not have this protein so they don’t interfere with vitamin B7 absorption.

Biotin is often recommended for hair loss, but does it work?

Vitamin B7 deficiency can lead to hair loss, but it is very rare. If the cause is in fact a deficiency, then supplementation could help. Otherwise, there is no evidence that supplementing this nutrient can promote hair growth. In fact, taking these supplements is not recommended because the FDA doesn’t regulate supplements so you could be taking more than what the label indicates. Too much biotin can interfere with lab test results, as seen on the last tile.

What about brittle nails? Tests indicate that biotin could help.

Same as with hair loss, a serious vitamin B7 deficiency could cause brittle nails. There are two uncontrolled, before and after studies that show some improvement in nail quality when supplementing with 2.5 mg of biotin. One of the trials showed a 25% increase in between 6 and 15 months. A controlled test using 10 mg, an extremely high amount, showed a substantial improvement in four months for 80% of the group. However, this dose may interfere with lab test results as seen on the next tile.

High levels of biotin supplementation interfere with lab test results.

While our daily value for biotin is 30 mcg, supplements often have much higher amounts, from 3 mg (3000 mcg) up to 10 mg. While toxicity has not been reported, there is a life-threatening issue that the FDA warns about. High amounts of biotin supplementation can interfere with hormonal lab tests such as pregnancy or thyroid function tests, as well as tests for markers of heart attacks like troponin. Always tell your doctor what supplements you are taking, and stop taking biotin supplements 1 to 5 days before doing any lab work, depending on the amount you are taking.

Our gut flora has a key role in maintaining proper biotin levels.

Back in 1989 this study showed that vegans had higher vitamin b7 levels than vegetarians and meat eaters. While there are plant-based foods high in biotin, another explanation could be that we have more of the gut flora that produces this and other b vitamins, such as bacillus subtilis, which comes from the soil and plants. Plus, a plant-based diet is packed with prebiotics that help this flora thrive.

According to ScienceDirect, most people can satisfy their needs from the synthesis of this vitamin by their own gut flora. At the same time, a prolonged use of antibiotics can lead to a biotin deficiency. So, be sure to talk to your doctor about testing your vitamin B7 levels after taking antibiotics for a long time.

About 50% of pregnant women in the U.S. have a marginal biotin deficiency.

Despite having a normal biotin intake, about half of the pregnant women in the U.S. are marginally deficient. The reason is unknown as well as its clinical relevance. Women lactating also have a mild deficiency. Talk to your doctor about getting your vitamin b7 levels tested. If you are deficient, ask him about supplementation and about increasing your dietary sources.

Eating raw eggs could cause a biotin deficiency. See why.

Egg whites have avidin, a protein that binds to biotin from our dietary sources or to the biotin produced by our gut bacteria. This keeps us from absorbing this nutrient, leading to deficiency, known as “egg white injury.” Cooked egg whites do not have this protein so they don’t interfere with vitamin B7 absorption.

Biotin is often recommended for hair loss, but does it work?

Vitamin B7 deficiency can lead to hair loss, but it is very rare. If the cause is in fact a deficiency, then supplementation could help. Otherwise, there is no evidence that supplementing this nutrient can promote hair growth. In fact, taking these supplements is not recommended because the FDA doesn’t regulate supplements so you could be taking more than what the label indicates. Too much biotin can interfere with lab test results, as seen on the last tile.

What about brittle nails? Tests indicate that biotin could help.

Same as with hair loss, a serious vitamin B7 deficiency could cause brittle nails. There are two uncontrolled, before and after studies that show some improvement in nail quality when supplementing with 2.5 mg of biotin. One of the trials showed a 25% increase in between 6 and 15 months. A controlled test using 10 mg, an extremely high amount, showed a substantial improvement in four months for 80% of the group. However, this dose may interfere with lab test results as seen on the next tile.

High levels of biotin supplementation interfere with lab test results.

While our daily value for biotin is 30 mcg, supplements often have much higher amounts, from 3 mg (3000 mcg) up to 10 mg. While toxicity has not been reported, there is a life-threatening issue that the FDA warns about. High amounts of biotin supplementation can interfere with hormonal lab tests such as pregnancy or thyroid function tests, as well as tests for markers of heart attacks like troponin. Always tell your doctor what supplements you are taking, and stop taking biotin supplements 1 to 5 days before doing any lab work, depending on the amount you are taking.

Comparison of Biotin Sources

You may be wondering about other potential sources of biotin, such as supplements and meat. Below we make a quick and simple comparison between the three options.

Plant-Based
Some of the richest sources include nutritional yeast, mushrooms, soybeans, soy fermented products, and peanuts. Beyond that, a plant-based diet can help us grow more of the healthy gut bacteria that produce biotin in our body.
Supplements
The evidence showing that biotin supplementation may help our skin, hair or nails is inconclusive and based on small studies or a few case reports.
Always tell your doctor if you are taking vitamin B7 supplements since they may lead to false normal or abnormal results in important lab tests, including thyroid function, pregnancy, vitamin D, or troponin (a biomarker for heart attacks).
Animal-based
Organ meats are very rich in biotin, other sources include eggs, salmon, pork and beef. However, animal-based foods may increase our triglycerides which in turn can result in lower biotin levels in our body. Plus, diets rich in animal-based products do not promote the growth of healthy biotin producing gut bacteria.

References