Basic Description Role in Health Support Summary of Food Sources Nutrient Rating Chart Impact of Cooking, Storage and Processing Risk of Dietary Deficiency Other Circumstances that Might Contribute to Deficiency

Relationship with Other Nutrients Risk of Dietary Toxicity Disease Checklist Public Health Recommendations References

Basic Description

Biotin is a B-complex vitamin that has been identified as a necessary nutrient for a century, but has only begun to be understood in the past two decades. It has also been previously referred to as coenzyme R, vitamin H, and vitamin B7, with the different names attesting to the confusion surrounding its role in normal metabolism.

Biotin first came to the attention of researchers for what is still its most famous characteristic—that raw egg whites can interfere with biotin nutrition. (For more on this please see the Impact of Cooking, Storage, and Processing section below.) More recently, we have learned about its central role in many pathways of metabolism. Most importantly, we see that biotin plays key roles in fat and sugar metabolism, roles that make deficiency of biotin show up in multiple and unrelated ways.

There is still much we don't know about biotin, however. Importantly, there are still major questions about how much biotin is needed to prevent deficiency.

We also have only a partial understanding of how much biotin is found in commonly eaten foods. Many of the foods that our charts say do not contain biotin actually more accurately contain an unknown quantity of the vitamin. Soybeans, mushrooms, and pumpkin and sunflower seeds are examples of foods with substantial amounts of biotin that are not quantified in the databases we use to determine the biotin concentrations in foods.

While we are still learning about how rich many of the World's Healthiest Foods are as biotin sources, we already know that we have peanuts and tomatoes as excellent sources of biotin. Among the World's Healthiest Foods, you will also find six very good and twelve good sources of biotin.

Role in Health Support

Blood sugar balance

Diets low in biotin impair the production of insulin, a key hormone in the balancing of blood sugar. More recently, researchers have shown that deficiency of biotin also affects the way insulin acts on cells, giving a second reason that low biotin intake potentially creates problems.

Happily, many of the biotin-rich foods we list are also strong sources of fiber, which make them great staples for people with blood sugar problems. Demonstrating this point, a Spanish research group reported that adding about an ounce of mixed nuts into the diet for 12 weeks led to significant improvement in blood sugar control in a group of people at high risk of developing diabetes.

Skin health

Deficiency of biotin is also known to cause skin rash. This symptom occurs because biotin is necessary to build healthy fats in the skin. These fats keep the skin supple and moist, and when they are gone, the skin becomes flaky and irritated.

Back in the 1940s, a researcher demonstrated that adding high biotin foods into the diet of a lactating mother reduced symptoms of cradle cap in nursing infants. Although this research hasn't been followed up in more modern settings, we think that nursing moms could consider focusing on foods high in both biotin and omega-3 fatty acids , including salmon and eggs from pasture-raised chickens.

Summary of Food Sources

Nuts, root vegetables, and eggs are among our best sources of biotin. Each can contain more than a quarter of your daily biotin need in a single serving.

Although their contribution is not fully noted in the charts on this page, tofu, mushrooms, and many types of seeds can be biotin-rich foods. Each of these can contain close to 10% of a daily requirement per serving.

Other animal foods like milk and meat can make up another chunk of your biotin requirement. Expect 2-10% of the daily requirement from each serving in this category.

As noted above, we are still learning about the average biotin content of many important staple foods. As such, the databases that we use to score nutrient content of foods contain some large gaps when it comes to biotin. It is likely that many of the foods you see listed as not containing any biotin may actually be contributing to your total intake; we just don't know exactly how much.

The limitations of our current knowledge make it hard to do a daily diet plan that would ensure an adequate intake of biotin. Since we know that an average adult eats about double the daily requirement we believe that you don't need to worry about obtaining your daily requirement for biotin from the World's Healthiest Foods eating plan (for more on this, see the Risk of Dietary Deficiency section below).

Nutrient Rating Chart

Introduction to Nutrient Rating System Chart

In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the World's Healthiest Foods that are either an excellent, very good, or good source of biotin. Next to each food name, you'll find the serving size we used to calculate the food's nutrient composition, the calories contained in the serving, the amount of biotin contained in one serving size of the food, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling." Read more background information and details of our rating system.

Impact of Cooking, Storage and Processing

Biotin is relatively stable to most common cooking techniques. For example, when you soak and boil your beans, you'll only lose about 10% of the biotin during preparation, much less change than you'll see with most other B vitamins. The canning process is a little harder on the nutrient, leading to losses of 40-80% of the original biotin. Luckily, most of our WHFoods that provide excellent, very good, and good amounts of biotin are foods that you would be very unlikely to buy in canned form. For example, we know that many people like to purchase beans like navies, pintos, or limas in canned form, but none of these beans are foods that you would be turning to for biotin even in non-canned form.

Raw eggs contain a compound called avidin that binds and prevents absorption of biotin. Avidin has such an affinity that it doesn't just bind up the biotin in eggs, but also that found in other foods eaten with raw eggs. Because of the risk of bacterial infection from raw eggs, we don't recommend regular inclusion of them in the diet, anyway.

Risk of Dietary Deficiency

At least compared to the adequate intake recommendation standard, it appears that biotin deficiency is not very common in America. Most estimates have put average biotin intake between 30 and 40 mcg per day, or just above daily requirement.

There is a problem with these research models, however. The tables these researchers use to rate the biotin content of foods are often incomplete, so this type of analysis can systematically under estimate our daily intake. A Canadian study that more carefully analyzed each food found that average intake was closer to 60 mcg per day, double the adult daily requirement. We feel that this estimate is more representative of the dietary patterns of the Western world, and that the risk of deficiency is small.

Ensuring that your diet includes legumes, nuts, seeds, and vegetables on a regular or daily basis will be your best way to prevent a deficiency of biotin. Given that these foods are heavily represented in our World's Healthiest Foods sample menus, we believe that our diet plan is a particularly good way to ensure biotin nutrition.

Other Circumstances that Might Contribute to Deficiency

As noted above, consumption of raw egg whites can interfere with biotin absorption. This is due to a constituent called avidin which is destroyed by cooking. It is not currently clear how many raw eggs you need to eat, or for how long you'll have to eat them, to induce a deficiency state. A 2009 report concluded that one man developed symptomatic biotin deficiency from eating the equivalent of two raw egg whites daily for three months. As mentioned previously, we do not recommend intake of raw eggs on any kind of regular basis for safety reasons

A number of medications, including seizure drugs, can contribute to biotin deficiency. This may be the most common reason for biotin deficiency in the United States at this time.

Relationship with Other Nutrients

Many of the processes involving biotin also require pantothenic acid. Interestingly, these two nutrients are absorbed in the same site in the intestine. There have not been any published reports, however, of negative interaction between dietary biotin and pantothenic acid.

Risk of Dietary Toxicity

There has never been a report of biotin toxicity from foods in any human or animal model that we have been able to find. Similarly, the National Academy of Sciences was unable to find any evidence for biotin toxicity, even at doses going up to nearly ten thousand times the adequate intake level recommendation. You can be confident that the amount of biotin found even in the richest food sources is not causing you any harm when these foods are consumed in everyday serving sizes.

Disease Checklist

• Hair loss
• Brittle nails
• Skin rash / seborrheic dermatitis / cradle cap
• Diabetes
• Seizures
• Pregnancy

Public Health Recommendations

In 1998, the Food and Nutrition Board of the National Academy of Sciences established a set of age-specific Adequate Intake (AI) levels for biotin. These are summarized in the chart below. These AI recommendations are used as the reference standard in the charts on this page. These AIs are as follows.

• 0-6 months: 5 mcg
• 6-12 months: 6 mcg
• 1-3 years: 8 mcg
• 4-8 years: 12 mcg
• 9-13 years: 20 mcg
• 14-18 years: 25 mcg
• 19+ years: 30 mcg
• Pregnant women: 30 mcg
• Lactating women: 35 mcg

There is no established Tolerable Upper Intake Level (UL) for biotin. Given that biotin doses several thousand times the AI have been used in medical settings, we believe it is extremely unlikely that dietary biotin presents any health risk, even in the most unusual circumstances.

The Daily Value (DV) for biotin was established by the U.S. Food and Drug Administration at 300 mcg per day per 2000 calories. It's worth noting that this DV is dramatically higher than the newer and better-researched National Academy of Sciences recommendation. Because of its newer and better-researched status, we used the National Academy of Sciences standard of 30 micrograms for adults 19 and older as our WHFoods recommended intake level for biotin.

References

• Ball, GFM. Biotin. In: Vitamins In Foods: Analysis, Bioavailability, and Stability. CRC Press, Boca Raton, FL, 220-30; 2005.
• Cammalleri L, Bentivegna P, Malaguarnera M. Egg white injury. Intern Emerg Med 2009;4:79-81.
• Casas-Aqustench P, Lopez-Uriarte P, Bullo M, et al. Effects of one serving of mixed nuts on serum lipids, insulin resistance and inflammatory markers in patients with the metabolic syndrome. Nutr Metab Cardiovasc Dis 2001;21:126-35.
• Food and Nutrition Board, Institute of Medicine. Dietary reference intakes for thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin, and choline. Washington, DC: National Academy Press; 1998;58-86.
• Larrieta E, Vega-Monroy ML, Vital P, et al. Effects of biotin deficiency on pancreatic islet morphology, insulin sensitivity and glucose homeostasis. J Nutr Biochem 2012;23:392-9.
• Mock DM. Marginal biotin deficiency is common in normal human pregnancy and is highly teratogenic in mice. J Nutr 2009;139:154-7.
• Said HM. Biotin: the forgotten vitamin. Am J Clin Nutr 2002;75:179-80.
• Staggs CG, Sealey WM, McCabe BJ, et al. Determination of the biotin content of select foods using accurate and sensitive HPLC / avidin binding. J Food Compost Anal 2004;17:767-76.
• Stratton SL, Horvath TD, Boqusiewicz A, et al. Plasma concentration of 3-hydroxyisovaleryl carnitine is an earlyl and sensitive indicator of marginal biotin deficiency in humans. Am J Clin Nutr 2010;92:1399-405.