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.
Some of the difficulty we have in determining the food content of biotin lies in the shortcomings of our methods for biotin analysis in the laboratory. Three primary methods of biotin analysis involve (1) bacterial growth studies, (2) studies in which biotin binds to a protein called avidin (or sometimes streptavidin), and (3) dye-based studies using a chemical called 4'-hydroxyazobenzene-2-carboxylic acid. All three methods have known limitations, and the results of these different methods can be quite inconsistent. In short, researchers are still figuring out how to accurately measure the biotin content of food.
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 tomatoes as an excellent source of biotin, and almonds as a very good source. Among the World's Healthiest Foods, you will also find 5 additional very good sources of biotin and 13 good sources of this vitamin.
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.
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.
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).
|World's Healthiest Foods ranked as quality sources of|
|Almonds||0.25 cup||132.2||14.72||49||6.7||very good|
|Eggs||1 each||77.5||8.00||27||6.2||very good|
|Onions||1 cup||92.4||7.98||27||5.2||very good|
|Carrots||1 cup||50.0||6.10||20||7.3||very good|
|Romaine Lettuce||2 cups||16.0||1.79||6||6.7||very good|
|Cauliflower||1 cup||28.5||1.61||5||3.4||very good|
|Sweet Potato||1 cup||180.0||8.60||29||2.9||good|
|Cow's milk||4 oz||74.4||2.32||8||1.9||good|
Density>=7.6 AND DRI/DV>=10%
Density>=3.4 AND DRI/DV>=5%
Density>=1.5 AND DRI/DV>=2.5%
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.
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.
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.
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.
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.
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.
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.