How many egg whites cause biotin deficiency? The truth about avidin and raw egg consumption

October 13, 2025 •

4 min read

According to one case history, consuming six raw egg whites daily for 18 months led to a clinical biotin deficiency. This raises a critical question for fitness enthusiasts and home chefs alike: how many egg whites cause biotin deficiency and what factors influence this rare but possible risk?

Quick Summary

Excessive, prolonged consumption of raw egg whites can lead to a biotin deficiency because of the avidin protein. Cooking eggs effectively denatures this protein, eliminating the risk.

Key Points

No Set Number: There is no specific number of raw egg whites that guarantees a biotin deficiency, as it depends on individual diet and duration of consumption.
Excessive Raw Consumption: Deficiency typically requires consuming large amounts of raw egg whites over a prolonged period, as demonstrated in a case study involving six raw eggs daily for 18 months.
Cooking is Key: Cooking eggs denatures avidin, the protein that binds biotin, completely eliminating the risk of egg white-induced deficiency.
Deficiency Symptoms: Signs of biotin deficiency include thinning hair, scaly skin rashes, and neurological symptoms like lethargy and depression.
Biotin is Widespread: Biotin is found in many other foods, and deficiency is very rare in people with a normal, balanced diet.
Bacterial Risk: A more immediate and serious risk from raw egg consumption is bacterial contamination, most notably with Salmonella.
Pasteurized Option: Using pasteurized egg whites is a safe way to consume them raw, as the heating process denatures avidin.

The Avidin-Biotin Connection

Biotin, also known as vitamin B7, is a water-soluble vitamin essential for metabolism, helping the body convert food into energy. Raw egg whites contain a protein called avidin, which has a remarkably strong binding affinity for biotin. When consumed raw, avidin binds to any available biotin in the digestive tract, forming an indigestible complex that prevents biotin absorption. This creates the potential for a deficiency, although it requires a specific set of circumstances to occur.

The Role of Heat: A Simple Solution

The crucial point in this dietary dynamic is the effect of heat. Avidin is a glycoprotein, and its protein structure is susceptible to heat denaturation. This means that cooking eggs, whether by frying, boiling, or baking, permanently alters the avidin molecule, causing it to lose its ability to bind to biotin. Once denatured, avidin is rendered harmless, and the biotin in the rest of the meal and the egg yolk is free to be absorbed by the body. Research has shown that to ensure complete inactivation, cooking for an adequate time is necessary, with a 1991 study noting that boiling for over 4 minutes was required to destroy all residual avidin activity.

How Much is 'Excessive' Raw Consumption?

For most people who consume a mixed diet, biotin deficiency caused by raw egg whites is extremely rare. However, those who regularly consume a high volume of raw or undercooked eggs over an extended period are at risk. The widely cited case study of a woman who developed a severe deficiency after consuming six raw eggs a day for 18 months provides a clear illustration of what 'excessive' looks like in practice. This level of consumption is significantly higher than what is typically found in a balanced diet. Moreover, even when consuming raw egg whites, the body needs a consistent, high intake to deplete its biotin stores, as symptoms typically appear gradually over a long period. For more information on dietary vitamins, the National Institutes of Health website offers a comprehensive overview.

Symptoms of Biotin Deficiency

Symptoms of biotin deficiency often develop gradually and can be non-specific, making them easy to miss in the early stages. However, recognizing the signs is key for anyone with a diet that includes a high volume of raw egg whites. Common symptoms include:

Dermatological Issues: Thinning hair, potentially progressing to complete hair loss (alopecia), and a red, scaly, eczematous rash, particularly around the eyes, nose, mouth, and groin.
Neurological Complications: Symptoms can range from lethargy, depression, and hallucinations to paresthesias (a 'pins and needles' sensation), especially in the hands and feet. In infants and young children, developmental delays and seizures can occur.
Other Manifestations: Other signs can include conjunctivitis (inflammation of the eye), muscle pain, and metabolic problems like ketolactic acidosis.

Safe Alternatives and Dietary Considerations

Instead of taking the risk with raw egg whites, there are several safe ways to increase protein intake without jeopardizing your biotin status or risking bacterial contamination from Salmonella.


A Comparison of Egg Preparation and Biotin Risk	Feature	Raw Egg Whites	Cooked Egg Whites	High-Biotin Foods (e.g., Cooked Egg Yolks, Liver)
Avidin Activity	High, active avidin binds biotin	None, avidin is denatured	None
Risk of Biotin Deficiency	Possible with excessive, prolonged consumption	Virtually non-existent	Non-existent, provides biotin
Bacterial Contamination	Significant risk (e.g., Salmonella)	Negligible risk	Varies by food type; low risk with proper handling
Primary Nutrient	Protein	Protein	Biotin, Protein, Fat, Vitamins

Other Biotin-Rich Foods

For those looking to boost their biotin intake, a variety of delicious and safe foods are excellent sources. These include:

Cooked egg yolks, which contain significant amounts of biotin.
Legumes, such as peanuts and soybeans.
Nuts and seeds, including walnuts and sunflower seeds.
Liver and other organ meats.
Certain vegetables like sweet potatoes and spinach.
Mushrooms and other fungi.

Conclusion: The Bottom Line for Your Diet

While consuming an occasional small amount of raw egg whites is unlikely to cause any harm in a healthy individual with a balanced diet, the practice carries unnecessary health risks. The potential for biotin deficiency, though rare, is a real concern for those who consume large quantities of raw eggs over an extended period. More immediate is the risk of bacterial foodborne illness, like Salmonella. Fortunately, the simple act of cooking eggs completely neutralizes avidin, making cooked egg whites a perfectly safe and healthy source of protein. For optimal nutrition and safety, it is best to cook your eggs thoroughly and rely on a variety of food sources for your biotin needs.

Is it safe to use pasteurized egg whites in smoothies?

Yes, pasteurized egg whites have been heated to a temperature that destroys most harmful bacteria and also denatures the avidin protein, so they are generally safe for raw consumption, including in smoothies.

Frequently Asked Questions

No, consuming one raw egg white per day is extremely unlikely to cause a biotin deficiency. The deficiency requires a high and consistent intake of avidin over a long period to significantly interfere with biotin absorption.

Yes, cooking eggs completely eliminates the risk of biotin deficiency caused by avidin. The heat denatures the avidin protein, rendering it incapable of binding to biotin.

Avidin is a protein found in raw egg whites that binds very strongly to biotin, a B vitamin. When avidin and biotin are bound together, the body cannot absorb the biotin.

Yes, other causes of biotin deficiency include prolonged use of certain antibiotics or anticonvulsant medications, certain genetic disorders like biotinidase deficiency, and total parenteral nutrition without adequate supplementation.

Symptoms of biotin deficiency include thinning hair, a red scaly rash around body openings, fatigue, depression, and neurological issues like 'pins and needles' in the extremities.

Yes, pasteurized egg whites are safe for raw consumption, including in smoothies or shakes. The pasteurization process uses heat to inactivate avidin and kill bacteria.

Yes, egg yolks can be consumed raw without causing a biotin deficiency because they do not contain avidin. In fact, egg yolks are a good dietary source of biotin.