Vitamin
Vitamin B7 (Biotin)
A helper for enzymes that process fat, carbohydrate and amino acids. Marketed for hair and nails, but the evidence for supplements in people who are not deficient is weak.
Women: 30 µg/dayMen: 30 µg/day
Adequate Intake
Best food sources
Fruit
- Avocado
- Banana
- Raspberries
Vegetables
- Sweet potato
- Mushrooms
- Spinach
- Broccoli
Other plant foods
- Sunflower seeds
- Almonds
- Peanuts
- Oats
- Sweet potato
- Nutritional yeast
Animal foods
- Egg yolk
- Salmon
- Pork
- Liver
How much is in a serving
- 1 cooked egg: about 10 µg
- 3 oz salmon: about 5 µg
- 1 oz sunflower seeds: about 2.6 µg
- 1/2 cup sweet potato: about 2.4 µg
Deficiency signs
Very rare. Hair thinning, a scaly red rash and brittle nails can occur with genetic disorders or long-term raw egg white consumption.
These signs overlap with many other conditions. A blood test through your doctor is the only way to confirm a deficiency; do not start high-dose supplements on a guess.
Absorption and interactions
- Raw egg white contains avidin, which binds biotin; cooking eggs solves this.
- High-dose biotin supplements interfere with several blood tests, including thyroid and troponin. Tell your doctor if you take them.
Meal ideas
- Cooked eggs with avocado
- Sweet potato and almond bowl
- Salmon with mushrooms
- Sunflower seed granola