vitamin B7. Raw eggs contain avidin, which can hinder the absorption of vitamin B7. People who like to eat raw beaten eggs are at risk of vitamin B7 deficiency. Boiled eggs are safe. Vitamin B7 deficiency is common in patients who require long-term parenteral nutrition or who are on anticonvulsant medications.
Prevention and Treatment of Diseases
• Treatment. Vitamin B7 supplements may mitigate the symptoms of multiple sclerosis (89) and type 2 diabetes (60) and help avoid brittle nails and hair loss.
Which Food Items Are Vitamin B7 Rich?
Many animal- and plant-based foods contain vitamin B7. Animal-based foods rich in vitamin B7 include internal organs, such as liver and kidneys. Egg yolks, oats, bananas, soybeans, nuts, milk, and wheat are excellent sources of vitamin B7.
This list of vitamin B7–rich food items is adapted from information provided by the USDA.
| FOOD | PORTION | VITAMIN B7 CONTENT, MCG | % DAILY REFERENCE VALUE |
|---|---|---|---|
| Beef liver (cooked) | 3 ounces | 31.0 | 10.0 |
| Eggs | 1 | 25.0 | 8.3 |
| Tomato | 1 cup | 7.2 | 2.4 |
| Salmon (cooked) | 3 ounces | 4.5 | 1.5 |
| Avocado | 1 | 4.0 | 1.3 |
| Pork (cooked) | 3 ounces | 3.0 | 1.0 |
| Bread | 1 slice | 3.0 | 1.0 |
| Cabbage | 1 cup | 2.0 | 0.7 |
| Cheese | 1 ounce | 1.2 | 0.4 |
| Raspberry | 1 cup | 1.1 | 0.3 |
Daily reference value of vitamin B7 is 300 mcg according to the 2013 FDA food-labeling guidelines.
What Are the Recommended Dietary Allowances for Vitamin B7?
Although vitamin B7 is considered an essential nutrient, bacteria living in the human colon make vitamin B7, which partially meets the body’s needs.
| 1–3 years | 8 mcg |
| 4–8 years | 12 mcg |
| 9–13 years | 20 mcg |
| 14–18 years | 25 mcg |
| 19 years and older | 30 mcg |
There is currently no upper intake limit for vitamin B7.
Vitamin B7 Supplements
• Dosage. The most common dosages of vitamin B7 supplements are 2,500–5,000 mcg.
• Diabetes. Vitamin B7 can mitigate the symptoms of type 2 diabetes. The suggested daily dose is 7,000–15,000 mcg.
• Nails and hair. Many shampoos and nail polishes contain vitamin B7, claiming that it can repair brittle nails and prevent hair loss. Vitamin B7 is a water-soluble vitamin, which cannot penetrate the skin. Salon products containing vitamin B7 are ineffective in repairing brittle nails or preventing hair loss. However, Vitamin B7 taken orally may treat brittle nails and hair loss. The suggested daily dose is 2,500 mcg for six months.
Safety Issues
• Side effects. So far, there is no known side effect associated with vitamin B7.
• Vitamin B5. High doses of vitamin B5 may interfere with the absorption of vitamin B7 by the intestines.
What Types of Drugs May Interact with Vitamin B7?
• Anticonvulsant drugs. Anticonvulsant drugs can lower the blood level of vitamin B7. Patients who take such drugs should consider supplementation with vitamin B7.
Vitamin B9 is also known as folic acid. In 1941, Henry Mitchell isolated a water-soluble nutrient from spinach leaves. This nutrient was essential for the growth of Streptococcus bacteria. He called it folic acid from the Latin word folium, meaning “leaves,” and found that it could cure megaloblastic anemia, a condition in which abnormally large red blood cells appear in the bloodstream. In the 1950s, scientists discovered that folic acid is involved in many enzymatic reactions. Recognizing its role as an essential nutrient, they named it vitamin B9.
Vitamin B9 participates in one-carbon metabolism involving the methylation of DNA and synthesis of methionine. A sufficient amount of vitamin B9 is needed to avoid incorrect synthesis of new DNA, which is of particular importance during the fetal and infant stages. Incorrect synthesis of DNA could lead to birth defects and growth retardation. The infants of pregnant women who are vitamin B9 deficient have a high risk of birth defects.
What Are the Symptoms of Vitamin B9 Deficiency?
• Major symptoms. The major symptoms of vitamin B9 deficiency are lack of appetite, weight loss, weakness, headache, irritability, and anemia. Vitamin B9 deficiency could retard growth in infants and children. Vitamin B9 deficiency during pregnancy can lead to premature births and new babies with neural tube defects.
• Megaloblastic anemia. Vitamin B9 deficiency can cause megaloblastic anemia, in which large, irregularly shaped red blood cells called megaloblastic cells circulate in the bloodstream.
What Are the Causes of Vitamin B9 Deficiency?
