My doctor and sister in-law, who is a nurse, told me that anesthesia can cause hair loss. I was under anesthesia five times between June 21 and October 9, 2007 and lost a bunch of hair. Luckily, my hair is thick so it wasn't noticeable. I just remember lots of hair coming out when I washed my hair.
Here's some helpful info on vitamins and minerals:
Healthy Hair Vitamins
Vitamin A - Antioxidant that helps produce healthy sebum in the scalp. Food sources: Fish liver oil, meat, milk, cheese, eggs, spinach, broccoli, cabbage, carrots, apricots and peaches. Daily Dose: 5,000 IU. Warnings: More than 25,000 IU daily is toxic and can cause hair loss and other serious health problems.
Vitamin C - Antioxidant that helps maintain skin & hair health. Food sources: Citrus fruits, strawberries, kiwi, cantaloupe, pineapple, tomatoes, green peppers, potatoes and dark green vegetables. Daily Dose: 60 mg.
Vitamin E - Antioxidant that enhances scalp circulation. Food sources: Cold-pressed vegetable oils, wheat germ oil, soybeans, raw seeds and nuts, dried beans, and leafy green vegetables. Daily dose: Up to 400 IU. Warnings: Can raise blood pressure and reduce blood clotting. People taking high blood pressure medication or anticoagulants should check with their doctors before taking Vitamin E supplements.
Biotin - Helps produce keratin, may prevent graying and hair loss. Food sources: Brewer's yeast, whole grains, egg yolks, liver, rice and milk. Daily dose: 150-300 mcg.
Inositol - Keeps hair follicles healthy at the cellular level. Food sources: Whole grains, brewer's yeast, liver and citrus fruits. Daily Dose: Up to 600 mg.
Niacin (Vitamin B3) - Promotes scalp circulation. Food sources: Brewer's yeast, wheat germ, fish, chicken, turkey and meat. Daily dose: 15 mg. Warnings: Taking more than 25 mg a day can result in "niacin flush" - a temporary heat sensation due to blood cell dialiation.
Pantothenic Acid (Vitamin B5) - Prevents graying and hair loss. Food sources: Whole grain cereals, brewer's yeast, organ meats and egg yolks. Daily dose: 4-7 mg.
Vitamin B6 - Prevents hair loss, helps create melanin, which gives hair its color. Food sources: Brewer's yeast, liver, whole grain cereals, vegetables, organ meats and egg yolk. Daily dose: 1.6 mg. Warnings: High doses can cause numbness in hands and feet.
Vitamin B12 - Prevents hair loss. Food sources: Chicken, fish, eggs and milk. Daily dose: 2 mg.
Healthy Hair Minerals
Calcium - Essential for healthy hair growth. Food sources: Dairy, tofu, fish, nuts, brewer's yeast, beans, lentils and sesame seeds. Daily dose: Up to 1,500 mg. Warnings: Too much calcium can inhibit the absorption of zinc and iron; An acid found in chocolate can inhibit calcium absorption.
Chromium - Helps prevent hyperglycemia and hypoglycemia, both of which can cause hair loss.. Food sources: Brewer's yeast, liver, beef and whole wheat bread. Daily dose: Up to 120 mg. Warnings: People who are allergic to yeast should not take chromium supplements.
Copper - Helps prevent hair loss as well as defects in hair color and structure. Food sources: Shellfish, liver, green vegetables, whole grains, eggs, chicken and beans. Daily dose: Up to 3 mg. Warnings: High levels can lead to dry hair, hair loss and sever health problems.
Iodine - Helps regulate thyroid hormones and prevents dry hair and hair loss. Food sources: Fish, seaweed, kelp, iodized salt, garlic. Daily dose: 150 mcg.
Iron - Prevents anemia and hair loss. Food sources: Liver, eggs, fish, chicken, whole grains, green vegetables and dried fruits. Daily dose: 15 mg. Warnings: Too much can lead to malfunctions of the liver and spleen.
Magnesium - Works with calcium to promote healthy hair growth. Food sources: Green vegetables, wheat germ, whole grains, nuts, soy beans, chickpeas and fish. Daily dose: 280 mg.
Manganese - Prevents slow hair growth. Food sources: Whole grain cereals, eggs, avocados, nuts, seeds, beans, peas, fish, meat and chicken. Daily dose: 3-9 mg.
Potassium - Regulates circulation and promotes healthy hair growth. Food sources: Avocados, bananas, lima beans, brown rice, dates, figs, dried fruit, garlic, nuts, potatoes, raisins, yams and yogurt. Daily dose: 3,500 mg.
Selenium - Keeps skin and scalp supple and elastic. Food souces: Brewer's yeast, meat, fish, grains, tuna and broccoli. Daily dose: 55 mcg. Warnings: An excess of Selenium can be toxic, leading to the loss of hair, nails and teeth.
Silica - Strengthens hair and prevents hair loss. Food sources: Seafood, rice, soybeans, green vegetables. Daily dose: 55 mcg. Warnings: An excess of Selenium can be toxic, leading to the loss of hair, nails and teeth.
Sulfur (methyl-sulfonyl-methane or MSM) - Sulfur is a main component to hair's structure. Food sources: Onions, garlic, eggs, asparagus, meat, fish and dairy products. Daily dose: 1-3 g.
Zinc - Zinc and Vitamin A work together; a deficiency in either can lead to dry hair and oily skin. Food sources: Spinach, sunflower seeds, mushrooms, whole grains, red meat and brewer's yeast. Daily dose: 12 mg. Warnings: Too much can interfere with iron absorption.
Good luck. There are also bottles that are dedicated to Hair and Nails.