Hello. Thank you for contacting HCM. The most likely possibility of brittle nails and hair is deficiency of vitamins....I would suggest a healthier diet and life style which you have mentioned you are following already. Start oral multivitamins....most importantly multivitamins containing zinc and iron. Also in females these changes may occur with the variations in hormone levels such as pregnancy or menopause and tend to become better after sometime. If your problem persists after a couple of months while using multivitamins or you start experiencing any other symptoms I would advise you consult your local physician. I hope this answers your query. Please feel free to contact HCM again in case you have any concerns. Wishing you good health.