Our daughter has recently begun treatment for a hyperthyroid. Can you give us any dietary guidelines?

Your daughter has too much thyroid hormone causing an overactive metabolic state. Many processes in the body (including digestion) are accelerated, which means that some foods will not be efficiently absorbed. To ensure she is properly nourished, the following supplements are recommended daily: a good multivitamin and mineral complex - try Quest's Super Once-A-Day Vitamin B complex 50mg three times, Vitamin C 1,000mg, manganese 10mg. Your daughter should eat broccoli, cabbage, cauliflower, sprouts, kale, spinach, turnips, peaches, pears and soybeans (these suppress thyroid hormone production) and avoid soft drinks, stimulants and dairy products.

I use a herbal cream containing hops, wild yam, fenugreek and dong quai on a daily basis, but I am worried that, as they are phytoestrogens, they might interfere with the contraceptive pill.

The dong quai and the wild yam are phytoestrogens. They possess weak oestrogenic activity, but can take up oestrogen receptor sites in the body, inhibiting the body's ability to absorb the more potent oestrogen from the pill, and rendering it less effective. Stop using the cream or use a barrier form of contraception instead.

Emma Mitchell is a natural health therapist. Send your questions to Wellbeing, Guardian Weekend, 119 Farringdon Road, London EC1R 3ER. Email: weekend@theguardian.com.