Is there a cure for brittle nails? As soon as my nails get beyond a very short length they split and layer. I am 17 and eat no meat or fish.

Insufficient protein can cause brittle nails. As you don't eat fish or meat, vegetarian sources of protein such as cooked eggs, cheese, nuts, soy products and yeast extract would be doubly beneficial because they also contain biotin, a B complex vitamin. Research studies in Switzerland and the US have shown that taking biotin improves brittle nails. Also take 2.5mg a day as part of a B complex. Take a daily multimineral containing iron, silica, calcium and sulphur; also eat dandelions and alfalfa - both are rich in nail nutrients. MSM cream will help if used as a hand cream (Higher Nature, 0870 066 0808). Try not to expose your nails to too much water and harsh soap, and wear rubber gloves when washing up.

I have recently had one cold sore after another as well as severe mouth ulcers. I also get cracks at the corners of my mouth. I suffer from irritable bowel syndrome (IBS) and was wondering if these symptoms could be related, and if you can suggest any remedies.

Mouth ulcers and cracks at the corners of the mouth are an indication of vitamin deficiency, especially B vitamins. The soreness could also be due to a food allergy. IBS is also triggered by food intolerances and leads to nutritional deficiencies, as foods are not digested properly. IBS sufferers are advised to increase their fibre intake, but this should not be wheat fibre. Eat fibre from vegetables, fruit, lentils, beans, rye, brown rice and psyllium husks, and drink lots of water. Supplement with a B vitamin complex.

· Emma Mitchell is a natural health therapist. Before following Emma's recommendations, you should consult your GP about any medical problems or special health conditions.

Send your questions to Wellbeing, Guardian Weekend, 119 Farringdon Road, London EC1R 3ER. Email: ask.emma@theguardian.com.