In 400 BC, Hippocrates, the father of modern medicine, said "let food be your medicine, and medicine be your food." After more than 2000 years, we now acknowledge that he was right: food can be a strong medicine.     Nutritional therapy is based on this sound and well established theory, that good health is based on good food.      It is hard to believe that the affluent West, with its overabundance of food, gives rise to a population lacking in essential nutrients, but our fast food culture, irradiated and cold stored foods, culture of a weekly or monthly shop and reliance on processed foods, may meant that, in terms of vitamins and minerals, our diet is poor.    What you eat can have an enormous effect on your health. Some of the most common items in your fridge or larder contain powerful properties that can protect from disease, alleviate symptoms and even help you live longer.     The right foods have anti-ageing properties, can lower cholesterol, ease menopausal symptoms and contribute to a healthy pregnancy.