Diet and disease.

Dietary factors are influential in the most important public health problems of Western society. Together, diseases such as coronary heart disease and stroke, cancers, and the effects of osteoporosis constitute the most common causes of disability and death. All of these diseases are multifactorial in their aetiology, but there remains some potential for disease prevention by dietary manipulation. For coronary heart disease and stroke, dietary factors play important roles in modulating blood lipids and their propensity for oxidation. In addition the propensity for thrombosis can be influenced by dietary factors, particularly by the inclusion of fish oils. For cancers, the influence of the diet is less certain, but fats, fibre and antioxidant vitamins and minerals have been most closely scrutinised. In osteoporosis the most important dietary factor is the availability of calcium. This is important both in building peak bone mass and in minimising bone loss later on. There is also some evidence that dietary factors can be helpful in minimising the symptoms of disease. Most notably, the inflammatory process in rheumatoid arthritis can be modified by fish and evening primrose oils, although these effects are relatively mild compared with standard pharmaceutical treatments.