Contemporary human diets and their relation to health and growth: overview and conclusions.

Contemporary human diets are probably as diverse now as they have ever been in the history of mankind. The abundance of food in the western world is in stark contrast to the lack of food and near starvation in parts of Africa, the continent where Homo sapiens evolved. The development of agriculture has enabled the population of the world to expand and to colonize almost the whole of its land surface, but the dependence on one staple food has introduced problems. If the staple crop fails, for example because of drought, there may be no alternative, and undernutrition and starvation are the result. Further, if the rest of the diet does not provide the nutrients that the staple food lacks, diseases due to specific nutrient deficiencies become widespread. Vitamin deficiencies among adults are less common now than they were 50 years ago, but even today millions of children in the poor rice-eating areas of the world are blind because their diets were deficient in vitamin A. For physiological reasons infants and young children will suffer most wherever there is a scarcity of food, of water, or of specific nutrients.