Genomics-assisted plant improvement to benefit human nutrition and health

Plant foods contain a bountiful array of vitamins, minerals and unique phytochemicals that are critical and/or beneficial for human health and well-being. A mixture of carbohydrates, lipids and protein (amino acids), as well as 17 mineral nutrients and 13 vitamins are essential components of the human diet. To prevent nutrient deficiencies, each dietary component must be consumed at a daily intake level at or above a defined minimum value; the level for each nutrient varies with age, sex and physiological status (e.g. pregnancy, lactation, disease-related stress). Additionally, the intake of some nutrients at higher, therapeutic levels has been associated with a reduction in risk for chronic conditions, such as cancers and cardiovascular diseases 1 World Cancer Research Fund, American Institute for Cancer Research (1997) Food, Nutrition and the Prevention of Cancer: A Global Perspective, American Institute for Cancer Research Google Scholar . Because almost all essential human nutrients can be obtained from a diverse, plant-based diet (the exceptions being vitamins B12 and D), plant foods have the potential to significantly impact human nutrition and health. Unfortunately, many people in the developing world exist on a simple diet composed primarily of staple foods (e.g. rice, wheat, maize) that are poor sources of many micronutrients, and even in developed countries, the average intake of fruits and vegetables is well below government recommendations 2 Subar A. et al. 5 A Day for Better Health: A Baseline Study of Americans' Fruit and Vegetable Consumption. National Cancer Institute, 1992 Google Scholar . Therefore, efforts are under way to improve the nutrient content and composition of plant foods as a means of increasing the consumption of various essential and health-enhancing compounds 3 Grusak M.A. DellaPenna D. Improving the nutrient composition of plants to enhance human nutrition and health. Annu. Rev. Plant Physiol. Plant Mol. Biol. 1999; 50: 133-161 Crossref PubMed Scopus (397) Google Scholar . An important new approach in this effort is the genomics-assisted strategy, used recently to improve tocopherol (vitamin E) composition in seeds 4 Shintani D. DellaPenna D. Elevating the vitamin E content of plants through metabolic engineering. Science. 1998; 282: 2098-2100 Crossref PubMed Scopus (431) Google Scholar . This is the first example of increasing the vitamin level in a plant tissue by molecular manipulation.