Decades of intensive agriculture can overwork and deplete soils. Accidents and Illnesses Burns lead to a loss of protein and essential trace nutrients such as vitamins and minerals. Teenagers Rapid growth spurts such as in the teenage years, particularly in girls, place high demands on nutritional resources to underwrite the accelerated physical, biochemical and emotional development in this age group. Pregnant Women Pregnancy created higher than average demands for nutrients, to ensure healthy growth of the baby and comfortable confinement for the mother. Oral Contraceptives Oral contraceptives can decrease absorption of folic acid and increase the need for vitamin B6 and possibly vitamin C, zinc and riboflavin.
Some people eat very sparingly, even without weight reduction goals.
Surveys have shown that an average woman maintains her weight on 7560 kilojoules per day, at which level her diet in likely to be low in thiamine, calcium and iron. The aged have been shown to have a low intake of vitamins and minerals, particularly iron, calcium and zinc. Bio-Individuality Wide fluctuations in individual nutrient requirements from the official recommended average vitamin and mineral intakes are common, particularly for those in high physical demand vocations, such as athletes and manual labour, taking into account body weight and physical type. Athletes Athletes consume large amounts of food and experience considerable stress. These factors affect their needs for B-group vitamins, vitamin C and iron in particular.