Fad Diets Bizarre diets that miss out on whole groups of foods can be seriously lacking in vitamins. Freezing food containing vitamin E can significantly reduce its levels one defrosted. A diet overly dependent on highly refined carbohydrates, such as sugar, white flour and white rice places greater demand on additional sources of B-group vitamins to process these carbohydrates. Antibiotics Some antibiotics although valuable in fighting infection, also kill of friendly bacteria in the gut, which would normally be producing B-group vitamins to be absorbed through the intestinal walls. The omission of whole food groups from the diet, as in the case of individuals allergic to gluten or lactose, can mean the loss of significant dietary sources of nutrients such as thiamine, riboflavin or calcium.
Some agricultural soils are deficient in trace elements.
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.