Macronutrients (proteins, fats and carbohydrates) and minerals (e.g., iron, phosporous and calcium) are substantially unaffected by radiation doses at approved levels. Some vitamins, particularly thiamine, undergo an appreciable reduction when exposed to radiation. In approving irradiation of meat, FDA acknowledged that maximal use of food irradiation on meat would result in a decline in the amount of B vitamins consumed in the average person's diet. In the totality of the diet, however, FDA determined that the average person's intake of these vitamins would be well above the RDA even in the "extreme case" in which all meats approved for irradiation were irradiated under approved conditions that would be most destructive to vitamins.