Sarah Schenker from the British Nutrition Foundation replies: Eggs have small but useful amounts of vitamin D, A (retinol) and B12, riboflavin, iodine, iron and protein. When an egg is cooked the heat denatures the protein, but other nutrients are largely unaffected. Only the addition of fat, such as in fried eggs or scrambled eggs, makes a difference to the nutritional composition. Aboiled egg provides 88 cals and 6.5g of fat, whereas a fried egg provides 108 cals and 8.3g of fat. Frying in lard increases the saturated fat content, whereas using vegetable oil increases the content of healthier fats. The extent to which the iron from eggs is absorbed by the body is dependent on other components of the meal; for example, foods with vitamin C, such as orange juice, increase its absorption.