An investigation has been made of the iron intake of sixty-three men and sixty-three women of the English middle class, living on freely chosen diets. Their intakes of total iron have been found to have mean values of 16·8 and 11·4 mg. per day respectively. The highest value found for any woman was only just above the average for the men, and 30 per cent, of the women were taking less than 10 mg. of iron a day.
“Available” or inorganic iron in the diets has also been calculated, and has been found to average 10·8 mg. per day for men and 7·9 mg. for women. If fairly large amounts of meat are eaten, the available iron may be less than half the total iron in the diet. If, on the other hand, the diet is mainly vegetarian, about 90 per cent, of the total iron may be available.
Haemoglobin determinations were made on more than 50 per cent, of the subjects. The men's average was 102 per cent, and the women's 93 per cent. No significant correlation could be found between the total or available iron intake and the haemoglobin level.
The effect of large doses of iron (100 mg. of iron a day as ferrous sulphate or ferric ammonium citrate) on normal haemoglobin levels has been investigated. This has scarcely altered the haemoglobin percentages of men, but has increased the values for women by 4–17 per cent, and a mean rise of over 10 per cent, has been observed.