Experimental methods for measuring the intakes of, and plasma levels of, most micronutrients do exist, however these are not practical to apply to large populations. Instead such small scale measurements are often confined to the research setting. The current intakes of micronutrients amongst World populations are therefore based purely on estimates. Such estimates come from food tables and large scale questionnaires, which often provides inaccuracies. For example food tables make the assumption that all foods of the same type have the same micronutrient levels, which is known to be false. In turn, food questionnaire make the assumption that the reporting of the intakes of foods by the subjects is accurate, which is also known to be false. Therefore these estimates are based on two assumptions that are known to be false. The poor health of most Westerns and the rise in lifestyle disease amongst such populations support the contention that nutritional estimates are accurate.
Evidence suggests that iron intakes may be too low in Western nations, particularly for at risk groups. If bioavailability is lower than expected, as some evidence suggests, this could compound the issue. As well as affecting energy levels, a poor iron status is also associated with cognitive dysfunction.
However, even estimates may exaggerate the actual intakes. A recent study published in the Journal of nutrition estimated the bioavailability of iron amongst populations living in the United States of America and suggested that the bioavailability may be lower than had previously been suggested. For example the study estimated that non-haem iron bioavailability, the iron that can be absorbed and utilised from non-meat sources, may be as low as 3.7 % in female and 2.6 % in males. Total iron bioavailability may be only 15.1 to 15.5 % depending on the model used. While this study used mathematical models, such analysis suggests that even if iron intakes have been accurately assessed (which there is no guarantee they have) the lower than expected bioavailability from iron may suggest that the iron status of this population (and other populations) may be poorer than previously expected. As iron is the most common nutritional deficiency in the World, these findings are perhaps not surprising.
Eat Well, Stay Healthy, Protect Yourself
RdB
