Background/aims Fortified breakfast cereals (FBCs) are an important source of iron in the UK diet. In order to quantify their contribution to iron nutrition, food composition data for these products must be accurate. The very large amount of products available, together with inter-brand differences in iron content mean that discrepancies between the iron content of many FBCs and values in standard food composition databases (FCD) exist. The variation in reported iron contents of FBCs was examined and the impact of this variation on measurement of iron intake using standard food composition tables was investigated.
Method Data on the reported iron content of 128 FBCs were collected. Completed food diaries from 291 participants of the UK Women's Cohort study were used in the analysis. Mean iron intake from a 4-day food diary was calculated using UK food tables’ values for FBCs. This was repeated using values reported by the manufacturer for each brand of cereal. The two sets of results were then compared.
Results There is wide variation in iron content of breakfast cereals available in the United Kingdom. Use of FCD values instead of brand-specific values under- or overestimates an individual's iron intake by as much as 28 or 22% respectively. These results suggest that use of FCD values for breakfast cereals is potentially a source of substantial error in measurement of individuals’ iron intake.
Conclusion Dietitians need to be aware of inter-brand differences in iron content and formulate advice accordingly. Failure to collect brand-specific data for the iron content of FBCs could lead to measurement error in measuring iron intake in dietary studies.