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Estimation of dietary iron bioavailability from food iron intake and iron status.

Dainty JR, Berry R, Lynch SR, Harvey LJ, Fairweather-Tait SJ - PLoS ONE (2014)

Bottom Line: Mean calculated dietary absorption was 8% in men (50th percentile for SF 85 µg/L) and 17% in women (50th percentile for SF 38 µg/L).At a ferritin level of 45 µg/L estimated absorption was similar in men (14%) and women (13%).This new method can be used to calculate dietary iron absorption at a population level using data describing total iron intake and SF concentration.

View Article: PubMed Central - PubMed

Affiliation: Institute of Food Research, Norwich Research Park, Norwich, United Kingdom.

ABSTRACT
Currently there are no satisfactory methods for estimating dietary iron absorption (bioavailability) at a population level, but this is essential for deriving dietary reference values using the factorial approach. The aim of this work was to develop a novel approach for estimating dietary iron absorption using a population sample from a sub-section of the UK National Diet and Nutrition Survey (NDNS). Data were analyzed in 873 subjects from the 2000-2001 adult cohort of the NDNS, for whom both dietary intake data and hematological measures (hemoglobin and serum ferritin (SF) concentrations) were available. There were 495 men aged 19-64 y (mean age 42.7±12.1 y) and 378 pre-menopausal women (mean age 35.7±8.2 y). Individual dietary iron requirements were estimated using the Institute of Medicine calculations. A full probability approach was then applied to estimate the prevalence of dietary intakes that were insufficient to meet the needs of the men and women separately, based on their estimated daily iron intake and a series of absorption values ranging from 1-40%. The prevalence of SF concentrations below selected cut-off values (indicating that absorption was not high enough to maintain iron stores) was derived from individual SF concentrations. An estimate of dietary iron absorption required to maintain specified SF values was then calculated by matching the observed prevalence of insufficiency with the prevalence predicted for the series of absorption estimates. Mean daily dietary iron intakes were 13.5 mg for men and 9.8 mg for women. Mean calculated dietary absorption was 8% in men (50th percentile for SF 85 µg/L) and 17% in women (50th percentile for SF 38 µg/L). At a ferritin level of 45 µg/L estimated absorption was similar in men (14%) and women (13%). This new method can be used to calculate dietary iron absorption at a population level using data describing total iron intake and SF concentration.

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Cumulative distribution of serum ferritin concentrations for men (♦) and women (▪).The data from the NDNS survey [13], [14] are described in the Materials and Methods section (Men, n = 495; Women (pre-menopausal), n = 378).
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pone-0111824-g002: Cumulative distribution of serum ferritin concentrations for men (♦) and women (▪).The data from the NDNS survey [13], [14] are described in the Materials and Methods section (Men, n = 495; Women (pre-menopausal), n = 378).

Mentions: The NDNS sample was a relatively iron sufficient population (Table 1); the distributions of SF values for each of the two groups are shown in Figure 2. No individuals were identified with high levels of the inflammatory marker, α1-ACT (>0.65 g/L). Mean total iron intake was 13.5 mg, and 9.8 mg for and men and women respectively. The relationship between the arbitrary series of iron bioavailability values and the capacity of the diet to meet the iron requirements of men and women is shown in Figure 3. By comparing this figure with the cumulative distributions of SF values in the same population samples (Figure 2), it is possible to identify the average dietary absorption required to sustain a selected average iron status (as defined by the SF concentration) in the population. For example, estimated dietary absorption was 13% in women and 14% in men with SF values of 45 µg/L, and it was 31% for women with depleted iron stores (SF <15 µg/L) (Table 2). There were too few iron deficient men to allow a similar estimate for men to be calculated.


Estimation of dietary iron bioavailability from food iron intake and iron status.

Dainty JR, Berry R, Lynch SR, Harvey LJ, Fairweather-Tait SJ - PLoS ONE (2014)

Cumulative distribution of serum ferritin concentrations for men (♦) and women (▪).The data from the NDNS survey [13], [14] are described in the Materials and Methods section (Men, n = 495; Women (pre-menopausal), n = 378).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4214798&req=5

pone-0111824-g002: Cumulative distribution of serum ferritin concentrations for men (♦) and women (▪).The data from the NDNS survey [13], [14] are described in the Materials and Methods section (Men, n = 495; Women (pre-menopausal), n = 378).
Mentions: The NDNS sample was a relatively iron sufficient population (Table 1); the distributions of SF values for each of the two groups are shown in Figure 2. No individuals were identified with high levels of the inflammatory marker, α1-ACT (>0.65 g/L). Mean total iron intake was 13.5 mg, and 9.8 mg for and men and women respectively. The relationship between the arbitrary series of iron bioavailability values and the capacity of the diet to meet the iron requirements of men and women is shown in Figure 3. By comparing this figure with the cumulative distributions of SF values in the same population samples (Figure 2), it is possible to identify the average dietary absorption required to sustain a selected average iron status (as defined by the SF concentration) in the population. For example, estimated dietary absorption was 13% in women and 14% in men with SF values of 45 µg/L, and it was 31% for women with depleted iron stores (SF <15 µg/L) (Table 2). There were too few iron deficient men to allow a similar estimate for men to be calculated.

Bottom Line: Mean calculated dietary absorption was 8% in men (50th percentile for SF 85 µg/L) and 17% in women (50th percentile for SF 38 µg/L).At a ferritin level of 45 µg/L estimated absorption was similar in men (14%) and women (13%).This new method can be used to calculate dietary iron absorption at a population level using data describing total iron intake and SF concentration.

View Article: PubMed Central - PubMed

Affiliation: Institute of Food Research, Norwich Research Park, Norwich, United Kingdom.

ABSTRACT
Currently there are no satisfactory methods for estimating dietary iron absorption (bioavailability) at a population level, but this is essential for deriving dietary reference values using the factorial approach. The aim of this work was to develop a novel approach for estimating dietary iron absorption using a population sample from a sub-section of the UK National Diet and Nutrition Survey (NDNS). Data were analyzed in 873 subjects from the 2000-2001 adult cohort of the NDNS, for whom both dietary intake data and hematological measures (hemoglobin and serum ferritin (SF) concentrations) were available. There were 495 men aged 19-64 y (mean age 42.7±12.1 y) and 378 pre-menopausal women (mean age 35.7±8.2 y). Individual dietary iron requirements were estimated using the Institute of Medicine calculations. A full probability approach was then applied to estimate the prevalence of dietary intakes that were insufficient to meet the needs of the men and women separately, based on their estimated daily iron intake and a series of absorption values ranging from 1-40%. The prevalence of SF concentrations below selected cut-off values (indicating that absorption was not high enough to maintain iron stores) was derived from individual SF concentrations. An estimate of dietary iron absorption required to maintain specified SF values was then calculated by matching the observed prevalence of insufficiency with the prevalence predicted for the series of absorption estimates. Mean daily dietary iron intakes were 13.5 mg for men and 9.8 mg for women. Mean calculated dietary absorption was 8% in men (50th percentile for SF 85 µg/L) and 17% in women (50th percentile for SF 38 µg/L). At a ferritin level of 45 µg/L estimated absorption was similar in men (14%) and women (13%). This new method can be used to calculate dietary iron absorption at a population level using data describing total iron intake and SF concentration.

Show MeSH
Related in: MedlinePlus