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Adaptation of iron absorption in men consuming diets with high or low iron bioavailability.
Am J Clin Nutr. 2000 Jan; 71(1):94-102.AJ

Abstract

BACKGROUND

Short-term measurements of iron absorption are substantially influenced by dietary bioavailability of iron, yet bioavailability negligibly affects serum ferritin in longer, controlled trials.

OBJECTIVE

Our objective was to test the hypothesis that in men fed diets with high or low iron bioavailability, iron absorption adapts to homeostatically maintain body iron stores.

DESIGN

Heme- and nonheme-iron absorption from whole diets were measured in 31 healthy men at 0 and 10 wk while the men consumed weighed, 2-d repeating diets with either high or low iron bioavailability for 12 wk. The diets with high and low iron bioavailability contained, respectively, 14.4 and 15.3 mg nonheme Fe/d and 1.8 and 0.1 mg heme Fe/d and had different contents of meat, ascorbic acid, whole grains, legumes, and tea.

RESULTS

Adaptation occurred with nonheme- but not with heme-iron absorption. Total iron absorption decreased from 0.96 to 0.69 mg/d (P < 0.05) and increased from 0.12 to 0.17 mg/d (P < 0.05) after 10 wk of the high- and low-bioavailability diets, respectively. This partial adaptation reduced the difference in iron bioavailability between the diets from 8- to 4-fold. Serum ferritin was insensitive to diet but fecal ferritin was substantially lower with the low- than the high-bioavailability diet. Erythrocyte incorporation of absorbed iron was inversely associated with serum ferritin.

CONCLUSIONS

Iron-replete men partially adapted to dietary iron bioavailability and iron absorption from a high-bioavailability diet was reduced to approximately 0.7 mg Fe/d. Short-term measurements of absorption overestimate differences in iron bioavailability between diets.

Authors+Show Affiliations

US Department of Agriculture, Agricultural Research Service, Grand Forks Human Nutrition Research Center, Grand Forks, ND 58202-9034, USA. jhunt@gfhnrc.ars.usda.govNo affiliation info available

Pub Type(s)

Clinical Trial
Comparative Study
Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

10617952

Citation

Hunt, J R., and Z K. Roughead. "Adaptation of Iron Absorption in Men Consuming Diets With High or Low Iron Bioavailability." The American Journal of Clinical Nutrition, vol. 71, no. 1, 2000, pp. 94-102.
Hunt JR, Roughead ZK. Adaptation of iron absorption in men consuming diets with high or low iron bioavailability. Am J Clin Nutr. 2000;71(1):94-102.
Hunt, J. R., & Roughead, Z. K. (2000). Adaptation of iron absorption in men consuming diets with high or low iron bioavailability. The American Journal of Clinical Nutrition, 71(1), 94-102.
Hunt JR, Roughead ZK. Adaptation of Iron Absorption in Men Consuming Diets With High or Low Iron Bioavailability. Am J Clin Nutr. 2000;71(1):94-102. PubMed PMID: 10617952.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Adaptation of iron absorption in men consuming diets with high or low iron bioavailability. AU - Hunt,J R, AU - Roughead,Z K, PY - 2000/1/5/pubmed PY - 2000/1/5/medline PY - 2000/1/5/entrez SP - 94 EP - 102 JF - The American journal of clinical nutrition JO - Am. J. Clin. Nutr. VL - 71 IS - 1 N2 - BACKGROUND: Short-term measurements of iron absorption are substantially influenced by dietary bioavailability of iron, yet bioavailability negligibly affects serum ferritin in longer, controlled trials. OBJECTIVE: Our objective was to test the hypothesis that in men fed diets with high or low iron bioavailability, iron absorption adapts to homeostatically maintain body iron stores. DESIGN: Heme- and nonheme-iron absorption from whole diets were measured in 31 healthy men at 0 and 10 wk while the men consumed weighed, 2-d repeating diets with either high or low iron bioavailability for 12 wk. The diets with high and low iron bioavailability contained, respectively, 14.4 and 15.3 mg nonheme Fe/d and 1.8 and 0.1 mg heme Fe/d and had different contents of meat, ascorbic acid, whole grains, legumes, and tea. RESULTS: Adaptation occurred with nonheme- but not with heme-iron absorption. Total iron absorption decreased from 0.96 to 0.69 mg/d (P < 0.05) and increased from 0.12 to 0.17 mg/d (P < 0.05) after 10 wk of the high- and low-bioavailability diets, respectively. This partial adaptation reduced the difference in iron bioavailability between the diets from 8- to 4-fold. Serum ferritin was insensitive to diet but fecal ferritin was substantially lower with the low- than the high-bioavailability diet. Erythrocyte incorporation of absorbed iron was inversely associated with serum ferritin. CONCLUSIONS: Iron-replete men partially adapted to dietary iron bioavailability and iron absorption from a high-bioavailability diet was reduced to approximately 0.7 mg Fe/d. Short-term measurements of absorption overestimate differences in iron bioavailability between diets. SN - 0002-9165 UR - https://www.unboundmedicine.com/medline/citation/10617952/Adaptation_of_iron_absorption_in_men_consuming_diets_with_high_or_low_iron_bioavailability_ L2 - https://academic.oup.com/ajcn/article-lookup/doi/10.1093/ajcn/71.1.94 DB - PRIME DP - Unbound Medicine ER -