Effects of different calcium sources on iron absorption in postmenopausal women

Deehr, Manya S.; Dallal, Gerard E.; Smith, Kenneth T.; Taulbee, John D.; Dawson‐Hughes, Bess

doi:10.1093/ajcn/51.1.95

Cited by 67 publications

(39 citation statements)

References 25 publications

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“…Na literatura, dentre os artigos publicados que abordaram a absorção de ferro, poucos analisaram fórmulas infantis ou leites utilizados por lactentes. Esses estudos demonstraram que o cálcio [5][6][7] e as proteínas do leite 5,10,16 diminuem a biodisponibilidade do ferro, enquanto outros fatores dietéticos, como o ácido ascórbico, favorecem a sua absorção 21 .…”

Section: Discussionunclassified

“…Apesar das evidências experimentais indicando que maiores quantidades de cálcio e proteína na dieta reduzem a absorção de ferro [5][6][7][8][9][10] , não existem estudos que avaliem seu efeito sobre os compartimentos corporais desse mineral durante o primeiro semestre da vida. Alguns métodos foram aplicados para avaliar a biodisponibilidade do ferro de alimentos utilizados por lactentes, principalmente técnicas in vitro 5,[10][11][12][13][14] e in vivo com adultos 6,7,10,15 e com ratos com 14 ou 21 dias de vida 11,16 .…”

Section: Introductionunclassified

“…Alguns métodos foram aplicados para avaliar a biodisponibilidade do ferro de alimentos utilizados por lactentes, principalmente técnicas in vitro 5,[10][11][12][13][14] e in vivo com adultos 6,7,10,15 e com ratos com 14 ou 21 dias de vida 11,16 . No entanto, em nenhum dos estudos da literatura foi comparada a absorção do ferro da fórmula infantil com a do leite de vaca integral fortificado, oferecido com frequência como única fonte de alimento para lactentes com menos de 6 meses não amamentados, considerando o leite de vaca integral como a opção de menor custo.…”

Section: Introductionunclassified

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Iron absorption from infant formula and iron-fortified cow’s milk: experimental model in weanling rats

Costa

Freitas²,

Amâncio

et al. 2009

J Pediatr (Rio J)

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Objective: To compare iron absorption from infant formula and iron-fortified cow's milk.Methods: Twenty-four weanling Wistar rats were maintained in metabolic cages during the whole experiment (10 days). On the first day, the animals were divided into three similar groups according to their weight, length, hematocrit and hemoglobin levels: 1) infant formula; 2) powdered whole cow's milk fortified with iron in the same quantity and type as the formula; 3) control -powdered whole cow's milk not fortified with iron. Deionized water and diet were offered ad libitum, and the volume consumed was measured. Weight, hematocrit, and hemoglobin levels were measured on the fifth and 10th days when length, fecal occult blood, and hepatic iron levels were also analyzed.Results: Group 1 consumed less diet (450.5±26.50 mL) than group 2 (658.8±53.73 mL) and control group (532.7±19.06 mL, p < 0.001). Hemoglobin levels were higher (p < 0.001) in group 1 (12.1±1.13 g/dL) than in group 2 (9.6±1.59 g/dL) and in control group (6.2±0.97 g/dL). Hepatic iron level showed the same pattern as hemoglobin (p < 0.001). There was no difference in weight and length between the three groups (p = 0.342). There was no fecal occult blood in the any of the animals. Conclusions:Despite the lower volume consumed, the group that received formula presented higher iron absorption and hemoglobin levels than the group fed with fortified whole cow's milk. Growth was similar in the three groups. J Pediatr (Rio J). 2009;85(5):449-454:Breast milk substitutes, dietary iron, biological availability, iron deficiency. ResumoObjetivo: Comparar a absorção do ferro da fórmula de partida e do leite de vaca integral fortificado. Métodos:Foram utilizados 24 ratos machos Wistar recém-desmamados, mantidos em gaiolas metabólicas durante todo o período do experimento (10 dias). No primeiro dia, os animais foram distribuídos em três grupos semelhantes quanto ao peso, comprimento, hematócrito e hemoglobina: 1) fórmula de partida para lactentes; 2) leite de vaca integral em pó fortificado com a mesma quantidade e tipo de sal de ferro da fórmula; e 3) controle -leite de vaca integral em pó não fortificado com ferro. Água e dieta foram oferecidas ad libitum com mensuração do volume consumido. Peso, hematócrito e hemoglobina foram mensurados no quinto e no 10º dia do experimento, quando foram analisados também comprimento, sangue oculto nas fezes e teor de ferro hepático.Resultados: O grupo 1 ingeriu menor volume de dieta (450,5±26,50 mL) que os grupos 2 (658,8±53,73 mL) e controle (532,7±19,06 mL; p < 0,001). As concentrações de hemoglobina foram maiores (p < 0,001) no grupo 1 (12,1±1,13 g/dL) que nos grupos 2 (9,6±1,59 g/dL) e controle (6,2±0,97 g/dL). O teor de ferro hepático apresentou o mesmo comportamento da hemoglobina (p < 0,001). Não foi observada diferença de peso e comprimento nos três grupos (p = 0,342). Não foi detectado sangue oculto nas fezes de nenhum dos animais. Conclusões:Apesar do menor volume ingerido, o grupo que recebeu fórmula apresentou maior abso...

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Section: Discussionunclassified

Section: Introductionunclassified

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Iron absorption from infant formula and iron-fortified cow’s milk: experimental model in weanling rats

Costa

Freitas²,

Amâncio

et al. 2009

J Pediatr (Rio J)

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“…When Ca and Fe supplements were taken in the fasting state (600 mg Ca, 18 mg Fe), absorption was reduced by 62% (P`0Á001); when taken with the hamburger meal, absorption was decreased by 57% (P 0Á015). Deehr et al (1990) studied the effect of a calcium citrate ± malate supplement containing 500 mg Ca given with a breakfast meal (3Á18 mg Fe, 238 mg Ca) on the absorption of the food Fe using an extrinsic tag and whole-body counting in nineteen Fe-replete post-menopausal women. Absorption was reduced by 28 % (P`0Á05).…”

Section: Effects Of Calcium Salts On Iron Absorption From Single Mealmentioning

confidence: 99%

“…Meal composition was important. The inhibitory effect could be overcome by the addition of a known enhancer of Fe absorption, such as ascorbic acid, in both experimental animals (Mehansho et al 1989) and human volunteers (Deehr et al 1990). …”

Section: Effects Of Dairy Products On Iron Absorption From Single Meamentioning

confidence: 99%

The effect of calcium on iron absorption

Lynch

2000

Nutr. Res. Rev.

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The experimental and epidemiological evidence demonstrating that Ca inhibits Fe absorption was reviewed, with the objectives of estimating the potential impact of variations in Ca intake on dietary Fe bioavailability and of providing some guidelines for predicting the effects on Fe status of recent recommendations for higher dietary Ca intake. In animal models Ca salts reduced both haem-and non-haem-Fe absorption, the effect being dependent on the amount of Ca administered rather than the Ca:Fe molar ratio; dairy products had a variable effect; factors other than Ca may have been important. In single-meal human absorption studies, both haem-and non-haem-Fe absorption was inhibited by Ca supplements and by dairy products, the effect depending on the simultaneous presence of Ca and Fe in the lumen of the upper small intestine and also occurring when Ca and Fe were given in the fasting state. The quantitative effect, although dose dependent, was modi®ed by the form in which Ca was administered and by other dietary constituents (such as phosphate, phytate and ascorbic acid) known to affect Fe bioavailability. The mechanism by which Ca in¯uences Fe absorption has not been elucidated. The effects of factors that modulate Fe bioavailability are known to be exaggerated in singlemeal studies, and measurements based on several meals are more likely to re¯ect the true nutritional impact. The results of most multiple-meal human studies suggest that Ca supplementation will have only a small effect on Fe absorption unless habitual Ca consumption is very low. Outcome analyses showed that Ca supplements had no effect on Fe status in infants fed Fe-forti®ed formula, lactating women, adolescent girls and adult men and women. However it should be noted that the subjects studied had adequate intakes of bioavailable Fe and, except in one study, had relatively high habitual Ca intakes. Although cross-sectional analyses in Europe have shown a signi®cant inverse correlation between Ca intake (derived primarily from dairy foods) and Fe stores, the quantitative effect was relatively small.

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Dairy Intake, Reduced Body Iron Stores, and the Development of Type 2 Diabetes Mellitus

Mascitelli¹,

Pezzetta²

2005

Arch Intern Med

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cited by Rehman et al 1 also found poorer hypertension control rates among African American men, yet no difference in BP control was noted between African American and white women. In their study, Rehman et al 1 looked just at the male hypertensive population and offered no explanation for this sex-related difference among African Americans. Qualitative differences in pharmacotherapy and their possible impact on ethnic BP control rates at Veterans Affairs (VA) and non-VA health care sites were also not specifically discussed.It is known that there are some ethnic differences in the causes of arterial hypertension, with African Americans presenting more often with a salt-sensitive form characterized by low renin levels 3 and abnormal hemodynamic reactivity manifested by increased vascular resistance to physical and mental stress. The proposed underlying pathophysiologic condition is sympathetic overactivity, along with an imbalance among endotheliumderived vasoactive mediators, including the potent vasoconstrictor peptide endothelin-1 and the vasodilator nitric oxide.In a study by Evans et al, 4 young normotensive African American men were found to have significantly higher circulating endothelin-1 levels compared with white men as well as with African American women. In fact, no difference was found in endothelin-1 levels between African American and white women.In another recent study, African American men showed 20% to 40% higher sympathetic discharge rates compared with women. 5 These sex-related differences in the African American population suggest that a specific pathophysiologic condition, possibly meriting a different pharmacologic approach, might be the main cause for poor BP control rates among African American men compared with other groups of hypertensive patients including African American women.

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Effects of different calcium sources on iron absorption in postmenopausal women

Cited by 67 publications

References 25 publications

Iron absorption from infant formula and iron-fortified cow’s milk: experimental model in weanling rats

Iron absorption from infant formula and iron-fortified cow’s milk: experimental model in weanling rats

The effect of calcium on iron absorption

Dairy Intake, Reduced Body Iron Stores, and the Development of Type 2 Diabetes Mellitus

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