Soy protein, phytate, and iron absorption in humans

Hurrell, Richard F.; Juillerat, Marcel A.; Reddy, Manju B.; Lynch, Shaina M.; Dassenko, S A; Cook, James D.

doi:10.1093/ajcn/56.3.573

Cited by 360 publications

(266 citation statements)

References 25 publications

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“…Studies by suggest that interactions with phytate may be important in meals containing bread. Phytates are powerful inhibitors of non-haem-Fe absorption (Hallberg et al 1989;Hurrell et al 1992). Poorly-soluble calcium phytate complexes formed in the dough during fermentation and baking may prevent phytate degradation by natural phytases in bread (Zhou & Erdman, 1995).…”

Section: Mechanisms Responsible For the Inhibitory Effects Of Calciummentioning

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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Section: Mechanisms Responsible For the Inhibitory Effects Of Calciummentioning

confidence: 99%

The effect of calcium on iron absorption

Lynch

2000

Nutr. Res. Rev.

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“…The absorption of mineral elements is a very complicated system and several components in foods can form soluble and insoluble complexes with these elements under intestinal conditions (Gibson et al, 2010). Legumes, cereals and other plant related foods, which form the base of diets for most African communities, contain phytate (myo-inositol hexaphosphate and other inositol phosphates), a known inhibitor of iron and zinc absorption (Hurrell et al, 1992;Lönnerdal, 2000;Afify et al, 2011). Normally encountered levels of phytates in cereals and legumes can reduce protein and amino acid digestibility by up to 10% (Gilani et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…However, absorption of mineral elements from diets is likely to be higher with an enhancer when compared with lowbioavailability diets (Collings et al, 2013). Phytic acid inhibits iron absorption in a dose-dependent manner above a molar ratio of phytate to iron of 1:7 (Hurrell, 1992). However, ascorbic acid counteracts the effect of phytate when ascorbic acid:iron ratio exceeds 4:1 (Zijp et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Effect of cooking on tannin and phytate content in different bean (Phaseolus vulgaris) varieties grown in Tanzania

Mamiro¹,

Mwanri²,

Mongi³

et al. 2017

Afr. J. Biotechnol.

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Phytates and tannins are present in varying proportions in legume based foods. Investigation on the effect of cooking on tannins and phytates was carried out on thirty eight raw and cooked bean (Phaseolus vulgaris) varieties. Tannins were assayed by vanillin-hydrochloric acid method, while phytates were determined by a method developed by Haugh and Lantzsch. There was a very high significant difference (P≤0.00001) in the tannin concentrations between the raw and cooked bean samples. The mean tannin content for the raw and cooked samples was 1.168±0.81 and 0.563±0.503%CE, respectively. Reduction of tannins after cooking ranged from 20%CE in M'mafutala to 81%CE in GLP 2 with an average reduction of 56.3%CE. Equally, there was a very high significant difference (P≤0.0001) in the phytate concentrations between the raw and cooked bean samples. The mean phytate content for the raw and cooked samples were 0.0219±002 and 0.0122±003 µg/mL, respectively. Cooking reduced the anti-nutritional factors significantly (p≤0.0001). The extent of antinutritional factors reduction varied between bean varieties. Cooking is therefore important for mineral absorption during digestion process in humans as it makes the minerals less bound and hence physiologically available.

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“…There is evidence that many forms of iron do not enter the iron common pool and remain unavailable for absorption. Secondly, soy protein [28] and milk proteins [29,30] have been associated with lower iron bioavailability even in the absence of phytic acid, but from these results, it appears that soy protein in SPC played a more significant role than milk proteins in DSMP to and further reduced iron bioavailability in SPC recipe. For adequate bioavailability of iron, the PA/Fe molar ratio should be <1 [30].…”

Section: Resultsmentioning

confidence: 96%

Estimated Iron and Zinc Bioavailability in Soybean-Maize-Sorghum Ready to Use Foods: Effect of Soy Protein Concentrate and Added Phytase

PO¹,

Egli²

2016

J Food Process Technol

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Citation: Akomo PO, Egli I, Okoth MW, Bahwere P, Cercamondi CI, et al. (2016) AbstractEfficacy and cost of nutritional supplements are critical in addressing malnutrition. Use of cheaper and locally available ingredients in manufacturing ready-to-use foods (RUF) can potentially reduce cost and increase access to supplements in resource-poor settings. Soy protein concentrate (SPC) is a cheaper source of protein and can potentially replace the more expensive milk powder in RUF. However, SPC contains phytic acid (PA) which inhibits mineral bioavailability. PA may be degraded by the enzyme phytase. This study aimed to determine the effect of replacing skim milk powder (MP) with SPC and of added phytase on bioavailability of iron and zinc in soybean-maize-sorghum RUF.RUF samples were made using either SPC or MP. Phytase was added to food samples with either low (<5%) or high (>50%) moisture prior to estimation of bioavailability of iron and zinc by in vitro dialysability. Compared to samples with MP, SPC-based foods had significantly higher content of PA (0.84 g/100 g vs. 0.57 g/100 g; p<0.001); lower bioavailability of iron (2.79% vs. 4.85%; p<0.001) and lower zinc bioavailability (3.61% vs. 8.69% for zinc; p<0.001). After one hour of incubation at 35°C, 68% of PA in high-moisture foods and 10% of PA in low moisture foods were degraded. The data indicate that replacing MP with SPC in SMS RUF increases PA content with subsequent reduction of bioavailability of iron and zinc. Added phytase significantly reduces PA content in high moisture foods and may potentially remain active in the Stomach where moisture is high. Adding such a phytase could be a promising approach to increase iron and zinc bioavailability from SMS RUFs and provide cheaper locally produced formulations for addressing malnutrition in resource-poor settings.

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Soy protein, phytate, and iron absorption in humans

Cited by 360 publications

References 25 publications

The effect of calcium on iron absorption

The effect of calcium on iron absorption

Effect of cooking on tannin and phytate content in different bean (Phaseolus vulgaris) varieties grown in Tanzania

Estimated Iron and Zinc Bioavailability in Soybean-Maize-Sorghum Ready to Use Foods: Effect of Soy Protein Concentrate and Added Phytase

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