Phytic Acid Intake Research Articles

Phytic acid actions on hepatic lipids and gut microbiota in rats fed a diet high in sucrose is influenced by dietary fat level

Phytic acid (PA) or myoinositol intake was recently reported by our group to suppress hepatic lipogenic gene expression and modulate gut microbiota in rats fed a high-sucrose diet (HSC). The aim of this study was to investigate the effect of PA and dietary fat level on fatty liver and gut microbiota in rats fed an HSC diet. Male Sprague-Dawley rats were fed a high-fat (HF), HSC diet or a low-fat (LF), HSC diet with or without 1.02% sodium PA for 12 days. Hepatic lipid levels, hepatic enzyme activity, and expression of the enzymes and transcriptional factors related to lipid metabolism, cecal organic acids, and fecal microbiota were evaluated. PA intake depressed hepatic total lipid and triglyceride levels; reduced hepatic activity and expression of lipogenic enzymes; elevated fecal proportion of Lactobacillus spp; and increased cecal succinate level in rats fed the LF diet. The HF diet, when compared with the LF diet, depressed hepatic total lipid and triglyceride levels; reduced hepatic activity and expression of lipogenic enzymes; increased hepatic expression of carnitine palmitoyl-transferase 1a and cAMP-responsive element binding protein 3-like 3; and elevated fecal proportions of Lactobacillus spp and Bifidobacterium spp. In the HF diet groups, PA intake did not affect the factors associated with hepatic lipid metabolism and gut microbiota. In conclusion, dietary fat level could change the effect of PA on hepatic lipid metabolism and gut microbiota and, in turn, could alter the degree of nutritional importance of PA in rats fed an HSC diet.

Salivary Cystatin SN Binds to Phytic Acid In Vitro and Is a Predictor of Nonheme Iron Bioavailability with Phytic Acid Supplementation in a Proof of Concept Pilot Study

ABSTRACTBackgroundAcute phytic acid intake has been found to decrease iron bioavailability; however, repeated phytic acid consumption leads to iron absorption adaptation. Salivary proline-rich proteins (PRPs) have been shown to inhibit iron chelation to tannins and may mediate similar iron absorption adaptation with phytic acid intake.ObjectivesThe objectives of this study were to determine whether salivary proteins bind to phytic acid in vitro, and to explore a proof of concept in a pilot study that examined the impact of 4-wk, daily phytic acid supplementation on individuals’ iron status, bioavailability, and salivary PRP concentrations.MethodsHigh-performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization–time of flight were used to characterize in vitro salivary protein–phytic acid interactions. Nonanemic women (n = 7) consumed 350 mg phytic acid supplements 3 times daily for 4 wk, and meal challenges were employed to determine iron bioavailability, iron status, and salivary protein concentrations before and after supplementation periods. Enzyme-linked immunosorbent assay (ELISA) analysis of purified protein fractions and participant saliva identified proteins bound to phytic acid.ResultsIn vitro salivary protein–phytic acid interaction identified cystatin SN, a non–proline rich salivary protein, as the specific bound protein to phytic acid. Iron bioavailability (P = 0.32), hemoglobin (P = 0.72), and serum ferritin (P = 0.08) concentrations were not reduced from week 0 to week 4 after phytic acid supplementation. Basic PRPs and cystatin SN concentrations were positively correlated with iron bioavailability at week 4.ConclusionsOverall, results suggest that phytic acid binds to the non-PRP cystatin SN and that salivary protein production may improve iron bioavailability with phytic acid consumption.

Intake of phytic acid and myo-inositol lowers hepatic lipogenic gene expression and modulates gut microbiota in rats fed a high-sucrose diet.

Dietary phytic acid (PA) was recently reported by our group to suppress hepatic lipogenic gene expression and modulate gut microbiota in rats fed a high-sucrose (HSC) diet. The present study aimed to investigate whether the modulatory effects of PA depend on the dietary carbohydrate source and are attributed to the myo-inositol (MI) ring of PA. Male Sprague-Dawley rats were fed an HSC or a high-starch (HSR) diet with or without 1.02% sodium PA for 12 days. Subsequently, the rats were fed the HSC diet, the HSC diet containing 1.02% sodium PA or an HSC diet containing 0.2% MI for 12 days. The HSC diet significantly increased the hepatic triglyceride (TG) concentration as well as the activity and expression of hepatic lipogenic enzymes compared with the HSR diet. The increases were generally suppressed by dietary PA with a concomitant increase in the fecal and cecal ratios of Lactobacillus spp. In rats fed the HSR diet, PA intake did not substantially affect the factors associated with hepatic lipid metabolism or gut microbiota composition. The effects of MI intake were similar to that of PA intake on hepatic lipogenesis and gut microbiota in rats fed the HSC diet. These results suggest that dietary PA downregulates hepatic lipogenic gene expression and modulates gut microbiota composition in rats fed an HSC diet but not in rats fed an HSR diet. The MI ring of PA may be responsible for the effects of PA intake on hepatic lipogenic gene expression and gut microbiota.

Prediction of Serum Zinc Levels in Mexican Children at 2 Years of Age Using a Food Frequency Questionnaire and Different Zinc Bioavailability Criteria.

The 2006 Mexican National Health and Nutrition Survey documented a prevalence of zinc deficiency of almost 30% in children under 2 years of age. We sought to validate a food frequency questionnaire (FFQ) for quantifying dietary bioavailable zinc intake in 2-year-old Mexican children accounting for phytic acid intake and using serum zinc as a reference. This cross-sectional study was nested within a longitudinal birth cohort of 333 young children in Mexico City. Nonfasting serum zinc concentration was measured and dietary zinc intake was calculated on the basis of a semiquantitative FFQ administered to their mothers. The relationship between dietary zinc intake and serum zinc was assessed using linear regression, adjusting for phytic acid intake, and analyzed according to two distinct international criteria to estimate bioavailable zinc. Models were stratified by zinc deficiency status. Dietary zinc, adjusted for phytic acid intake, explained the greatest proportion of the variance of serum zinc. For each milligram of dietary zinc intake, serum zinc increased on average by 0.95 μg/dL (0.15 μmol/L) (p = .06). When stratified by zinc status, this increase was 0.74 μg/dL (p = .12) for each milligram of zinc consumed among children with adequate serum zinc (n = 276), whereas among those children with zinc deficiency (n = 57), serum zinc increased by only 0.11 μg/dL (p = .82). A semiquantitative FFQ can be used for predicting serum zinc in relation to dietary intake in young children, particularly among those who are zinc-replete, and when phytic acid or phytate intake is considered. Future studies should be conducted accounting for both zinc status and dietary zinc inhibitors to further elucidate and validate these findings.

The relative validity and repeatability of an FFQ for estimating intake of zinc and its absorption modifiers in young and older Saudi adults.

To assess the relative validity and repeatability of a sixty-four-item FFQ for estimating dietary intake of Zn and its absorption modifiers in Saudi adults. In addition, we used the FFQ to investigate the effect of age and gender on these intakes. To assess validity, all participants completed the FFQ (FFQ1) and a 3 d food record. After 1 month, the FFQ was administered for a second time (FFQ2) to assess repeatability. Jeddah, Saudi Arabia. One hundred males and females aged 20-30 years and 60-70 years participated. Mean intakes of Zn and protein from FFQ1 were significantly higher than those from the food record while there were no detectable differences between tools for measurement of phytic acid intake. Estimated intakes of Zn, protein and phytate by both approaches were strongly correlated (P<0·001). Bland-Altman analysis showed for protein that the difference in intake as measured by the two methods was similar across the range of intakes while for Zn and phytic acid, the difference increased with increasing mean intake. Zn and protein intakes from FFQ1 and FFQ2 were highly correlated (r>0·68, P<0·001) but were significantly lower at the second measurement (FFQ2). Older adults consumed less Zn and protein compared with young adults. Intakes of all dietary components were lower in females than in males. The FFQ developed and tested in the current study demonstrated reasonable relative validity and high repeatability and was capable of detecting differences in intakes between age and gender groups.

Dietary Fiber Intake Increases the Risk of Zinc Deficiency in Healthy and Diabetic Women

Phytic acid is a major determinant of zinc bioavailability. Little is known about phytic acid intakes or indices of zinc bioavailability in type 2 diabetes mellitus (DM), a condition that predisposes to zinc deficiency. The aim of this cross-sectional study was to measure and explore the relationships among phytic acid intake, zinc bioavailability, and molecular markers of zinc homeostasis in 20 women with DM compared to 20 healthy women. The phytate/zinc, (calcium)(phytate)/zinc, and (calcium + magnesium)(phytate)/zinc molar ratios were used to indicate zinc bioavailability. Plasma zinc concentrations and zinc transporter (ZnT1, ZnT8, and Zip1) gene expression in mononuclear cells were measured. Participants with DM consumed 1,194 ± 824 mg/day (mean ± SD) phytic acid, an amount similar to the intake of healthy women (1,316 ± 708 mg/day). Bread products and breakfast cereals contributed more than 40 % of the phytic acid intake in each group. A positive relationship was observed in all participants between phytic acid and dietary fiber (r = 0.6, P < 0.001) and between dietary fiber and the (calcium)(phytate)/zinc ratio (r = 0.5, P < 0.001). Compared to the healthy group, the messenger RNA ratio of ZnT1 (zinc export) to Zip1 (zinc import) was lower in participants with DM, which may indicate perturbed zinc homeostasis in the disorder. The plasma zinc concentration was not predicted by age, body mass index, health status, zinc bioavailability, or zinc transporter expression. Healthy and diabetic women consume phytic acid in amounts that are likely to decrease the bioavailability of dietary zinc. Recommendations to consume greater amounts of dietary fiber, much of which is associated with phytate, increase the risk of zinc deficiency.

Contents of Phytic Acid of Various Cereal Crops Produced in Korea

The main objective of the study was to investigate the phytic acid contents of various cereals and legumes produced in Korea. The results showed that the phytic acid contents of buckwheat, foxtail millets, sorghum, millet, barley, jobs' tears, yellow corn and wheat flour (Urimil) were in a range of 0.13 to 2.27%. The contents of the phytic acid ranged from 1.03 to 1.16% for legumes including red Indian bean, black Indian bean, mung bean, and black soybean. The phytic acid content of brown rice was five times higher than those of 100% polished rice. The polishing process of the rice decreased significantly the content of the phytic acid. We estimate that the daily phytic acid intake from rice was changed from 653 mg/day in 1995 to 430 mg/day in 2005 based on the results of a national nutrition survey.

Low Phytic Acid Lentils (Lens culinaris L.): A Potential Solution for Increased Micronutrient Bioavailability

Phytic acid is an antinutrient present mainly in seeds of grain crops such as legumes and cereals. It has the potential to bind mineral micronutrients in food and reduce their bioavailability. This study analyzed the phytic acid concentration in seeds of 19 lentil ( Lens culinaris L.) genotypes grown at two locations for two years in Saskatchewan, Canada. The objectives of this study were to determine (1) the levels of phytic acid in commercial lentil genotypes and (2) the impact of postharvest processing and (3) the effect of boiling on the stability of phytic aid in selected lentil genotypes. The phytic acid was analyzed by high-performance anion exchange separation followed by conductivity detection. The Saskatchewan-grown lentils were naturally low in phytic acid (phytic acid = 2.5-4.4 mg g(-1); phytic acid phosphorus = 0.7-1.2 mg g(-1)), with concentrations lower than those reported for low phytic acid mutants of corn, wheat, common bean, and soybean. Decortication prior to cooking further reduced total phytic acid by >50%. As lowering phytic acid intake can lead to increased mineral bioavailability, dietary inclusion of Canadian lentils may have significant benefits in regions with widespread micronutrient malnutrition.

Phytate in foods and significance for humans: Food sources, intake, processing, bioavailability, protective role and analysis

The article gives an overview of phytic acid in food and of its significance for human nutrition. It summarises phytate sources in foods and discusses problems of phytic acid/phytate contents of food tables. Data on phytic acid intake are evaluated and daily phytic acid intake depending on food habits is assessed. Degradation of phytate during gastro-intestinal passage is summarised, the mechanism of phytate interacting with minerals and trace elements in the gastro-intestinal chyme described and the pathway of inositol phosphate hydrolysis in the gut presented. The present knowledge of phytate absorption is summarised and discussed. Effects of phytate on mineral and trace element bioavailability are reported and phytate degradation during processing and storage is described. Beneficial activities of dietary phytate such as its effects on calcification and kidney stone formation and on lowering blood glucose and lipids are reported. The antioxidative property of phytic acid and its potentional anticancerogenic activities are briefly surveyed. Development of the analysis of phytic acid and other inositol phosphates is described, problems of inositol phosphate determination and detection discussed and the need for standardisation of phytic acid analysis in foods argued.

Determination of the phytic acid levels in infant foods using different analytical methods

The analytical methods of phytic acid determination in infant foods were evaluated, and then, the method suggested in this study was applied to determine the phytic acid level in commercially available infant foods for both the flour and paste types. The spectrophotometric (AOAC and Wade reagent) and chromatographic (GC-FID and HPLC) methods were compared, and the spectrophotometrically determined value showed higher phytic acid levels than that of the chromatographic methods ( p < 0.05). The AOAC method showed a complete recovery for the infant foods after spiking the phytic acid, while a poor recovery was observed by GC-FID and HPLC-RI. The average levels of phytic acid in the infant foods determined by the AOAC methods were 363 mg/100 g for the flour type and 46.3 mg/100 g for the paste type on a wet basis. When the phytic acid level was converted into a dry basis, the phytic acid levels of the paste types were much higher than that of the flour type. Thus, the amount of phytic acid intake per meal was calculated, and the phytic acid level per meal was high in the paste type as wells as the flour type. Therefore, a problem with phytic acid might be considered for the infant foods of both the flour and paste types.

Physical fitness and vegetarian diets: is there a relation?

The available evidence supports neither a beneficial nor a detrimental effect of a vegetarian diet on physical performance capacity, especially when carbohydrate intake is controlled for. Concerns have been raised that an emphasis on plant foods to enhance carbohydrate intake and optimize body glycogen stores may lead to increases in dietary fiber and phytic acid intake to concentrations that reduce the bioavailability of several nutrients, including zinc, iron, and some other trace minerals. There is no convincing evidence, however, that vegetarian athletes suffer impaired nutrient status from the interactive effect of their heavy exertion and plant-food based dietary practices to the extent that performance, health, or both are impaired. Although there has been some concern about protein intake for vegetarian athletes, data indicate that all essential and nonessential amino acids can be supplied by plant food sources alone as long as a variety of foods is consumed and the energy intake is adequate. There has been some concern that vegetarian female athletes are at increased risk for oligoamenorrhea, but evidence suggests that low energy intake, not dietary quality, is the major cause. In conclusion, a vegetarian diet per se is not associated with improved aerobic endurance performance. Although some concerns have been raised about the nutrient status of vegetarian athletes, a varied and well-planned vegetarian diet is compatible with successful athletic endeavor.

Ca and P bioavailability of processed lentils as affected by dietary fiber and phytic acid content

The influence of germination for 6 days and dry-heating at 120°C for 15 min on the content of calcium, phosphorus, phytic acid and dietary fiber in lentils was studied. Germination lowered total phosphorus (P) and phytic acid content whereas dry-heating did not modify total P but slightly decreased phytic acid. Both treatments increased cellulose (CL) and lignin (LN) content and reduced hemicellulose (HMC) of lentils. The apparent digestibility coefficient (ADC) and balance of calcium (Ca) improved in animals fed dry-heated and germinated lentils which was related with the decrease in HMC. Phytic acid intake was significantly reduced by dry-heating and germination, the lowest P intake and P absorption observed in animals fed germinated lentils led to a null P balance. The results obtained in muscle and femur by comparing control (casein) and experimental diets indicated that muscle is more sensitive tissue than bone at lower Ca and P retention.

Nutritional meaning of dietary fibre and phytic acid in meat-based homogenised weaning foods

Twenty-seven meat based homogenised weaning foods purchased in supermarkets and pharmacies in Murcia were analysed to determine the total dietary fibre (TDF) and phytic acid content. The samples were grouped according to the type of meat used: lamb, ham, chicken, veal, beef, chicken and veal, and beef and ham. In a 250 jar, the TDF ranged from 0.45 to 4.25 g, whereas the phytic acid content varied from 0.08 to 0.69 g. In general, the weaning foods studied provided a good percentage of the recommended dietary intakes (RDI) of TDF, but according to the phytate/Ca, phytate/Zn and phytate × Ca Zn molar ratios, the phytic acid content could compromise the Ca and Zn availability in some samples. No trend was observed between TDF and phytic acid content, provided by the plant food ingredients to the weaning foods. It is clear that the selection of ingredients (vegetables, legumes and cereals) for homogenised weaning foods should be made in accordance with their contribution to TDF and phytic acid intake, in order to improve the percentage of TDF, to reduce the phytic acid content and to ensure an adequate mineral availability.

Growth and body composition of periurban Guatemalan children in relation to zinc status: a cross-sectional study

In a study of periurban Guatemalan school-children (89 males, 73 females) aged 81.5 +/- 7.0 mo (mean +/- SD), height, weight, arm circumference, and triceps-skinfold-thickness (TSF) measurements were examined in relation to plasma and hair zinc concentrations, plasma and red blood cell alkaline phosphatase activities, recognition thresholds for salt (RTS), delayed-cutaneous hypersensitivity response to seven recall skin test antigens, and cognitive measures. Children were stunted [median height-for-age (HA) Z score -1.49] but not wasted [median weight-for-height (WH) Z score 0.20], with median midarm muscle area (MAMA) and midarm-fat area (MAFA) Z scores of -0.57 and -0.35, respectively. Of the children, 63.5% of males and 44.1% of females had hair zinc < 1.68 mumol/g (P < 0.05); 12.3% of males and 1.5% of females had plasma zinc < 10.71 mumol/L (P < 0.05). Children with hair zinc < 1.68 mumol/g had higher (P < 0.05) medians for WA Z and WH Z scores, RTS, and phytic acid intake than did those with hair zinc > or = 1.68 mumol/g. Zinc status explained some of the variance in growth (HA, WA, and WH Z scores), body composition (MAFA Z scores), and taste acuity. Suboptimal zinc status arose partly from diets low in readily available zinc.

Mineral balance of adult men consuming whole or dephytinized wheat bran

Ten men consumed for 15 days each, 36 g daily of either whole or dephytinized wheat bran. Mineral intakes were the same for each dietary regimen. Phytic acid intake was 2 or 0.2 g and the phytate/zinc molar ratio was 12 or 1.2 when eating whole or dephytinized bran, respectively. Apparent absorption (intake-fecal excretion) of iron, zinc, copper, managenese, magnesium, and calcium tended to be lower when whole bran was consumed. However, balances (intake-[fecal+urinary excretion]) for the last 10 days were for the most part positive regardless of which type of bran and more positive when whole bran was eaten. The whole wheat bran did not have a deleterious effect on mineral nutriture of adult men under the conditions of this study.

EFFECT OF INCREASED DIETARY PHYTIC ACID ON CHOLECALCIFEROL REQUIREMENTS IN RATS

The effect of a high dietary phytic-acid intake on plasma-calcium homœostasis has been studied in rats. The effect of phytic acid in groups of rats on an adequate cholecalciferol intake has been compared with groups of animals on an increased cholecalciferol intake. Despite an increased intake of cholecalciferol, high dietary phytic acid was associated with the development of hypocalcæmia. These findings are relevant to the ætiology of rickets and osteomalacia among Asian immigrants in the United Kingdom.