Long-Term Dose-Response Condensed Tannin Supplementation Does Not Affect Iron Status or Bioavailability

Citation: Delimont, N. M., Fiorentino, N. M., Kimmel, K. A., Haub, M. D., Rosenkranz, S. K., & Lindshield, B. L. (2017). Long-Term Dose-Response Condensed Tannin Supplementation Does Not Affect Iron Status or Bioavailability. Current Developments in Nutrition, 1(10), e001081. https://doi.org/10.3945/cdn.117.001081Background: Repeated phytic acid consumption leads to iron absorption adaptation but, to the best of our knowledge, the impact of repeated tannin consumption has not yet been established. Salivary proline-rich proteins (PRPs) may improve iron absorption by precipitating tannins. Objectives: This study aimed to determine the effect of long-term, dose-response condensed tannin supplementation on iron bioavailability and status and to assess the effect of salivary proteins on iron bioavailability during prolonged condensed tannin consumption. A secondary objective was to assess astringency as a potential marker for adaptation to tannins and iron bioavailability. Methods: Eleven nonanemic women were enrolled in a double-blind 3-dose crossover trial. Three (1.5, 0.25, or 0.03 g) condensed tannin supplements were consumed 3 times/d for 4 wk in random order, with 2-wk washouts in between. Meal challenges were employed before and after supplementation to assess iron bioavailability, iron status, salivary PRP changes, and astringency. Results: Tannin supplementation in any dose did not change iron bioavailability at any dose (P . 0.82) from weeks 0 to 4. Hemoglobin (P = 0.126) and serum ferritin (P = 0.83) were unchanged by tannin dose from weeks 0 to 4. There were significant correlations among tannin supplementation and iron bioavailability, basic proline-rich proteins (bPRPs) (r = 0.366, P = 0.003), and cystatin production (r = 0.27, P = 0.03). Astringency ratings did not change significantly within or between tannin doses (P . 0.126), but there were negative relations among bPRP (r , 20.32, P , 0.21), cystatin production (r , 20.2, P , 0.28), and astringency ratings. Conclusions: Condensed tannin consumption did not affect iron bioavailability or status regardless of the supplementation period in premenopausal nonanemic women. Correlation analyses suggest that bPRPs and cystatins are associated with improved iron bioavailability and that lower ratings of astringency may predict improved iron absorption with repeated tannin consumption. Curr Dev Nutr 2017;1:e001081

Newly formulated, protein quality-enhanced, extruded sorghum-, cowpea-, corn-, soya-, sugar- and oil-containing fortified-blended foods lead to adequate vitamin A and iron outcomes and improved growth compared with non-extruded CSB+ in rats

Citation: Delimont, N. M., Fiorentino, N. M., Opoku-Acheampong, A. B., Joseph, M. V., Guo, Q., Alavi, S., & Lindshield, B. L. (2017). Newly formulated, protein quality-enhanced, extruded sorghum-, cowpea-, corn-, soya-, sugar- and oil-containing fortified-blended foods lead to adequate vitamin A and iron outcomes and improved growth compared with non-extruded CSB+ in rats. Journal of Nutritional Science. doi:10.1017/jns.2017.15Corn and soyabean micronutrient-fortified-blended foods (FBF) are commonly used for food aid. Sorghum and cowpeas have been suggested as alternative commodities because they are drought tolerant, can be grown in many localities, and are not genetically modified. Change in formulation of blends may improve protein quality, vitamin A and Fe availability of FBF. The primary objective of this study was to compare protein efficiency, Fe and vitamin A availability of newly formulated extruded sorghum-, cowpea-, soya- and corn-based FBF, along with a current, non-extruded United States Agency for International Development (USAID) corn and soya blend FBF (CSB+). A second objective was to compare protein efficiency of whey protein concentrate (WPC) and soya protein isolate (SPI) containing FBF to determine whether WPC inclusion improved outcomes. Eight groups of growing rats (n 10) consumed two white and one red sorghum–cowpea (WSC1 + WPC, WSC2 + WPC, RSC + WPC), white sorghum–soya (WSS + WPC) and corn–soya (CSB14 + WPC) extruded WPC-containing FBF, an extruded white sorghum–cowpea with SPI (WSC1 + SPI), non-extruded CSB+, and American Institute of Nutrition (AIN)-93G, a weanling rat diet, for 4 weeks. There were no significant differences in protein efficiency, Fe or vitamin A outcomes between WPC FBF groups. The CSB+ group consumed significantly less food, gained significantly less weight, and had significantly lower energy efficiency, protein efficiency and length, compared with all other groups. Compared with WSC1 + WPC, the WSC1 + SPI FBF group had significantly lower energy efficiency, protein efficiency and weight gain. These results suggest that a variety of commodities can be used in the formulation of FBF, and that newly formulated extruded FBF are of better nutritional quality than non-extruded CSB+. Copyright © The Author(s) 2017 This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited

The Impact of Tannin Consumption on Iron Bioavailability and Status: A Narrative Review

Iron deficiency remains a global health issue, and antinutritional factors, such as tannins, are often cited as contributors to the high prevalence of deficiency. Despite this, tannin-rich diets may have potential beneficial cardiovascular and cancer-fighting properties because of the antioxidant activity of tannins. Furthermore, epidemiologic studies and long-term trials involving participants who consumed diets rich in antinutritional factors, particularly tannins, conflict with single-meal bioavailability studies. The purpose of this narrative review is to determine the effect of tannins on iron bioavailability and status and establish whether adaptation to tannins reduces the antinutritional effects of tannins over time. We also aimed to compare tannins used in iron studies. Common themes related to iron bioavailability and iron status with tannin consumption were collected and collated for summary and synthesis based on models and subjects used. Overall, there was dissonance between iron bioavailability and status in studies. Single-meal studies with hydrolyzable and oligomeric catechin and epicatechin tannins (tea and tannic acid) generally support reductions in bioavailability related to tannin consumption but not consumption of condensed tannin, which are more commonly found in food. Long-term animal model, epidemiologic, and multimeal studies generally do not support changes in iron status related to tannin intake. Studies suggest that long-term tannin consumption may impact iron status in a different manner than single-meal studies or bioavailability iron models predict. Furthermore, iron bioavailability studies that use condensed tannins, which are more commonly consumed, may better predict mealtime iron bioavailability. More research is needed to develop representative antinutritional iron studies and investigate mechanisms underlying the adaptation to tannins and other antinutritional factors that occur over time

The MFFAPP Tanzania Efficacy Study Protocol: Newly Formulated, Extruded, Fortified Blended Foods for Food Aid

Fortified blended foods (FBFs) are micronutrient-fortified blends of milled cereals and pulses that represent the most commonly distributed micronutrient-fortified food aid. FBFs have been criticized due to lack of efficacy in treating undernutrition, and it has also been suggested that alternative commodities, such as sorghum and cowpea, be investigated instead of corn and soybean. The Micronutrient Fortified Food Aid Pilot Project (MFFAPP) Tanzania efficacy study was the culmination of economic, processing, sensory, and nutrition FBF research and development. MFFAPP Tanzania was a 20-wk, partially randomized cluster design conducted between February and July 2016 that enrolled children aged 6–53 mo in the Mara region of Tanzania with weight-for-height z scores >−3 and hemoglobin concentrations <10.3 mg/dL. The intervention was complementary feeding of newly formulated, extruded FBFs (white sorghum cowpea variety 1, white sorghum-cowpea variety 2, red sorghum-cowpea, white sorghum-soy blend, and corn-soy blend 14) compared with Corn Soy Blend Plus (CSB+), a current US Agency for International Development–distributed corn-soy blend, and a no-FBF-receiving control. Screened participants (n = 2050) were stratified by age group (6–23 and 24–53 mo) and allocated to 1 of 7 FBF clusters provided biweekly. Biochemical and anthropometric data were measured every 10 wk at weeks 0, 10, and 20. The primary objectives of this study were to determine whether newly formulated, extruded corn-, soy-, sorghum-, and cowpea-based FBFs result in equivalent vitamin A or iron outcomes compared with CSB+. Changes in anthropometric outcomes were also examined. Results from the MFFAPP Tanzania Efficacy Study will inform food aid producers and distributers about whether extruded sorghum- and cowpea-based FBFs are viable options for improving the health of the undernourished. This trial was registered at clinicaltrials.gov as NCT02847962