Partially hydrolyzed guar gum increases intestinal absorption of iron in growing rats with iron deficiency anemia

Anemia and frailty in the aging population: implications of dietary fiber intake (findings of the US NHANES from 2007-2018)

BACKGROUND

Frailty has long been seen as an indicator of reduced physical functions in the elderly, which may be caused by a variety of chronic illnesses or cancerous tumors. Dietary fiber was connected with anemia and frailty, whereas it was uncertain if dietary fiber consumption modifies the impact of anemia on frailty in elderly adults.

METHODS

We performed a secondary analysis using older adults aged 60 years and over from the National Health and Nutrition Examination Survey (NHANES) 2007-2018 cycles. Dietary fiber intake was estimated using two 24-h dietary recalls. Participants were dichotomized as frail or non-frail based on a modified Fried physical frailty phenotype from previous NHANES studies. The weighted logistic regression was used to estimate the odds ratio (OR) and confidence interval (CI) for the associations between hemoglobin levels and frailty at high- and low-dietary fiber intake levels.

RESULTS

A total of 9644 older adults were included in this study, and the weighted sample was 56,403,031, of whom 3,569,186 (6.3%) were deemed to be frail, and the remainder were deemed to be non-frail. Among the low dietary fiber intake group, higher hemoglobin was significantly associated with a lower risk of frailty (OR = 0.79, 95% CI: 0.71-0.87), and anemia was associated with an almost threefold elevated risk of frailty (OR = 3.24, 95% CI:1.98-5.29) in the fully adjusted model. However, this phenomenon was not observed in groups with high dietary fiber intake. In addition, L-shaped dose response relationship was found in the high dietary fiber intake group (P overall association < 0.001; P non-linear association = 0.076). Whereas the dose response relationship was not significant in the high dietary fiber intake group (P overall association 0.752; P non-linear association = 0.734).

CONCLUSIONS

Frailty was positively associated with the severity of anemia in older adults with low, but not high, dietary fiber intake. Adequate fiber intake may be an innovative dietary strategy to reduce frailty in older adults.

The prebiotic effects of soluble dietary fiber mixture on renal anemia and the gut microbiota in end-stage renal disease patients on maintenance hemodialysis: a prospective, randomized, placebo-controlled study

BACKGROUND

Renal anemia is caused by end-stage renal disease (ESRD) but has a complex etiology. The application of dietary fiber (DF) to regulate the gut microbiota has shown effective therapeutic effects in some diseases, but its role in renal anemia is not clear. The aim of this study was to explore the effect of DF on renal anemia by regulating the gut microbiota and its metabolite, short-chain fatty acids (SCFAs).

METHODS

A total of 162 ESRD patients were enrolled and randomly distributed into a DF or a control group (received oral DF or potato starch, 10 g/day for 8 weeks). Hemoglobin (Hb), serum iron (Fe²⁺), serum ferritin (SF), soluble transferrin receptor (sTfR), hepcidin and the dosage of recombinant human erythropoietin (rhEPO) before and after intervention in patients were analyzed. The gut microbiota and SCFAs in both groups were analyzed by 16S rDNA sequencing and gas chromatography-mass spectrometry, respectively. Spearman's correlation test was used to analyze the correlation between the gut microbiota, SCFAs and the hematological indicators.

RESULTS

Compared with the control group, (1) the patients in the DF group had higher Hb [117.0 (12.5) g/L vs. 94.0 (14.5) g/L, p < 0.001], Fe²⁺ [13.23 (4.83) μmol/L vs. 10.26 (5.55) μmol/L, p < 0.001], and SF levels [54.15 (86.66) ng/ml vs. 41.48 (36.60) ng/ml, p = 0.003]. (2) The rhEPO dosage in the DF group was not significantly decreased (p = 0.12). (3) Bifidobacterium adolescentis, Lactobacillus and Lactobacillaceae were increased in the DF group, and Lactobacillus and Lactobacillaceae were positively correlated with Hb (r = 0.44, p < 0.001; r = 0.44, p < 0.001) and Fe²⁺ levels (r = 0.26, p = 0.016; r = 0.26, p = 0.016) and negatively correlated with rhEPO dosage (r = - 0.45, p < 0.001; r = - 0.45, p < 0.001). (4) Patients in the DF group had elevated serum butyric acid (BA) levels [0.80 (1.65) vs. 0.05 (0.04), p < 0.001] and BA levels were positively correlated with Hb (r = 0.26, p = 0.019) and Fe²⁺ (r = 0.31, p = 0.005) and negatively correlated with rhEPO dosage (r = - 0.36, p = 0.001). Lactobacillus and Lactobacillaceae were positively correlated with BA levels (r = 0.78, p < 0.001; r = 0.78, p < 0.001).

CONCLUSION

DF may improve renal anemia in ESRD patients by regulating the gut microbiota and SCFAs. Trial registration This study was registered in the China Clinical Trial Registry ( www.chictr.org.cn ) on December 20, 2018 ( ChiCTR1800020232 ).

Is There Such a Thing as "Anti-Nutrients"? A Narrative Review of Perceived Problematic Plant Compounds

Plant-based diets are associated with reduced risk of lifestyle-induced chronic diseases. The thousands of phytochemicals they contain are implicated in cellular-based mechanisms to promote antioxidant defense and reduce inflammation. While recommendations encourage the intake of fruits and vegetables, most people fall short of their target daily intake. Despite the need to increase plant-food consumption, there have been some concerns raised about whether they are beneficial because of the various ‘anti-nutrient’ compounds they contain. Some of these anti-nutrients that have been called into question included lectins, oxalates, goitrogens, phytoestrogens, phytates, and tannins. As a result, there may be select individuals with specific health conditions who elect to decrease their plant food intake despite potential benefits. The purpose of this narrative review is to examine the science of these ‘anti-nutrients’ and weigh the evidence of whether these compounds pose an actual health threat.

[Effect of quinoa extract consumption on iron deficiency-induced anemia in mice]

OBJECTIVES

To determine the effect of quinoa extract consumption on iron deficiency-induced anemia in mice.

MATERIALS AND METHODS

Thirty male M. musculus albino mice of the Balb/c strain, with an average weight of 24±32.7 g, were used. Three groups of ten mice each were formed: 1) a negative control group of iron-sufficient (IS) mice that received 40g/d of balanced feed for 7 weeks; 2) a positive control group of iron-deficient (ID) mice that received 40g/d of feed rich in iron for 7 weeks; and 3) an experimental group of ID mice that received 40 g/d of feed rich in iron for 7 weeks and 20 g/d of quinoa extract (QE) from week 5. Hemoglobin levels were measured.

RESULTS

At the end of the treatment, a significant difference was found in hemoglobin levels between the positive (ID mice: 8.9±1.1 g/dL) and experimental (ID+QU mice: 11.4±0.5 g/dL) groups (student's t, p<0.05). No significant difference was found in hemoglobin levels at the end of the induction period between the positive (IS mice: 9.1±1.1) and experimental (ID mice: 9.3±0.7) groups (student's t, p>0.05).

CONCLUSIONS

Under experimental conditions, quinoa has an antianemic effect based on the results of hemoglobin levels.

Effect of fructo-oligosaccharide supplementation in soya beverage on the intestinal absorption of calcium and iron in newly weaned rats

Studies have shown the positive effects of prebiotics on the intestinal absorption of Ca and Fe. The present study evaluated the effect of fructo-oligosaccharide (FOS) supplementation in soya beverage (SB) on absorption mechanisms of Ca and Fe in recently weaned rats. Male Wistar rats were divided into four groups: lactose-free cows' milk (CM), lactose-free CM with FOS (0·8 g/100 ml) (CMF), SB and soya beverage with FOS (0·8 g/100 ml) (SBF). These rats were euthanised after 1 week of treatment. Organ weight, pH of the caecal content and absorption mechanisms of Ca and Fe were evaluated. The results showed that the weight of the caecal contents increased in the CMF and SBF groups, and the pH of the caecal contents was lower in these groups. The Hb levels of the CMF and SB groups were higher when compared with that of the CM group and lower in relation to the SBF group. The apparent Ca and Fe absorption and apparent Ca retention in the CM group were higher when compared with the SB group, whereas in the CMF group, they were higher in relation to the SBF group. Divalent metal transporter 1 (DMT1) protein expression in the duodenum was higher in the SBF group than in the SB and CMF groups. SB resulted in lower intestinal Ca absorption and higher Hb concentration, despite the lower apparent Fe absorption in relation to CM. Supplementation with FOS provided beneficial effects on Hb and DMT1 protein expression in the duodenum, in addition to improving the absorption process.

Oat beta-glucan as a dietary supplement for dogs

The aim of this study was to evaluate the effects of oat beta-glucan supplementation on metabolic, physiological, immunological and nutritional variables in adult dogs. Fourteen dogs were fed a control diet or a diet supplemented with 1% beta-glucan during 71 days. Serum concentrations of glucose, total cholesterol and lipoprotein fractions, as well as plasma concentrations of peptide YY and ghrelin, were determined. In addition, coefficient of total tract apparent macronutrient digestibility (CTTAD), food intake and fecal output, score, and pH were evaluated. For evaluation of immunological variables, serum concentrations of interleukin-4 and interferon gamma were determined on days 0, 57 and 71, which corresponded to blood collection prior to beta-glucan supplementation, and at 7 and 14 days post first and second dose of vaccination (Pneumodog^®, Merial, Campinas, Brazil), respectively. Animals fed the supplemented diet showed (P<0.05) lower serum concentrations of total cholesterol and low and very low density lipoproteins, lower coefficients of total tract apparent digestibility of dry matter, organic matter, mineral matter and ether extract, higher fecal output and lower fecal consistency, as well as a tendency (P = 0.07) of decreasing the coefficient of total tract apparent digestibility of crude protein. Moreover, the supplemented diet resulted in lower number of red blood cells, hematocrit percentage and hemoglobin concentration 21 days post-vaccination as well as lower serum concentration of interleukin-4 seven days post-vaccination (P<0.05). It is concluded that oat beta-glucan extract can be used as a dietary supplement for dogs at a dose of 10 g/kg of food, being effective in reducing blood concentrations of total cholesterol, LDL-c and VLDL-c as well as CTTAD of nutrients, demonstrating a potential to be used in the feeding of obese animals. In addition, by reducing the predominance of a Th2 response, oat beta-glucan can positively modulate the vaccine response of animals.

Intake of Polydextrose Alters Hematology and the Profile of Short Chain Fatty Acids in Partially Gastrectomized Rats

Polydextrose (PDX) ingestion may increase the intestinal absorption of iron. This study evaluated the effects of 7.5% polydextrose supplementation on markers of iron uptake, transport and storage in partially gastrectomized rats. Half of a batch of 40 male Wistar rats (250 g) underwent Billroth II partial gastrectomy with anterior truncal vagotomy (GXT), while the other half underwent sham gastrectomy (SHAM). At 7 postoperative days, the animals were subdivided into four groups (n = 10): Sham Control and GXT Control (no polydextrose); Sham PDX and GXT PDX (with 7.5% PDX). The animals were euthanized after 60 day of PDX treatment. Organ weight, cecal pH, the characterization and quantification of short-chain fatty acids (SCFA), hematological parameters, hepatic iron content and the expression of ferroportin (FPT) in the jejunum, cecum, colon and liver were evaluated. PDX caused changes in the cecum of the supplemented animals, where there was a decrease in pH, increase in cecal wall and marked production of SCFA, especially acetic and propionic acids (p < 0.05). Hepatic iron levels were lower in GXT animals. PDX increased hemoglobin (HGB) values by 29.2% and hematocrit (HCT) by 55.8% in the GXT PDX group compared to the GXT Control group. The GXT PDX group had lower hepatic FPT expression (p < 0.05). PDX led to increased SCFA concentration in the supplemented animals. Considering that SCFAs play a central role in the increasing nutrients uptake, this mechanism may be involved in altering the hematology profile observed in these animals but not enough to reverse iron deficiency anemia in post-gastrectomy rats.

Partially Hydrolyzed Guar Gum Increases Ferroportin Expression in the Colon of Anemic Growing Rats

Studies have reported a positive effect of prebiotics on the bioavailability of iron. This study evaluated the effect of partially hydrolyzed guar gum (PHGG) on iron absorption mechanisms in anemic rats. Male Wistar rats were fed 75g American Institute of Nutrition Rodent Diets for growth, pregnancy and lactation (AIN93-G) without iron for three weeks in order to induce iron deficiency anemia. Then they were fed a control diet (n = 12; without fiber) or a diet with 7.5% of PHGG (n = 12), both without iron. Food intake, body growth and the feed efficiency coefficient (FEC) were measured. The animals were euthanized after two weeks of treatment. The weight of the organs, the pH of the cecal content, and the hepatic iron and ferroportin expression in the cecum, duodenum, and liver were assessed. The intake of PHGG reduced food intake without affecting body growth, and there was a difference between the groups regarding the FEC (p = 0.026), with the highest value found in the PHGG group. The weight of the cecal content increased (p ≤ 0.001) and the pH of the cecal content was significantly lower in the PHGG group. The intake of PHGG significantly increased ferroportin expression in the cecum;however, the difference was not significant in the duodenum and the liver. PHGG seems to have a positive influence on iron absorption through transporter expression, and structural and physiological changes in the colon of anemic growing animals.

Real-time monitoring of trans-epithelial electrical resistance in cultured intestinal epithelial cells: the barrier protection of water-soluble dietary fiber

OBJECTIVES

In this study we aimed to verify a real-time trans-epithelial electrical resistance (TEER) monitoring system in a Caco-2 monolayer and to investigate the therapeutic effect of partially hydrolyzed guar gum (PHGG), a dietary fiber, against interferon (IFN)-γ-induced intestinal barrier dysfunction using this monitoring system.

METHODS

We measured TEER using a real-time monitoring system and evaluated epithelial paracellular permeability using fluorescein isothiocyanate-conjugated dextran (4 kDa; FD4) in Caco-2 monolayers treated with IFN-γ for 48 h. The expression and distribution of tight junction (TJ)-associated proteins, ZO-1 and occludin, were analyzed by Western blot and immunocytochemistry, respectively. In some experiments PHGG was added prior to IFN-γ treatment in order to investigate its protective effect on barrier function.

RESULTS

IFN-γ treatment significantly decreased TEER and increased FD4 flux across Caco-2 monolayers, indicating a great influence of IFN-γ on the intestinal epithelial paracellular permeability. In contrast, the pretreatment of PHGG significantly reduced the IFN-γ-induced increment of FD4 flux without affecting TEER. Neither IFN-γ nor PHGG treatment affected the expressions of TJ-associated proteins, while immunocytochemistry showed that IFN-γ-induced redistribution of occludin was clearly restored by PHGG.

CONCLUSIONS

Real-time TEER monitoring enabled us to evaluate the dynamic changes of intestinal epithelial barrier function. PHGG may have a protective effect against IFN-γ-induced barrier dysfunction by attenuating the paracellular hyperpermeability; thus, its promotion as a functional food is anticipated.

Post-meal perceivable satiety and subsequent energy intake with intake of partially hydrolysed guar gum

Partially hydrolysed guar gum (PHGG), a soluble dietary fibre, has been shown to provide many health benefits. Previous studies had suggested that the combination of PHGG with protein provided a significant satiation effect on visual analogue scales (VAS). What was lacking was only the effect of administration of small doses of PHGG on post-meal satiation and subsequent energy intake. The objectives of the present investigations were to find the subjective perception of post-meal satiety with acute and long term administration of small amounts of PHGG alone with food, its effects on subsequent energy intake and the comparative effects among different types of soluble fibres. The following three separate studies were conducted: in study 1, healthy subjects (n 12) consumed PHGG along with breakfast, lunch and an evening snack; in study 2, healthy subjects (n 24) consumed 2 g of PHGG or dextrin along with yogurt as breakfast for 2 weeks; in study 3, healthy subjects (n 6) took 6 g each of either PHGG or indigestible dextrin or inulin along with lunch. In all the studies, various satiety parameters were measured on VAS before and after consumption of PHGG. The addition of PHGG showed significant (P < 0.05) acute (studies 1 and 3) and long-term (studies 1 and 2) satiety effects compared to the control and/or an equal amount of carbohydrate or other types of soluble fibre. Study 2 also indicated that the prolonged consumption of PHGG may significantly (P < 0.05) reduce energy intake from whole-day snacking. PHGG could be an ideal natural soluble fibre for delivering acute and long term satiety effects for comfortable appetite control.

Safety assessment and caloric value of partially hydrolyzed guar gum

Guar gum and partially hydrolyzed guar gum (PHGG) are food ingredients that have been available for many years. PHGG is the partially hydrolyzed product from guar gum obtained from the Indian cluster bean (Cyanopsis tetragonolopus). The gum (CAS Registry No. 9000-30-0) is composed of galactomannan, a gel-forming polysaccharide with a molecular weight ranging from 200 to 300 kDa. The intact and partially hydrolyzed forms have multiple food applications. The intact material can be used to control the viscosity, stability, and texture of foods. PHGG is highly soluble and has little physical impact on foods. Both forms are indigestible but are excellent sources of fermentable dietary fiber. The caloric value of intact guar gum is accepted as 2.0, whereas the caloric value of PHGG has not been firmly established. It is the goal of this paper to review the chemistry, safety, in vivo effects, and caloric value of PHGG.

High-performance inulin and oligofructose prebiotics increase the intestinal absorption of iron in rats with iron deficiency anaemia during the growth phase

Considering the high frequency of anaemia due to Fe deficiency, it is important to evaluate the effects of prebiotics on the absorption of Fe. The aim of the present study was to evaluate the effects of high-performance (HP) inulin, oligofructose and synergy1 during recovery from anaemia in rats through the intestinal absorption of Fe, food intake, body growth, caecal pH and weight of the intestine. Wistar rats (n 47) were fed with rations of AIN93-G with no Fe to induce Fe deficiency anaemia. At 36 d of life, anaemic rats were divided into four groups: (1) the HP inulin group; (2) the synergy1 group; and (3) the oligofructose group, all with 100 g of the respective prebiotic per kg of ration; and (4) a control group, in which the prebiotic was replaced by maize starch. Then, 25 mg of elemental Fe/kg of ration was added to all rations to allow recovery from anaemia. The final values of Hb in the HP inulin, synergy1, oligofructose and control groups were, respectively: 98 (94–99); 83 (81–92); 100 (90–114); 77 (72–81) g/l, with a statistically significant difference (P ≤ 0·001) between the oligofructose and control groups and the HP inulin and control groups. The four groups had an increase in weight and body length and had similar consumption of rations. The intestinal weight and caecal pH were significantly different between the groups that consumed prebiotics and the control group. HP inulin and oligofructose increased the intestinal absorption of Fe in rats.

Effect of dietary fibre mixture on growth and intestinal iron absorption in rats recovering from iron-deficiency anaemia

There is concern regarding the possible negative effects of ingestion of dietary fibre on growth and intestinal Fe absorption in infants. The aim of the present study was to compare the effect of a fibre mixture on the growth and the intestinal absorption of Fe in rats with Fe-deficiency anaemia with that of a diet without fibres. Faecal weight and caecal pH were also evaluated. According to the Hb depletion–repletion model, twenty-two male weaned Wistar rats were fed the AIN93-G diet without Fe until Fe-deficiency anaemia was induced with Hb < 70 g/l. The anaemic rats were divided into two groups: (1) fibre mixture group – fed 100 g of fibre mixture/kg of diet (soya polysaccharide, inulin, resistant starch, Arabic gum, fructo-oligossaccharide and cellulose) (n 11); (2) control group – fed without fibres (n 11). All diets had 157 mg of ferric citrate (30 mg of elemental Fe) added to lead to recovery from anaemia. Fe intestinal absorption was measured by Hb repletion efficiency (HRE) and apparent Fe intestinal absorption. The HRE was 44·8 (sd 9·5) % in the fibre mixture group and 43·0 (sd 9·5) % in the control group (P = 0·664). The apparent Fe absorption was 46·2 (sd 16·5) and 47·2 (sd 10·2) % (P = 0·861) in the fibre mixture and control groups, respectively. The faecal weight median was 6·17 g in the fibre mixture group and 2·11 g in the control group (P < 0·001). The caecal pH was in the same order: 6·11 (sd 0·59) and 7·07 (sd 0·34) (P < 0·001). Both the groups consumed similar quantities of diet, and growth was similar in both the groups. The fibre mixture had no influence either on growth or on Fe intestinal absorption in rats recovering from anaemia. This mixture favoured an increase in faecal weight and a decrease in caecal pH.

Effect of soluble fiber pectin on growth and intestinal iron absorption in rats during recovery from iron deficiency anemia

The objective of this study was to verify whether soluble fiber pectin interferes in growth and intestinal iron absorption in rats during iron deficiency anemia recovery. Twenty-one-day-old Wistar rats (n = 48) were fed for 2 weeks on a diet without iron in order to induce iron deficiency anemia. The anemic animals (age = 36 days) were divided into two groups: (1) pectin, 50 g of pectin per kilogram of diet, and (2) control, diet without dietary fiber. Iron was added to the diets for the two groups in order to reverse the anemia. During the iron deficiency anemia recovery phase (3 weeks), the pectin group showed lower mean values (p < 0.05) of weekly food intake (89.18 +/- 10.82; 107.60 +/- 11.70; 114.50 +/- 16.29 g, respectively, for the pectin group and 99.56 +/- 10.60; 116.36 +/- 15.33; 125.66 +/- 17.25 g, respectively, for the control group). The body weight of the pectin group was lower (p < 0.05) during the study's second and third weeks (192.42 +/- 16.67 and 228.75 +/- 19.81 g, respectively, and 202.87 +/- 19.96 and 243.51 +/- 20.44 g for the control group). Pectin led to a reduction in food intake and growth but not to iron absorption when taking into account the regeneration of hemoglobin mass.