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

Iron homeostasis in older adults: balancing nutritional requirements and health risks

Iron plays a crucial role in many physiological processes, including oxygen transport, bioenergetics, and immune function. Iron is assimilated from food and also recycled from senescent red blood cells. Iron exists in two dietary forms: heme (animal based) and non-heme (mostly plant based). The body uses iron for metabolic purposes, and stores the excess mainly in splenic and hepatic macrophages. Physiologically, iron excretion in humans is inefficient and not highly regulated, so regulation of intestinal absorption maintains iron homeostasis. Iron losses occur at a steady rate via turnover of the intestinal epithelium, blood loss, and exfoliation of dead skin cells, but overall iron homeostasis is tightly controlled at cellular and systemic levels. Aging can have a profound impact on iron homeostasis and induce a dyshomeostasis where iron deficiency or overload (sometimes both simultaneously) can occur, potentially leading to several disorders and pathologies. To maintain physiologically balanced iron levels, reduce risk of disease, and promote healthy aging, it is advisable for older adults to follow recommended daily intake guidelines and periodically assess iron levels. Clinicians can evaluate body iron status using different techniques but selecting an assessment method primarily depends on the condition being examined. This review provides a comprehensive overview of the forms, sources, and metabolism of dietary iron, associated disorders of iron dyshomeostasis, assessment of iron levels in older adults, and nutritional guidelines and strategies to maintain iron balance in older adults.

Iron Absorption: Factors, Limitations, and Improvement Methods

Iron is an essential element for human life since it participates in many functions in the human body, including oxygen transport, immunity, cell division and differentiation, and energy metabolism. Iron homeostasis is mainly controlled by intestinal absorption because iron does not have active excretory mechanisms for humans. Thus, efficient intestinal iron bioavailability is essential to reduce the risk of iron deficiency anemia. There are two forms of iron, heme and nonheme, found in foods. The average daily dietary iron intake is 10 to 15 mg in humans since only 1 to 2 mg is absorbed through the intestinal system. Nutrient-nutrient interactions may play a role in dietary intestinal iron absorption. Dietary inhibitors such as calcium, phytates, polyphenols and enhancers such as ascorbic acid and proteins mainly influence iron bioavailability. Numerous studies have been carried out for years to enhance iron bioavailability and combat iron deficiency. In addition to traditional methods, innovative techniques are being developed day by day to enhance iron bioavailability. This review will provide information about iron bioavailability, factors affecting absorption, iron deficiency, and recent studies on improving iron bioavailability.

Effects of soy protein isolate hydrolysates on cholecystokinin released by rat intestinal mucosal cells and food intake in rats

Soy protein isolate hydrolysates (SPIH) were prepared from soy protein isolate (SPI). Effects of SPIH on a satiety signal cholecystokinin (CCK) and feeding behavior in rats were investigated. SPIH induced more CCK release (164.66 ± 2.40 pg/mL) by rat intestinal mucosal cells than SPI (143.33 ± 3.71 pg/mL). Meal size (MS), intermeal interval (IMI), and satiety ratio (SR = MS/IMI) of rats received different daily doses of SPIH or dietary fiber were detected for 40 days. A 100 mg/kg dose of SPIH resulted in a greater SR than an identical dose of dietary fiber, while a 300 mg/kg dose resulted in a less MS and IMI. A 500 mg/kg dose of SPIH had similar effects to the same dose of dietary fiber on reducing MS, extending IMI, and increasing SR, but resulted in a significantly less body weight at the end of the experiment (318.15 ± 17.83 g) than the dietary fiber group (340.28 ± 6.15 g).

Fortifying pork liver mixture: Evaluation of protein quality and iron bioavailability – Part 2

ABSTRACT Objective To evaluate the protein quality and iron bioavailability of a fortifying mixture based on pork liver. Methods Determinations of protein efficiency ratio, net protein utilization, true digestibility and hemoglobin regeneration efficiency by depletion and repletion were performed. In the depletion phase, the animals (male Wistar rats) received an iron-free AIN–93G diet and in the repletion phase they received the following diets: standard AIN–93G diet, fortifying mixture and standard diet containing heptahydrated ferrous sulfate for comparison. Results For standard AIN–93G diet and fortifying mixture the results were 3.75 and 4.04 for protein efficiency ratio and 3.53 and 3.63 for net protein retention, showing that the presence of pork liver in the diet promoted an increase in protein efficiency ratio and net protein retention (not statistically significant). True digestibility results obtained with the fortifying mixture (97.16%) were higher than those obtained with the standard AIN–93G diet (casein), but without significant difference. The hemoglobin regeneration efficiency values obtained for standard AIN–93G diet, fortifying mixture and standard diet containing heptahydrated ferrous sulfate were 50.69, 31.96 and 29.96%, respectively, showing a statistically significant difference between the control (standard AIN–93G diet) and test (fortifying mixture and standard diet containing heptahydrated ferrous sulfate) samples, but not between the test samples. Conclusion The fortifying mixture showed a high protein efficiency ratio value of 4.04 and a high relative biological value (108%) and it can be added to soups, creams and meats in day-care centers for the prevention of iron-deficiency in children of school age.

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.

Ameliorating effects of herbal formula hemomine on experimental subacute hemorrhagic anemia in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Hemomine (HM) is an herbal mixture consisting of 5 varieties of the hematopoietic herbal extracts (Angelica gigas Nakai, Cnidium officinale Makino, Paeonia lactiflora Pall., Rehmannia glutinosa Liboschitz ex Stueudel, Glycyrrhiza uralensis Fischer).

AIM OF THE STUDY

Anemia has been treated with iron supplements, whereas it could cause adverse side effects such as digestive discomfort. In the present study, HM was applied to SHA rats to test for several activities so as to verify its therapeutic potentials on anemia and digestive discomfort.

MATERIALS AND METHODS

Sprague-Dawley rats were assigned to seven groups: (Two controls, two references (ferric hydroxide polymatose (FM) and ferritin extract glycerin hydrate (FA)), three different concentrations of HM, n=8 per groups), and induced subacute hemorrhagic anemia (SHA) through blood exsanguinations once a day for 7 days.

RESULTS

The SHA animal model showed changes in the markers related to classic iron-deficient and regenerative anemia in this experiment. However, the SHA related anemic signs were dose-dependently inhibited by the administration of HM 2, 1, and 0.5ml/kg for 7 days, and more favorably than the equal dosages of FM and FA. In addition, FM and FA showed the typical constipation signs, including reduction of in thickness of the colonic mucosa, in contrast, HM 2, 1, and 0.5ml/kg groups had no effects on the gastrointestinal motilities and the colonic mucous components when compared to the controls. The results suggested that the HM significantly showed to have therapeutic effects in the experimental SHA in rats, and is more potent than the commercial iron supplement through the proliferation of hematopoietic stem cells with reduced digestive discomfort.

CONCLUSIONS

Therefore, Hemomine may prove to be a promising hematopoietic and therapeutic agent for anemia.

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.