Contribution of a novel high-density micronutrient condiment (HDMC) to nutrient adequacy of home-prepared Guatemalan dishes

BACKGROUND

The diet of low-income Guatemalan populations is mostly plant-based, deficient in some vitamins and minerals, and rich in antinutritional compounds that reduce the bioavailability of several micronutrients. Objective. To describe the manner in which low-income Guatemalan women in rural and urban settings would prepare dishes for main meals using a high-density multimicronutrient condiment (HDMC) and to compare the nutrient density and contribution to the recommended dietary allowance (RDA) of the dishes with and without added HDMC.

METHODS

A sample of 30 women, 15 each from rural and urban households, were enrolled. The women were given 20 g of the HDMC and asked to prepare a dish at home, serve it to their families at a time of their own choosing, record the recipe and the amount of condiment added, and report these facts to an interviewer on the following day. The nutrient content of each dish was calculated from food-composition table values for raw, whole ingredients and the package label values for the HDMC.

RESULTS

For all dishes combined, the HDMC provided on average 78% of the total vitamins. The proportion of the total vitamins provided by the HDMC varied greatly among different dishes. Typically a single serving of a dish without added HDMC provided less than half of the RDA (vitamin B12 and folate) for children and adult women. The midday meal is the most important meal of the day and should provide at least half of the RDA of all essential nutrients. With the HDMC added, the dishes on average provided 2 to 10 times the RDA for nutrients such as vitamins B6 and C and niacin in the reference children, and just satisfied the RDA intake for corresponding nutrients in adult women.

CONCLUSIONS

The proportion of the RDAs of micronutrients provided by this novel, micronutrient-rich condiment varies over a wide range, depending on idiosyncrasies of recipe ingredients, amounts of condiment added, individuals served, and age- and physiology-dependent requirements. HDMCs could provide an efficient way to deliver essential micronutrients to vulnerable populations.

Traditional food-processing and preparation practices to enhance the bioavailability of micronutrients in plant-based diets

Dietary quality is an important limiting factor to adequate nutrition in many resource-poor settings. One aspect of dietary quality with respect to adequacy of micronutrient intakes is bioavailability. Several traditional household food-processing and preparation methods can be used to enhance the bioavailability of micronutrients in plant-based diets. These include thermal processing, mechanical processing, soaking, fermentation, and germination/malting. These strategies aim to increase the physicochemical accessibility of micronutrients, decrease the content of antinutrients, such as phytate, or increase the content of compounds that improve bioavailability. A combination of strategies is probably required to ensure a positive and significant effect on micronutrient adequacy. A long-term participatory intervention in Malawi that used a range of these strategies plus promotion of the intake of other micronutrient-rich foods, including animal-source foods, resulted in improvements in both hemoglobin and lean body mass and a lower incidence of common infections among intervention compared with control children. The suitability of these strategies and their impact on nutritional status and functional health outcomes need to be more broadly assessed.

Bioreclamation of coalmine overburden dumps--with special empasis on micronutrients and heavy metals accumulation in tree species

Major environmental impacts of opencast mining are degradation of landscape and aesthetics of the area by creating huge overburden dumps and deep voids at the mining sites. These overburden dumps are characterised by high rock fragment contents, low moisture retention capacity, higher bulk density, low nutrients, lower pH and elevated metal concentrations. Overburden dumps are reclaimed by tree species for stabilising as well as pollution control and overall improvement of the visual aesthetics. A field study was carried out in the old reclaimed coal mine overburden dumps at KD Heslong project, Central Coalfields, India to study the physico-chemical changes in the reclaimed overburden dumps and determines the magnitude of trace elements accumulation in the planted tree species. Total, bioavailable and acid extractable trace metals concentration in minesoils of overburden dump and topsoil in the mining areas was compared with undisturbed soil. The study showed that tree plantation improves the moisture contents, bulk density, pH and overall nutrient contents of minesoils. The study revealed that lower pH in the minesoils increases the bioavailabity of metals but concentration were found within toxic limits. However, ratio between total and bioavailable metals was found lower in overburden dumps than topsoil due to low pH and lack of organic matter. Out of six tree species studied, Bambusa shows highest accumulation of Fe and Cr. Bioaccumulation coefficient for Cr and Zn was found 74 times in Bambusa and 83 times in Dalbergia sissoo. The results of the study underscore the need for close monitoring of trace elements in reclaimed overburden dumps. Tree species like Dalbergia sissoo, Eucalyptus, Cassia seamea, Acaccia mangium and Peltaphorum were found to be the best species for bioreclamation of overburden dumps.

Biofortification of essential nutritional compounds and trace elements in rice and cassava

Plant biotechnology can make important contributions to food security and nutritional improvement. For example, the development of 'Golden Rice' by Professor Ingo Potrykus was a milestone in the application of gene technology to deliver both increased nutritional qualities and health improvement to wide sections of the human population. Mineral nutrient and protein deficiency as well as food security remain the most important challenges for developing countries. Current projects are addressing these issues in two major staple crops, cassava (Manihot esculenta Crantz) and rice. The tropical root crop cassava is a major source of food for approximately 600 million of the population worldwide. In sub-Saharan Africa >200 million of the population rely on cassava as their major source of dietary energy. The nutritional quality of the cassava root is not sufficient to meet all dietary needs. Rice is the staple food for half the world population, providing approximately 20% of the per capita energy and 13% of the protein for human consumption worldwide. In many developing countries the dietary contributions of rice are substantially greater (29.3% dietary energy and 29.1% dietary protein). The current six most popular 'mega' rice varieties (in terms of popularity and acreage), including Chinese hybrid rice, have an incomplete amino acid profile and contain limited amounts of essential micronutrients. Rice lines with improved Fe contents have been developed using genes that have functions in Fe absorption, translocation and accumulation in the plant, as well as improved Fe bioavailability in the human intestine. Current developments in biotechnology-assisted plant improvement are reviewed and the potential of the technology in addressing human nutrition and health are discussed.

Improving the bioavailability of nutrients in plant foods at the household level

Plant foods are the major staples of diets in developing countries, in which the consumption of animal-source foods is often low because of economic and/or religious concerns. However, such plant-based diets are often associated with micronutrient deficits, exacerbated in part by poor micronutrient bioavailability. Diet-related factors in plant foods that affect bioavailability include: the chemical form of the nutrient in food and/or nature of the food matrix; interactions between nutrients and other organic components (e.g. phytate, polyphenols, dietary fibre, oxalic acid, protein, fat, ascorbic acid); pretreatment of food as a result of processing and/or preparation practices. Consequently, household strategies that reduce the content or counteract the inhibiting effects of these factors on micronutrient bioavailability are urgently needed in developing-country settings. Examples of such strategies include: germination, microbial fermentation or soaking to reduce the phytate and polyphenol content of unrefined cereal porridges used for young child feeding; addition of ascorbic acid-containing fruits to enhance non-haem-Fe absorption; heating to destroy heat-labile anti-nutritional factors (e.g. goitrogens, thiaminases) or disrupt carotenoid-protein complexes. Such strategies have been employed in both experimental isotope-absorption and community-based studies. Increases in Fe, Zn and Ca absorption have been reported in adults fed dephytinized cereals compared with cereals containing their native phytate. In community-based studies in rural Malawi improvements in dietary quality and arm-muscle area and reductions in the incidence of anaemia and common infections in young children have been observed.

Skin bioavailability of dietary vitamin E, carotenoids, polyphenols, vitamin C, zinc and selenium

Dietary bioactive compounds (vitamin E, carotenoids, polyphenols, vitamin C, Se and Zn) have beneficial effects on skin health. The classical route of administration of active compounds is by topical application direct to the skin, and manufacturers have substantial experience of formulating ingredients in this field. However, the use of functional foods and oral supplements for improving skin condition is increasing. For oral consumption, some dietary components could have an indirect effect on the skin via, for example, secondary messengers. However, in the case of the dietary bioactive compounds considered here, we assume that they must pass down the gastrointestinal tract, cross the intestinal barrier, reach the blood circulation, and then be distributed to the different tissues of the body including the skin. The advantages of this route of administration are that the dietary bioactive compounds are metabolized and then presented to the entire tissue, potentially in an active form. Also, the blood continuously replenishes the skin with these bioactive compounds, which can then be distributed to all skin compartments (i.e. epidermis, dermis, subcutaneous fat and also to sebum). Where known, the distribution and mechanisms of transport of dietary bioactive compounds in skin are presented. Even for compounds that have been studied well in other organs, information on skin is relatively sparse. Gaps in knowledge are identified and suggestions made for future research.

Functional and structural impact of linuron on a freshwater community of primary producers: the use of immobilized algae

An approach in determining ecosystem integrity and stress on ecosystem level is to assess processes within ecosystems. The aim of the present study was to evaluate the potential use of an in situ assay with immobilized Chlorella vulgaris as an indicator of effects on ecosystem functioning with regard to primary production. The herbicide linuron, applied in concentrations of 20, 60, and 180 microg linuron/L, was used to induce direct effects on primary producers. Direct and indirect changes in structure and function within outdoor model ecosystems of 3 m3 were monitored. The intermediate and highest concentration of linuron caused a decline in growth of the macrophyte Elodea sp., resulting in a significant increase of concentrations of nutrients. The increase in concentrations of nutrients caused an indirectly stimulated growth of immobilized C. vulgaris at the intermediate concentration, whereas similar concentrations of nutrients, at the highest treatment, did not stimulate Chlorella growth. It appeared that the direct effect of linuron on C. vulgaris growth was masked by nutrient availability at the intermediate but not at the highest linuron concentration. The observed immobilized algal growth was an accumulated effect of toxic and trophic pressures within the ecosystem, resulting in an integrative endpoint to detect actual impairment of ecosystem function.

Broiler litter as a micronutrient source for cotton: concentrations in plant parts

Analytically, poultry litter contains nearly all essential micronutrients but the extent of phytoavailability of these nutrients and whether cotton (Gossypium hirsutum L.) and other crop plants can receive adequate amounts of these nutrients from litter is not fully known. The objective of this research was to determine whether cotton receives sufficient amounts of Fe, Cu, Mn, and Zn from litter and estimate the efficiency of cotton in extracting these metal nutrients from litter in the absence of any other source of the micronutrients. The greenhouse research used plastic pots filled with approximately 11 kg of a 2:1 (v/v) sand to vermiculite growing mix. Cotton (cv. Stoneville 474) was grown in the pots fertilized with broiler litter at rates of 30, 60, 90, or 120 g pot(-1) in a factorial combination with four supplemental nutrient solution (NS) treatments. The nutrient solutions consisted of full Hoagland's nutrient solution (NS-full); a solution of the macronutrients N, P, K, Ca, and Mg (NS-macro); a solution of the micronutrients Fe, Zn, Mn, Cu, B, and Mo (NS-micro); and water (NS-none). Based on tissue nutrient analysis, a one-time broiler litter application supplied adequate amounts of Fe, Cu, and Mn to bring the concentration of these nutrients in upper leaves within published sufficiency ranges. Zinc, with <17 mg kg(-1) concentration in the upper leaves, was the only micronutrient below the established sufficiency range regardless of the rate of applied litter. Cotton extracted Fe and Mn more efficiently than Cu or Zn, removing as much as 8.8% of Fe and 7.2% of Mn supplied by 30 g litter pot(-1). In contrast, the extraction efficiency was 1.7% for Cu and 1.9% for Zn. Roots accumulated 58% of the total absorbed Fe and 64% of Cu, and leaves accumulated 32% of the Fe and only 13% of the Cu supplied by litter. In contrast, only 16% of the total absorbed Mn and 23% of Zn accumulated in roots while leaves accumulated 64% of the total Mn and 37% of Zn. These results demonstrate that broiler litter is a valuable source of the metal nutrients supplying Fe, Cu, and Mn in full and Zn in part, but a very large fraction of the litter-supplied metal nutrients remained in the growing mix.

A comparison of concentration ratios for technetium and nutrient uptake by three plant species

Technetium (Tc) is a non-essential element for which accumulation mechanisms in plants have recently been discussed, but only from the viewpoint of existence of anion transport proteins in plant cells. In this study, using three kinds of plants (Cucumis sativus L., Raphanus sativus L., and Brassica chinensis L.), uptake of Tc and Re (a chemical analogue of Tc) were observed. The results showed that Tc and Re uptake occurred not only with water mass flow or active nutrient uptake, but also with uptake of nutrient cations such as K+. It is suggested here that most stable chemical form under aerobic conditions, TcO4-, is used in cation transport as a substitute ions, such as Cl-. After TcO4- passes through a root surface, it moves through the xylem together with cations. Due to these uptake mechanisms, Tc is highly accumulated in plants.

Effect of the diuretic furosemide on urinary essential nutrient loss and on body stores in growing rats

Studies using a model of non-infectious diarrhea, have shown that increasing fecal mass by using laxatives resulted in greater fecal losses of nutrients and lower intestinal absorption. In the present study we used a diuretic to determine if increasing urine volume could result in greater urinary losses of essential nutrients. This is a relevant question because diuretics are widely and successfully used in the treatment of diseases associated with water retention and hypertension. They are known to increase potassium losses. However, there is less information on the effect of diuretics on the urinary losses of essential nutrients. Accordingly, urinary nitrogen, phosphorous, sodium, potassium, magnesium, zinc and retinol were measured in young rats consuming increasing concentrations of furosemide (0, 0.5, 1.0, 1.5 mg/g diet) in the diet over 15 days. The results showed that dietary furosemide caused a dose-dependent polyuria. In addition it reduced food intake and feed efficiency and leaded to poor growth and greater urinary losses of all the measured nutrients and electrolytes. These losses were proportional to urine volume and represented an important fraction of the rats daily intake. The losses were negatively associated with the body and liver content of the same electrolytes and nutrients. In general, this study showed that the diuretic furosemide caused malnutrition in a short period of time by reducing food intake as well as the capacity of retaining macro and micronutrients including the liposoluble vitamin A in a relatively short period of time. This study, together with our previous studies on diarrhea, indicate that proper nutrient utilization requires both an adequate intestinal and renal function.

Apparent absorption of eight micronutrients and phytic acid from vegetarian meals in ileostomized human volunteers

OBJECTIVES

Apparent absorption of eight micronutrients and degradation of phytic acid were studied in human subjects who underwent ileostomy. The prominent factors affecting micronutrient absorption from vegetarian Indian meals (n = 11) were identified.

METHODS

Levels of beta-carotene, ascorbic acid, riboflavin, and thiamine in food and ileostomy contents were estimated by spectrophotometry and spectrofluorometry. Contents of zinc, iron, copper, and manganese were estimated by atomic absorption spectrometry and that of phytic acid by gradient elution ion exchange chromatography. Statistical analyses were done with SPSS 10.0.

RESULTS

Absorption of beta-carotene, ascorbic acid, riboflavin, and thiamine was 63% to 75.6%. There was a negative non-significant trend in values of beta-carotene absorption with increased intake of beta-carotene (r = - 0.51, P > 0.1) and iron (r = -0.67, P = 0.1) but a positive significant trend with riboflavin intakes (r = 0.84, P = 0.018). Percentage of absorption of ascorbic acid showed weak positive associations with intakes of riboflavin (r = 0.71) and ascorbic acid (r = 0.5). Percentage of absorption of ascorbic acid was positively correlated with percentage of absorption of beta-carotene (r = 0.80, P < 0.05), iron, and riboflavin (r = 0.64, P = 0.086), indicating some common influencing factors. Percentages of absorption for zinc (20.2), iron (9.9), and copper (17.6) was comparable with those reported for soy protein-based, high phytate diets. Pattern of phytic acid in the meals and output indicated partial degradation and absorption (34%).

CONCLUSIONS

For vegetarian Indian meals, apparent absorptions of beta-carotene and ascorbic acid were 76% and 73.5% and of riboflavin and thiamine was 63%. Zinc, copper, and iron showed a lower absorption (10% to 20%).

Effects of arsenic on concentration and distribution of nutrients in the fronds of the arsenic hyperaccumulator Pteris vittata L

Pteris vittata was the first terrestrial plant known to hyperaccumulate arsenic (As). However, it is unclear how As hyperaccumulation influences nutrient uptake by this plant. P. vittata fern was grown in soil spiked with 0-500 mg As kg(-1) in the greenhouse for 24 weeks. The concentrations of essential macro- (P, K, Ca, and Mg) and micro- (Fe, Mn, Cu, Zn, B and Mo) elements in the fronds of different age were examined. Both macro- and micronutrients in the fronds were found to be within the normal concentration ranges for non-hyperaccumulators. However, As hyperaccumulation did influence the elemental distribution among fronds of different age of P. vittata. Arsenic-induced P and K enhancements in the fronds contributed to the As-induced growth stimulation at low As levels. The frond P/As molar ratios of 1.0 can be used as the threshold value for normal growth of P. vittata. Potassium may function as a counter-cation for As in the fronds as shown by the As-induced K increases in the fronds. The present findings not only demonstrate that P. vittata has the ability to maintain adequate concentrations of essential nutrients while hyperaccumulating As from the soil, but also have implications for soil management (fertilization in particular) of P. vittata in As phytoextraction practice.

Initial tree establishment on blocky quarry waste ameliorated with hydrogel or slate processing fines

Pocket planting reclamation techniques developed in the 1970s for revegetating blocky quarrying waste have met with very limited success, often because the low water-holding capacity of the waste and limited root development within a small volume of planting pocket material result in severe drought mortality. We tested pocket planting approaches for waste tip reclamation at Europe's largest slate quarry, and compared materials for enhancing the continuity of water- and nutrient-holding down into the interior of the waste tip. When small compost-filled pocket planting bags were placed above slate processing fines (SPF) or water absorbent cross-linked polyacrylamide gel ("hydrogel"), tree growth rates increased in comparison with pocket planting bags alone. The SPF significantly improved tree survival especially during severe drought, but survival was not enhanced by the use of hydrogel. The sorption characteristics of hydrogel indicated that its presence may help to reduce nutrient leaching, but that it may have a negative effect on nitrogen availability. A more likely explanation for the poor performance of pure hydrogel is that it did not maintain sufficient available water, because of discontinuities caused by shrinkage and movement of the hydrogel, and/or degradation of water-holding capacity with environmental exposure. However, the root growth observed in the hydrogel treatments suggests that this technique, if adapted to reduce the effects of hydrogel shrinkage by using finer-grade hydrogel, mixing it with other soil-forming material, and reducing its exposure to extremes of temperature or sunlight, might have the potential to improve the growth and survival of trees planted on sites where delivery of heavy materials such as SPF is impractical. Fine mineral processing waste is freely available at active quarries and should be seen as a key resource for reclamation schemes.

Agriculture: the real nexus for enhancing bioavailable micronutrients in food crops

Human existence requires that agriculture provide at least 50 nutrients (e.g., vitamins, minerals, trace elements, amino acids, essential fatty acids) in amounts needed to meet metabolic demands during all seasons. If national food systems do not meet these demands, mortality and morbidity rates increase, worker productivity declines, livelihoods are diminished and societies suffer. Today, many food systems within the developing world cannot meet the nutritional needs of the societies they support mostly due to farming systems that cannot produce enough micronutrients to meet human needs throughout the year. Nutrition transitions are also occurring in many rapidly developing countries that are causing chronic disease (e.g., cancer, heart disease, stroke, diabetes, and osteoporosis) rates to increase substantially. These global developments point to the need to explicitly link agricultural technologies to human health. This paper reviews some ways in which agriculture can contribute significantly to reducing micronutrient malnutrition globally. It concludes that it is imperative that close linkages be forged between the agriculture, nutrition and health arenas in order to find sustainable solutions to micronutrient malnutrition with agriculture becoming the primary intervention tool to use in this fight.

The potential impact of soil ingestion on human mineral nutrition

Geophagia, the intentional and repeated ingestion of soil material, is a complex eating behaviour with incomprehensible aetiology. It is generally assumed that geophagia may help supplement mineral nutrients and thus should not be dissuaded, particularly in subsistence communities. This is largely based on the assumption that a large proportion of mineral nutrients in geophagic materials is potentially available for absorption in the body. We tested this hypothesis on five soils collected from geophagia-prevalent communities by using an in vitro soil ingestion simulation test that is broadly similar to the gastrointestinal (GI) tract. The results show that, despite the soils being rich in mineral nutrients, soil ingestion, inadvertent or through geophagia can potentially reduce the absorption of already bioavailable nutrients, particularly micronutrients such as Fe, Cu and Zn. These in vitro findings, while disagreeing with the commonly held view of geophagia as a source of nutrient supplementation, are consistent with micronutrient deficiency problems observed in clinical nutrition studies conducted amongst geophagic populations. The work also showed that, in some cases, the ingested soils may become a source of Ca, Mg and Mn, although it is not clear why other similar soils should not release any of these mineral nutrients.

Effects of cadmium on nutrient uptake and translocation by Indian Mustard

Plants that hyperaccumulate metals are ideal subjects for studying the mechanisms of metal and mineral nutrient uptake in the plant kingdom. Indian Mustard (Brassica juncea) has been shown to accumulate moderate levels of Cd, Pb, Cr, Ni, Zn, and Cu. In this experiment, 10 levels of Cd concentration treatments were imposed by adding 10-190 mg Cd kg(-1) to the soils as cadmium nitrate [Cd(NO3)2]. The effect of Cd on phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and the micronutrients iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in B. juncea was studied. Plant growth was affected negatively by Cd, root biomass decreased significantly at 170 mg Cd kg(-1) dry weight soils treatment. Cadmium accumulation both in shoots and roots increased with increasing soil Cd treatments. The highest concentration of Cd was up to 300 mg kg(-1) d.w. in the roots and 160 mg kg(-1) d.w. in the shoots. The nutrients mainly affected by Cd were P, K, Ca, Fe, and Zn in the roots, and P, K, Ca, and Cu in the shoots. K and P concentrations in roots increased significantly when Cd was added at 170 mg kg(-1), and this was almost the same level at which root growth was inhibited. Zn concentrations in roots decreased significantly when added Cd concentration was increased from 50 to 110 mg kg(-1), then remained constant with Cd treatments from 110 to 190 mg kg(-1). However, Zn concentrations in the shoots seemed less affected by Cd. It is possible that Zn uptake was affected by the Cd but not the translocation of Zn within the plant. Ca and Mg accumulation in roots and shoots showed similar trends. This result indicates that Ca and Mg uptake is a non-specific process.

Bioavailability of iron, zinc, folate, and vitamin C in the IRIS multi-micronutrient supplement: effect of combination with a milk-based cornstarch porridge

The effect of combining a multi-micronutrient supplement with a milk-based cornstarch porridge on the bioavailability of iron, zinc, folate, and vitamin C was evaluated using the plasma curve response over time (8 hours) in healthy women. Three tests were carried out in a crossover design: S (multi-micronutrient supplement), MS (multi-micronutrient supplement plustest meal), and M (test meal). Relative bioavailability was determined as the percent ratio of the area under the curve (AUC) in MS corrected by M, and AUC in S. Compared to S, AUC in MS was smaller for iron (p < .05), for zinc (p < .01), and for folate (p < .05), but not different for vitamin C. Relative bioavailability was lower (p < .05) than 100% for iron (80%), zinc (70%), and folate (85%). The decrease in bioavailability of these nutrients when the multi-micronutrient supplement is combined with a milk-based cornstarch porridge is small. Therefore, the tested meal is a suitable vehicle for the multi-micronutrient supplement.

Validation and sensitivity analysis of probabilistic models of dietary exposure to micronutrients: an example based on vitamin B6

Probabilistic modelling can be used to get an insight into the variability and uncertainty of the nutrient intake in a population. When a probabilistic model is used, it is important that it is validated. Furthermore, a sensitivity analysis of the model output can give an insight into the most important input variables of the model and can be used as an aid to describe the reliability of the model. In this study, four models to estimate vitamin B(6) intake among males and females were validated using the method of Kaaks et al. This method compares the relationship between three different kind of measurements with the unknown 'true' intake. In each of these four models, only one input variable (concentration or bioavailability) was changed compared with a reference model. A sensitivity analysis was also performed. The results of the validation showed that for males, a model using a fixed bioavailability factor at the food group level was valid, while for females a model using either a fixed value or a distribution for the bioavailability factor was valid. Use of a distribution for the concentration of vitamin B(6) in supplements was not valid. The results of the sensitivity analysis showed that the concentration of vitamin B(6) in food and supplements was the key contributor to variability and uncertainty in the model estimates of vitamin B(6) intake, in both males and females. All results indicated that when taking variability and uncertainty into account by using probabilistic modelling, the effect on the nutrient intake for nutrients that are present in many common eaten foods, is small. For these broadly available nutrients, fixed concentrations and bioavailability factors give a good estimate of the nutrient intake in a population. When using probabilistic modelling, it is very important to collect more actual information about the concentration.

Factors affecting intestinal absorption of highly lipophilic food microconstituents (fat-soluble vitamins, carotenoids and phytosterols)

Highly lipophilic food microconstituents (HLFMs) with octanol-water partition coefficients log10 P(c) > 8 include the fat-soluble vitamins (A, E, D and K) and phytochemicals with potential health benefits, the carotenoids and phytosterols. It has been assumed that these compounds have the same metabolism in the human upper gastrointestinal tract and that they follow the same fate as lipids. However, a literature review shows that the metabolism of HLFMs in the upper gastrointestinal tract depends on each HLFM species. For example, some HLFM esters are hydrolyzed mainly by pancreatic lipase, others by bile salt-stimulated lipase; some HLFMs are apparently absorbed by passive diffusion, others by a transporter. Also, although some factors (HLFM molecular species, fat, food matrix) affect absorption efficiency of most HLFMs, other factors (fibers, microconstituents) apparently affect absorption only of some HLFMs. The mnemonic acronym SLAMENGHI, previously proposed to list the factors affecting the bioavailability of carotenoids, was used here to review current knowledge of the factors suspected to affect the intestinal absorption of HLFMs. The available data reveal numerous gaps in the knowledge of the metabolism of HLFMs and the factors that affect their absorption. These gaps need to be filled to be able to formulate HLFMs so as to promote greater absorption efficiency.

[Iron metabolism: current concepts of an essential micronutrient]

Iron is an essential micronutrient involved in multiple biochemical and physiological process. In this review we discuss the most relevant aspect of its metabolism in order to reach a better comprehension of the relevant roll that this micronutrient plays in human health.

Plasma changes in micronutrients following a multivitamin and mineral supplement in healthy adults

OBJECTIVE

To estimate the micronutrient (riboflavin, folate, vitamin C, vitamin B(12), iron, zinc and copper) bioavailability in healthy adults from a multi-micronutrient dietary supplement to assess the possible influence on it by the tablet disintegration properties and by the relative intestinal permeability of subject.

METHODS

The bioavailability of seven micronutrients from a single brand of multi-micronutrient dietary supplement was measured on two separate occasions in the presence of a standardized test meal in 15 healthy adult subjects. Each subject visited the Metabolic Research Unit on four separate randomized occasions for an absorption test. One test measured the intestinal permeability. The other three tests measured the postprandial changes in plasma or serum concentrations after consuming a test meal alone (control:placebo effect), or the test meal with either whole or crushed and powdered dietary supplements. 15 healthy Caucasian adult volunteers, aged 42 +/- 14 years.

RESULTS

The 12 hour-post-dose AUC for riboflavin, folate and vitamin C (whole and crushed tablet), and that for vitamin B(12) (only for the crushed tablet treatment) and iron (only for the whole tablet treatment) were all significantly (p < 0.001) higher than after a test meal alone. In contrast there was no significant increase in the AUC after supplement intake for zinc and copper. Neither the form of the supplement for all micronutrients tested nor intestinal permeability of the subject for riboflavin, folate, vitamin C, iron, zinc and copper influenced the postdose nutrient AUC. In contrast, for vitamin B(12) the intestinal permeability of the subject influenced significantly the nutrient AUC (p = 0.003).

CONCLUSION

Tablet disintegration characteristics of this dietary supplement did not limit absorption of these seven micronutrients. The intestinal permeability of subject was only positively correlated with the B(12) bioavailability. Results are suggestive of using multi-micronutrients dietary supplements as a vehicle to decrease the prevalence of multiple micronutrient deficiencies overall for vitamins in healthy adults.

Efficacy of a multi-micronutrient dietary intervention based on haemoglobin, hair zinc concentrations, and selected functional outcomes in rural Malawian children

OBJECTIVE

To investigate the efficacy of enhancing the content and bioavailability of micronutrients in diets of stunted rural Malawian children on their growth and body composition, morbidity, anaemia and hair zinc concentrations.

DESIGN

A quasi-experimental design with non-equivalent control group involving 410 intervention and 220 control children aged 30-90 months.

SETTING AND SUBJECTS

Children from two intervention and two control villages in Mangochi District, Southern Malawi participated in a 6 month dietary intervention. Anthropometry, malarial screening, haemoglobin, and hair zinc were measured at baseline and after 12 months, as well as socio-economic status at baseline, and common infections monthly post-intervention.

RESULTS

Groups were comparable at baseline. Post-intervention children had greater Z-scores for lean body mass (mid-upper arm circumference -0.75 vs -1.05; arm muscle area: 0.63 vs -1.03, P<0.001) than controls but Z-scores for weight-for-height and height-for-age were similar. After controlling for baseline variables, mean haemoglobin was higher (107 vs 102 g/l, P<0.01), whereas the incidence of both anaemia (62 vs 80%) and common infections (based on a median overall illness score for fever, diarrhoea, upper and lower respiratory infections) were lower in intervention compared to controls, with no change in hair zinc concentrations or malaria status post-intervention.

CONCLUSION

Improvements in the micronutrient adequacy of diets of post-intervention children were associated with a favourable increase in indices of lean body mass and reductions in the incidence of anaemia and common infections in these rural Malawian stunted children.

Biotechnology: a solution for improving nutrient bioavailability

Biotechnology strategies are now available to improve the amount and availability of nutrients in plant crops. Those strategies include simple plant selection for varieties with high nutrient density in the seeds, cross-breeding for incorporating a desired trait within a plant, and genetic engineering to manipulate the nutrient content of the plant. In plant cross-breeding, all genes of the parent plants are combined and the progeny have both desirable and undesirable traits. To eliminate undesirable traits, plant breeders "back-cross" the new plant varieties with other plants over several generations. This technique, called hybridization, has been used to create varieties of low-phytate corn, barley, and rice. Using the techniques of genetic engineering, the gene(s) encoding for a desired trait(s) in a plant are introduced in a precise and controlled manner within a relatively short period of time. Golden rice, containing carotenoids, and rice with higher amounts of iron, are two examples of genetically engineered plants for improved nutrition. Genetic engineering has tremendous potential for revolutionizing nutrition. However, public concerns regarding safety, appearance, and ethics must be overcome before these products can be effectively introduced into the food supply.