Green tea (Camellia sinensis) for the prevention of cancer.

BACKGROUND: This review is an update of a previously published review in the Cochrane Database of Systematic Reviews (2009, Issue 3).Tea is one of the most commonly consumed beverages worldwide. Teas from the plant Camellia sinensis can be grouped into green, black and oolong tea, and drinking habits vary cross-culturally. C sinensis contains polyphenols, one subgroup being catechins. Catechins are powerful antioxidants, and laboratory studies have suggested that these compounds may inhibit cancer cell proliferation. Some experimental and nonexperimental epidemiological studies have suggested that green tea may have cancer-preventative effects. OBJECTIVES: To assess possible associations between green tea consumption and the risk of cancer incidence and mortality as primary outcomes, and safety data and quality of life as secondary outcomes. SEARCH METHODS: We searched eligible studies up to January 2019 in CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and reference lists of previous reviews and included studies. SELECTION CRITERIA: We included all epidemiological studies, experimental (i.e. randomised controlled trials (RCTs)) and nonexperimental (non-randomised studies, i.e. observational studies with both cohort and case-control design) that investigated the association of green tea consumption with cancer risk or quality of life, or both. DATA COLLECTION AND ANALYSIS: Two or more review authors independently applied the study criteria, extracted data and assessed methodological quality of studies. We summarised the results according to diagnosis of cancer type. MAIN RESULTS: In this review update, we included in total 142 completed studies (11 experimental and 131 nonexperimental) and two ongoing studies. This is an additional 10 experimental and 85 nonexperimental studies from those included in the previous version of the review. Eleven experimental studies allocated a total of 1795 participants to either green tea extract or placebo, all demonstrating an overall high methodological quality based on 'Risk of bias' assessment. For incident prostate cancer, the summary risk ratio (RR) in the green tea-supplemented participants was 0.50 (95% confidence interval (CI) 0.18 to 1.36), based on three studies and involving 201 participants (low-certainty evidence). The summary RR for gynaecological cancer was 1.50 (95% CI 0.41 to 5.48; 2 studies, 1157 participants; low-certainty evidence). No evidence of effect of non-melanoma skin cancer emerged (summary RR 1.00, 95% CI 0.06 to 15.92; 1 study, 1075 participants; low-certainty evidence). In addition, adverse effects of green tea extract intake were reported, including gastrointestinal disorders, elevation of liver enzymes, and, more rarely, insomnia, raised blood pressure and skin/subcutaneous reactions. Consumption of green tea extracts induced a slight improvement in quality of life, compared with placebo, based on three experimental studies. In nonexperimental studies, we included over 1,100,000 participants from 46 cohort studies and 85 case-control studies, which were on average of intermediate to high methodological quality based on Newcastle-Ottawa Scale 'Risk of bias' assessment. When comparing the highest intake of green tea with the lowest, we found a lower overall cancer incidence (summary RR 0.83, 95% CI 0.65 to 1.07), based on three studies, involving 52,479 participants (low-certainty evidence). Conversely, we found no association between green tea consumption and cancer-related mortality (summary RR 0.99, 95% CI 0.91 to 1.07), based on eight studies and 504,366 participants (low-certainty evidence). For most of the site-specific cancers we observed a decreased RR in the highest category of green tea consumption compared with the lowest one. After stratifying the analysis according to study design, we found strongly conflicting results for some cancer sites: oesophageal, prostate and urinary tract cancer, and leukaemia showed an increased RR in cohort studies and a decreased RR or no difference in case-control studies. AUTHORS' CONCLUSIONS: Overall, findings from experimental and nonexperimental epidemiological studies yielded inconsistent results, thus providing limited evidence for the beneficial effect of green tea consumption on the overall risk of cancer or on specific cancer sites. Some evidence of a beneficial effect of green tea at some cancer sites emerged from the RCTs and from case-control studies, but their methodological limitations, such as the low number and size of the studies, and the inconsistencies with the results of cohort studies, limit the interpretability of the RR estimates. The studies also indicated the occurrence of several side effects associated with high intakes of green tea. In addition, the majority of included studies were carried out in Asian populations characterised by a high intake of green tea, thus limiting the generalisability of the findings to other populations. Well conducted and adequately powered RCTs would be needed to draw conclusions on the possible beneficial effects of green tea consumption on cancer risk.

Dietary mineral supplies in Africa.

Dietary micronutrient deficiencies (MNDs) are widespread, yet their prevalence can be difficult to assess. Here, we estimate MND risks due to inadequate intakes for seven minerals in Africa using food supply and composition data, and consider the potential of food-based and agricultural interventions. Food Balance Sheets (FBSs) for 46 countries were integrated with food composition data to estimate per capita supply of calcium (Ca), copper (Cu), iron (Fe), iodine (I), magnesium (Mg), selenium (Se) and zinc (Zn), and also phytate. Deficiency risks were quantified using an estimated average requirement (EAR) 'cut-point' approach. Deficiency risks are highest for Ca (54% of the population), followed by Zn (40%), Se (28%) and I (19%, after accounting for iodized salt consumption). The risk of Cu (1%) and Mg (<1%) deficiency are low. Deficiency risks are generally lower in the north and west of Africa. Multiple MND risks are high in many countries. The population-weighted mean phytate supply is 2770 mg capita(-1) day(-1). Deficiency risks for Fe are lower than expected (5%). However, 'cut-point' approaches for Fe are sensitive to assumptions regarding requirements; e.g. estimates of Fe deficiency risks are 43% under very low bioavailability scenarios consistent with high-phytate, low-animal protein diets. Fertilization and breeding strategies could greatly reduce certain MNDs. For example, meeting HarvestPlus breeding targets for Zn would reduce dietary Zn deficiency risk by 90% based on supply data. Dietary diversification or direct fortification is likely to be needed to address Ca deficiency risks.

EURRECA-Estimating selenium requirements for deriving dietary reference values.

Current reference values for selenium, an essential micronutrient, are based on the intake of selenium that is required to achieve maximal glutathione peroxidase activity in plasma or erythrocytes. In order to assess the evidence of relevance to setting dietary reference values for selenium, the EURRECA Network of Excellence focused on systematic searches, review, and evaluation of (i) selenium status biomarkers and evidence for relationships between intake and status biomarkers, (ii) selenium and health (including the effect of intake and/or status biomarkers on cancer risk, immune function, HIV, cognition, and fertility), (iii) bioavailability of selenium from the diet, and (iv) impact of genotype/single nucleotide polymorphisms on status or health outcomes associated with selenium. The main research outputs for selenium and future research priorities are discussed further in this review.

EURRECA-Estimating iron requirements for deriving dietary reference values.

Currently, a factorial approach is used to derive reference values for iron. Calculations include the use of a bioavailability factor to convert the physiological requirement, derived from obligatory losses and requirements for growth and development, into a dietary intake value. A series of systematic reviews undertaken by the EURRECA Network of Excellence aimed to identify data that may increase the accuracy of factorial calculations across all population groups. The selection of robust data was guided by the use of standardized review methodology and the evidence-based selection of status biomarkers and dietary intake assessment techniques. Results corroborated the dearth of relevant factorial data, including whole-diet bioavailability data, and confirmed the need to continue extrapolating physiological requirements across population groups. Data were also unavailable that would allow reference values to be based on selected health outcomes associated with iron intake or status. Ideally, a series of observational and randomized controlled trial (RCT) studies need to be undertaken across all population groups and life stages to generate robust data for setting dietary reference values for iron. It will also be essential to include information on polymorphisms that potentially influence iron absorption and status in the derivation process.

EURRECA-Principles and future for deriving micronutrient recommendations.

The EURopean micronutrient RECommendations Aligned (EURRECA) Network of Excellence (NoE) explored an approach for setting micronutrient recommendations, which would address the variation in recommendations across Europe. Therefore, a framework for deriving and using micronutrient Dietary Reference Values (DRVs) has been developed. This framework comprises four stages (defining the problem-monitoring and evaluating-deriving dietary reference values-using dietary reference values in policy making). The aim of the present paper is to use this framework to identify specific research gaps and needs related to (1) knowledge available on specific micronutrients (folate, iodine, iron, selenium, vitamin B12, vitamin D, and zinc) and (2) the methodology presented in the framework. Furthermore, the paper describes the different outputs that support the process like protocols, guidelines, systematic review databases, and peer-reviewed publications, as well as the principal routes of dissemination of these outputs to ensure their optimal uptake in policy, practice, and research collaborations. The importance of ensuring transparency in risk assessment and risk management, systematic searching the literature, and taking into account policy options is highlighted. [Supplementary materials are available for this article. Go to the publisher's online edition of Critical Reviews in Food Science and Nutrition for the following free supplemental files: Additional tables.].

A high prevalence of zinc- but not iron-deficiency among women in rural Malawi: a cross-sectional study.

BACKGROUND: Zinc deficiency is often associated with nutritional iron deficiency (ID), and may be exacerbated by low selenium status. AIM: To investigate risk of iron and zinc deficiency in women with contrasting selenium status. METHODS: In a cross-sectional study, 1-day diet composites and blood samples were collected from self-selected Malawian women aged 18-50 years from low- (Zombwe) (n=60) and high-plant-available soil selenium (Mikalango) (n=60) districts. Diets were analyzed for trace elements and blood for biomarkers. RESULTS: Zinc deficiency (>90 %) was greater than ID anemia (6 %), or ID (5 %), attributed to diets low in zinc (median 5.7 mg/day) with high phytate:zinc molar ratios (20.0), but high in iron (21.0 mg/day) from soil contaminant iron. Zombwe compared to Mikalango women had lower (p<0.05) intakes of selenium (6.5 vs. 55.3 µg/day), zinc (4.8 vs. 6.4 mg/day), iron (16.6 vs. 29.6 mg/day), lower plasma selenium (0.72 vs. 1.60 µmol/L), and higher body iron (5.3 vs. 3.8 mg/kg), although plasma zinc was similar (8.60 vs. 8.87 µmol/L). Body iron and plasma zinc were positive determinants of hemoglobin. CONCLUSION: Risk of zinc deficiency was higher than ID and was shown not to be associated with selenium status. Plasma zinc was almost as important as body iron as a hemoglobin determinant.

Selenium status and immunity.

Selenium is found at the active centre of twenty-five selenoproteins which have a variety of roles, including the well-characterised function of antioxidant defense, but it also is claimed to be involved in the immune system. However, due to limited and conflicting data for different parameters of immune function, intakes of selenium that have an influence on immune function are uncertain. This review covers the relationship between selenium and immune function in man, focusing on the highest level of evidence, namely that generated by randomised controlled trials (RCT), in which the effect of selective administration of selenium, in foods or a supplement, on immune function was assessed. A total of nine RCT were identified from a systematic search of the literature, and some of these trials reported effects on T and natural killer cells, which were dependent on the dose and form of selenium administered, but little effect of selenium on humoral immunity. There is clearly a need to undertake dose-response analysis of cellular immunity data in order to derive quantitative relationships between selenium intake and measures of immune function. Overall, limited effects on immunity emerged from experimental studies in human subjects, though additional investigation on the potential influence of selenium status on cellular immunity appears to be warranted.

Dietary requirements for magnesium, but not calcium, are likely to be met in Malawi based on national food supply data.

Mineral malnutrition is widespread in sub-Saharan Africa but its extent is difficult to quantify. Using Malawi as a case study, the aim of this work was to investigate the adequacy of calcium (Ca) and magnesium (Mg) nutrition by combining national food supply and food composition data with a new spatial survey of maize grain. Non-maize dietary sources of Ca and Mg were estimated using existing food supply and composition data. Calcium and Mg concentrations in maize grain were determined at 88 field sites, representing > 75 % of Malawi’s land area in terms of soil classification. Median maize grain concentrations from the survey were 34 and 845 mg kg(-1), representing a per capita supply of 12 and 299 mg d(-1) of Ca and Mg, respectively. Combining these data with food supply and composition data reveals that average Ca nutrition is likely to be inadequate for many individuals, whereas average Mg nutrition appears adequate. Optimal supply of Ca per capita depends critically on balanced food availability and choice. Since maize grain sourced from highly calcareous soils is still unlikely to deliver > 5 % of estimated average requirements, agronomic solutions to rectify Ca malnutrition via maize are limited, in comparison with strategies for dietary diversification.

Zinc and selenium supplementation in COVID-19 prevention and treatment: a systematic review of the experimental studies.

BACKGROUND AND AIM: The COVID-19 pandemic has severely affected the world's population in the last two years. Along with non-pharmacological public health interventions, major efforts have also been made to identify effective drugs or active substances for COVID-19 prevention and treatment. These include, among many others, the trace elements zinc and selenium, based on laboratory studies and some observational human studies. However, both of these study designs are not adequate to identify and approve treatments in human medicine, and experimental studies in the form of randomized controlled trials are needed to demonstrate the effectiveness and the safety of any interventions. METHODS: We undertook a systematic review in which we searched for published and unpublished clinical trials using zinc or selenium supplementation to treat or prevent COVID-19 in the Pubmed, Scopus and ClinicalTrials databases up to 10 January 2022. RESULTS: Amongst the published studies, we did not find any trial with selenium, whereas we retrieved four eligible randomized clinical trials using zinc supplementation, only one of which was double-blind. One of these trials looked at the effect of the intervention on the rate of new SARS-CoV-2 infections, and three at the COVID-19 clinical outcome in already infected individuals. The study populations of the four trials were very heterogeneous, ranging from uninfected individuals to those hospitalized for COVID-19. Only two studies investigated zinc alone in the intervention arm with no differences in the endpoints. The other two studies examined zinc in association with one or more drugs and supplements in the intervention arm, therefore making it impossible to disentangle any specific effects of the element. In addition, we identified 22 unpublished ongoing clinical trials, 19 on zinc, one on selenium and two on both elements. CONCLUSION: No trials investigated the effect of selenium supplementation on COVID-19, while the very few studies on the effects of zinc supplementation did not confirm efficacy. Therefore, preventive or therapeutic interventions against COVID-19 based on zinc or selenium supplementation are currently unjustified, although when the results of the on-going studies are published, this may change our conclusion.

Critical Role of Maternal Selenium Nutrition in Neurodevelopment: Effects on Offspring Behavior and Neuroinflammatory Profile.

Research in both animals and humans shows that some nutrients are important in pregnancy and during the first years of life to support brain and cognitive development. Our aim was to evaluate the role of selenium (Se) in supporting brain and behavioral plasticity and maturation. Pregnant and lactating female rats and their offspring up to postnatal day 40 were fed isocaloric diets differing in Se content-i.e., optimal, sub-optimal, and deficient-and neurodevelopmental, neuroinflammatory, and anti-oxidant markers were analyzed. We observed early adverse behavioral changes in juvenile rats only in sub-optimal offspring. In addition, sub-optimal, more than deficient supply, reduced basal glial reactivity in sex dimorphic and brain-area specific fashion. In female offspring, deficient and sub-optimal diets reduced the antioxidant Glutathione peroxidase (GPx) activity in the cortex and in the liver, the latter being the key organ regulating Se metabolism and homeostasis. The finding that the Se sub-optimal was more detrimental than Se deficient diet may suggest that maternal Se deficient diet, leading to a lower Se supply at earlier stages of fetal development, stimulated homeostatic mechanisms in the offspring that were not initiated by sub-optimal Se. Our observations demonstrate that even moderate Se deficiency during early life negatively may affect, in a sex-specific manner, optimal brain development.

Low-pH cola beverages do not affect women's iron absorption from a vegetarian meal.

Preliminary data in the literature indicate that iron absorption from a meal may be increased when consumed with low-pH beverages such as cola, and it is also possible that sugar iron complexes may alter iron availability. A randomized, crossover trial was conducted to compare the bioavailability of nonheme iron from a vegetarian pizza meal when consumed with 3 different beverages (cola, diet cola, and mineral water). Sixteen women with serum ferritin concentrations of 11-54 µg/L were recruited and completed the study. The pizza meal contained native iron and added ferric chloride solution as a stable isotope extrinsic label; the total iron content of the meal was ~5.3 mg. Incorporation of iron from the meal into RBC was not affected by the type of drink (9.9% with cola, 9.4% with diet cola, and 9.6% with water). Serum ferritin and plasma hepcidin were correlated (r = 0.66; P<0.001) and both were significant predictors of iron bioavailability, but their combined effect explained only 30% of the inter-individual variation (P<0.001) and illustrates the current lack of understanding of mechanisms responsible for the fine-tuning of iron absorption. Although there was no effect of low-pH drinks on iron bioavailability in healthy women, their effect on absorption of fortification iron that requires solubilization in dilute acid, such as reduced iron, and in individuals with low gastric acid production, such as older people and individuals with Helicobacter pylori infection, warrants further investigation.

Sodium and Potassium Content of Foods Consumed in an Italian Population and the Impact of Adherence to a Mediterranean Diet on Their Intake.

High sodium and low potassium intakes are associated with increased levels of blood pressure and risk of cardiovascular diseases. Assessment of habitual dietary habits are helpful to evaluate their intake and adherence to healthy dietary recommendations. In this study, we determined sodium and potassium food-specific content and intake in a Northern Italy community, focusing on the role and contribution of adherence to Mediterranean diet patterns. We collected a total of 908 food samples and measured sodium and potassium content using inductively coupled plasma mass spectrometry. Using a validated semi-quantitative food frequency questionnaire, we assessed habitual dietary intake of 719 adult individuals of the Emilia-Romagna region. We then estimated sodium and potassium daily intake for each food based on their relative contribution to the overall diet, and their link to Mediterranean diet patterns. The estimated mean sodium intake was 2.15 g/day, while potassium mean intake was 3.37 g/day. The foods contributing most to sodium intake were cereals (33.2%), meat products (24.5%, especially processed meat), and dairy products (13.6%), and for potassium they were meat (17.1%, especially red and white meat), fresh fruits (15.7%), and vegetables (15.1%). Adherence to a Mediterranean diet had little influence on sodium intake, whereas potassium intake was greatly increased in subjects with higher scores, resulting in a lower sodium/potassium ratio. Although we may have underestimated dietary sodium intake by not including discretionary salt use and there may be some degree of exposure misclassification as a result of changes in food sodium content and dietary habits over time, our study provides an overview of the contribution of a wide range of foods to the sodium and potassium intake in a Northern Italy community and of the impact of a Mediterranean diet on intake. The mean sodium intake was above the dietary recommendations for adults of 1.5-2 g/day, whilst potassium intake was only slightly lower than the recommended 3.5 g/day. Our findings suggest that higher adherence to Mediterranean diet patterns has limited effect on restricting sodium intake, but may facilitate a higher potassium intake, thereby aiding the achievement of healthy dietary recommendations.

Estimating the bioavailability factors needed for setting dietary reference values.

Estimated average requirements for micronutrients are central to deriving Dietary Reference Values. These are used for nutrition policies and programs, and also for regulatory and labeling purposes, and are traditionally devised to cover the needs of virtually all individuals in any population group. In order to estimate the average requirement, an appropriate endpoint (biomarker) is selected which describes the relationship between dietary intake and health. However, for some micronutrients, such as zinc, there are no good biomarkers, and for others, such as iron, the intake-status relationship is confounded by variations in absorption. Average requirements for these nutrients are derived using a factorial approach in which physiological needs for tissue growth and maintenance and endogenous losses are estimated, and the total converted to a dietary requirement by taking into account the overall absorption from the diet; i. e. multiplying the requirement by a bioavailability factor. The latter can be determined using algorithms, or estimates from absorption studies, some of which are described in this short review paper.

Reminiscences of my life as a nutritionist-and looking to the future.

In this invited article for the Crystal Ball series, I have tried to briefly cover my undergraduate and post-graduate training and subsequent career in nutrition, and end with some thoughts about the future. It has not been possible to give a comprehensive account of my many years of nutrition research, so I have selected a few events that might amuse readers. Also, due to the lack of space, I have been unable to mention all the wonderful colleagues and friends with whom I have interacted, but, if they read this article, they know who they are. Unfortunately, a growing number are no longer with us and I would like to pay tribute to them and their important contribution to human nutrition.

Lead exposure in an Italian population: Food content, dietary intake and risk assessment.

BACKGROUND AND AIM: Lead is a highly toxic heavy metal released into the environment after natural and anthropogenic activities. Excluding populations in occupations where there is possible lead contamination, food is the major source of human exposure. In this study, we determined lead contamination in food and beverages consumed in a Northern Italy community and performed a health risk assessment. METHODS: We collected a total of 908 food samples and measured lead levels using inductively coupled plasma mass spectrometry. Using a validated food frequency questionnaire, we assessed the dietary habits and estimated daily lead dietary intakes in a sample of 719 adult individuals. We performed risk assessment using a benchmark dose and margin of exposure approach, based on exposure levels for both adverse effect of systolic blood pressure and chronic kidney disease. RESULTS: Foods with the highest lead levels include non-chocolate confectionery (48.7 µg/kg), leafy (39.0 µg/kg) and other vegetables (42.2 µg/kg), and crustaceans and molluscs (39.0 µg/kg). The estimated mean lead intake was 0.155 µg/kg bw-day in all subjects, with little lower intakes in men (0.151 µg/kg bw-day) compared to women (0.157 µg/kg bw-day). Top food contributors were vegetables, cereals, and beverages, particularly wine. In relation to risk assessment, the estimated dietary intake was lower than levels associated with cardiovascular risk and nephrotoxicity. CONCLUSIONS: Our study provides an updated assessment of lead food contamination and dietary exposure in a Northern Italian community. The margin of exposure risk assessment approach suggests that risk of detrimental effects due to dietary lead intake is low in the investigated population. Nonetheless, these exposure levels for adverse effects are not reference health standards, and no safety threshold value can be established for lead. As a consequence, other and more subtle adverse effects may still occur in vulnerable and occupationally exposed individuals, particularly in relation to the nervous system.

Changing from a Western to a Mediterranean-style diet does not affect iron or selenium status: results of the New Dietary Strategies Addressing the Specific Needs of the Elderly Population for Healthy Aging in Europe (NU-AGE) 1-year randomized clinical trial in elderly Europeans.

BACKGROUND: Mediterranean diets limit red meat consumption and increase intakes of high-phytate foods, a combination that could reduce iron status. Conversely, higher intakes of fish, a good source of selenium, could increase selenium status. OBJECTIVES: A 1-y randomized controlled trial [New Dietary Strategies Addressing the Specific Needs of the Elderly Population for Healthy Aging in Europe (NU-AGE)] was carried out in older Europeans to investigate the effects of consuming a Mediterranean-style diet on indices of inflammation and changes in nutritional status. METHODS: Selenium and iron intakes and status biomarkers were measured at baseline and after 1 y in 1294 people aged 65-79 y from 5 European countries (France, Italy, the Netherlands, Poland, and the United Kingdom) who had been randomly allocated either to a Mediterranean-style diet or to remain on their habitual, Western diet. RESULTS: Estimated selenium intakes increased significantly with the intervention group (P < 0.01), but were not accompanied by changes in serum selenium concentrations. Iron intakes also increased (P < 0.001), but there was no change in iron status. However, when stratified by study center, there were positive effects of the intervention on iron status for serum ferritin for participants in Italy (P = 0.04) and France (P = 0.04) and on soluble transferrin receptor (sTfR) for participants in Poland (P < 0.01). Meat intake decreased and fish intake increased to a greater degree in the intervention group, relative to the controls (P < 0.01 for both), but the overall effects of the intervention on meat and fish intakes were mainly driven by data from Poland and France. Changes in serum selenium in the intervention group were associated with greater changes in serum ferritin (P = 0.01) and body iron (P = 0.01), but not sTfR (P = 0.73); there were no study center × selenium status interactions for the iron biomarkers. CONCLUSIONS: Consuming a Mediterranean-style diet for 1 y had no overall effect on iron or selenium status, although there were positive effects on biomarkers of iron status in some countries. The NU-AGE trial was registered at clinicaltrials.gov as NCT01754012.

Relative bioavailability of micronized, dispersible ferric pyrophosphate added to an apple juice drink.

BACKGROUND: Food iron fortification is a sustainable and relatively simple strategy to reduce/prevent iron deficiency but is a challenge for the food industry because of possible adverse organoleptic changes caused by the added iron. A micronized dispersible ferric pyrophosphate, trademarked as SunActive Fe, has recently been developed. SunActive Fe has a small particle size, is water soluble and may be suitable for fortifying liquid products. AIM OF THE STUDY: To determine the relative bioavailability of SunActive Fe and its suitability for addition to pure apple juice. METHODS: Iron absorption from SunActive Fe added to pure apple juice (Minute Maid) was compared with absorption from ferrous sulphate, a highly bioavailable form of iron, in 15 women with relatively low iron stores. Both forms of iron were enriched with an iron stable isotope and iron absorption from the apple juice drinks was calculated from the isotopic enrichment of red blood cells 14 days after the last test meal. RESULTS: Although mean absorption of iron from SunActive Fe was significantly lower than from ferrous sulphate (5.5% compared with 9.1%), the mean bioavailability of SunActive Fe iron relative to ferrous sulphate was 0.6, indicating that it is a good source of bioavailable iron. Iron Absorption from SunActive Fe was positively correlated (r = 0.97, P = 0.01) with absorption from ferrous sulphate, and negatively correlated with serum ferritin concentration (ferrous sulphate r = -0.81, P < 0.001; SunActive Fe r = -0.76, P = 0.01). CONCLUSIONS: SunActive Fe was well absorbed from apple juice and is a potentially useful fortificant for liquid food products.

Does ageing affect zinc homeostasis and dietary requirements?

Dietary intakes of zinc are lower in the elderly because of reduced energy requirements, and it is not clear whether ageing impacts on adaptive homeostatic mechanisms, namely absorptive efficiency and endogenous losses in the GI tract. Physiological requirements for zinc are unlikely to change significantly, but there are several attributes of ageing that may affect aspects of zinc metabolism (e.g. changes in gut structure and function, disease states, chronic inflammation, epigenetic changes in genes that express zinc-related proteins and drug regimens) that are worthy of further investigation. There is, as yet, no information on the effects of ageing on zinc transporters, and there are no sensitive and specific measures of zinc status, therefore dietary recommendations for zinc have been derived from factorial calculations using information on zinc absorption and loss, and estimates of dietary bioavailability.

L-alpha-glycerophosphocholine contributes to meat's enhancement of nonheme iron absorption.

In this research, our aim was to isolate and characterize the substance known as "meat factor," which is reported to enhance nonheme iron absorption. We used various analytical techniques, and the final step was a human study to measure the effect of a candidate compound on iron absorption. Lean beef was selected for study, as it is known to increase nonheme iron absorption. Cooked ground beef was homogenized and aliquots were taken through a simulated gastric and intestinal digestion. This was followed by purification using fast protein liquid chromatography. The fractions were collected and applied to a Caco-2 cell system designed to measure iron absorption using radioiron. Fractions with an enhancing effect were analyzed by mass spectrometry, nuclear magnetic resonance, and HPLC, and a proposed empirical formula was obtained for the substance in the most active fraction (C(8)H(20) NO(6)P). Tandem mass spectrometry was used to identify the compound as L-alpha-glycerophosphocholine (L-alpha) by comparing the spectra against authentic material. We added a commercially available food grade source of L-alpha to vegetarian lasagna, with and without 100 mg ascorbic acid (a known enhancer of nonheme iron absorption), at the same enhancer:iron molar ratio (2:1), and fed meals to 13 women of child-bearing age with low iron stores. The nonheme iron was labeled with stable isotopes of iron to provide a total dose per meal of 10 mg iron, and absorption was measured from erythrocyte incorporation. Nonheme iron absorption from lasagna was increased by the addition of either ascorbic acid (P = 0.010) or L-alpha (P = 0.023). We have identified L-alpha as a component of muscle tissue that enhances nonheme iron absorption, and this finding provides new opportunities for iron fortification of foods.

Oily fish increases iron bioavailability of a phytate rich meal in young iron deficient women.

BACKGROUND: Iron deficiency is a major health problem worldwide, and is associated with diets of low iron bioavailability. Non-heme iron absorption is modulated by dietary constituents, one of which is the so-called "meat factor", present in meat, fish (oily and lean) and poultry, which is an important enhancer of iron absorption in humans. Food processing also affects iron bioavailability. OBJECTIVE: To evaluate the effect of consuming sous vide cooked salmon fish on non-heme iron bioavailability from a bean meal, rich in phytate, in iron-deficient women. DESIGN: Randomized crossover trial in 21 young women with low iron stores (ferritin < 30 microg/L). Two test meals were extrinsically labelled with stable isotopes of iron (Fe-57 or Fe-58). Iron bioavailability was measured as the incorporation of stable isotopes into erythrocytes 14 d after meals consumption. RESULTS: The addition of fish to the bean meal significantly increased (p < 0.001) iron absorption. Serum ferritin concentration and iron absorption were inversely correlated for both the bean meal (R(2) = 0.294, p = 0.011) and the fish and bean meal (R(2) = 0.401, p = 0.002). CONCLUSION: Sous vide cooked salmon fish increases iron absorption from a high phytate bean meal in humans.