Catherine Geissler

Iron, Meat and Health

This article is a summary of the publication “Iron and Health” by the Scientific Advisory Committee on Nutrition (SACN) to the U.K. Government (2010), which reviews the dietary intake of iron and the impact of different dietary patterns on the nutritional and health status of the U.K. population. It concludes that several uncertainties make it difficult to determine dose-response relationships or to confidently characterize the risks associated with iron deficiency or excess. The publication makes several recommendations concerning iron intakes from food, including meat, and from supplements, as well as recommendations for further research.

Oral ferrous sulphate leads to a marked increase in pro‐oxidant nontransferrin‐bound iron

Sir, Serum nontransferrin-bound iron (NTBI) is a potential catalyst for the production of reactive oxygen species, contributing to tissue damage. Nontransferrin-bound iron not only occurs in iron overload but also during intravenous iron infusion, possibly owing to the rapid saturation of transferrin, as a result of a rapid influx of iron [1]. More recently, NTBI was found to be positively correlated with lipid peroxidation in Beta-Thalassaemia and haemodialysis patients [2,3], although the relationship between NTBI and oxidative damage in vivo is contentious. Nevertheless, the presence of NTBI may explain published reports of lipid peroxidation after oral FeSO 4 [4,5], and as this is the usual treatment for IDA the occurrence of pro-oxidant NTBI during FeSO 4 treatment could have serious clinical implications. Therefore, we aimed to determine whether oral FeSO 4 results in the formation of serum NTBI in anaemic women. Seven anaemic women (mean haemoglobin 111 ± 5 g L − 1 ; serum ferritin 11·4 ± 2 μ g L − 1 ) who were otherwise healthy and of childbearing age completed this study. All subjects were recruited from the student and staff population at Kings College London and were not taking any medications nor had any history of chronic illness including gastrointestinal disease, although the exact causes of anaemia were not investigated. After an overnight fast, subjects were administered a tablet containing 200 mg of FeSO 4 (65 mg of elemental iron; Alpharma, Barnstaple, UK), with two slices of toasted white bread, margarine, honey and dilute orange cordial (visit 1), or 200 mg of FeSO 4 with the same drink but without food (visit 2). The meal (including drink) was low in inhibitors of iron absorption and contained only a trace of vitamin C. Serial blood samples were taken through an indwelling venous catheter before and after oral iron for 4 h on both occasions. Blood was drawn into vacutainers without additives to determine total serum iron, total iron binding capacity (TIBC) and serum NTBI. Serum ferritin, full blood count, total serum iron and TIBC were measured using routine laboratory methods, and serum was prepared for NTBI analysis using a method described elsewhere [6] and analyzed using an iron-free high-performance liquid chromatography system. Transferrin saturation was calculated (serum iron × 100/TIBC), and the rate of iron absorption was estimated using a recently reported equation [7]. We used a repeated measures  to test the increase in total serum iron, NTBI and transferrin saturation following FeSO 4 , and a simple linear fit to evaluate the correlation between NTBI and iron absorption, and NTBI and transferrin saturation. Neither the increase in total serum iron nor NTBI differed significantly when FeSO 4 was taken with or without food (both P < 0·001; Fig. 1), probably because the meal was low in compounds that inhibit iron absorption and vitamin C levels were similarly low on both occasions. On both occasions, serum transferrin concentration was in the normal range and was similar at baseline and 210 min after 200 mg of FeSO 4 (visit 1: 2·65 ± 0·10 g L − 1 at 0 min vs. 2·67 ± 0·08 g L − 1 at 210 min; and visit 2: 2·71 ± 0·09 g L − 1 vs. 2·82 ± 0·08 g L − 1 ). However, transferrin saturation increased from baseline to 210 min post-FeSO 4 , in conjunction with an increase in serum NTBI (Fig. 2). The mean ( ± SE) peak increase in serum NTBI was 4·6 ± 0·5 μ mol L − 1 and 3·9 ± 1·1 μ mol L − 1 , following 200 mg of All authors contributed to the study concept, while C. Hutchinson designed the study and prepared the manuscript with contributions from C.A. Geissler, R.C. Hider and J.J. Powell. W. Al-Ashgar carried out the study under the supervision of C. Hutchinson, and D.Y. Liu analyzed serum samples for NTBI. All authors approved and contributed academically to the final manuscript.

Effect of dietary quercetin on oxidative DNA damage in healthy human subjects.

The effect of dietary intake of flavonols (predominantly quercetin) on oxidative DNA damage was studied in thirty-six healthy human subjects (sixteen men, twenty women). The study was a randomised crossover study, comprising two 14 d treatments of either a low-flavonol (LF) or high-flavonol (HF) diet with a 14 d wash-out period between treatments. Subjects were asked to avoid foods containing flavonols, flavones and flavanols during the LF dietary treatment period and to consume one 150 g onion (Allium cepa) cake (containing 89.7 mg quercetin) and one 300 ml cup of black tea (containing 1.4 mg quercetin) daily during the HF dietary treatment. A 7 d food diary was kept during each dietary period and blood samples were taken after each dietary treatment. Products of oxidative damage to DNA bases were measured in DNA from leucocytes. The study had more than 95% power to detect a change of 20% in DNA damage products Plasma vitamin C and plasma quercetin concentrations were also measured. No significant differences in intake of macronutrients or assessed micronutrients, measured DNA base damage products, or plasma vitamin C were found between the HF and LF dietary treatments. The plasma quercetin concentration was significantly higher after the HF dietary treatment period (228.5 (SEM 34.7) nmol/l) than after the LF dietary treatment period (less than the limit of detection, i.e. <66.2 nmol/l). These findings do not support the hypothesis that dietary quercetin intake substantially affects oxidative DNA damage in leucocytes.

The iron-chelating potential of silybin in patients with hereditary haemochromatosis

Milk thistle contains silybin, which is a potential iron chelator. We aimed to determine whether silybin reduced iron absorption in patients with hereditary haemochromatosis. In this crossover study, on three separate occasions, 10 patients who were homozygous for the C282Y mutation in the HFE gene (and fully treated) consumed a vegetarian meal containing 13.9 mg iron with: 200 ml water; 200 ml water and 140 mg silybin (Legalon Forte); or 200 ml tea. Blood was drawn once before, then 0.5, 1, 2, 3 and 4 h after the meal. Consumption of silybin with a meal resulted in a reduction in the postprandial increase in serum iron (AUC±s.e.) compared with water (silybin 1726.6±346.8 versus water 2988.8±167; P<0.05) and tea (silybin 1726.6±346.8 versus tea 2099.3±223.3; P<0.05). In conclusion, silybin has the potential to reduce iron absorption, and this deserves further investigation, as silybin could be an adjunct in the treatment of haemochromatosis.

China: the soyabean-pork dilemma

In 1996 the population of China reached 1.23 billion, 22% of the world population, and is expected to increase to 1.5 billion by 2020. As China has only 7% of the worlds arable land such population increases are likely to have an important impact on food supply in China and the world. Projections of the potential impact are discussed. The restructuring of Chinese agriculture at the end of the 1970s has led to dramatic increases in agricultural production and food consumption, in particular of animal products, fruit and vegetables. Along with these rapid changes there is evidence of a nutrition transition in which diseases associated with affluence are becoming more prevalent than deficiency diseases. This transition has led to concern about the evolving dietary pattern. The replacement of legumes, including soyabean, by meat and other animal products as rich sources of protein and other nutrients has been controversially argued on grounds of nutritional health, ecological impact, economic effects and world food supply. These arguments are reviewed and the pressures internal and external to China concerning the production and consumption of animal v. legume products are presented. It is concluded that nutritional policies to promote the consumption of soyabean are unlikely to be effective in the context of an increasingly free and global market.

Post-prandial iron absorption in humans: Comparison between HFE genotypes and iron deficiency anaemia

BACKGROUND & AIMS Measurement of serum iron increase after ingestion of a meal could be an efficient method of comparing post-prandial iron absorption between groups of individuals. We determined whether the rise in post-prandial serum iron is increased in fully treated patients with hereditary haemochromatosis (HFE C282Y+/+; HH) compared to iron deficiency anaemia (IDA), iron-replete heterozygous subjects (HFE C282Y+/-) and iron-replete controls (HFE C282Y-/-). METHODS Serum iron increase was measured over 4h after a meal containing 13.1 mg non-haem iron. RESULTS Post-prandial increase in serum iron was similar in treated HH versus IDA (P=0.54), but greater than control subjects (P<0.0001). In five HH patients, using (58)Fe as a tracer, the rate of iron absorption was increased (P<0.05) and serum non-transferrin bound iron showed a tendency to increase (P=0.06). Serum iron curves did not differ for heterozygous subjects and controls (P=0.65). CONCLUSIONS Using the serum iron method we found a comparable increase in post-prandial iron absorption in treated HH and IDA compared with controls. While post-prandial iron absorption in the group heterozygous for the C282Y mutation was modestly increased relative to controls, this difference was not statistically significant.

A food-group based algorithm to predict non-heme iron absorption

Objective To develop an algorithm to predict the percentage non-heme iron absorption based on the foods contained in a meal (wholemeal cereal, tea, cheese, etc.). Existing algorithms use food constituents (phytate, polyphenols, calcium, etc.), which can be difficult to obtain. Design A meta-analysis of published studies using erythrocyte incorporation of radio-isotopic iron to measure non-heme iron absorption. Methods A database was compiled and foods were categorized into food groups likely to modify non-heme iron absorption. Absorption data were then adjusted to a common iron status and a weighted multiple regression was performed. Results Data from 53 research papers (3,942 individual meals) were used to produce an algorithm to predict non-heme iron absorption (R2=0.22, P<0.0001). Conclusions The percentage non-heme iron absorption can be predicted from information on the types of foods contained in a meal with similar efficacy to that of food-constituent-based algorithms (R2=0.16, P=0.0001).

Capacity building in public health nutrition.

The aim of the present paper is to review capacity building in public health nutrition (PHN), the need for which has been stressed for many years by a range of academics, national and international organisations. Although great strides have been made worldwide in the science of nutrition, there remain many problems of undernutrition and increasingly of obesity and related chronic diseases. The main emphasis in capacity building has been on the nutrition and health workforce, but the causes of these health problems are multifactorial and require collaboration across sectors in their solution. This means that PHN capacity building has to go beyond basic nutrition and beyond the immediate health workforce to policy makers in other sectors. The present paper provides examples of capacity building activities by various organisations, including universities, industry and international agencies. Examples of web-based courses are given including an introduction to the e-Nutrition Academy. The scope is international but with a special focus on Africa. In conclusion, there remains a great need for capacity building in PHN but the advent of the internet has revolutionised the possibilities.

North Yemen: from farming to foreign funding

Abstract Since 1970 North Yemen has made rapid economic progress, largely due to external development financing and to remittances from migrant labour. Massive migration has resulted in the deterioration of agriculture. The food supply nevertheless increased from 1909 to 2474 kcal/cap/day between 1965 and 1980, but largely as a result of imports, including food aid, particularly of cereals and dairy products. The nutritional status of the population is still deficient, due in part to inadequate child feeding and poor sanitation. National structures exist to monitor nutrition and develop food and nutrition policies. These need to be strengthened to improve nutrition and food security.