Should bioactive trace elements not recognized as essential,but with beneficial health effects,have intake recommendations

Today, most nutritionists do not consider a trace element essential unless it has a defined biochemical function in higher animals or humans. As a result, even though it has been found that trace elements such as boron and silicon have beneficial bioactivity in higher animals and humans, they generally receive limited attention or mention when dietary guidelines or intake recommendations are formulated. Recently, the possibility of providing dietary intake recommendations such as an adequate intake (AI) for some bioactive food components (e.g., flavonoids) has been discussed. Boron, chromium, nickel, and silicon are bioactive food components that provide beneficial health effects by plausible mechanisms of action in nutritional and supra nutritional amounts, and thus should be included in the discussions. Although the science base may not be considered adequate for establishing AIs, a significant number of findings suggest that statements about these trace elements should be included when dietary intake guidance is formulated. An appropriate recommendation may be that diets should include foods that would provide trace elements not currently recognized as essential in amounts shown to reduce the risk of chronic disease and/or promote health and well-being.     

Dietary Exposure to Lead and Cadmium in Yugoslavia

Abstract

Lead exposure still represents a matter of health concern especially in Yugoslavia. To assess the exposure of normal urban population to lead and cadmium through food, a preliminary monitoring was performed on a small group of urban population. Lead, cadmium and some essential elements (calcium, zinc, iron, copper and manganese) were analysed in collected duplicate diet samples and compared to similar population in Sweden. We found that dietary exposure to lead and cadmium is similar to other countries although Yugoslav urban population is exposed to much higher concentrations of lead in air than in cities of developed countries, due to high lead in gasoline. However, daily intake of some essential elements was significantly lower.

Also populations living around lead smelters in various parts of Yugoslavia are still exposed to elevated environmental lead and cadmium levels. To assess the exposure of the population living in this area, a cumulative long-term exposure to lead was determined by measuring lead in deciduous teeth. Concentrations of lead and cadmium in vegetables, soil and meals from the same region were also analysed. Values obtained for lead and cadmium in food products grown in exposed and control area were found to be related to respective concentrations of these elements in soil as well as to the distance from the smelter. Meals prepared in this region show the same trend, revealing very high intake particularly of lead.

The influence of nutritional factors, i.e. dietary calcium on lead metabolism, was also studied. Blood lead concentration was determined in two groups of peasant women living in two regions with different dietary calcium intake. Lower blood lead values were found in the higher dietary calcium intake region.     

Nutritional Differences between Two Orangutan Habitats: Implications for Population Density

Bottom-up regulatory factors have been proposed to exert a strong influence on mammalian population density. Studies relating habitat quality to population density have typically made comparisons among distant species or communities without considering variation in food quality among localities. We compared dietary nutritional quality of two Bornean orangutan populations with differing population densities in peatland habitats, Tuanan and Sabangau, separated by 63 km. We hypothesized that because Tuanan is alluvial, the plant species included in the orangutan diet would be of higher nutritional quality compared to Sabangau, resulting in higher daily caloric intake in Tuanan. We also predicted that forest productivity would be greater in Tuanan compared to Sabangau. In support of these hypotheses, the overall quality of the diet and the quality of matched dietary items were higher in Tuanan, resulting in higher daily caloric intake compared to Sabangau. These differences in dietary nutritional quality may provide insights into why orangutan population density is almost two times greater in Tuanan compared to Sabangau, in agreement with a potentially important influence of diet quality on primate population density.     

Biomarkers in nutritional epidemiology: applications, needs and new horizons

Modern epidemiology suggests a potential interactive association between diet, lifestyle, genetics and the risk of many chronic diseases. As such, many epidemiologic studies attempt to consider assessment of dietary intake alongside genetic measures and other variables of interest. However, given the multi-factorial complexities of dietary exposures, all dietary intake assessment methods are associated with measurement errors which affect dietary estimates and may obscure disease risk associations. For this reason, dietary biomarkers measured in biological specimens are being increasingly used as additional or substitute estimates of dietary intake and nutrient status. Genetic variation may influence dietary intake and nutrient metabolism and may affect the utility of a dietary biomarker to properly reflect dietary exposures. Although there are many functional dietary biomarkers that, if utilized appropriately, can be very informative, a better understanding of the interactions between diet and genes as potentially determining factors in the validity, application and interpretation of dietary biomarkers is necessary. It is the aim of this review to highlight how some important biomarkers are being applied in nutrition epidemiology and to address some associated questions and limitations. This review also emphasizes the need to identify new dietary biomarkers and highlights the emerging field of nutritional metabonomics as an analytical method to assess metabolic profiles as measures of dietary exposures and indicators of dietary patterns, dietary changes or effectiveness of dietary interventions. The review will also touch upon new statistical methodologies for the combination of dietary questionnaire and biomarker data for disease risk assessment. It is clear that dietary biomarkers require much further research in order to be better applied and interpreted. Future priorities should be to integrate high quality dietary intake information, measurements of dietary biomarkers, metabolic profiles of specific dietary patterns, genetics and novel statistical methodology in order to provide important new insights into gene-diet-lifestyle-disease risk associations.     

Trace elements and melanoma.

Melanoma incidence has been steadily increasing in recent years in most western countries, thus suggesting a role of environmental risk factors. Among these determinants, it has been hypothesized that some trace elements of nutritional and toxicological interest may be implicated in the etiology of the disease. We examined patients with newly diagnosed melanoma of the skin and population controls from the Modena province northern Italy. Clinical and dietary data were collected through questionnaires, and toenails were sampled for trace element determination. Levels of cadmium, chromium, lead, selenium, zinc, copper and iron in toenails were measured by inductively coupled plasma optical emission spectrometry and by neutron activation analysis. Data obtained from 58 cases and 58 controls indicated higher levels of copper and lower concentrations of iron in melanoma patients, whilst no other differences were seen for the remaining elements. Patterns of correlations of zinc and copper with the estimated intake of some dietary factors were different between cases and controls. Results of the present study suggest that abnormal intake or metabolism of copper and of iron might be implicated in the etiology of melanoma, whilst they do not indicate an involvement of exposure to cadmium, chromium, lead, selenium and zinc in this disease.     

Dietary Exposure Estimates of 14 Trace Elements in Xuanwei and Fuyuan,Two High Lung Cancer Incidence Areas in China

Xuanwei and Fuyuan, located in the Yunnan province in southwest of China, are known to have a strikingly high incidence of lung cancer. Among the many factors that have been explored, the association between lung cancer and trace elements has not received enough attention. In this study, dietary samples were collected from 60 families of the lung cancer and control groups and abundances of 14 trace elements were determined using inductively coupled–plasma mass spectroscopy. Accuracy and sensitivity of the method were demonstrated by analyzing national standard reference materials. The results showed that the dietary intake of the trace elements contributed 96.6% of total intake. Among the 14 elements tested, cadmium and titanium were found to be present at a significantly higher level in the food consumed by the cancer group than by the control group. The intake of selenium by the population living in the areas is much lower than what it should be, with the people in the cancer group experiencing even more severe selenium deficiency. In addition, in both groups, the intakes of several essential elements (iron, copper, and zinc) from food and the drinking water were found to be significantly lower than required according to the Chinese Dietary Reference Intakes. The present study of the relationship between trace element intakes of lung cancer cases and controls provides important information urgently needed for the assessment of lung cancer risk of healthy subjects. The study also gives rational dietary suggestions to local residents which is important to the early diagnosis and pretreatment of lung cancer.     

Dietary Intake of Metals by the Population of Tarragona County (Catalonia,Spain): Results from a Duplicate Diet Study

The daily intakes of arsenic (As), beryllium, cadmium (Cd), cobalt, chromium, copper, mercury (Hg), manganese, nickel, lead (Pb), antimony, tin, thallium, uranium, vanadium, and zinc by an adult population living in Tarragona County (Catalonia, Spain) were determined by the duplicate diet method with a 10-day sampling period. Duplicate diet samples, prepared as per consumption, were collected during September 2010 in 20 restaurants offering a variety of daily menus (breakfast, lunch, and dinner). A total of 200 composite samples, corresponding to 600 individual samples, were prepared for trace elements analyses, which were carried out by inductively coupled plasma mass spectrometry. The results were compared with data from previous total diet studies (TDS) recently performed in the same geographical area. Notable differences in the intake of the toxic elements As, Cd, Hg, and Pb were found depending on the method used. It is concluded that both the duplicate diet method and the TDS may provide important and useful information to estimate human exposure to metals through the diet and their derived health risks. However, for comparison between surveys or for establishing temporal trends in the intake of metals, it seems to be recommendable to use always the same method. Notwithstanding, if the interest is only to know whether the intake of a certain element is below the tolerable intake, both methods are useful.     

Calcium in the diet of selected groups of people]

Calcium-content was determined in 23,557 daily food rations of the individuals fed individually or in sets of food or meals prepared in various institutions (3,298) in 1975-1987. Calcium deficit in daily food of girls and adult women has ranged from 50% to 6.2% in comparison with daily intakes recommended in Poland. Mean content of calcium per 1000 kcal ranged from 191.6 mg to 276.2 mg in 24 of the analysed meals. Calcium deficit amounted to 14-37.4% in 20 out of 24 analysed daily meals for boys and men. Calcium content in the remaining daily food rations was equal or even higher than the Polish daily intake recommendation. A mean calcium content per 1000 kcal ranged from 211.6 mg to 342.1 mg. These results suggest, that the daily calcium intake in several groups of the general population is to low, especially in women. Authors suggest, that such a low calcium intake in the diet increases the risk of osteoporosis, and intoxications with lead and cadmium salts, especially in children.     

The Influence of Weekday Eating Patterns on Energy Intake and BMI Among Female Elementary School Personnel

Many health practitioners recommend eating small, frequent meals for weight loss, yet the relationship of eating patterns, such as eating occasion frequency (EOF), to energy intake and body weight is controversial. Broad‐based efforts to promote worksite wellness programs increase the importance of this issue, as many work environments inherently restrict eating patterns. The eating patterns of school personnel are understudied, but are of particular interest, not only because they have limited eating opportunities during the day but also because their diet and weight outcomes are likely to influence behaviors of a much larger population. We examined relationships between weekday EOF and energy intake and BMI among female elementary school personnel in 22 schools in a suburban county of southeastern Louisiana. Two 24‐h dietary recalls were administered to randomly‐selected employees (n = 329) on nonconsecutive days by registered dietitians. Measured heights and weights were used to calculate BMI (weight/height²). On average, employees consumed 2.2 of their total 5.9 meals and snacks during the school day, accounting for 37% of daily energy. In multiple regression models controlling for demographic and health variables, EOF as well as separate counts of meal and snack frequency were each positively and significantly associated with energy intake. However, neither the number of meals, snacks, nor overall EOF was associated with BMI. The proportion of energy consumed during the school day and the positive association of weekday EOF with energy intake suggest an important role for worksite wellness programs that target the dietary improvement of elementary school personnel.     

Dietary Intake of Minerals,Vitamins, and Trace Elements Among Geriatric Population in India

The geriatric population is at a high risk of developing deficiencies of essential micronutrients such as minerals, vitamins, and trace elements and their related deficiency signs and symptoms. Scarce data is available on the dietary intake of essential micronutrients among geriatric subjects in India. Hence, to fill the gap in the existing knowledge, a community-based cross-sectional study was conducted during 2015–2016 in District Nainital, Uttarakhand State, India. A total of 255 geriatric subjects were enrolled from 30 clusters (villages) identified by using population proportionate to size sampling methodology. Data were collected on sociodemographic profile and dietary intake of essential micronutrients (24-h dietary recall, food frequency questionnaire) from all the geriatric subjects. A high percentage of geriatric subjects did not consume the recommended daily intake for essential micronutrients such as energy (78%), protein (78%), calcium (51%), thiamine (33%), riboflavin (64%), niacin (88%), vitamin C (42%), iron (72%), folic acid (72%), magnesium (48%), zinc (98%), copper (81%) and chromium (89%) adequately. Food groups rich in essential micronutrients such as pulses, green leafy vegetables, roots and tubers, other vegetables, fruits, nonvegetarian food items, and milk and milk products were consumed irregularly by the subjects. The overall intake of energy and essential micronutrients was inadequate among the geriatric population in India, possibly due to poor quality and quantity of the diet consumed.     

Differentiation between occupational and dietary-related intake of barium in the skeleton

On the basis of the reconstruction of general nutritional patterns by trace element data on historic populations, an examination on occupational Ba intakes in the skeleton was carried out for a historical metallurgy population. The concentrations of the trace elements Ba, Sr, and Pb as well as the matrix element Ca were determined by AAS analysis. Their correlations within the population were analysed statistically. Evidence of a correlation between Ba and Sr concentrations and the lack of a correlation between Ba and Pb concentrations is interpreted as evidence for a probably solely dietary-related Ba intake in the skeleton. Ba intake from working in ore smelting plants is therefore unlikely or at least insignificant. These conclusions are supported by analysis results of modern food items from the catchment area of the historical population. A sufficient Ba supply through rye was determined, thereby explaining the concentration of Ba in the bone material of the historic population.     

Dietary zinc intake of a group of longstay mentally handicapped women some bioavailability considerations

Dietary factors affecting zinc bioavailability were evaluated according to their relative distribution in the individual daily meals making up the basic diet of 17 institutionalized, mentally handicapped adult women. Mean intake values of zinc, phytate, nonstarch polysaccharides (NSP), calcium, protein, and energy were calculated from a dietary survey of 7 consecutive days, which also served to obtain values for the two zinc bioavailability predictor formulas, phytate/Zn millimolar ratio and [Ca] [phytate]/[Zn][energy] ratio. Mean daily zinc intake was 8.5 ±1.8 mg, with noon and evening meals accounting for the highest contribution to this value (45% and 35%, respectively), whereas breakfast meals’ contribution was 16%. The mean protein intake was 55 ±13 g, with noon and evening meals being the major contributors to total daily intake (42% and 38%, respectively). Breakfast meals accounted for 77% of daily phytate intake, giving a respective phytate/Zn millimolar ratio of 20.4 ±7.6 and a [Ca][phytate]/[Zn][energy] ratio of 336 ±127 mmol/Mcal. Values for both ratios based on noon and evening meals were negligible in comparison. The mean daily NSP intake was 9.8 ±4.2 g, with 53% of total daily intake supplied from breakfast meals, whereas noon and evening meals accounted for 30% and 14%, respectively. The results, while suggesting that zinc bioavailability is unlikely to be adversely affected, indicated that dietary fiber intake levels are probably inadequate, particularly in view of the nonambulant condition and low physical activity prevalent in such individuals, who may, as a consequence, be susceptible to health disorders associated with impaired bowel function and constipation.     

Environmental exposure to cadmium and factors affecting trace-element metabolism and metal toxicity

In the general population, food constitutes the major environmental source of cadmium (Cd) in nonsmokers. It is established that leafy vegetables, roots, and grains (wheat or rice) can accumulate relatively high amounts of Cd from the soil. Beef liver and kidney and shellfish are also major dietary sources of Cd. The daily intake of Cd in various parts of the world is different and depends on both the dietary habits and concentration of Cd in foodstuffs. Because of the long biological half-life of Cd in humans and absence of any specific indicators of its toxicity, the environmental exposure of Cd should be monitored in various countries. Although environmental Cd poisoning is rare, there are isolated reports on excessive exposure to Cd in Japan and Shipham, a zinc-mining town in England. The body retention and toxicity of Cd depends on various factors, such as daily intake, the form of Cd in food, its interactions with essential elements, and nutritional status of the population. Since kidney is considered a critical organ in Cd toxicity, the indicators of renal dysfunction have been widely used for evaluation of Cd poisoning in occupationally exposed people. It is unclear whether similar indicators can be used for monitoring environmental Cd exposure.     

Comparison of Apolipoprotein (apoB/apoA-I) and Lipoprotein (Total Cholesterol/HDL) Ratio Determinants. Focus on Obesity, Diet and Alcohol Intake

The ratio between apolipoprotein B and apolipoprotein A-I (apoB/apoA-I) has been suggested to be a powerful and more accurate predictor of future cardiovascular disease risk than total cholesterol and HDL cholesterol. Since diet and lifestyle can directly influence dyslipidemia, it is of interest to identify modifiable factors that are associated with high levels of the apolipoprotein ratio and if they can have a different association with a more traditional indicator of cardiovascular risk such as total cholesterol/HDL. The relationship between obesity and dyslipidemia is established and it is of interest to determine which factors can modify this association. This study investigated the cross-sectional association of obesity, diet and lifestyle factors with apoB/apoA-I and total cholesterol/HDL respectively, in a Swedish population of 2,907 subjects (1,537 women) as part of the INTERGENE study. The apolipoprotein and lipoprotein ratios were highly correlated, particularly in women, and obesity was strongly associated with both. Additionally, age, cigarette smoking and alcohol intake were important determinants of these ratios. Alcohol was the only dietary factor that appreciably attenuated the association between obesity and each of the ratios, with a stronger attenuation in women. Other dietary intake and lifestyle-related factors such as smoking status and physical activity had a lower effect on this association. Because the apolipoprotein and lipoprotein ratios share similar diet and lifestyle determinants as well as being highly correlated, we conclude that either of these ratios may be a sufficient indicator of dyslipidemia.     

Distinctive modulation of inflammatory and metabolic parameters in relation to zinc nutritional status in adult overweight/obese subjects

Overweight and obesity are associated with low grade of inflammation and chronic inflammatory response characterized by abnormal production and activation of some pro-inflammatory signalling pathways. Taking into account that obesity is the direct result of an imbalance between energy intake and energy expenditure, the nutritional factors in the diet, with particular focus on zinc, may play a pivotal role in the development of obesity-associated comorbidities. Considering the potential interactions among zinc nutritional status, inflammation, overweight/obesity and insulin secretion, the aim of the present work was to clarify the influence of zinc dietary intake on some metabolic, inflammatory and zinc status parameters in adult overweight/obese subjects. We found a close interrelationship between nutritional zinc and obesity. In particular, subjects with a lower zinc dietary intake display a deeper inflammatory status, general impairment of the zinc status, an altered lipid profile and increased insulin production with respect to obese subjects with normal zinc dietary intake. Moreover, in the presence of low dietary zinc intake, the obese subjects are less capable to respond to oxidative stress and to inflammation leading to the development of obesity or to a worsening of already preexisting obesity status. In conclusion, a possible zinc supplementation in obese subjects with a deeper inflammatory status and more altered zinc profile may be suggested in order to limit or reduce the inflammation, taking also into account that zinc supplementation normalizes “inflammaging” as well as zinc profile leading to a correct intra- and extracellular zinc homeostasis.     

Special feature for the Olympics: effects of exercise on the immune system: modification of immune responses to exercise by carbohydrate, glutamine and anti-oxidant supplements

Immunosuppression in athletes involved in heavy training is undoubtedly multifactorial in origin. Training and competitive surroundings may increase the athlete's exposure to pathogens and provide optimal conditions for pathogen transmission. Heavy prolonged exertion is associated with numerous hormonal and biochemical changes, many of which potentially have detrimental effects on immune function. Furthermore, improper nutrition can compound the negative influence of heavy exertion on immunocompetence. An athlete exercising in a carbohydrate-depleted state experiences larger increases in circulating stress hormones and a greater perturbation of several immune function indices. The poor nutritional status of some athletes may predispose them to immunosuppression. For example, dietary deficiencies of protein and specific micronutrients have long been associated with immune dysfunction. Although it is impossible to counter the effects of all of the factors that contribute to exercise-induced immunosuppression, it has been shown to be possible to minimize the effects of many factors. Athletes can help themselves by eating a well-balanced diet that includes adequate protein and carbohydrate, sufficient to meet their energy requirements. This will ensure a more than adequate intake of trace elements without the need for special supplements. Consuming carbohydrate (but not glutamine or other amino acids) during exercise attenuates rises in stress hormones, such as cortisol, and appears to limit the degree of exercise-induced immunosuppression, at least for non-fatiguing bouts of exercise. Evidence that high doses of anti-oxidant vitamins can prevent exercise-induced immunosuppression is also lacking.     

Significance of iron bioavailability for iron recommendations

Recently, recommended dietary allowances (RDA) have been formulated by the Dutch Nutrition Council for minerals and trace elements, including iron (Fe). For some population groups in the Netherlands, it is questionable whether they easily meet the Fe recommendation. An increase in Fe intake is not always possible, but “manipulation” of Fe bioavailability ultimately may result in better Fe utilization. Various factors are known to affect Fe bioavailability. Generally, much attention is paid to diet-related factors, such as inhibitors and enhancers of Fe availability for absorption. Factors such as pH, oxidation potential, structure of food, and time of digestion often are overlooked. Of the diet-related factors, heme Fe and ascorbic acid have a strong positive effect on Fe availability for absorption, whereas oxalate and polyphenols seem to be strong inhibitors of Fe availability. Because of the many interactions that may occur simultaneously, the net effect of the various combined factors in a meal is not equal to the sum of the individual factors.     

Update on the possible nutritional importance of silicon

Convincing evidence that silicon is a bioactive beneficial trace element continues to accumulate. The evidence, which has come from human, animal, and in vitro studies performed by several laboratories, indicate that silicon in nutritional and supra nutritional amounts promotes bone and connective tissue health, may have a modulating effect on the immune or inflammatory response, and has been associated with mental health. A plausible mechanism of action for the beneficial effects of silicon is the binding of hydroxyl groups of polyols such that it influences the formation and/or utilization of glycosaminoglycans, mucopolysaccharides, and collagen in connective tissue and bone. In addition, silicon may affect the absorption, retention or action of other mineral elements (e.g., aluminum, copper, magnesium). Based on findings from both animal and human experiments, an intake of silicon of near 25 mg/d would be a reasonable suggestion for an adequate intake that would assure its nutritional benefits. Increased intakes of silicon through consuming unrefined grains, certain vegetables, and beverages and cereals made from grains should be recognized as a reasonable dietary recommendation.     

Dietary exposure and risk assessment to trace elements and iodine in seaweeds

IntroductionSeaweeds are a rich source of elements such as iodine, and are also able to accumulate contaminants such as trace elements.MethodsThe aim of this study was to assess the dietary exposure as well as the risk from iodine and trace elements in edible seaweeds for the French population using current consumption data. The contribution of seaweeds to overall dietary exposure to trace elements and iodine was evaluated, and for those substances with minimal contribution to overall dietary exposure, simulations were performed to propose increased maximal limits in seaweeds.ResultsCadmium, inorganic arsenic and mercury in seaweeds were very low contributors to total dietary exposure to these contaminants (0.7 % 1.1 % and 0.1 % on average, respectively). Dietary exposure to lead via seaweed may contribute up to 3.1 % of total dietary exposure. Dietary consumption of iodine via seaweed may contribute up to 33 % of total exposure to iodine, which makes seaweeds the strongest contributor to iodine in diet.DiscussionNew maximal values in seaweeds are proposed for the very low contributors to total dietary exposure: 1 mg/kg dw for cadmium, 10 mg/kg dw for inorganic arsenic and 0.3 mg/kg dw for mercury.