Showing papers in "Annals of Nutrition and Metabolism in 2012"

Probiotic Mechanisms of Action

Abstract: Probiotics are live microorganisms that provide health benefits to the host when ingested in adequate amounts. The strains most frequently used as probiotics include lactic acid bacteria and bifidobacteria. Probiotics have demonstrated significant potential as therapeutic options for a variety of diseases, but the mechanisms responsible for these effects have not been fully elucidated yet. Several important mechanisms underlying the antagonistic effects of probiotics on various microorganisms include the following: modification of the gut microbiota, competitive adherence to the mucosa and epithelium, strengthening of the gut epithelial barrier and modulation of the immune system to convey an advantage to the host. Accumulating evidence demonstrates that probiotics communicate with the host by pattern recognition receptors, such as toll-like receptors and nucleotide-binding oligomerization domain-containing protein-like receptors, which modulate key signaling pathways, such as nuclear factor-ĸB and mitogen-activated protein kinase, to enhance or suppress activation and influence downstream pathways. This recognition is crucial for eliciting measured antimicrobial responses with minimal inflammatory tissue damage. A clear understanding of these mechanisms will allow for appropriate probiotic strain selection for specific applications and may uncover novel probiotic functions. The goal of this systematic review was to explore probiotic modes of action focusing on how gut microbes influence the host.

Cardiovascular disease mortality and cancer incidence in vegetarians: a meta-analysis and systematic review.

Abstract: Background: Prospective cohort studies have examined mortality and overall cancer incidence among vegetarians, but the results have been inconclusive. &l

Global burden of maternal and child undernutrition and micronutrient deficiencies.

Abstract: Maternal and child undernutrition and micronutrient deficiencies affect approximately half of the world’s population. These conditions include intrauterine growth restriction (IUGR), low birth weight, protein-energy malnutrition, chronic energy deficit of women, and micronutrient deficiencies. Although the rates of stunting or chronic protein-energy malnutrition are increasing in Africa, the absolute numbers of stunted children are much higher in Asia. The four common micronutrient deficiencies include those of iron, iodine, vitamin A, and zinc. All these conditions are responsible directly or indirectly for more than 50% of all under-5 deaths globally. According to more recent estimates, IUGR, stunting and severe wasting are responsible for one third of under-5 mortality. About 12% of deaths among under-5 children are attributed to the deficiency of the four common micronutrients. Despite tremendous progress in different disciplines and unprecedented improvement with many health indicators, persistently high undernutrition rates are a shame to the society. Human development is not possible without taking care to control undernutrition and micronutrient deficiencies. Poverty, food insecurity, ignorance, lack of appropriate infant and young child feeding practices, heavy burden of infectious illnesses, and poor hygiene and sanitation are factors responsible for the high levels of maternal and child undernutrition in developing countries. These factors can be controlled or removed by scaling up direct nutrition interventions and eliminating the root conditions including female illiteracy, lack of livelihoods, lack of women’s empowerment, and poor hygiene and sanitation.

A history of vitamin E.

Abstract: Vitamin E (α-tocopherol) was discovered nearly 100 years ago because it was required to prevent fetal resorption in pregnant, vitamin E-deficient rats fed lard-containing diets that were easily oxidizable. The human diet contains eight different vitamin E-related molecules synthesized by plants; despite the fact that all of these molecules are peroxyl radical scavengers, the human body prefers α-tocopherol. The biological activity of vitamin E is highly dependent upon regulatory mechanisms that serve to retain α-tocopherol and excrete the non-α-tocopherol forms. This preference is dependent upon the combination of the function of α-tocopherol transfer protein (α-TTP) to enrich the plasma with α-tocopherol and the metabolism of non-α-tocopherols. α-TTP is critical for human health because mutations in this protein lead to severe vitamin E deficiency characterized by neurologic abnormalities, especially ataxia and eventually death if vitamin E is not provided in large quantities to overcome the lack of α-TTP. α-Tocopherol serves as a peroxyl radical scavenger that protects polyunsaturated fatty acids in membranes and lipoproteins. Although specific pathways and specific molecular targets have been sought in a variety of studies, the most likely explanation as to why humans require vitamin E is that it is a fat-soluble antioxidant.

Evidence-based guideline of the German Nutrition Society: carbohydrate intake and prevention of nutrition-related diseases.

Abstract: The relative contribution of nutrition-related chronic diseases to the total disease burden of the society and the health care costs has risen continuously over the last decades. Thus, there is an urgent necessity to better exploit the potential of dietary prevention of diseases. Carbohydrates play a major role in human nutrition - next to fat, carbohydrates are the second biggest group of energy-yielding nutrients. Obesity, type 2 diabetes mellitus, dyslipoproteinaemia, hypertension, metabolic syndrome, coronary heart disease and cancer are wide-spread diseases, in which carbohydrates could have a pathophysiologic relevance. Correspondingly, modification of carbohydrate intake could have a preventive potential. In the present evidence-based guideline of the German Nutrition Society, the potential role of carbohydrates in the primary prevention of the named diseases was judged systematically. The major findings were: a high carbohydrate intake at the expense of total fat and saturated fatty acids reduces the concentrations of total, LDL and HDL cholesterol. A high carbohydrate consumption at the expense of polyunsaturated fatty acids increases total and LDL cholesterol, but reduces HDL cholesterol. Regardless of the type of fat being replaced, a high carbohydrate intake promotes an increase in the triglyceride concentration. Furthermore, a high consumption of sugar-sweetened beverages increases the risk of obesity and type 2 diabetes mellitus, whereas a high dietary fibre intake, mainly from whole-grain products, reduces the risk of obesity, type 2 diabetes mellitus, dyslipoproteinaemia, cardiovascular disease and colorectal cancer at varying evidence levels. The practical consequences for current dietary recommendations are presented.

New Reference Values for Vitamin D

Abstract: In the recent past, many studies have been published on the association between vitamin D and bone health or the risk of various chronic diseases. Thus, the D-A-CH reference values [D-A-CH arises from the initial letters of the common country identification for the countries Germany (D), Austria (A) and Switzerland (CH)] for the intake of vitamin D have been revised based on a critical review by the German Nutrition Society. Both dietary intake and endogenous synthesis contribute to the body’s vitamin D status. Since different factors modulate the extent of endogenous vitamin D formation, quantification is hardly possible. Therefore, the new reference values for vitamin D intake are specified for a situation in which endogenous synthesis is completely missing. Based on the findings of the critical review, serum 25-hydroxyvitamin D concentrations of 50 nmol/l or higher are considered an indicator of an optimal vitamin D status. When endogenous synthesis is missing, adequate vitamin D intake is estimated as 20 µg per day for children, adolescents and adults. Dietary vitamin D intake from habitual diet is not sufficient to achieve this value. This gap has to be covered by endogenous vitamin D synthesis and/or additional intake of vitamin D. It is clearly stated that the desired vitamin D supply can be achieved without using vitamin D supplements by frequent sun exposure.

The evaluation of body composition: a useful tool for clinical practice

Abstract: Undernutrition is insufficiently detected in in- and outpatients, and this is likely to worsen during the next decades. The increased prevalence of obesity together with chronic illnesses associated with fat-free mass (FFM) loss will result in an increased prevalence of sarcopenic obesity. In patients with sarcopenic obesity, weight loss and the body mass index lack accuracy to detect FFM loss. FFM loss is related to increasing mortality, worse clinical outcomes, and impaired quality of life. In sarcopenic obesity and chronic diseases, body composition measurement with dual-energy X-ray absorptiometry, bioelectrical impedance analysis, or computerized tomography quantifies the loss of FFM. It allows tailored nutritional support and disease-specific therapy and reduces the risk of drug toxicity. Body composition evaluation should be integrated into routine clinical practice for the initial assessment and sequential follow-up of nutritional status. It could allow objective, systematic, and early screening of undernutrition and promote the rational and early initiation of optimal nutritional support, thereby contributing to reducing malnutrition-induced morbidity, mortality, worsening of the quality of life, and global health care costs.

Global nutrition epidemiology and trends.

Abstract: In the year 2011, 6.9 million children under the age of 5 years died worldwide, one third of them related to increased susceptibility to illnesses due to undernutrition. An estimated 178 million children under 5 years are stunted, 55 million are wasted, and 19 million of these are severely affected and are at a higher risk of premature death, the vast majority being from sub-Saharan Africa and South-Central Asia. Globally, over 2 billion people are at risk for vitamin A, iodine, and/or iron deficiency. Other micronutrient deficiencies of public health concern include zinc, folate, and the B vitamins. The risk factors for undernutrition include low birth weight, inadequate breastfeeding, improper complementary feeding, and recurrent infections. Infectious diseases often coexist with micronutrient deficiencies and exhibit complex interactions leading to the vicious cycle of malnutrition and infections. Diarrhea along with the poor selection and intake of complementary food are the major contributors to undernutrition. Possible strategies to combat malnutrition include promotion of breastfeeding, dietary supplementation of micronutrients, prevention of protein-energy malnutrition, and improvement in the standard of preparation and hygiene of available weaning foods. The universal coverage with the full package of these proven interventions at observed levels of program effectiveness could prevent about one quarter of child deaths under 36 months of age and reduce the prevalence of stunting at 36 months by about one third. The median coverage rate of interventions along the continuum of care for Countdown countries has however been ≥80% for vaccination and vitamin A supplementation. However, for several interventions, including early initiation and exclusive breastfeeding below 6 months of age and case management of childhood illnesses, the median coverage rate hovers at or below 50%. This suggests that interventions requiring strong health systems or behavior change appear to be stalled and need to be re-examined to find more effective ways of delivery.

Effect of Lycopene and Tomato Products on Cholesterol Metabolism

Abstract: Background/Aims: Increased ingestion of tomato, containing lycopene, has been associated with a decreased risk for atherosclerosis, although the exact molecular mechanism is still unknown. Here we review the available evidence for a direct regulation of tomato lycopene on cholesterol metabolism using results from experimental and human studies. Results: In human macrophages lycopene dose dependently reduced intracellular total cholesterol. Such an effect was associated with a decrease in cholesterol synthesis through a reduction of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and expression, a modulation of low- density lipoprotein (LDL) receptor and acyl-coenzyme A:cholesterol acyltransferase activity. An increase in cholesterol efflux through an enhancement of ABCA1 and caveolin-1 expression was also observed. In animal models of atherosclerosis, lycopene and tomato products decreased plasma total cholesterol, LDL cholesterol and increased high-density lipoprotein cholesterol. In agreement with the experimental results, most human intervention trials analyzed show that dietary supplementation with lycopene and/or tomato products reduced plasma LDL cholesterol dependently on the dose and the time of administration. Conclusions: Although lycopene and tomato products seem to possess direct hypocholesterolemic properties, more experimental studies are needed to better understand the mechanisms involved. There is also a need for more well-designed human dietary intervention studies to better clarify the role of lycopene as a hypocholesterolemic agent.

Complementary foods and flavor experiences: setting the foundation.

Abstract: Increased fruit and vegetable consumption early in life may lead to life-long intake of fruits and vegetables, which in turn may be beneficial for weight control and other health outcomes in later life. Although health officials worldwide recommend delaying solid foods until 6 months of age, younger infants often receive solid food, which may affect later obesity rates. The timing of introduction to solid foods is important both nutritionally and developmentally and may affect acceptance of foods both in infancy and later in life. Infants can clearly discriminate the flavors of different fruits and vegetables. Repeated flavor experiences promote the willingness to eat a variety of foods: infants will consume more of foods that have a familiar flavor and are more accepting of novel flavors if they have experience with flavor variety. Many flavors that the mother either ingests or inhales are transmitted to her milk and/or amniotic fluid. Mothers can help the transition from a diet exclusively of milk or formula to a mixed diet by providing the infant familiar flavors in both milk or formula and solid foods. Exposure to a variety of flavors during and between meals appears to facilitate acceptance of novel foods. Providing novelty in the context of a familiar food might prove to be an optimal combination to progressively accustom infants to a diversity of novel foods. When repeatedly exposing infants to flavors of some vegetables that have bitter tastes, mothers should focus not on infants' facial expressions but on their willingness to eat the food and should continue to provide repeated opportunities to taste the food. Introducing children repeatedly to individual as well as a variety of fruits and vegetables, both within and between meals, might help them be more accepting of fruits and vegetables, which is difficult to enhance beyond toddlerhood.

Vitamin D Deficiency: A New Risk Factor for Type 2 Diabetes

Abstract: Recent compelling evidence suggests a role of vitamin D deficiency in the pathogenesis of insulin resistance and insulin secretion derangements, with a consequent possible interference with type 2 diabetes mellitus. The mechanism of this link is incompletely understood. In fact, vitamin D deficiency is usually detected in obesity in which insulin resistance is also a common finding. The coexistence of insulin resistance and vitamin D deficiency has generated several hypotheses. Some cross-sectional and prospective studies have suggested that vitamin D deficiency may play a role in worsening insulin resistance; others have identified obesity as a risk factor predisposing individuals to exhibit both vitamin D deficiency and insulin resistance. The available data from intervention studies are largely confounded, and inadequate considerations of seasonal effects on 25(OH)D concentrations are also a common design flaw in many studies. On the contrary, there is strong evidence that obesity might cause both vitamin D deficiency and insulin resistance, leaving open the possibility that vitamin D and diabetes are not related at all. Although it might seem premature to draw firm conclusions on the role of vitamin D supplementation in reducing insulin resistance and preventing type 2 diabetes, this manuscript will review the circumstances leading to vitamin D deficiency and how such a deficiency can eventually independently affect insulin sensitivity.

Nutrigenetics and modulation of oxidative stress.

Abstract: Oxidative stress develops as a result of an imbalance between the production and accumulation of reactive species and the body's ability to manage them using exogenous and endogenous antioxidants. Exogenous antioxidants obtained from the diet, including vitamin C, vitamin E, and carotenoids, have important roles in preventing and reducing oxidative stress. Individual genetic variation affecting proteins involved in the uptake, utilization and metabolism of these antioxidants may alter their serum levels, exposure to target cells and subsequent contribution to the extent of oxidative stress. Endogenous antioxidants include the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, paraoxanase, and glutathione S-transferase. These enzymes metabolize reactive species and their by-products, reducing oxidative stress. Variation in the genes coding these enzymes may impact their enzymatic antioxidant activity and, thus, the levels of reactive species, oxidative stress, and risk of disease development. Oxidative stress may contribute to the development of chronic disease, including osteoporosis, type 2 diabetes, neurodegenerative diseases, cardiovascular disease, and cancer. Indeed, polymorphisms in most of the genes that code for antioxidant enzymes have been associated with several types of cancer, although inconsistent findings between studies have been reported. These inconsistencies may, in part, be explained by interactions with the environment, such as modification by diet. In this review, we highlight some of the recent studies in the field of nutrigenetics, which have examined interactions between diet, genetic variation in antioxidant enzymes, and oxidative stress.

The discovery of vitamin K and its clinical applications.

Abstract: Vitamin K was discovered fortuitously in 1929 as part of experiments on sterol metabolism and was immediately associated with blood coagulation. In the decade that followed, the principal K vitamers, phylloquinone and the menaquinones, were isolated and fully characterized. In the early 1940s, the first vitamin K antagonists were discovered and crystallized with one of its derivatives, warfarin, still being widely used in today's clinical setting. However, major progress in our understanding of the mechanisms of action of vitamin K came in the 1970s with the discovery of γ-carboxyglutamic acid (Gla), a new amino acid common to all vitamin K proteins. This discovery not only provided the basis to understanding earlier findings about prothrombin but later led to the discovery of vitamin K-dependent proteins (VKDPs) not involved in hemostasis. The 1970s also saw an important breakthrough with respect to our understanding of the vitamin K cycle and marked the discovery of the first bone VKDP, osteocalcin. Important studies relating to the role of vitamin K in sphingolipid synthesis were also underway at that time and would pave the way to further work 15 years later. The decades that followed saw the discovery of additional VKDPs showing wide tissue distribution and functional scope, the latest members having been identified in 2008. The 1990s and 2000s were also marked by important epidemiological and intervention studies that focused on the translational impact of recent vitamin K discoveries, notably with respect to bone and cardiovascular health. This short review presents an overview of the history of vitamin K and of its recent developments.

Food intake, diet quality and behavioral problems in children: results from the GINI-plus/LISA-plus studies.

Abstract: Background/Aims: To assess the association between food intake and diet quality and behavioral problems at the 10-year follow-up of the two population-based birth

Timing of introduction of complementary food: short- and long-term health consequences.

Abstract: Complementary food is needed when breast milk (or infant formula) alone is no longer sufficient for both nutritional and developmental reasons The timing of its introduction, therefore, is an individual decision, although 6 months of exclusive breastfeeding can be recommended for most healthy term infants The new foods are intended to 'complement' ongoing breastfeeding with those dietary items whose intake has become marginal or insufficient Both breastfeeding and complementary feeding can have direct or later consequences on health The evaluation of consequences of both early and late introduction of complementary food can neither disregard the effect of breastfeeding compared to formula feeding nor the composition or quality of the complementary food Possible short-term health effects concern growth velocity and infections, and possible long-term effects may relate to atopic diseases, type 1 and 2 diabetes, obesity and neuromuscular development On the basis of the currently available evidence, it is impossible to exactly determine the age when risks related to the start of complementary feeding are lowest or highest for most of these effects, with the possible exception of infections and early growth velocity The present knowledge on undesirable health effects, however, is mainly based on observational studies, and although some mechanisms have been proposed, further prospective studies have to clarify these unsolved issues Even less evidence on the consequences of the timing of complementary food introduction is available for formula-fed infants

The discovery of vitamin C.

Abstract: The term 'scurvy' for the disease resulting from prolonged vitamin C deficiency had origins in 'scorbutus' (Latin), 'scorbut' (French), and 'Skorbut' (German). Scurvy was a common problem in the world's navies and is estimated to have affected 2 million sailors. In 1747, James Lind conducted a trial of six different treatments for 12 sailors with scurvy: only oranges and lemons were effective in treating scurvy. Scurvy also occurred on land, as many cases occurred with the 'great potato famine' in Ireland in 1845. Many animals, unlike humans, can synthesize their own vitamin C. Axel Holst and Theodor Frolich fortuitously produced scurvy in the guinea pig, which like humans requires vitamin C in the diet. In 1928, Albert Szent-Gyorgyi isolated a substance from adrenal glands that he called 'hexuronic acid'. Four years later, Charles Glen King isolated vitamin C in his laboratory and concluded that it was the same as 'hexuronic acid'. Norman Haworth deduced the chemical structure of vitamin C in 1933.

A brief history of choline.

Abstract: In 1850, Theodore Gobley, working in Paris, described a substance, 'lecithine', which he named after the Greek 'lekithos' for egg yolk. Adolph Strecker noted in 1862 that when lecithin from bile was heated, it generated a new nitrogenous chemical that he named 'choline'. Three years later, Oscar Liebreich identified a new substance, 'neurine', in the brain. After a period of confusion, neurine and choline were found to be the same molecule, and the name choline was adapted. Lecithin was eventually characterized chemically as being phosphatidylcholine. In 1954, Eugene Kennedy described the cytidine 5-dihphosphocholine pathway by which choline is incorporated into phosphatidylcholine. A second route, the phosphatidylethanolamine-N-methyltransferase pathway, was identified by Jon Bremer and David Greenberg in 1960. The role of choline as part of the neurotransmitter acetylcholine was established by Otto Loewi and Henry Dale. Working in the 1930s at the University of Toronto, Charles Best showed that choline prevented fatty liver in dogs and rats. The importance of choline as an essential nutrient for human health was determined in the 1990s through controlled feeding studies in humans. Recently, an understanding of the role of genetic variation in setting the dietary requirement for choline in people is being unraveled.

Effect of L-arginine and selenium added to a hypocaloric diet enriched with legumes on cardiovascular disease risk factors in women with central obesity: A randomized, double-blind, placebo-controlled trial

Abstract: Background/Aims: We aimed to discover if L-arginine and selenium alone or together can increase the effect of a hypocaloric diet enriched in legumes (HDEL) on central obesity and cardiovascular risk factors in women with central obesity. Methods: This randomized, double-blind, placebo-controlled trial was undertaken in 84 premenopausal women with central obesity. After a 2-week run-in period on an isocaloric diet, participants were randomly assigned to a control diet (HDEL), L-arginine (5 g/day) and HDEL, selenium (200 µg/day) and HDEL or L-arginine, selenium and HDEL for 6 weeks. Cardiovascular risk factors were assessed before intervention and 3 and 6 weeks afterwards. Results: After 6 weeks, L-arginine had significantly reduced waist circumference (WC); selenium had significantly lowered fasting concentrations of serum insulin and the homeostasis model assessment of insulin resistance index; the interaction between L-arginine and selenium significantly reduced the fasting concentration of nitric oxides (NOx), and HDEL lowered triglycerides (TG) and WC and significantly increased the fasting concentration of NOx. HDEL reduced high-sensitivity C-reactive protein levels in the first half of the study and returned them to basal levels in the second half. Conclusion: These data indicate the beneficial effects of L-arginine on central obesity, selenium on insulin resistance and HDEL on serum concentrations of NOx and TG.

B vitamins and n-3 fatty acids for brain development and function: review of human studies.

Abstract: Background: Nutrition is one of many factors that affect brain development and functioning, and in recent years the role of certain nutrients has been investigate

Effect of the intake of resveratrol, resveratrol phosphate, and catechin-rich grape seed extract on markers of oxidative stress and gene expression in adult obese subjects.

Abstract: Background: The preventive effect of resveratrol (RES) on the development of human diseases has been verified by numerous epidemiological studies. Resveratrol tri

Adherence Issues in Inherited Metabolic Disorders Treated by Low Natural Protein Diets

Abstract: Common inborn errors of metabolism treated by low natural protein diets [amino acid (AA) disorders, organic acidemias and urea cycle disorders] are responsible for a collection of diverse clinical symptoms, each condition presenting at different ages with variable severity. Precursor-free or essential L-AAs are important in all these conditions. Optimal long-term outcome depends on early diagnosis and good metabolic control, but because of the rarity and severity of conditions, randomized controlled trials are scarce. In all of these disorders, it is commonly described that dietary adherence deteriorates from the age of 10 years onwards, at least in part representing the transition of responsibility from the principal caregivers to the patients. However, patients may have particular difficulties in managing the complexity of their treatment because of the impact of the condition on their neuropsychological profile. There are little data about their ability to self-manage their own diet or the success of any formal educational programs that may have been implemented. Trials conducted in non-phenylketonuria (PKU) patients are rare, and the development of specialist L-AAs for non-PKU AA disorders has usually shadowed that of PKU. There remains much work to be done in refining dietary treatments for all conditions and gaining acceptable dietary adherence and concordance, which is crucial for an optimal outcome. Copyright (C) 2012 S. Karger AG, Basel

Effect of daily consumption of probiotic yogurt on oxidative stress in pregnant women: a randomized controlled clinical trial.

Abstract: Background: Due to the enhanced oxygen requirement of the mitochondria-rich placenta primarily during the third trimester, pregnancy is associated with elevated levels of oxidative

On the 'discovery' of vitamin A.

Abstract: Vitamin A is essential for normal growth, reproduction, immunity, and vision. The characterization of vitamin A spanned a period of about 130 years. During this long, incremental process, there is no single event that can be called the 'discovery' of vitamin A. The physiologist Francois Magendie conducted nutritional deprivation experiments with dogs in 1816 that resulted in corneal ulcers and high mortality - a finding similar to the common clinical situation in poorly fed, abandoned infants in Paris. In the 1880s, Nicolai Lunin showed that there was an unknown substance in milk that was essential for nutrition. Carl Socin suggested that an unknown substance for growth in egg yolk was fat soluble. Frederick Gowland Hopkins proposed in 1906 that there were 'unsuspected dietetic factors' that were necessary for life. In 1911, Wilhelm Stepp demonstrated that this essential substance in milk was fat soluble. The following year, Hopkins showed that there were 'accessory factors' present in 'astonishingly small amounts' in milk that supported life. Contrary to the dogma that all fats had similar nutritional value, in 1913, Elmer McCollum and Marguerite Davis at Wisconsin and Thomas Osborne and Lafayette Mendel at Yale showed butter and egg yolk were not equivalent to lard and olive oil in supporting the growth and survival of rats. The growth-supporting 'accessory factor' became known as 'fat-soluble A' in 1918 and then 'vitamin A' in 1920. Paul Karrer described the chemical structure of vitamin A in 1932. Harry Holmes and Ruth Corbet isolated and crystallized vitamin A in 1937. Methods for the synthesis of vitamin A came with the work of David Adriaan van Dorp and Jozef Ferdinand Arens in 1946 and Otto Isler and colleagues in 1947. Further work on the role of vitamin A in immunity and child survival continued until through the 1990s.

Interaction of nutrition and infections globally: an overview.

Abstract: The interaction of nutrition and infections is known by experience by generations of medical doctors. Before the era of antibiotics, diet was an integral part of the management of infections. Now, it is necessary to take a fresh look at this interaction as the understanding of immune response has expanded considerably. Comparatively little research has addressed the impact of nutrition interventions on the management of infectious diseases. Most observations of the interaction between nutrition and infections are epidemiological in character. This holds especially true for measles as well as for tuberculosis. In AIDS, the deterioration of the nutritional status is an indicator of disease progression. Infections in undernourished children are a common cause of death, and taking this finding into account helps to reduce the case fatality rate in severely malnourished patients. Regarding the immune response, cellular as well as soluble components are affected by deficiencies of single nutrients or general undernutrition. The immunosuppressive effect of undernutrition starts during intrauterine life already: maternal nutrition status has been shown to impact on immune function in adult animals. Recent research suggests that not only undernutrition but also caloric overnutrition impacts on immune response to infections and immunization. This is partly due to the chronic inflammatory activity of the adipose tissue and partly due to neuroendocrine alterations. Infectious diseases also impact on the nutritional status, either specifically or through unspecific mechanisms, such as anorexia, tachypnea, and vomiting.

The history of the discovery of vitamin D and its daughter steroid hormone.

Abstract: It is largely through historical accident in the interval of 1920-1940 that vitamin D(3) became classified as a vitamin rather than as a steroid hormone. The formal definition of a vitamin is that it is a trace dietary constituent required to produce the normal function of a physiological process or processes. The emphasis here is on trace and the fact that the vitamin must be supplied regularly in the diet; this implies that the body is unable to metabolically synthesize the vitamin in question. However, the ultraviolet exposure of 7-dehydrocholesterol present in the skin results in the photochemical production of vitamin D(3). Thus, vitamin D(3) becomes a true vitamin only when the animal or human does not have regular access to sunlight or ultraviolet light. Under normal physiological circumstances, all mammals, including humans, can generate, via ultraviolet exposure of 7-dehydrocholesterol present in the skin, adequate quantities of vitamin D(3) to meet their nutritionally defined requirements. There is a vibrant historical record beginning in 1650 and culminating in 1963 concerned with the determination of the chemical structures of vitamin D(3) and vitamin D(2). A surprising aspect concerning vitamin D(3) is that it is itself biologically inert. There are no known essential biological actions or contributions that rely specifically on the molecule vitamin D(3). While chemists had certainly appreciated the strong structural similarity between the vitamins D and other steroids, this correlation was never widely acknowledged in the biological, clinical, or nutritional sciences until 1965-1970. The biological role of vitamin D(3) is to serve as a substrate for the liver 25-hydroxylase which produces 25-hydroxyvitamin D(3) [25(OH)D(3)]. 25(OH)D(3) in turn serves as the substrate for the kidney proximal tubule 25(OH)D(3)-1α-hydroxylase enzyme which produces the steroid hormone 1α,25(OH)(2)-vitamin D(3) [1α,25(OH)(2)D(3)].

The discovery and characterization of riboflavin.

Abstract: The first observation of a pigment in milk with yellow-green fluorescence can be traced to the English chemist Alexander Wynter Blyth in 1872, but it was not until the early 1930s that the substance was characterized as riboflavin. Interest in accessory food factors began in the latter half of the 19th century with the discovery of the first vitamin, thiamin. Thiamin was water soluble and given the name vitamin B(1). However, researchers realized that there were one or more additional water-soluble factors and these were called the vitamin B-2 complex. The search to identify these accessory food factors in milk, whole wheat, yeast, and liver began in the early 1900s. As there is no classical nutritional disease attributable to riboflavin deficiency, it was the growth-stimulating properties of the food extracts given to young rats that provided the tool with which to investigate and eventually extract riboflavin. Riboflavin was the second vitamin to be isolated and the first from the vitamin B-2 complex; the essential nature of the vitamin as a food constituent for man was shown in 1939.

Magnesium: Novel Applications in Cardiovascular Disease – A Review of the Literature

Abstract: Magnesium is an ubiquitous element and its formulation determines its efficacy and administration. It is used for gastrointestinal and obstetric disease and recently cardiovascular and neurological indications have also been explored. The role of serum/dietary magnesium intake on cardiovascular disease, carotid intima-media thickness (CIMT), hypertension (HTN) and cholesterol synthesis has been investigated. Despite differences in patient populations, some observational and interventional studies have suggested that low serum/dietary magnesium is associated with higher CIMT and more cardiovascular risk factors. A few clinical and basic science interventional studies have also shown the benefits of magnesium administration in cardiovascular disease prevention and as a neuroprotective agent. Low magnesium levels have been implicated in inflammation and endothelial dysfunction. Hypomagnesemia results in increased C-reactive protein and cytokine exaggeration, increased nuclear factor kappa B and platelet dysfunction, which can lead to thrombosis. Magnesium appears to play a vital function in cardiovascular stability and health, but an optimal dose and formulation has not been defined. Potentially promising avenues include the combination of magnesium with a statin to reduce cholesterol, C-reactive protein and CIMT, and its early use to reduce stroke morbidity and mortality. Understanding the role of magnesium in inflammation and mineralization and how it has the potential for playing a role in modulating cardiovascular and neurological disease can be a new frontier in medicine.

Exercise training with weight loss and either a high- or low-glycemic index diet reduces metabolic syndrome severity in older adults.

Abstract: Background: The efficacy of combining carbohydrate quality with exercise on metabolic syndrome risk is unclear. Thus, we determined the effects of exercise training with a low (LoGIx)- or high (HiGIx)-glycemic index diet on the severity of the metabolic syndrome (Z-score). Methods: Twenty-one adults (66.2 ± 1.1 years; BMI = 35.3 ± 0.9 kg/m2) with the metabolic syndrome were randomized to 12 weeks of exercise (60 min/day for 5 days/week at about 85% HRmax) and provided a LoGIx (n = 11) or HiGIx (n = 10) diet. Z-scores were determined from: blood pressure, triglycerides (TGs), high-density lipoproteins (HDLs), fasting plasma glucose (FPG), and waist circumference (WC) before and after the intervention. Body composition, aerobic fitness, insulin resistance, and nonesterfied fatty acid (NEFA) suppression were also assessed. Results: LoGIx and HiGIx diets decreased body mass and insulin resistance and increased aerobic fitness comparably (p Conclusions: Our findings highlight that exercise with weight loss reduces the severity of the metabolic syndrome whether individuals were randomized to a HiGIx or a LoGIx diet.

French children start their school day with a hydration deficit.

Abstract: Background and Aims: Fluid requirements of children vary as a function of gender and age. To our knowledge, there is very little literature on the hydration statu

Have we enough glutamine and how does it work? A clinician's view.

Abstract: There is a gap between the scientific basis of the claim that in several disease states glutamine is lacking and the widespread belief that supplementation of glutamine to the nutritional regimen is beneficial in severely ill patients. Glutamine shortage exists when consuming tissues, playing a crucial role in the response to trauma and disease, receive insufficient amounts of glutamine. In these tissues (immune system, wound), glutamine is only partly oxidized but has more specific roles as nontoxic nitrogen carrier, precursor of several crucial metabolites required for cell proliferation and for maintenance of the redox potential, and as osmolyte. In inflammatory states, glutamine concentrations in plasma and tissues are decreased due to many disease-related factors, precluding its use as a reliable indicator of shortage. Isotope studies have yielded equivocal results, precluding their use as a reliable indicator of glutamine shortage or adequacy. The increase in the net release of glutamine from peripheral tissues to central tissues (immune system, liver, spleen, wound) in inflammatory states provides a better basis for the necessity to supplement the organism with extra glutamine in these conditions. Glutamine supplementation was beneficial in a few studies in burn or trauma patients. The clinical benefit of parenteral glutamine supplementation in patients with severe inflammation has been demonstrated more convincingly. The amounts of glutamine supplemented approximate the amounts released by peripheral tissues and utilized by central organs operative in host defense and are therefore in the physiological range.