Markers to measure immunomodulation in human nutrition intervention studies

Chicken lines divergently selected for antibody responses to sheep red blood cells show line-specific differences in sensitivity to immunomodulation by diet. Part I: Humoral parameters

Individual differences in nutrient sensitivity have been suggested to be related with differences in stress sensitivity. Here we used layer hens divergently selected for high and low specific antibody responses to SRBC (i.e., low line hens and high line hens), reflecting a genetically based differential immune competence. The parental line of these hens was randomly bred as the control line and was used as well. Recently, we showed that these selection lines differ in their stress reactivity; the low line birds show a higher hypothalamic-pituitary-adrenal (HPA) axis reactivity. To examine maternal effects and neonatal nutritional exposure on nutrient sensitivity, we studied 2 subsequent generations. This also created the opportunity to examine egg production in these birds. The 3 lines were fed 2 different nutritionally complete layer feeds for a period of 22 wk in the first generation. The second generation was fed from hatch with the experimental diets. At several time intervals, parameters reflecting humoral immunity were determined such as specific antibody to Newcastle disease and infectious bursal disease vaccines; levels of natural antibodies binding lipopolysaccharide, lipoteichoic acid, and keyhole limpet hemocyanin; and classical and alternative complement activity. The most pronounced dietary-induced effects were found in the low line birds of the first generation: specific antibody titers to Newcastle disease vaccine were significantly elevated by 1 of the 2 diets. In the second generation, significant differences were found in lipoteichoic acid natural antibodies of the control and low line hens. At the end of the observation period of egg parameters, a significant difference in egg weight was found in birds of the high line. Our results suggest that nutritional differences have immunomodulatory effects on innate and adaptive humoral immune parameters in birds with high HPA axis reactivity and affect egg production in birds with low HPA axis reactivity.

Toxicology and safety of DHA

Docosahexaenoic acid (DHA) is a long-chain polyunsaturated fatty acid with activities in both infants and adults. The objective of the current work was to evaluate the published literature concerning the toxicological assessment of DHA-rich oils in animals and the safety profile of DHA consumption in humans. Structured literature searches concerning DHA toxicology and DHA effects on platelet function, lipid levels, oxidative potential, glycemic control, and immune function were conducted. The toxicological profile of DHA derived from single-cell organisms demonstrates that these oils are safe in rats (up to a consumption level of 3290 mg/kg body weight/d) in 90-d toxicology evaluations, as well as in reproductive and developmental toxicology studies. The maximum DHA level in human breast milk exceeds 1% of total fatty acids in high-fish-consuming populations. Consumption of DHA-rich human milk as sole source of nutrition provides approximately 315 mg/d in infants 1-6 months of age, and appears to be a safe level of intake. DHA supplementation studies in adults have employed doses ranging from less than 1 to 7.5 g/d, and have not resulted in any consistent adverse responses in platelet function, lipid levels, in vivo oxidation parameters, glycemic control, or immune function. In conclusion, DHA consumption does not result in consistent adverse events in infants or adults. Safe intake levels may be modeled on DHA intake from human milk in infants, and may be at least as high as the upper doses studied in adults.

Dangers, and benefits of the cytokine mediated response to injury and infection

The inflammatory response is essential for survival in an environment where continuous exposure to noxious events threaten the integrity of the organism. However, the beneficial effects of the response are influenced by factors, which disadvantage individuals within a population. These factors include malnutrition, infection, genotype, gender, pre-existing inflammation, and chronic intoxication. Although the inflammatory response is generally successful in dealing with noxious events, life-long exposure to these events takes its toll on the integrity of the body and becomes apparent as chronic disease, atherosclerosis, organ failure, and frailty. Progress in ameliorating the consequences of lifetime exposure to inflammatory events can only occur if a fuller understanding can be obtained of the factors, which influence the persistence and outcome of the inflammatory response at an individual level. A multitude of studies has shown that specific nutrients, diets, and dietary restriction are able to modulate the inflammatory response in the population as a whole. To advance in this area, precise knowledge is needed of how the disadvantageous factors, mentioned above, affect the individual's response to anti-inflammatory nutrients.

Nanonized black soybean enhances immune response in senescence-accelerated mice

Soy isoflavones may have applications in cancer prevention and anti-inflammation, therefore this study was conducted to investigate the effect of dietary supplementation with black soybean on the immune response in the senescence-accelerated-prone mice (SAMP8) and -resistant mice (SAMPR1, as controls). The mechanism of isoflavones was also investigated. Six-month-old male SAMP8 and SAMR1 mice were divided into the control groups and experimental groups supplemented with nanonized (Nano-soy) or microparticled (Micro-soy) black soybeans (n = 8/group), respectively for 12 weeks. Human peripheral blood mononuclear cells (PBMC) and murine splenocytes were stimulated with mitogens and cytokines were determined by reverse transcriptase-polymerase chain reaction and/or ELISA. The results showed that body weight, food intake, and relative weights of organs did not differ among the SAMP8 control and experimental groups. Isoflavone (daidzin and genistin) intake was higher in the Nano-soy group than the Micro-soy group. The lymphoproliferation and production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) in the Nano-soy group had a significantly higher (P < 0.05) than those in the control and Micro-soy groups. The Nano-soy supplemented mice reached these cytokine levels similar to SAMR1 mice. This result was consistent with the in vitro data that daidzein (a metabolite of daidzin), at a concentration of 10 muM, increased IL-2, IL-4, and IFN-gamma production from phytohemagglutinin-stimulated PBMC (P < 0.05). However at higher concentrations (> 50 microM), daidzein only reduced IL-10 and IFN-gamma levels, whereas genistein reduced levels of the IL-2, IL-4, IL-10, IFN-gamma mRNA and protein and these results suggest that the Nano-soy supplementation improved immune response in SAMP8 mice which may be attributable to higher daidzin content in the black soybean preparation.

Effect of hydration status on high-intensity rowing performance and immune function

PURPOSE

This study determined the effect of dehydration and rehydration (DR) on performance, immune cell response, and tympanic temperature after high-intensity rowing exercise.

METHODS

Seven oarswomen completed two simulated 2000-m rowing race trials separated by 72 h in a random, cross-over design. One trial was completed in a euhydrated (E) condition and the other using a DR protocol.

RESULTS

The DR condition resulted in a 3.33+/-0.14% reduction in body mass (P<.05) over a 24-h period followed by a 2-h rehydration period immediately before the simulated rowing race. There was a greater change in tympanic temperature observed in the DR trial (P<.05). There were increases in the blood concentration of leukocytes, lymphocytes, lymphocyte subsets (CD3+, CD3+/4+, CD3+/8+, CD3-/16+, CD4+/25+; P<.05) and decreases in lymphocyte proliferation and neutrophil oxidative burst activity immediately following the simulated race (P<.05) in both trials. Blood leukocyte and neutrophil concentrations were greater after exercise in the DR trial (P<.05). Whereas most immune measures returned to resting values after 60 min of recovery in both trials, lymphocyte proliferation and the concentrations of CD3+/4+ and CD4+/25+ cells were significantly lower than before exercise. Blood leukocyte and neutrophil concentrations were significantly higher before and after exercise in the E trial.

CONCLUSION

The effects of dehydration/rehydration did not negatively influence simulated 2000-m rowing race performance in lightweight oarswomen but did produce a higher tympanic temperature and had a differential effect on blood leukocyte, neutrophil, and natural killer (CD3-/16+) cell concentrations after exercise compared with the euhydrated state.

Proximity to traffic, inflammation, and immune function among women in the Seattle, Washington, area

BACKGROUND

Traffic-related air pollution has been associated with adverse health outcomes, and the immune system may be a biologic mediator of health effects.

OBJECTIVES

We analyzed associations between living near major roads and immune status as measured by five immune assays. We hypothesized that living near a freeway, arterial, or truck route would be associated with increased inflammation and decreased immune function.

METHODS

We used a geographic information system (GIS) to determine residential proximity to major roads among 115 postmenopausal, overweight women in the greater Seattle, Washington (USA), area whose immunity was assessed at the baseline visit of an exercise intervention trial. We evaluated three inflammatory markers (C-reactive protein, serum amyloid A, and interleukin-6) and two functional assays of cellular immunity [natural killer (NK) cell cytotoxicity and T-lymphocyte proliferation].

RESULTS

Women living within 150 m of arterial roads had 21% lower NK cytotoxicity compared with women who lived farther from an arterial [mean cytotoxicity, 19.5%; 95% confidence interval (CI), 15.6-23.5%; vs. mean cytotoxicity, 24.8%; 95% CI, 22.0-27.5%], after adjustment for both individual-level and census tract-level demographic characteristics. This association was limited to women who reported exercising near traffic. Fewer women lived near freeways and truck routes. Markers of inflammation and lymphocyte proliferation did not consistently differ according to proximity to major roads.

CONCLUSIONS

If the observed association between residential proximity to traffic and decreased NK cytotoxicity is confirmed in other populations, our results may have implications for local land use policy.

Markers of innate immune function are associated with vitamin a stores in men

Recommendations for vitamin A intake and liver stores are based on maintaining normal vision. We propose that higher levels may be required to maintain normal innate immune function. To test this hypothesis, we conducted an 8-wk residential study among 36 healthy Bangladeshi men with low vitamin A stores. Subjects were randomized to receive vitamin A (240 mg in 4 doses) or placebo during study wk 2 and 3. They received 2 vaccines during wk 5 and vitamin A stores were estimated by isotopic dilution at wk 8. The serum concentration of the chemokine interferon-gamma-induced protein 10, a component of T-helper 1 (Th1) response, increased significantly after supplementation and was positively and significantly associated with vitamin A stores. Blood concentrations of natural killer (NK) and NK T-cells, which have anticancer and antiviral activity, were positively associated with stores (P < 0.05), as was monocyte oxidative burst (P < 0.05), a marker of bacterial killing ability. However, serum interleukin (IL)-6 and IL-17, cytokines that regulate the antibacterial Th17 response, were significantly and negatively associated with stores, as was production of the regulatory cytokine IL-10 by whole-blood cultures stimulated with bacterial lipopolysaccharide. In summary, vitamin A stores were positively associated with several measures of innate immune activity across a broad range of stores, suggesting that vitamin A enhances protection against diverse pathogens even at concentrations above those needed to maintain normal vision. The negative association of stores with serum IL-6 and IL-17 suggests that not all protective responses are similarly enhanced by vitamin A.

Regulatory effects of a fermented food concentrate on immune function parameters in healthy volunteers

OBJECTIVE

Nutrition is known to influence the immune system and can thereby modulate resistance to infection. The objective of this clinical trial was to assess the influence of a cascade-fermented food consisting of fruits, nuts, and vegetables rich in polyphenols (Regulat) on the immune system in healthy volunteers.

METHODS

The clinical trial was double-blinded and placebo-controlled. In total, 48 healthy men 20-48 y of age with a body mass index of 20-28 kg/m(2) were enrolled in the clinical trial. The group was characterized according to lifestyle parameters and only men with regular low to moderate intake of fruit and vegetables were enrolled. The intervention lasted for a period of 4 wk. Volunteers received Regulat twice daily or a placebo product (essence of vinegar).

RESULTS

The intake of Regulat significantly enhanced intracellular glutathione content in lymphocytes (P < 0.05), monocytes (P < 0.05), and natural killer cells (P < 0.01). Furthermore, activation of natural killer cell cytotoxicity in response to interleukin-2 stimulation (P < 0.05), a reduction of total lipid peroxidation, and a reduction of soluble vascular cell adhesion molecule-1 (P < 0.01) and soluble intercellular adhesion molecule-1 (P < 0.05) as inflammatory blood markers were found in the Regulat but not in the placebo group.

CONCLUSION

In summary, the results from this intervention study demonstrate promising physiologic effects of immune regulation on the innate immune system and antioxidative and anti-inflammatory parameters after Regulat supplementation. However, these promising results need to be confirmed in more volunteers with a more prolonged application to ensure significant beneficial effects of Regulat in the general population.

Modulation of the fecal microflora profile and immune function by a novel trans-galactooligosaccharide mixture (B-GOS) in healthy elderly volunteers

BACKGROUND

Aging is associated with reduced numbers of beneficial colonic bifidobacteria and impaired immunity. Galactooligosaccharides (GOSs) stimulate the growth of bifidobacteria in younger adults, but little is known about their effects in the elderly and their immunomodulatory capacity.

OBJECTIVE

We assessed the effect of a prebiotic GOS mixture (B-GOS) on immune function and fecal microflora composition in healthy elderly subjects.

DESIGN

In a double-blind, placebo-controlled, crossover study, 44 elderly subjects were randomly assigned to receive either a placebo or the B-GOS treatment (5.5 g/d). Subjects consumed the treatments for 10 wk, and then went through a 4-wk washout period, before switching to the other treatment for the final 10 wk. Blood and fecal samples were collected at the beginning, middle (5 wk), and end of the test period. Predominant bacterial groups were quantified, and phagocytosis, natural killer (NK) cell activity, cytokine production, plasma cholesterol, and HDL cholesterol were measured.

RESULTS

B-GOS significantly increased the numbers of beneficial bacteria, especially bifidobacteria, at the expense of less beneficial groups compared with the baseline and placebo. Significant increases in phagocytosis, NK cell activity, and the production of antiinflammatory cytokine interleukin-10 (IL-10) and significant reduction in the production of proinflammatory cytokines (IL-6, IL-1beta, and tumor necrosis factor-alpha) were also observed. B-GOS exerted no effects on total cholesterol or HDL-cholesterol production, however.

CONCLUSIONS

B-GOS administration to healthy elderly persons resulted in positive effects on both the microflora composition and the immune response. Therefore, B-GOS may be a useful dietary candidate for the enhancement of gastrointestinal health and immune function in elderly persons.

Eukaryotic-microbiota crosstalk: potential mechanisms for health benefits of prebiotics and probiotics

The ability to link dietary consumption of prebiotic food ingredients and probiotic microorganisms to health benefits rests, in part, on our ability to identify both the extent to which these factors alter human microbiome activity and/or structure and the ability to engage eukaryotic cells necessary to transduce signals originating from the microbiome. The human microbiome consists of bacterial, archaeal, and fungal components that reside in mucosal surfaces of the gut, the airways, and the urogenital tract. Characterization of the symbiotic nature of the relationship between eukaryotic cells and the bacterial and archaeal components of the microbiota has revealed significant contributions in energy balance, bowel function, immunologic function, sensory perception, glycemic control, and blood pressure regulation. Elucidating the complex interactions between the microbiota and their associated epithelial, immune, and neural cells may provide mechanistic insights and a rational basis for our belief that dietary consumption of probiotic microorganisms and prebiotics produces health benefits.

Record citations in 2007, but impact factor slips

Through publishing, authors disseminate their work in order that others may see it and act upon it in some way.

Prebiotics, immune function, infection and inflammation: a review of the evidence

Beta2-1 fructans are carbohydrate molecules with prebiotic properties. Through resistance to digestion in the upper gastrointestinal tract, they reach the colon intact, where they selectively stimulate the growth and/or activity of beneficial members of the gut microbiota. Through this modification of the intestinal microbiota, and by additional mechanisms, beta2-1 fructans may have beneficial effects upon immune function, ability to combat infection, and inflammatory processes and conditions. In this paper, we have collated, summarised and evaluated studies investigating these areas. Twenty-one studies in laboratory animals suggest that some aspects of innate and adaptive immunity of the gut and the systemic immune systems are modified by beta2-1 fructans. In man, two studies in children and nine studies in adults indicate that the adaptive immune system may be modified by beta2-1 fructans. Thirteen studies in animal models of intestinal infections conclude a beneficial effect of beta2-1 fructans. Ten trials involving infants and children have mostly reported benefits on infectious outcomes; in fifteen adult trials, little effect was generally seen, although in specific situations, certain beta2-1 fructans may be beneficial. Ten studies in animal models show benefit of beta2-1 fructans with regard to intestinal inflammation. Human studies report some benefits regarding inflammatory bowel disease (four positive studies) and atopic dermatitis (one positive study), but findings in irritable bowel syndrome are inconsistent. Therefore, overall the results indicate that beta2-1 fructans are able to modulate some aspects of immune function, to improve the host's ability to respond successfully to certain intestinal infections, and to modify some inflammatory conditions.

Structural and functional aspects of prebiotics used in infant nutrition

Breast-feeding is associated with several benefits. Among them, the balanced postnatal development of the immune system is 1 of the key functions of breast-feeding. Although this effect is of multifactorial origin, it is widely accepted that the entire intestinal microbiota of breast-fed infants represents an important stimulating factor of the postnatal development of the immune system. The effect of breast-feeding on the intestinal microbiota can not be attributed to a single compound, but there is accumulating evidence that human milk oligosaccharides play a crucial role. Because there is a broad consensus that the intestinal microbiota plays an important physiological role for the host, many attempts have been made to influence the intestinal flora by dietary interventions. This article summarizes results of intervention studies in which nonmilk oligosaccharides have been used to mimic the prebiotic effect of breast-feeding. A second focus has been related to the question of whether the prebiotic activity has beneficial effects on the postnatal development of the immune system. The data clearly demonstrate that prebiotics of nonmilk origin can mimic the prebiotic effect of breast-feeding, and this has positive consequences for the postnatal development of the immune system.

Restoration of the immune functions in aged mice by supplementation with a new herbal composition, HemoHIM

The effect of a new herbal composition, HemoHIM, on immune functions was examined in aged mice, in which various immune responses had been impaired. The composition HemoHIM was prepared by adding the ethanol-insoluble fraction to the total water extract of a mixture of three edible herbs, Angelica Radix, Cnidium Rhizoma and Paeonia Radix. Supplementation to the aged mice with HemoHIM restored the proliferative response and cytokine production of splenocytes with a response to ConA. Also, HemoHIM recovered the NK cell activity which had been impaired in the aged mice. Meanwhile aging is known to reduce the Th1-like function, but not the Th2-like function, resulting in a Th1/Th2 imbalance. HemoHIM restored the Th1/Th2 balance in the aged mice through enhanced IFN-gamma and IgG2a production, and conversely a reduced IL-4 and IgG1 production. It was found that one factor for the Th1/Th2 imbalance in the aged mice was a lower production of IL-12p70. However, HemoHIM restored the IL-12p70 production in the aged mice. These results suggested that HemoHIM was effective for the restoration of impaired immune functions of the aged mice and therefore could be a good recommendation for immune restoration in elderly humans.

Bacterial metabolism and health-related effects of galacto-oligosaccharides and other prebiotics

Most studies involving prebiotic oligosaccharides have been carried out using inulin and its fructo-oligosaccharide (FOS) derivatives, together with various forms of galacto-oligosaccharides (GOS). Although many intestinal bacteria are able to grow on these carbohydrates, most investigations have demonstrated that the growth of bifidobacteria, and to a lesser degree lactobacilli, is particularly favoured. Because of their safety, stability, organoleptic properties, resistance to digestion in the upper bowel and fermentability in the colon, as well as their abilities to promote the growth of beneficial bacteria in the gut, these prebiotics are being increasingly incorporated into the Western diet. Inulin-derived oligosaccharides and GOS are mildly laxative, but can result in flatulence and osmotic diarrhoea if taken in large amounts. However, their effects on large bowel habit are relatively minor. Although the literature dealing with the health significance of prebiotics is not as extensive as that concerning probiotics, considerable evidence has accrued showing that consumption of GOS and FOS can have significant health benefits, particularly in relation to their putative anti-cancer properties, influence on mineral absorption, lipid metabolism, and anti-inflammatory and other immune effects such as atopic disease. In many instances, prebiotics seem to be more effective when used as part of a synbiotic combination.

Immunosupportive therapies in aging

The primary role of the immune system is to protect the organism against pathogens, but age-associated alterations to immunity increase the susceptibility of the elderly to infectious disease. The exact nature of these changes is still controversial, but the use of screening procedures, such as the SENIEUR protocol to exclude underlying illness, helped to better characterize the changes actually related to physiological aging rather than pathology. It is generally agreed that the most marked changes occur in the cellular immune response reflecting profound alterations in T cells. Much of this is due to thymic involution as well as changes in the proportions of T cell subpopulations resulting from antigen exposure, and altered T cell activation pathways. However, a body of data indicates that innate immune responses, including the critical bridge between innate and adaptive immunity, and antigen presenting capacity are not completely resistant to senescence processes. The consequences of all these alterations are an increased incidence of infections, as well as possibly cancers, autoimmune disorders, and chronic inflammatory diseases. The leading question is what, if anything, can we do to prevent these deleterious changes without dangerously dysregulating the precarious balance of productive immunity versus immunopathology? There are many potential new therapeutic means now available to modulate immunosenescence and many others are expected to be available shortly. One main problem in applying these experimental therapies is ethical: there is a common feeling that as ageing is not a disease; the elderly are not sick and therefore do not require adventurous therapies with unpredictable side-effects in mostly frail individuals. Animal models are not helpful in this context. In this chapter we will first briefly review what we think we know about human immunosenescence and its consequences for the health status of elderly individuals. We will then discuss possible interventions that might one day become applicable in an appropriate ethical environment.

Mass spectrometry in nutrition: understanding dietary health effects at the molecular level

In modern nutrition research, mass spectrometry has developed into a tool to assess health, sensory as well as quality and safety aspects of food. In this review, we focus on health-related benefits of food components and, accordingly, on biomarkers of exposure (bioavailability) and bioefficacy. Current nutrition research focuses on unraveling the link between dietary patterns, individual foods or food constituents and the physiological effects at cellular, tissue and whole body level after acute and chronic uptake. The bioavailability of bioactive food constituents as well as dose-effect correlations are key information to understand the impact of food on defined health outcomes. Both strongly depend on appropriate analytical tools to identify and quantify minute amounts of individual compounds in highly complex matrices--food or biological fluids--and to monitor molecular changes in the body in a highly specific and sensitive manner. Based on these requirements, mass spectrometry has become the analytical method of choice with broad applications throughout all areas of nutrition research. The current review focuses on selected areas of application: protein and peptide as well as nutrient and metabolite analysis.

Associations between healthy eating patterns and immune function or inflammation in overweight or obese postmenopausal women

BACKGROUND

The link between poor nutritional status and impaired immune function is well established; however, most studies have focused on individual nutrients instead of overall dietary patterns.

OBJECTIVE

Our objective was to investigate associations between 3 indexes of overall diet quality [the Diet Quality Index (DQI), the DQI including supplementary calcium (DQI-Ca), and the Healthy Eating Index (HEI)] and biomarkers of inflammation and immunity.

DESIGN

This cross-sectional study included 110 overweight or obese postmenopausal women. Dietary intake measured by food-frequency questionnaire was used to calculate diet quality scores. C-reactive protein (CRP) and serum amyloid A (SAA) were measured by latex-enhanced nephelometry. Flow cytometry was used to measure natural killer (NK) cell cytotoxicity and to enumerate and phenotype lymphocyte subsets. T lymphocyte proliferation was assessed by (3)H-thymidine incorporation as well as by the carboxyfluorescein-succinimidyl ester method of cell division tracking. Multivariable-adjusted linear regression analysis was used to investigate associations between diet quality scores and markers of inflammation and immune function.

RESULTS

Higher diet quality was associated with increased proportions of cytotoxic and decreased proportions of helper T lymphocytes. CRP and SAA concentrations were higher among women with a lower-quality diet; these associations became nonsignificant after adjustment for body mass index or percentage body fat. We observed limited evidence for an association between healthy eating patterns and greater lymphocyte proliferation and no evidence for an association with NK cell cytotoxicity.

CONCLUSION

Our results provide limited evidence that healthy eating patterns contribute to enhanced immune function and reduced inflammation in overweight and obese postmenopausal women.

Contribution of selected vitamins and trace elements to immune function

Adequate intakes of vitamins and trace elements are required for the immune system to function efficiently. Micronutrient deficiency suppresses immune functions by affecting the innate T-cell-mediated immune response and adaptive antibody response, and leads to dysregulation of the balanced host response. This increases the susceptibility to infections, with increased morbidity and mortality. In turn, infections aggravate micronutrient deficiencies by reducing nutrient intake, increasing losses, and interfering with utilization by altering metabolic pathways. Insufficient intake of micronutrients occurs in people with eating disorders, in smokers (both active and passive), in individuals with chronic alcohol abuse, in patients with certain diseases, during pregnancy and lactation, and in the elderly. With aging a variety of changes are observed in the immune system, which translate into less effective innate and adaptive immune responses and increased susceptibility to infections. Antioxidant vitamins and trace elements (vitamins C, E, selenium, copper, and zinc) counteract potential damage caused by reactive oxygen species to cellular tissues and modulate immune cell function through regulation of redox-sensitive transcription factors and affect production of cytokines and prostaglandins. Adequate intake of vitamins B(6), folate, B(12), C, E, and of selenium, zinc, copper, and iron supports a Th1 cytokine-mediated immune response with sufficient production of proinflammatory cytokines, which maintains an effective immune response and avoids a shift to an anti-inflammatory Th2 cell-mediated immune response and an increased risk of extracellular infections. Supplementation with these micronutrients reverses the Th2 cell-mediated immune response to a proinflammatory Th1 cytokine-regulated response with enhanced innate immunity. Vitamins A and D play important roles in both cell-mediated and humoral antibody response and support a Th2-mediated anti-inflammatory cytokine profile. Vitamin A deficiency impairs both innate immunity (mucosal epithelial regeneration) and adaptive immune response to infection resulting in an impaired ability to counteract extracellular pathogens. Vitamin D deficiency is correlated with a higher susceptibility to infections due to impaired localized innate immunity and defects in antigen-specific cellular immune response. Overall, inadequate intake and status of these vitamins and minerals may lead to suppressed immunity, which predisposes to infections and aggravates malnutrition.

Influence of lycopene and vitamin C from tomato juice on biomarkers of oxidative stress and inflammation

A human study was carried out to investigate whether tomato juice, rich in natural lycopene and fortified with vitamin C, is able to reduce several biomarkers of oxidative stress and inflammation and whether the effect can be attributed to lycopene, vitamin C or any other micronutrient. Following a 2-week depletion phase, volunteers were assigned randomly to ingest either tomato juice with (LC) or without (L) vitamin C fortification for 2 weeks (daily dose 20·6 mg lycopene and 45·5/435 mg vitamin C). Plasma and urine were analysed for carotenoids and vitamin C, lipid status, antioxidant capacity, thiobarbituric acid reactive substances (TBARS) and 8-epi-PGF2α, protein carbonyls, cytokines IL-1β and TNFα and C-reactive protein (CRP). The consumption of tomato juice led to a reduction in total cholesterol levels (L: 157·6v. 153·2 mg/dl,P = 0·008; LC: 153·4v. 147·4 mg/dl,P = 0·002) and that of CRP (L: 315·6v. 262·3 μg/l,P = 0·017; LC: 319·2v. 247·1 μg/l,P = 0·001) in both groups. The vitamin C-fortified juice slightly raised the antioxidant capacity in urine and decreased TBARS in plasma and urine. All other markers were affected to a lesser extent or remained unchanged. Cholesterol reduction was correlated with lycopene uptake (P = 0·003), whereas the other effects could not be related with particular micronutrients. Any beneficial effects of tomato consumption for human health cannot be attributed only to lycopene and, as the additional supplementation with ascorbic acid indicates, a variety of antioxidants might be needed to optimize protection against chronic diseases.

Differential immunomodulation with long-chain n-3 PUFA in health and chronic disease

The balance of intake of n-6 and n-3 PUFA, and consequently their relative incorporation into immune cells, is important in determining the development and severity of immune and inflammatory responses. Some disorders characterised by exaggerated inflammation and excessive formation of inflammatory markers have become among the most important causes of death and disability in man in modern societies. The recognition that long-chain n-3 PUFA have the potential to inhibit (excessive) inflammatory responses has led to a large number of clinical investigations with these fatty acids in inflammatory conditions as well as in healthy subjects. The present review explores the presence of dose-related effects of long-chain n-3 PUFA supplementation on immune markers and differences between healthy subjects and those with inflammatory conditions, because of the important implications for the transfer of information gained from studies with healthy subjects to patient populations, e.g. for establishing dose levels for specific applications. The effects of long-chain n-3 PUFA supplementation on ex vivo lymphocyte proliferation and cytokine production by lymphocytes and monocytes in healthy subjects have been studied in twenty-seven, twenty-five and forty-six treatment cohorts respectively, at intake levels ranging from 0.2 g EPA+DHA/d to 7.0 g EPA+DHA/d. Most studies, particularly those with the highest quality study design, have found no effects on these immune markers. Significant effects on lymphocyte proliferation are decreased responses in seven of eight cohorts, particularly in older subjects. The direction of the significant changes in cytokine production by lymphocytes is inconsistent and only found at supplementation levels > or =2.0 g EPA+DHA/d. Significant changes in inflammatory cytokine production by monocytes are decreases in their production in all instances. Overall, these studies fail to reveal strong dose-response effects of EPA+DHA on the outcomes measured and suggest that healthy subjects are relatively insensitive to immunomodulation with long-chain n-3 PUFA, even at intake levels that substantially raise their concentrations in phospholipids of immune cells. In patients with inflammatory conditions cytokine concentrations or production are influenced by EPA+DHA supplementation in a relatively large number of studies. Some of these studies suggest that local effects at the site of inflammation might be more pronounced than systemic effects and disease-related markers are more sensitive to the immunomodulatory effects, indicating that the presence of inflamed tissue or 'sensitised' immune cells in inflammatory disorders might increase sensitivity to the immunomodulatory effects of long-chain n-3 PUFA. In a substantial number of these studies clinical benefits related to the inflammatory state of the condition have been observed in the absence of significant effects on immune markers of inflammation. This finding suggests that condition-specific clinical end points might be more sensitive markers of modulation by EPA+DHA than cytokines. In general, the direction of immunomodulation in healthy subjects (if any) and in inflammatory conditions is the same, which indicates that studies in healthy subjects are a useful tool to describe the general principles of immunomodulation by n-3 PUFA. However, the extent of the effect might be very different in inflammatory conditions, indicating that studies in healthy subjects are not particularly suitable for establishing dose levels for specific applications in inflammatory conditions. The reviewed studies provide no indications that the immunomodulatory effects of long-chain n-3 PUFA impair immune function or infectious disease resistance. In contrast, in some conditions the immunomodulatory effects of EPA+DHA might improve immune function.

Update: effects of antioxidant and non-antioxidant vitamin supplementation on immune function

The purpose of this manuscript is to review the impact of supplementation with vitamins E and C, carotenoids, and the B vitamins on parameters of innate and adaptive immune function as reported from clinical trials in humans. There is evidence to support causal effects of supplementation with vitamins E and C and the carotenoids singly and in combination on selected aspects of immunity, including the functional capacity of innate immune cells, lymphocyte proliferation, and the delayed-type hypersensitivity (DTH) response. Controlled intervention trials of B vitamin-containing multivitamin supplements suggest beneficial effects on immune parameters and clinical outcomes in HIV-positive individuals.

Effect of Zinc Supplementation on the Immune Status of Healthy Older Individuals Aged 55-70 Years: The ZENITH Study

Aging is associated with alterations in the immune system, effects which may be exacerbated by inadequate zinc (Zn) status. We examined the relationship between Zn status and markers of immunity and the effect of supplementation with 15 mg or 30 mg Zn/d for 6 months on immune status in healthy individuals. Zn status was assessed by dietary intake and biochemical indices. Immune status was assessed by multiple flow cytometric methods. At baseline, Zn concentration was positively associated with lymphocyte subpopulation counts and T-lymphocyte activation. Zn supplementation of 30 mg/d significantly lowered B-lymphocyte count, albeit at month 3 only. Lower doses of Zn (15 mg Zn/d) significantly increased the ratio of CD4 to CD8 T lymphocytes at month 6. Overall, these findings suggest that total Zn intake (diet plus supplementation) of up to 40 mg Zn/d do not have significant long-term effects on immune status in apparently healthy persons aged 55-70 years.

Immunological parameters: what do they mean?

The immune system acts to protect the host from infectious agents that exist in the environment and from other noxious insults. It is constantly active, acting to discriminate "nonself" from "self." The immune system has 2 functional divisions: the innate and the acquired. Both involve various blood-borne factors and cells. A number of methodologies exist to assess aspects of immune function; many of these rely on studying cells in culture ex vivo. There are large interindividual variations in many immune functions even among the healthy. Many factors, including genetics, gender, age, nutrient status, and gut flora, contribute to the observed variation. Individuals with immune responses significantly below "normal" are more susceptible to infectious agents and exhibit increased infectious morbidity and mortality. However, it is not clear how the variation in immune function among healthy individuals relates to variation in susceptibility to infection.

Ribonucleotides: conditionally essential nutrients shown to enhance immune function and reduce diarrheal disease in infants

It remains a goal of pediatric nutrition to provide optimal nourishment for infants who are not fed human milk. Investigators have attempted to emulate the composition and functionality of human milk, the gold standard for infant nutrition. These efforts began with the analysis of milk components and continued with assessments of biological effects that culminated in clinical studies in infants. This chapter summarizes the path that researchers followed to study ribonucleotides and their role in infant nutrition. Based on analytical methods for the quantification of ribonucleotides in human milk, investigators assessed their potential impact on the immune systems of infants and looked for concomitant mechanistic explanations. These inquiries evolved into clinical trials in which ribonucleotide-supplemented formula performance was compared with that of non-supplemented formulas and with human milk. This chapter intends to summarize an area of pediatric nutrition that has yielded both enlightening evidence and seemingly contradictory data.

Dietary synbiotics reduce cancer risk factors in polypectomized and colon cancer patients

BACKGROUND

Animal studies suggest that prebiotics and probiotics exert protective effects against tumor development in the colon, but human data supporting this suggestion are weak.

OBJECTIVE

The objective was to verify whether the prebiotic concept (selective interaction with colonic flora of nondigested carbohydrates) as induced by a synbiotic preparation-oligofructose-enriched inulin (SYN1) + Lactobacillus rhamnosus GG (LGG) and Bifidobacterium lactis Bb12 (BB12)-is able to reduce the risk of colon cancer in humans.

DESIGN

The 12-wk randomized, double-blind, placebo-controlled trial of a synbiotic food composed of the prebiotic SYN1 and probiotics LGG and BB12 was conducted in 37 colon cancer patients and 43 polypectomized patients. Fecal and blood samples were obtained before, during, and after the intervention, and colorectal biopsy samples were obtained before and after the intervention. The effect of synbiotic consumption on a battery of intermediate bio-markers for colon cancer was examined.

RESULTS

Synbiotic intervention resulted in significant changes in fecal flora: Bifidobacterium and Lactobacillus increased and Clostridium perfringens decreased. The intervention significantly reduced colorectal proliferation and the capacity of fecal water to induce necrosis in colonic cells and improve epithelial barrier function in polypectomized patients. Genotoxicity assays of colonic biopsy samples indicated a decreased exposure to genotoxins in polypectomized patients at the end of the intervention period. Synbiotic consumption prevented an increased secretion of interleukin 2 by peripheral blood mononuclear cells in the polypectomized patients and increased the production of interferon gamma in the cancer patients.

CONCLUSIONS

Several colorectal cancer biomarkers can be altered favorably by synbiotic intervention.

Healthy lifestyles are associated with higher levels of perforin, granulysin and granzymes A/B-expressing cells in peripheral blood lymphocytes

OBJECTIVE

It is well documented that natural killer (NK) cells provide host defense against tumors and viruses. We previously showed that lifestyle affects human NK and LAK activities. In order to explore the underlying mechanism, we investigated the effect of lifestyle on intracellular perforin, granulysin, and granzymes A/B in peripheral blood lymphocytes (PBL).

METHODS

114 healthy male subjects, aged 20-59 years, from a large company in Osaka, Japan were selected with informed consent. The subjects were divided into groups reporting good, moderate, and poor lifestyles according to their responses on a questionnaire regarding eight health practices (cigarette smoking, alcohol consumption, sleeping hours, working hours, physical exercise, eating breakfast, balanced nutrition, and mental stress). Peripheral blood was taken, and numbers of NK, T, perforin, granulysin, and granzymes A/B-expressing cells in PBL were measured by flow cytometry.

RESULTS

Subjects with good or moderate lifestyle showed significantly higher numbers of NK, and perforin, granulysin, and granzymes A/B-expressing cells and a significantly lower number of T cells in PBL than subjects with poor lifestyle. Among the eight health practices, cigarette smoking, physical exercise, eating breakfast, and balanced nutrition significantly affect the numbers of NK, T cells, perforin, granulysin, and/or granzymes A/B-expressing cells, and alcohol consumption significantly affects the number of granzyme A-expressing cells. On the other hand, mental stress, sleeping, and working hours had no effect on those parameters.

CONCLUSIONS

Taken together, these findings indicate that poor lifestyle significantly decreases the numbers of NK, perforin, granulysin, and granzymes A/B-expressing cells in PBL.

Dietary supplementation with antioxidants improves functions and decreases oxidative stress of leukocytes from prematurely aging mice

OBJECTIVES

Aging is accompanied by chronic inflammation and oxidative stress, which lead to a marked impairment of immune function and therefore increased mortality. This study assessed the effect of dietary supplementation, for 15 wk, with 5% and 20% (w/w) of biscuits enriched with nutritional doses of vitamins C and E, zinc, selenium, and beta-carotenes on function and oxidative stress parameters of peritoneal leukocytes from middle-aged, prematurely aging mice (PAM) and non-prematurely aging mice (NPAM).

METHODS

After supplementation we measured leukocyte functions (adherence, chemotaxis, phagocytosis, intracellular reactive oxygen species levels, lymphoproliferation, natural killer activity, and interleukin-2 release), antioxidant defenses (superoxide dismutase, glutathione peroxidase, and reduced glutathione), oxidant compounds (extracellular O(2)(-), glutathione disulfide, glutathione disulfide/reduced glutathione ratio, tumor necrosis factor-alpha, nitric oxide, and prostaglandin E(2)), and lipid and DNA oxidative damage, measured by malondialdehyde and 8-oxo,7,8-dihydro-2'-deoxyguanosine levels, respectively.

RESULTS

In general, leukocyte functions were improved and redox homeostasis was restored after intake of antioxidants. In consequence, malondialdehyde and 8-oxo,7,8-dihydro-2'-deoxyguanosine in PAM and NPAM were strikingly decreased after 5% and 20% supplementation (malondialdehyde, P < 0.001 in PAM; P < 0.01 in NPAM after both treatments; 8-oxo,7,8-dihydro-2'-deoxyguanosine, P < 0.01 after 5% supplementation and P < 0.001 after 20% supplementation in PAM and NPAM). Moreover, the effect of the antioxidants was stronger in PAM than in NPAM, and 20% supplementation was more effective than 5%.

CONCLUSION

Our data suggest that improvement of leukocyte function and restoration of redox balance after consumption of adequate levels of antioxidants from adulthood may be useful to attain healthy aging, especially in animals with premature aging.

Effect of a mixture of micronutrients, but not of bovine colostrum concentrate, on immune function parameters in healthy volunteers: a randomized placebo-controlled study

Background

Supplementation of nutritional deficiencies helps to improve immune function and resistance to infections in malnourished subjects. However, the suggested benefits of dietary supplementation for immune function in healthy well nourished subjects is less clear. Among the food constituents frequently associated with beneficial effects on immune function are micronutrients such as vitamin C, vitamin E, β-carotene and zinc, and colostrum. This study was designed to investigate the effects these ingredients on immune function markers in healthy volunteers.

Methods

In a double-blind, randomized, parallel, 2*2, placebo-controlled intervention study one hundred thirty-eight healthy volunteers aged 40–80 y (average 57 ± 10 y) received one of the following treatments: (1) bovine colostrum concentrate 1.2 g/d (equivalent to ~500 mg/d immunoglobulins), (2) micronutrient mix of 288 mg vitamin E, 375 mg vitamin C, 12 mg β-carotene and 15 mg zinc/day, (3) combination of colostrum and micronutrient mix, or (4) placebo. Several immune function parameters were assessed after 6 and 10 weeks. Data were analyzed by analysis of variance. Groups were combined to test micronutrient treatment versus no micronutrient treatment, and colostrum treatment versus no colostrum treatment.

Results

Overall, consumption of the micronutrient mix significantly enhanced delayed-type hypersensitivity (DTH) responses (p < 0.05). Adjusted covariance analysis showed a positive association between DTH and age. Separate analysis of younger and older age groups indicated that it was the older population that benefited from micronutrient consumption. The other immune function parameters including responses to systemic tetanus and oral typhoid vaccination, phagocytosis, oxidative burst, lymphocyte proliferation and lymphocyte subset distribution were neither affected by the consumption of micronutrients nor by the consumption of bovine colostrum concentrate.

Conclusion

Consumption of bovine colostrum had no effect on any of the immune parameters assessed. The micronutrient mix enhanced cellular immunity as measured by DTH, with an increased effect by incremental age, but did not affect any of the other immune parameters measured. Although correlations between decreased DTH and enhanced risk of certain infection have been reported, it remains unclear whether and enhanced DTH response actually improves immune defense. The present data suggests that improvement of immune parameters in a population with a generally good immune and nutritional status is limited and that improvement of immune function in this population may be difficult.

Immune system adaptation in elite athletes

PURPOSE OF REVIEW

To evaluate the effects of exercise on immune function in relation to infection susceptibility.

RECENT FINDINGS

Postexercise immune function depression is most pronounced when exercise is continuous, prolonged, of moderate to high intensity and performed without food intake. Periods of intensified training that result in overreaching have been shown to chronically depress immune function, with leukocyte functions measured at rest still depressed 24 h after the last exercise bout. Several studies indicate that the incidence of symptoms of upper respiratory tract illness is increased in the days following prolonged strenuous endurance events and it has been generally assumed that this is due to the temporary exercise-induced depression of immune function. More recently it has been proposed that at least some of these symptoms are attributable to inflammation of the upper respiratory tract rather than to infectious episodes.

SUMMARY

Although elite athletes are not clinically immune deficient, it is possible that the combined effects of small changes in several immune parameters may compromise resistance to common minor illnesses. Although it is possible that immune depression linked with prolonged intensive training may determine susceptibility to infection, convincing evidence of a cause and effect relationship remains elusive.

A specific prebiotic oligosaccharide mixture stimulates delayed-type hypersensitivity in a murine influenza vaccination model

Analogous to reported immunomodulatory effects of probiotics, this study was performed to analyse the immunomodulatory properties of prebiotic oligosaccharides that share chemical characteristics with human milk oligosaccharides. A mixture containing galacto- and fructo-oligosaccharides (GOS/FOS; ratio 9:1) was tested at dietary doses between 1% and 10% (w/w of total diet) in an influenza vaccination model, using 10 C56BL/6JolaHsd mice per group. The modulation of vaccine specific delayed-type hypersensitivity (DTH) responses was studied as a marker of T-helper 1 (Th1) immunity, as well as other immune parameters. GOS/FOS enhanced DTH responses dose-dependently (optimum at 5% w/w of total diet; 41.4+/-14.1% increased compared to controls, p<0.05). No significant changes were detected on splenocyte proliferation or vaccine-specific antibody concentrations. Simultaneously, GOS/FOS dose-dependently increased the proportion of faecal bifidobacteria and lactobacilli (maximal effect at 10% w/w of total diet; 16.8+/-2.4% and 5.8+/-1.3% increased compared to controls respectively, p<0.01 for both parameters). In a comparative experiment, GOS/FOS and FOS/inulin (both at 2% w/w of total diet) induced similar significant effects on the gut microbiota. In contrast to GOS/FOS, FOS/inulin did not enhance DTH responses, indicating that an increase in the proportions of bifidobacteria and lactobacilli is not sufficient for an immunomodulatory effect in this model. The use of GOS/FOS in dietary products might provide an opportunity to stimulate the adaptive immune response in a Th1-direction and subsequently inhibit infections and Th2-related immune disorders in humans, for instance allergies. Clinical studies are being performed to confirm this.

Oxidative stress in leukocytes from young prematurely aging mice is reversed by supplementation with biscuits rich in antioxidants

Aging is associated with a progressive dysregulation of immune responses as a result of increased oxidative stress. Therefore, we have assessed the oxidative stress status of peritoneal leukocytes from young prematurely aging mice (PAM) as compared with non-prematurely aging mice (NPAM), as well as the effects on this oxidative stress of a dietary supplementation with biscuits rich in antioxidants (vitamin C, vitamin E, beta-carotenes, zinc and selenium). We found that, in the peritoneal leukocytes, the levels of several parameters of oxidation such as extracellular superoxide anion (O(2)(-)), Prostaglandin E(2) (PGE(2)), nitric oxide, oxidized glutathione (GSSG) and lipid peroxidation (malondialdehyde, MDA) were higher in PAM as compared with NPAM, whereas the antioxidant defences such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities, as well as reduced glutathione (GSH) levels, were decreased. Consequently, young PAM showed an oxidative stress in their leukocytes, which is characteristic of mice of an older chronological age. Antioxidant diet supplementation was able to restore redox homeostasis, increasing the antioxidant and decreasing the oxidant levels. Accordingly, supplementation with adequate levels of antioxidants, from an early age, could be useful to preserve health, especially in prematurely aging populations.