Potential Effects of Sucralose and Saccharin on Gut Microbiota: A Review.

Artificial sweeteners are additives widely used in our diet. Although there is no consensus, current evidence indicates that sucralose and saccharin could influence the gut microbiota. The aim of this study was to analyze the existing scientific evidence on the effects of saccharin and sucralose consumption on gut microbiota in humans. Different databases were used with the following search terms: sweeteners, non-caloric-sweeteners, sucralose, splenda, saccharin, sugartwin, sweet'n low, microbiota, gut microbiota, humans, animal model, mice, rats, and/or in vitro studies. In vitro and animal model studies indicate a dose-dependent relationship between the intake of both sweeteners and gut microbiota affecting both diversity and composition. In humans, long-term study suggests the existence of a positive correlation between sweetener consumption and some bacterial groups; however, most short-term interventions with saccharin and sucralose, in amounts below the ADI, found no significant effect on those groups, but there seems to be a different basal microbiota-dependent response of metabolic markers. Although studies in vitro and in animal models seem to relate saccharin and sucralose consumption to changes in the gut microbiota, more long-term studies are needed in humans considering the basal microbiota of participants and their dietary and lifestyle habits in all population groups. Toxicological and basal gut microbiota effects must be included as relevant factors to evaluate food safety and nutritional consequences of non-calorie sweeteners. In humans, doses, duration of interventions, and number of subjects included in the studies are key factors to interpret the results.

Association of Moderate Beer Consumption with the Gut Microbiota and SCFA of Healthy Adults.

Fermented alcoholic drinks' contribution to the gut microbiota composition is mostly unknown. However, intestinal microorganisms can use compounds present in beer. This work explored the associations between moderate consumption of beer, microbiota composition, and short chain fatty acid (SCFA) profile. Seventy eight subjects were selected from a 261 healthy adult cohort on the basis of their alcohol consumption pattern. Two groups were compared: (1) abstainers or occasional consumption (ABS) (n = 44; <1.5 alcohol g/day), and (2) beer consumption ≥70% of total alcohol (BEER) (n = 34; 200 to 600 mL 5% vol. beer/day; <15 mL 13% vol. wine/day; <15 mL 40% vol. spirits/day). Gut microbiota composition (16S rRNA gene sequencing) and SCFA concentration were analyzed in fecal samples. No differences were found in α and ß diversity between groups. The relative abundance of gut bacteria showed that Clostridiaceae was lower (p = 0.009), while Blautia and Pseudobutyrivibrio were higher (p = 0.044 and p = 0.037, respectively) in BEER versus ABS. In addition, Alkaliphilus, in men, showed lower abundance in BEER than in ABS (p = 0.025). Butyric acid was higher in BEER than in ABS (p = 0.032), and correlated with Pseudobutyrivibrio abundance. In conclusion, the changes observed in a few taxa, and the higher butyric acid concentration in consumers versus non-consumers of beer, suggest a potentially beneficial effect of moderate beer consumption on intestinal health.

Microbiota and Lifestyle: A Special Focus on Diet.

It is widely known that a good balance and healthy function for bacteria groups in the colon are necessary to maintain homeostasis and preserve health. However, the lack of consensus on what defines a healthy gut microbiota and the multitude of factors that influence human gut microbiota composition complicate the development of appropriate dietary recommendations for our gut microbiota. Furthermore, the varied response to the intake of probiotics and prebiotics observed in healthy adults suggests the existence of potential inter- and intra-individual factors, which might account for gut microbiota changes to a greater extent than diet. The changing dietary habits worldwide involving consumption of processed foods containing artificial ingredients, such as sweeteners; the coincident rise in emotional disorders; and the worsening of other lifestyle habits, such as smoking habits, drug consumption, and sleep, can together contribute to gut dysbiosis and health impairment, as well as the development of chronic diseases. This review summarizes the current literature on the effects of specific dietary ingredients (probiotics, prebiotics, alcohol, refined sugars and sweeteners, fats) in the gut microbiota of healthy adults and the potential inter- and intra-individual factors involved, as well as the influence of other potential lifestyle factors that are dramatically increasing nowadays.

2-OHOA supplementation reduced adiposity and improved cardiometabolic risk to a greater extent than n-3 PUFA in obese mice.

OBJECTIVE: We aimed to assess whether 2-hydroxyoleic acid (2-OHOA) and n-3 polyunsaturated fatty acids (PUFA) could counteract changes on adipokine secretion and cardiometabolic risk biomarkers associated with high-fat diet-induced obesity in mice. METHODS: Female ICR/CD1 mice (8 weeks old) were divided into four groups receiving different diets (n=8/group): (1) standard chow (control) for 18 weeks; (2) 22% fat for 4 weeks + 60% fat for 14 weeks (obesogenic diet, OD); 3) OD + 2-OHOA (1500mgkg-1 diet) for the last 6 weeks (ODHO); and 4) OD+n-3 PUFA (eicosapentaenoic+docosahexaenoic acids, 1500+1500mgkg-1 diet) for the last 6 weeks (OD-N3). After 18 weeks, body weight, periovarian visceral fat, heart and liver weights were measured, as well as cardiometabolic parameters (systolic and diastolic blood pressure, blood glucose, insulin, HOMA index, triglycerides, total cholesterol, apolipoproteins A1 and E), plasma adipokines and inflammatory proteins (leptin, adiponectin, plasminogen activator inhibitor 1 [PAI1], soluble E-selectin [sE-selectin], matrix metalloproteinase-9 [MMP-9], fibrinogen, soluble intercellular adhesion molecule [sICAM] and soluble vascular adhesion molecule [sVCAM]), and secretion of pro-inflamatory cytokines and inflammatory biomarkers from periovarian adipocytes. RESULTS: OD mice had greater body and heart weights, and plasma leptin, and lower adiponectin and resistin secretion from adipocytes. Supplementation with 2-OHOA reduced body and heart weights, blood pressure, triglycerides and leptin, and restored adiponectin and resistin secretion, while n-3 PUFA only reduced triglyceride levels (all P<0.05). CONCLUSION: 2-OHOA supplementation was more effective in reducing adiposity, modulating adipokine secretion and ameliorating cardiometabolic risk than n-3 PUFA.

Self-reported sleep duration, white blood cell counts and cytokine profiles in European adolescents: the HELENA study.

BACKGROUND: Sleep patterns face important changes during adolescence. This can have implications for the immune system, which is regulated by the sleep-wake cycle; however, most studies relating sleep and immune system have been conducted on adults. OBJECTIVE: To study the relationships between sleep duration, immune cell counts, and cytokines in European adolescents participating in the HELENA Cross-Sectional Study. METHODS: Adolescents (12.5-17.5 years; n = 933; 53.9% girls) were grouped according to self-reported sleep duration into <8, 8-8.9 and ≥9 h/night. Blood samples were collected in the morning after an overnight fast to analyze counts of white blood cells (WBC), neutrophils, lymphocytes, monocytes, eosinophils, basophils, the lymphocyte subsets CD3(+), CD4(+), CD8(+), CD45RA(+), CD45RO(+), CD3(-)CD16(+)56(+) and CD19(+), and concentrations of cortisol, CRP, IL-1, IL-2, IL-4, IL-5, IL-6, IL-10, TNF-α and IFN-γ. Pro-/anti-inflammatory and Th1/Th2 cytokine ratios were calculated. Immune parameters were correlated to sleep duration and compared between the three groups. RESULTS: Sleep duration was negatively associated with cortisol levels and WBC, neutrophil, monocyte, CD4(+) and CD4(+)CD45RO(+) counts; in girls it is also negatively associated with IL-5 and IL-6 levels. The 8-8.9 h/night group presented the highest IL-4 values and the lowest pro-/anti-inflammatory and Th1/Th2 cytokine ratios. CONCLUSION: A sleep duration of 8-8.9 h/night was associated with a healthier immune profile in our adolescents.

Changes in gut microbiota due to supplemented fatty acids in diet-induced obese mice.

Consumption of a high-fat diet (HFD), which is associated with chronic 'low-grade' systemic inflammation, alters the gut microbiota (GM). The aim of the present study was to investigate the ability of an oleic acid-derived compound (S1) and a combination of n-3 fatty acids (EPA and DHA, S2) to modulate both body weight and the GM in HFD-induced obese mice. A total of eighty mice were fed either a control diet or a HFD, non-supplemented or supplemented with S1 or S2. At week 19, faeces were collected in order to analyse the GM. Group-specific primers for accurate quantification of several major bacterial groups from faecal samples were assayed using quantitative PCR. The HFD induced an increase in body weight, which was reduced by supplementation with S1. Furthermore, S1 supplementation markedly increased total bacterial density and restored the proportions of bacteria that were increased (i.e. clostridial cluster XIVa and Enterobacteriales) or decreased (i.e. Bifidobacterium spp.) during HFD feeding. S2 supplementation significantly increased the quantities of Firmicutes (especially the Lactobacillus group). Correlation analysis revealed that body weight correlated positively with the phylum Firmicutes and clostridial cluster XIVa, and negatively with the phylum Bacteroidetes. In conclusion, the consumption of a HFD induced changes in the faecal microbiota, which were associated with the appearance of an obese phenotype. Supplementation of the HFD with S1 counteracted HFD-induced gut dysbiosis, together with an improvement in body weight. These data support a role for certain fatty acids as interesting nutrients related to obesity prevention.

Validation of the Diet Quality Index for Adolescents by comparison with biomarkers, nutrient and food intakes: the HELENA study.

Food-based dietary guidelines (FBDG) aim to address the nutritional requirements at population level in order to prevent diseases and promote a healthy lifestyle. Diet quality indices can be used to assess the compliance with these FBDG. The present study aimed to investigate whether the newly developed Diet Quality Index for Adolescents (DQI-A) is a good surrogate measure for adherence to FBDG, and whether adherence to these FBDG effectively leads to better nutrient intakes and nutritional biomarkers in adolescents. Participants included 1804 European adolescents who were recruited in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) Study. Dietary intake was assessed by two, non-consecutive 24 h recalls. A DQI-A score, considering the components' dietary quality, diversity and equilibrium, was calculated. Associations between the DQI-A and food and nutrient intakes and blood concentration biomarkers were investigated using multilevel regression analysis corrected for centre, age and sex. DQI-A scores were associated with food intake in the expected direction: positive associations with nutrient-dense food items, such as fruits and vegetables, and inverse associations with energy-dense and low-nutritious foods. On the nutrient level, the DQI-A was positively related to the intake of water, fibre and most minerals and vitamins. No association was found between the DQI-A and total fat intake. Furthermore, a positive association was observed with 25-hydroxyvitamin D, holo-transcobalamin and n-3 fatty acid serum levels. The present study has shown good validity of the DQI-A by confirming the expected associations with food and nutrient intakes and some biomarkers in blood.

Six-year trend in active commuting to school in Spanish adolescents. The AVENA and AFINOS Studies.

BACKGROUND: Promoting daily routine activities, such as active commuting to school, may have important health implications for young people. PURPOSE: The aim of the study was to examine the secular trend of active commuting to school in Spanish adolescents over a 6-year period (2001-2002 to 2006-2007). We also examined several factors that might explain this trend. METHODS: Data comes from two separate cross-sectional studies, both representatives from the city of Madrid (Spain): AVENA and AFINOS studies. These took place in 2001-2002 and 2006-2007 and included 415 (198 girls) and 891 (448 girls) adolescents aged 13-17, respectively. Commuting to school was assessed using a standardized question about their habitual mode of transportation to school: walking, cycling, bus/subway, car, or motorcycle. Chi-square and binary logistic regression were used. RESULTS: Percentage of active commuting girls decreased significantly from 61 % to 48 % (p = 0.002) from 2001-2002 to 2006-2007. Walking declined from 61 % to 46 % and the use of bus/subway increased from 25 % to 37 % in girls. Girls belonging to average/small families had lower odds of being active commuters than girls of large families (OR, 95 % CI: 0.69, 0.48 to 0.98). There were no significant differences in mode of commuting to school for boys (p = 0.269). CONCLUSION: Spanish adolescent girls in 2007-2008 had lower levels of active commuting to school, mainly walking, than their counterparts 6 years before. Belonging to a large family was related with higher active commuting in girls.

Sedentary behaviours and its association with bone mass in adolescents: the HELENA Cross-Sectional Study.

BACKGROUND: We aimed to examine whether time spent on different sedentary behaviours is associated with bone mineral content (BMC) in adolescents, after controlling for relevant confounders such as lean mass and objectively measured physical activity (PA), and if so, whether extra-curricular participation in osteogenic sports could have a role in this association. METHODS: Participants were 359 Spanish adolescents (12.5-17.5 yr, 178 boys,) from the HELENA-CSS (2006-07). Relationships of sedentary behaviours with bone variables were analysed by linear regression. The prevalence of low BMC (at least 1SD below the mean) and time spent on sedentary behaviours according to extracurricular sport participation was analysed by Chi-square tests. RESULTS: In boys, the use of internet for non-study was negatively associated with whole body BMC after adjustment for lean mass and moderate to vigorous PA (MVPA). In girls, the time spent studying was negatively associated with femoral neck BMC. Additional adjustment for lean mass slightly reduced the negative association between time spent studying and femoral neck BMC. The additional adjustment for MVPA did not change the results at this site. The percentage of girls having low femoral neck BMC was significantly smaller in those participating in osteogenic sports (≥ 3 h/week) than in the rest, independently of the cut-off selected for the time spent studying. CONCLUSIONS: The use of internet for non-study (in boys) and the time spent studying (in girls) are negatively associated with whole body and femoral neck BMC, respectively. In addition, at least 3 h/week of extra-curricular osteogenic sports may help to counteract the negative association of time spent studying on bone health in girls.

Food consumption and screen-based sedentary behaviors in European adolescents: the HELENA study.

OBJECTIVE: To examine the association between time spent on different sedentary behaviors and consumption of certain food and beverage groups in a sample of European adolescents. DESIGN: Data from the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-sectional Study. SETTING: Eight survey centers (Athens, Dortmund, Ghent, Lille, Rome, Stockholm, Vienna, and Zaragoza). PARTICIPANTS: A total of 2202 participants (45.5% boys) aged 12½ to 17½ years. MAIN OUTCOME MEASURES: Information on sedentary behaviors (weekdays and weekends) collected via a standardized self-reported questionnaire, including watching television, playing computer and video games, using the Internet for studying or recreation, and studying. Food and beverage consumption data of selected groups were obtained using 2 nonconsecutive 24-hour recalls. RESULTS: Boys reporting more than 4 h/d of watching television, playing computer games, and using the Internet for recreation were more likely to consume sweetened beverages (weekends) (odds ratio [OR], 1.83 [95% CI, 1.21-2.75]; 1.99 [1.31-3.01]; and 1.73 [1.03-2.91], respectively), and less likely to consume fruit (weekdays) (0.39 [0.21-0.72], 0.37 [0.18-0.77], and 0.39 [0.19-0.78], respectively) than those who spent less than 2 h/d. Girls spending more time per day watching television and playing computer or video games (weekdays) and playing computer games or surfing the Internet for recreation (weekends) were more likely to drink sweetened beverages (OR, 1.89 [95% CI, 1.21-2.94]; 1.57 [1.00-2.46]; 2.14 [1.16-3.97]; and 2.30 [1.24-4.28], respectively) and less likely to consume fruit (weekdays) (0.43 [0.23-0.80], 0.40 [0.19-0.83], 0.37 [0.14-0.94], and 0.42 [0.20-0.85], respectively) than those who spent less than 2 h/d. CONCLUSION: Increased television viewing and computer and Internet use during adolescence is associated with higher odds of consumption of sweetened beverages and lower odds of fruit consumption.

Iron and vitamin status biomarkers and its association with physical fitness in adolescents: the HELENA study.

There is a lack of studies that analyze the association between micronutrient-related biomarker status and physical fitness in adolescents. In the present study, biochemical parameters for iron and vitamin status were studied, along with objective measures of physical fitness in healthy male and female European adolescents. One thousand eighty-nine adolescents (580 girls, 12.5-17.5 yr) from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) cross-sectional study were included. Hierarchical linear models were performed to determine the associations between micronutrient biomarkers and physical fitness. Age, seasonality, latitude, body mass index, menarche (in girls), and physical activity were used as covariates. For cardiorespiratory fitness, concentrations of hemoglobin, retinol, and vitamin C in male adolescents and ß-carotene and 25(OH)D in female adolescents were associated with maximal oxygen consumption. For muscular fitness, concentrations of hemoglobin, ß-carotene, retinol, and α-tocopherol in male adolescents and ß-carotene and 25(OH)D in female adolescents were associated with better performance of the standing long jump test. In summary, concentrations of hemoglobin and most antioxidant vitamins in male adolescents and ß-carotene and 25(OH)D in female adolescents were positively associated with cardiorespiratory and muscular fitness, after controlling for relevant confounders. The associations between physical fitness and iron or vitamin status observed in this cross-sectional study in adolescents should be followed up by a study specifically designed to evaluate causal relationships.

Sexual dimorphism in the early life programming of serum leptin levels in European adolescents: the HELENA study.

AIM: The aim of this study was to test the hypothesis that a lower birth weight, as an indicator of adverse intrauterine environment, is associated with higher serum leptin levels in European adolescents. We also examined the possible sexual dimorphism in this relationship. METHODS: Fasting serum leptin was measured in 757 European born at term adolescents (429 females) aged 14.6 ± 1.2 yr. We measured weight and height, and body mass index was calculated. Birth weight, duration of pregnancy, and duration of breast-feeding were obtained from parental records. Duration of pregnancy and breast-feeding, pubertal status, center, body mass index, and physical activity were entered as confounders in the analyses. RESULTS: There was a significant interaction effect between sex and birth weight on serum leptin levels (P = 0.044). We observed that body weight at birth was negatively and significantly associated with serum leptin levels only in female adolescents (ß = -0.109; adjusted P = 0.008). The association persisted after further controlling for physical activity (ß = -0.115; adjusted P = 0.016). CONCLUSIONS: These findings provide further evidence for a sex-specific programming effect of birth weight on serum leptin levels. Our results also contribute to explain the detrimental health effects associated with lower birth weight, such as long-term increased risk of developing obesity and type 2 diabetes.

The effect of ponderal index at birth on the relationships between common LEP and LEPR polymorphisms and adiposity in adolescents.

This study examined the effect of ponderal index (PI) at birth on the relationships between eight common polymorphisms of the leptin (LEP) and leptin receptor (LEPR) genes and adiposity in adolescents. A total of 823 European adolescents (45.4% girls) aged 14.8 ± 1.4 years were genotyped for the LEP (rs2167270, rs12706832, rs10244329, rs2071045, and rs3828942) and LEPR (rs1137100, rs1137101, and rs8179183) polymorphisms. The PI was calculated from parental reports of birth weight and length. Fat mass index (FMI) was calculated. Analyses were adjusted for relevant confounders. An "adiposity-risk-allele score" based on genotypes at the three single-nucleotide polymorphisms (SNPs) associated with adolescents' FMI in adolescents within the lower tertile of PI was calculated. The LEP rs10244329 and rs3828942 polymorphisms were associated with higher FMI only in adolescents within the lower PI tertile (+0.55 kg/m(2) per minor T allele, P = 0.040, and +0.58 kg/m(2) per major G allele, P = 0.028, respectively). The LEPR rs8179183 polymorphism was significantly associated with higher FMI in adolescents within the lower PI tertile (+0.87 kg/m(2) per minor C allele, P = 0.006). After correction for multiple comparisons, only the association between the LEPR rs8179183 and FMI persisted. However, each additional risk allele conferred 0.53 kg/m(2) greater FMI in adolescents within the lower tertile of PI (P = 0.008). In conclusion, our results suggest that those adolescents born with lower PI could be more vulnerable to the influence of the LEP rs10244329 and rs3828942 polymorphisms and LEPR rs8179183 polymorphism on total adiposity content. Due to the relatively small sample size, these findings should be replicated in further larger population samples.

Active commuting to school and cognitive performance in adolescents: the AVENA study.

OBJECTIVE: To examine the associations between active commuting to school and cognitive performance in adolescents. DESIGN: Cross-sectional study. SETTING: Five cities (Granada, Madrid, Murcia, Santander, and Zaragoza) in Spain. PARTICIPANTS: A total of 1700 adolescents (892 girls) aged 13 to 18.5 years. MAIN EXPOSURES: Mode and duration of transportation to school and participation in extracurricular physical activity were self-reported. MAIN OUTCOME MEASURES: Cognitive performance (verbal, numeric, and reasoning abilities and an overall score) was measured by the Spanish version of the SRA Test of Educational Ability. RESULTS: Active commuting to school was associated with better cognitive performance (all P < .05) in girls but not in boys, independent of potential confounders including participation in extracurricular physical activity. In addition, adolescent girls who spent more than 15 minutes actively commuting to school had better scores in 3 of the 4 cognitive performance variables (all P < .05) than those who spent less time actively commuting to school (≤15 minutes) as well as better scores in all of the cognitive performance variables (all P < .001) than girls inactively commuting. CONCLUSION: Active commuting to school and its duration may positively influence cognitive performance in adolescent girls.

Haematological reference values in Spanish adolescents: the AVENA study.

OBJECTIVES: To provide reference values for haematological indices in Spanish adolescents according to age and gender. METHODS: A cross sectional study conducted in five Spanish cities was performed. Blood was drawn from a representative sample of 581 adolescents with age ranging from 13 to 17-18.5 yr. Age- and gender-specific means, standard deviations and percentiles were determined for the following parameters: total red blood cell counts (RBC), haemoglobin concentration (Hb), haematocrit percentage (Hct), mean corpuscular volume (MCV), mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, red cell distribution width and total white blood cell (WBC) counts as well as counts and percentage of neutrophils, lymphocytes, monocytes, eosinophils and basophils; platelet count (PLT), mean platelet volume and plateletcrit percentage. RESULTS: Younger male subjects presented lower RBC, Hb, Hct and MCV means that their older counterpart. By contrast these differences were not observed in female subjects. As expected, RBC, Hb and Hct mean values in males were found significantly higher than in girls for all studied age groups. No significant differences were observed in WBC by age and gender. PLT values gradually decreased with age, except for females aged 17-18.5 yr. CONCLUSION: The present study provides reference data on the distribution of haematological indices of Spanish adolescents. These data can be useful biomarkers of the nutritional status in adolescents.

Effects of moderate beer consumption on blood lipid profile in healthy Spanish adults.

BACKGROUND AND AIMS: To analyse the association of moderate beer consumption on the blood lipid profile in healthy Spanish adults. METHODS AND RESULTS: The study had an intervention longitudinal design in which each subject established their own control with a previous wash-out phase. After a 30-day alcohol abstinence period, 57 healthy volunteers were submitted to a daily moderate intake of beer for 30 days. Serum total cholesterol, HDL-cholesterol, triacylglycerols, GOT, GPT, GGT and glucose values, as well as blood erythrocytes, haemoglobin, haematocrit and MCV levels, together with anthropometric parameters were determined at the beginning of the study (baseline levels) (a), after 1 month of alcoholic abstinence (b) and after 1 month of moderate beer consumption (c). Dietary intake was assessed twice by a 7-day dietary record. HDL-cholesterol, erythrocytes, haematocrit and MCV levels increased significantly (p<0.05) after moderate beer consumption in women. In men, a decrease in HDL-cholesterol levels was observed after alcohol abstention. Haematocrit and MCV counts also increased significantly (p<0.05) in men after moderate beer consumption. There were no dietary changes during the study. CONCLUSION: In healthy Spanish adults, the effects of moderate beer consumption during 1 month were associated with favourable changes on the blood lipid profile.

Moderate alcohol consumption and the immune system: a review.

Increasing evidence suggests that light to moderate amounts of polyphenol-rich alcoholic beverages like wine or beer could have health benefits. Scientists have long debated the effects of alcohol on immune function, showing on the one hand, that high doses of alcohol consumption can directly suppress a wide range of immune responses, and that alcohol abuse is associated with an increased incidence of a number of infectious diseases. On the other hand, moderate alcohol consumption seems to have a beneficial impact on the immune system compared to alcohol abuse or abstinence. Therefore, the link between alcohol consumption, immune response, as well as infectious and inflammatory processes remains not completely understood. With this in mind, it is important to realise that other factors, unrelated or indirectly related to immune function, like drinking patterns, beverage type, amount of alcohol, or gender differences, will affect the influence that alcohol consumption may have on the immune system. This review summarises published data describing the effects that light to moderate amounts of polyphenol-rich beverages like wine or beer seem to have on immunity in healthy adults.

Immunomodulatory effects of probiotics in different stages of life.

The immunomodulatory properties of lactic acid bacteria (LAB) and foods containing them (e.g., fermented milks) is a topic currently under investigation. Individuals could potentially benefit from the inclusion of LAB in the diet at different times during the life cycle. One of the most accepted specific uses of probiotic bacteria is the prevention of atopic eczema in infants with family history of the disease who receive the probiotic bacteria early, through supplementation of the gestating mother and orally after birth. Immune enhancing effects have also been suggested to be beneficial in diarrhoea treatment, especially in children infected with rotavirus and in malnourished patients, infants and adolescents, whose capacity to produce IFN-gamma can be increased after LAB-containing yoghurt intake. Regarding young people and adults, investigations have been conducted exploring the immunomodulation by LAB in subjects under stressful situations, in the prevention of urinary tract infections in fertile women and in the treatment of allergy. However, the beneficial effects of probiotics in these conditions remain controversial and the scientific evidence provided so far is not considered to be conclusive. The elderly population has been the focus of investigations aimed at identifying the capacity of probiotics to counteract the immunosenescence process by increasing phagocytic and natural killer (NK) cell activities and to protect against infection. The mechanisms involved in the different effects attributed to LAB remain to be clarified. Moreover, considering that the immunomodulatory properties are strain-specific, defining the optimal dose of a certain bacteria or combination of bacteria strains and the duration of treatment for a desired effect in a target population group is essential in order to substantiate health claims.

Changes in the immune system after moderate beer consumption.

BACKGROUND/AIM: Epidemiological studies have suggested that moderate alcohol consumption is associated with lower morbidity. However, intervention studies are needed to elucidate mechanisms involved. This study was aimed to determine the effects of moderate beer consumption on the immune function of healthy adults, taking into account gender differences. METHODS: After a 30-day alcohol abstinence period, 57 healthy volunteers consumed a moderate intake of beer (330 ml for women and 660 ml for men) for 30 days. Total leukocyte and lymphocyte counts; absolute values of T-lymphocyte CD3+, CD4+, and CD8+ subsets; delayed-hypersensitivity skin response (DHSR); absolute values of B lymphocytes (CD19+) and serum immunoglobulin concentrations (IgG, IgA, and IgM); and cytokine production (IL-2, IL-4, IL-6, IL-10, IFN-gamma, and TNF-alpha) were evaluated following the abstinence and alcohol consumption periods. RESULTS: After moderate beer consumption CD3+ cells increased only in women (p < 0.05). IgG, IgM, and IgA concentrations, as well as IL-2, IL-4, IL-10, and IFN-gamma cytokine production increased while IFN-gamma/IL-10 ratio decreased in both men and women (p < 0.05). The rest of the immunological parameters analyzed remained unchanged. CONCLUSION: Moderate beer consumption produced an immunomodulatory effect in a healthy adult Spanish population; this effect appears to be more relevant in women than in men.