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PubMed2001

Use of Metabolic Inhibitors to Characterize Ecological Interactions in an Estuarine Microbial Food Web.

Understanding microbial food web dynamics is complicated by the multitude of competitive or interdependent trophic interactions involved in material and energy flow. Metabolic inhibitors can be used to gain information on the relative importance of trophic pathways by uncoupling selected microbial components and examining the net effect on ecosystem structure and function. A eukaryotic growth inhibitor (cycloheximide), a prokaryotic growth inhibitor (antibiotic mixture), and an inhibitor of photosynthesis (DCMU) were used to examine the trophodynamics of microbial communities from the tidal creek in North Inlet, a salt marsh estuary near Georgetown, South Carolina. Natural microbial communities were collected in the spring, summer, and fall after colonization onto polyurethane foam substrates deployed in the tidal creek. Bacterial abundance and productivity, heterotrophic ciliate and flagellate abundance, and phototrophic productivity, biomass, and biovolume were measured at five time points after inhibitor additions. The trophic responses of the estuarine microbial food web to metabolic inhibitors varied with season. In the summer, a close interdependency among phototrophs, bacteria, and protozoa was indicated, and the important influence of microzooplanktonic nutrient recycling was evident (i.e., a positive feedback loop). In the fall, phototroph and bacteria interactions were competitive rather than interdependent, and grazer nutrient regeneration did not appear to be an important regulatory factor for bacterial or phototrophic activities. The results indicate a seasonal shift in microbial food web structure and function in North Inlet, from a summer community characterized by microbial loop dynamics to a more linear trophic system in the fall. This study stresses the important role of microbial loops in driving primary and secondary production in estuaries such as North Inlet that are tidally dominated by fluctuations in nutrient supply and a summer phytoplankton bloom.

Journal Article↗

PubMed1988

Feeding and drinking behaviour following angiotensin converting enzyme blockade: role of injectant pH.

Angiotensin converting enzyme (ACE) is a circulating dipeptidase which has a broad specificity and is known to metabolise a range of circulating peptides. While a number of circulating peptides are believed to modulate food intake, it is not known if ACE plays a role in the control of feeding behaviour and therefore in this study we have examined the effect of the potent, specific ACE antagonists captopril (SQ 14225) and enalapril (MK421) on food and water intake following food deprivation and 2-deoxyglucose treatment in the rat. One hour captopril (50 mg/kg, IP) pretreatment significantly reduced the food intake of 24 hr food deprived rats. Because captopril solutions have a low pH (2.0), the effect of buffered captopril on food intake following 24 hr food deprivation was also examined. Buffered captopril also significantly reduced the food intake of 24 hr food deprived rats, but not to the same extent as unbuffered captopril. Naloxone pretreatment (1 mg/kg, IP) did not antagonize the effect of captopril on food intake indicating that the anorexic action of captopril was not due to alterations in opiate peptide levels. Buffered captopril did not reduce the food intake of food-replete rats receiving 2-deoxyglucose (300 mg/kg, IP) or alter blood gases or pH. However, an equimolar buffered dose of the structurally different ACE inhibitor enalapril failed to significantly alter food deprivation-induced food intake, suggesting that this action of captopril in reducing food intake was unrelated to ACE blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2001

Pemphigus vulgaris: environmental factors. Occupational, behavioral, medical, and qualitative food frequency questionnaire.

BACKGROUND: There have been reports suggesting the involvement of environmental factors in the disease process of pemphigus. Factors suggested include exposure to pesticides or certain drugs. OBJECTIVE: To analyze the association of pemphigus with environmental exposure to various agents, including smoking, recreational and occupational insults, drugs, and food. DESIGN AND SETTING: In-person interviews of pemphigus patients and control subjects were conducted by trained medical investigators using a structured questionnaire. Questions included occupational, behavioral, medical, and qualitative food frequency details. The multicenter study was conducted at outpatient services of teaching hospitals in Bulgaria, Brazil, India, Israel, Italy, Spain, and the USA. PARTICIPANTS: A total of 126 pemphigus patients (55 men, 71 women; age, 54 +/- 17 years) and 173 healthy controls (87 men, 86 women; age 50 +/- 19 years) were interviewed in the period between October 1, 1999 and March 31, 2000. The diagnosis of pemphigus was based on clinical, histologic, immunohistologic, and immunohistochemical criteria. The disease duration was 2-27 years (8.4 +/- 7.2 years). Individuals with skin diseases other than pemphigus were selected as control subjects. MAIN OUTCOME MEASURE: Information on drugs, foods, and occupational, environmental, constitutional, and other possible risk factors was analyzed by t-tests and chi-squared tests as applicable. A multivariate logistic regression model was applied to the data to study simultaneously the independent relationship between each risk factor and pemphigus vulgaris. RESULTS: The risk for pemphigus vulgaris was lower for ex-smokers and current smokers than for patients who had never smoked. Exposure to pesticides and occupational exposure to metal vapor were associated with an increased risk of pemphigus. Pemphigus patients had more pregnancies than controls. There were differences in environmental factors between countries, with exposure to gardening materials and pesticides being highest among patients from Bulgaria, followed by Israel. Disease characteristics also exhibited differences between countries. Bulgarian patients less frequently had oral mucous membrane lesions: 66% compared to 92% for Israeli patients and 83% for Italians. The distribution of the disease in skin and mucous membranes was similar among patients from all countries. Exclusive skin involvement was seen in 50% of patients, mucous membranes alone in 23% of patients, and both skin and mucous membranes in 27% of patients. CONCLUSIONS: The beneficial effect of smoking on pemphigus might be explained by its effect on the immune system. In addition, smoking has an antiestrogenic effect, while pesticides have an estrogenic effect. The lower numbers of smokers among patients, the higher exposure rates to pesticides, and the higher number of female patients who had been pregnant may point to the contribution of estrogens to the disease process. It remains to be determined whether measures, such as avoiding exposure to pesticides or metal vapor, may be beneficial in the clinical context. As the present study was a survey, more definitive studies should be conducted to validate the results.

Agriculture↗

PubMed1997

Feeding patterns and brain evolution in ostariophysean fishes.

The sense of taste plays a crucial role in a fish's ability to locate and select appropriate food. Functionally, the taste system is divisible into two subsystems, with external taste, utilized to locate food in the environment, being mediated by the facial nerve while intraoral taste, crucial for triggering swallowing, is mediated by the vagus nerve. Each of these nerves connects to its own portion of the medullary viscerosensory column. In most teleosts, the viscerosensory column forms a continuous, relatively undifferentiated column of neuropil in the dorsomedial medulla. The taste bud-bearing surfaces of the fish are mapped onto this column with external taste buds being represented anteriorly and pharyngeal taste buds caudally. Taste information reaching the vagal taste area, the "vagal lobe", is relayed directly to motoneurons that control the oropharyngeal musculature. In goldfish, unlike most teleosts, the vagal lobe is laminated, highly differentiated structure containing both sensory and motor layers. This derived neural structure is related to the specialized palatal food sorting apparatus utilized by the fish to separate food from substrate material. Despite the complex morphology of the vagal lobe in goldfish, the underlying circuitry is essentially identical to that of other fishes, i.e. after an obligatory synapse in the sensory layers, the gustatory input is relayed to the oropharyngeal motoneurons comprising the motor layer. Thus evolution of the derived, laminated brain structure did not entail generation of new connectivity but merely involved rearrangement of previously existing neuronal populations.

Animals↗

PubMed2000

Exposure to behaviourally relevant odour reveals differential characteristics in rat central olfactory pathways as studied through oscillatory activities.

This study investigated how changes in nutritional motivation modulate odour-related oscillatory activities at several levels of the olfactory pathway in non-trained rats. Local field potential recordings were obtained in freely moving animals in the olfactory bulb (OB), anterior and posterior parts of the piriform cortex (APC and PPC respectively) and lateral entorhinal cortex (EC). Dynamic signal analysis detected changes in power during odour presentation for several frequency bands The results showed that in most cases odour presentation was associated with changes in a wide 15-90 Hz frequency band of activity in each olfactory structure. However, nutritional state modulated initial responses to food odour (FO) in the OB and EC selectively in the 15-30 Hz frequency band. Changes in nutritional state also modulated responses to repeated FO stimuli. Habituation was expressed differentially across structures with a clear dissociation between the two parts of the piriform cortex. Finally, systemic injections of scopolamine (0.125 mg/kg) selectively blocked expression of the nutritional modulation in the OB found in the beta band. These results suggest that internal state can differentially modulate odour processing among different olfactory areas and point to a cholinergic-sensitive beta band oscillation during presentation of a behaviourally meaningful odorant.

Animals↗

PubMed1997

[Induction of passive cutaneous anaphylaxis by oral administration of antigen].

Passive cutaneous anaphylaxis (PCA) reaction was developed by Ovary et al. as an animal model of mainly human type I allergic inflammation reaction. This is the most sensitive reaction for the detection of cutaneously sensitizing antibodies and provides a very effective means by which to investigate immunological reactions concerning the mechanisms of development and inhibition of allergic reactions, levels and specificity of antibodies, and the structure of antigens. These cutaneous inflammations mimic atopic dermatitis. Food ingestion has been pointed out as one of the worsened factors of atopic dermatitis. However, the body is generally protected against the invasion of high molecular substances such as non-ingested food by several barriers including digestive enzymes that break down complex food molecules into simpler substances and gastrointestinal mucosae. Accordingly, oral ingestion of food antigen seems to be physiologically and immunologically in conflict with the occurrence of dermatitis. With a view to determining whether allergic dermatitis occurs after oral ingestion of food, the present study was carried out on animals, utilizing the PCA reaction. C 57 BL/6 Ncr j mice were immunized with immunogen derived from commercially obtained eggs. Wistar rats were used as a model of PCA reaction. The results of the present investigation are summarized as follows. 1) Blue spots of 10 mm diameter were observed as a PCA reaction 50 min or more after oral administration of antigen, and the blue spots reached maximum size (20-21 mm, 1.8-1.7 micrograms) after 90-120 min. The PCA reaction was induced 20 min or more after intravenous administration of antigen. When the maximum reaction was compared between the oral and the intravenous routes after 50 min (29.5 micrograms) and 90 min (1.8 micrograms) respectively, there was about a 16-fold difference in the capacity to induce inflammations. 2) The maximum PCA reaction values were 100 and 1,600 for the oral and intravenous routes, respectively, there being a 16-fold difference between the two routes. 3) The minimum antigen concentration required to induce the PCA reaction was 10 mg/ ml for the oral route and 0.01 mg/ml for the intravenous, there being a 1,000-fold difference between the two routes. 4) Reactions with anti-egg mixture antibody and main egg constituents were specific. The PCA inhibition test results confirmed that the undigested structural portion of antigen was associated with the induction of PCA. The present investigation demonstrated that there existed a mechanism by which type I allergy is induced via the gastro-intestinal tract. This fact indicates that part of the food ingested undergoes no change in its molecular structure when transferred to the blood, thus acting as a PCA inducing antigen. This phenomenon suggests that this animal model of human type I allergic dermatitis is a useful system that strongly suggests the association of food antigen with the development of allergic dermatitis.

Administration, Oral↗

PubMed1998

X-ray diffraction of food polysaccharides.

The morphologies of food polysaccharides described in this chapter illustrate the power of x-ray fiber diffraction in conjunction with computer modeling and sophisticated refinement techniques. On the other hand, the lack of information on structures such as xanthan reflects the inadequacy of the experimental techniques used to date. But the demands from academic and industrial sectors to investigate the molecular interactions in multicomponent systems, including protein-protein, protein-polysaccharide, polysaccharide-polysaccharide, and other complexes, are high and growing, because they have important food applications. These complexes are structurally more difficult than those solved in the past 40 years and it is improbable that any chosen system will be amenable for crystallographic investigation, crystals or fibers. Modern research facilities that include two-dimensional area detectors, millisecond exposures with synchrotron x-ray radiation, interactive computer graphics, sophisticated molecular dynamics calculations, unbelievably fast and inexpensive computers, and our own intellectual abilities are indispensable tools for the future of structural science in general and food polysaccharides in particular.

Carbohydrate Conformation↗

PubMed2025

Structural properties of short-chain carboxylic acids and alcohols relate to the molecular and physiological response of Salmonella enterica in an acidic environment.

Short-chain carboxylic acids (SCCA) and short-chain alcohols (SCALC) are naturally occurring antimicrobials that contribute to the biopreservation of food fermentations. This study investigated the effect of structurally different SCCA/SCALC with two-carbon (acetic acid; phenylacetic acid; 2-phenylethanol), three-carbon (propionic acid; 3-phenylpropionic acid; 3-phenylpropanol), and three-carbon chain with an additional hydroxyl group (lactic acid; 3-phenyllactic acid; 1-phenylpropanol) on the fitness, metabolic activity and gene expression of the pathogen Salmonella enterica at pH 4.5. SCCA inhibited Salmonella at lower concentrations than SCALC with the exception of lactic acid, which was partly consumed. The presence of a phenyl group enhanced antimicrobial activity. SCCA but not SCALC increased the lag phase of S. enterica, and in general, acetate was formed when cell growth was reduced by 20% suggesting a negative impact on bacteria fitness. Principal component analysis and hierarchical clustering indicated distinct gene expression profiles of S. enterica in response to SCCA or SCALC. In the presence of certain SCCA/SCALC, Salmonella activated pathways related to cellular pH control, and 1,2-propanediol, propionic acid and ethanolamine metabolism that involved the formation of metabolosomes. Genes related to flagellar assembly were less expressed and mobility was lower in the presence of lactic and 3-phenyllactic acid compared to controls suggesting a compound-specific response. KEY POINTS: • Differences in response among structurally different SCCA/SCALC at acidic condition. • SCCA/SCALC stress interfered with cell growth and metabolism of acetic and propionic acid. • Lactic acid prolonged the lag phase and reduced motility of Salmonella.

Salmonella enterica↗

PubMed2004

Comprehensive two-dimensional gas chromatography of complex samples by using a 'reversed-type' column combination: application to food analysis.

The practicability and potential of a non-orthogonal approach in comprehensive two-dimensional gas chromatography (GC x GC) were studied and compared to those of the orthogonal approach for two different complex matrices, and using conventional flame ionisation (FID) and time-of-flight mass spectrometry (ToF MS) detection. The separation of a diesel oil showed that the non-orthogonal approach also provides interesting, but completely reversed, ordered structures. For the more extensively studied flavour analysis in food samples, improved peak shapes and, also, different types of ordered structures and retention behaviour, and improved detectability for polar compounds make the two approaches complementary to each other. As a consequence, identification and/or determination of targets and/or unknowns can be performed more reliably. Analytical performance (close to three-order linearity; LODs, 2-30 pg injected in most cases; R.S.D.s, 1-6% (n = 6)) was fully satisfactory.

Chromatography, Gas↗

PubMed2002

Melanoidins exert a weak antiradical activity in watery fluids.

The Maillard reaction has a dramatic impact on the overall acceptance and nutritional quality of most of the foods consumed daily in European countries. Melanoidins are polymeric structures formed in the last stage of the Maillard reaction with nearly unknown effect on the human health. The antiradical activity of several melanoidins isolated from model systems and coffee has been studied. A novel antiradical efficiency concept has been applied to describe the antiradical activity in an aqueous medium by bleaching the radical cation N,N-dimethyl-p-phenylenediamine (DMPD(*)(+)). Melanoidins exerted a significantly lower antiradical activity than classical antioxidant compounds (tannic acid, ferrulic acid, caffeic acid, gallic acid, and Trolox) in an aqueous medium. Significant differences have been observed according to the type of amino acid used as reactant during the formation of the melanoidin structure and the antiradical efficiency exerted.

Antioxidants↗

PubMed2006

Assessing food safety and associated food handling practices in street food vending.

Street vendors in the city of Bloemfontein were investigated in order to assess the microbiological quality of the food being sold as well as the level of hygiene conditions under which these food stalls operate. The food samples which were collected included beef, chicken and gravy, while surface samples were taken from the food preparation tables and the hands of the vendors. A structured questionnaire and checklist were used in interviews to determine the status of the vending sites and associated food handling practices. The overall microbiological quality of the foods served by the street vendors was found to be within acceptable safety limits, although the presence of specific microorganisms such as Escherichia coli, Staphylococcus aureus, Salmonella and yeasts is indicative of a degree of ignorance on the part of the food handlers towards proper hygienic practices.

Colony Count, Microbial↗

PubMed2002

Identification and fine mapping of IgG and IgE epitopes in ovomucoid.

Ovomucoid is a major allergen in hen egg white which causes a serious IgE-mediated food allergy reaction. This study determined eight IgG epitopes, 5-11 amino acids in length, and nine IgE epitopes, 5-16 amino acids in length, within the primary sequence in ovomucoid using arrays of overlapping peptides synthesized on cellulose membranes. Pooled sera from eight egg-allergic patients were used to probe the membrane. We also analyzed the amino acids that are critical for antibody binding by substituting a single amino acid within each epitope. Mutational analysis of the epitopes indicated that charged amino acids (aspartic acid, glutamic acid, and lysine) and some hydrophobic (leucine, phenylalanine, and glycine) and polar (serine, threonine, tyrosine, and cystein) amino acids were important for antibody binding. These results provide useful information for the molecular design necessary to reduce the allergenicity of ovomucoid, and a better understanding of structure-function relationships of allergic epitopes in food proteins.

Amino Acid Sequence↗

PubMed1989

Differential effects of clonidine analogs on food intake in rabbits and monkeys.

The present study examined the effect of structural analogs of clonidine on feeding in both rabbits and monkeys. In rabbits, lofexidine and tizanidine either did not influence or decreased food intake in contrast to clonidine, which stimulated food intake. Lofexidine elicited easily observed decreases in motor behavior with several of the doses used in the study. Changes in motor behavior induced by tizanidine were more subtle. Conversely, lofexidine and tizanidine significantly increased feeding behavior in Stumptail macaque monkeys, as did clonidine. The results suggest that, in contrast to rabbits, Stumptail monkeys are more useful in searching for an 'orectic' effect of clonidine analogs.

Animals↗

PubMed1997

Two crystal structures of pectin lyase A from Aspergillus reveal a pH driven conformational change and striking divergence in the substrate-binding clefts of pectin and pectate lyases.

BACKGROUND: Microbial pectin and pectate lyases are virulence factors that degrade the pectic components of the plant cell wall. The homogalacturan backbone of pectin varies in its degree of methylation from the highly methylated and relatively hydrophobic form known as pectin, to the fully demethylated and highly charged form known as pectate. Methylated and demethylated regions of pectin are cleaved by pectin lyase and calcium-dependent pectate lyases, respectively. Protein engineering of lyases specific for particular patterns of methylation, will yield modified pectins of high value to the food and pharmaceutical industries. RESULTS: The crystal structures of pectin lyase A from two strains of Aspergillus niger, N400 and 4M-147, have been determined at pH 6.5 (2.4 A resolution) and pH 8.5 (1.93 A resolution), respectively. The structures were determined by a combination of molecular replacement, multiple isomorphous replacement and intercrystal averaging. Pectin lyase A folds into a parallel beta helix and shares many of the structural features of pectate lyases, despite no more than 17% sequence identity after pairwise structure-based alignment. These shared structural features include amino acid stacks and the asparagine ladder. However, the differences in the substrate-binding clefts of these two enzymes are striking. In pectin lyase A, the cleft is dominated by aromatic residues and is enveloped by negative electrostatic potential. In pectate lyases, this cleft is rich in charged residues and contains an elongated ribbon of positive potential when Ca2+ is bound. The major difference between the two pectin lyase A structures from the two strains is in the conformation of the loop formed by residues 182-187. These observed differences are due to the different pH values of crystallization. CONCLUSIONS: The substrate-binding clefts and catalytic machinery of pectin and pectate lyases have diverged significantly. Specificity is dictated by both the nature of the protein-carbohydrate interaction and long-range electrostatic forces. Three potential catalytic residues have been identified in pectin lyase, two of these are common to pectate lyases. Pectin lyase A does not bind Ca2+ but an arginine residue is found in an equivalent position to the Ca2+ ion in pectate lyase, suggesting a similar role in catalysis. The activity of pectin lyase A is pH -dependent with an optimum activity at pH 5.5. The activity drops above pH 7.0 due to a conformational change at the binding cleft, triggered by the proximity of two buried aspartate residues.

Aspergillus niger↗

PubMed2000

Immunoblot analysis of IgE-binding antigens in paprika and tomato pollen.

BACKGROUND: The high incidence of occupational allergy in horticulture has only recently been recognized. We determined IgE against pollen and fruit from paprika and tomato plants in sera from 3 greenhouse workers and in 3 sera from food-allergic patients. METHODS: Proteins in extracts of paprika and tomato pollen were incubated with patients' sera after covalent coupling of these proteins to agarose beads, or in immunoblots. RESULTS: IgE against paprika pollen, but no IgE against tomato pollen, was found in serum from 2 greenhouse workers who worked with paprika plants only. IgE binding of these 2 sera to agarose-bound paprika pollen extract could be inhibited by paprika pollen but not by tomato pollen extract. A greenhouse worker, who cultivated tomato plants, had IgE against both tomato and paprika pollen. IgE binding of this serum to agarose-bound paprika pollen extract could be inhibited by both paprika pollen and tomato pollen extract. Three food-allergic patients also had IgE against tomato and paprika pollen. IgE from 2 food-allergic patients recognized IgE-binding structures in paprika or tomato pollen that were also present in fruit from the corresponding plant. In contrast, no substantial cross-reactivity was observed between paprika pollen and fruit towards IgE from 3 greenhouse workers. In 4 of 5 sera that were positive in the paprika pollen immunoblot major IgE binding to allergens of about 30 and 64 kD occurred. CONCLUSION: The presence of IgE against paprika or tomato pollen is not restricted to workers in horticulture; IgE against these pollen can also be present in food-allergic patients who have serum IgE against paprika and/or tomato fruit.

Adult↗

PubMed1996

Diet and Parkinson's disease. I: A possible role for the past intake of specific foods and food groups. Results from a self-administered food-frequency questionnaire in a case-control study.

In a case-control study, we compared the past dietary habits of 342 Parkinson's disease (PD) patients recruited from nine German clinics with those of 342 controls from the same neighborhood or region. Data were gathered with a structured interview and a self-administered food-frequency questionnaire, and analyzed using multivariate conditional logistic regression to control for educational status and cigarette smoking. There was no significant difference between cases and controls in the consumption of fruits and vegetables, although there was a negative trend for the consumption of raw vegetables. Controls reported a higher potato consumption than patients (OR = 0.43, 95% confidence interval [CI]: 0.24-0.74, highest versus lowest quartile). Patients reported eating significantly larger quantities of sweet foods as well as having more snacks than controls. This may, however, be the result of an illness-related change in dietary habits leading to a selective recall effect, since sweet foods may enhance the transport of L-dopa across the blood-brain barrier. We also found that patients consumed less beer (OR = 0.26, 95% CI: 0.14-0.49) and spirits (OR = 0.56, 95% CI: 0.36-0.86), but not wine, and they consumed less coffee (OR = 0.27, 95% CI: 0.14-0.52, highest versus lowest quartile), but not tea, than controls. This may relate to a possible interaction between dopaminergic activity and the intake of ethanol or caffeine. Significantly more patients than controls reported ever consuming raw meat (OR = 1.78, 95% CI: 1.21-2.63). These results suggest that the intake of certain foods may be associated with the development of PD.

Case-Control Studies↗

PubMed1996

Diet and Parkinson's disease. II: A possible role for the past intake of specific nutrients. Results from a self-administered food-frequency questionnaire in a case-control study.

In a case-control study, we compared the past dietary habits of 342 Parkinson's disease (PD) patients recruited from nine German clinics with those of 342 controls from the same neighborhood or region. Data were gathered with a structured interview and a self-administered food-frequency questionnaire. Nutrient intakes were calculated from the reported food intakes through linkage with the German Federal Food Code and analyzed using multivariate conditional logistic regression to control for total energy intake, educational status, and cigarette smoking. At the macronutrient level, patients reported higher carbohydrate intake than controls after adjustment for total energy intake, smoking, and educational status (OR = 2.74, 95% confidence interval [CI]: 1.30-6.07, for the highest versus lowest quartile, p trend = 0.02). This was reflected in higher monosaccharide and disaccharide intakes at the nutrient level. There was no difference between patients and controls in protein and fat intake after adjustment for energy intake. We found an inverse association between the intakes of beta-carotene (OR = 0.67, 95% CI: 0.37-1.19, p trend = 0.06) and ascorbic acid (OR = 0.60, 95% CI: 0.33-1.09, p trend = 0.04) by patients, although only the trend for ascorbic acid intake reached statistical significance. There was no difference between groups for alpha-tocopherol intake after adjustment for energy intake. We also found that patients reported a significantly lower intake of niacin than controls (OR = 0.15, 95% CI: 0.07-0.33, p trend < 0.00005). Our results suggest that if antioxidants play a protective role in this disease, the amounts provided by diet alone are insufficient. Although the interpretation of the inverse association between niacin intake and PD is complicated by the high niacin content in coffee and alcoholic beverages, which were also inversely associated with PD in this study, the strength of this association and its biologic plausibility warrant further investigation.

Case-Control Studies↗

PubMed2004

An application of meta-analysis in food safety consumer research to evaluate consumer behaviors and practices.

Meta-analysis provides a structured method for combining results from several studies and accounting for and differentiating between study variables. Numerous food safety consumer research studies often focus on specific behaviors among different subpopulations but fail to provide a holistic picture of consumer behavior. Combining information from several studies provides a broader understanding of differences and trends among demographic subpopulations, and thus, helps in developing effective risk communication messages. In the illustrated example, raw/undercooked ground beef consumption and hygienic practices were evaluated according to gender, ethnicity, and age. Percentages of people engaging in each of the above behaviors (referred to as effect sizes) were combined using weighted averages of these percentages. Several measures, including sampling errors, random variance between studies, sample sizes of studies, and homogeneity of findings across studies, were used in the meta-analysis. The statistical significance of differences in behaviors across demographic segments was evaluated using analysis of variance. The meta-analysis identified considerable variability in effect sizes for raw/undercooked ground beef consumption and poor hygienic practices. More males, African Americans, and adults between 30 and 54 years (mid-age) consumed raw/undercooked ground beef than other demographic segments. Males, Caucasians, and Hispanics and young adults between 18 and 29 years were more likely to engage in poor hygienic practices. Compared to traditional qualitative review methods, meta-analysis quantitatively accounts for interstudy differences, allows greater consideration of data from studies with smaller sample sizes, and offers ease of analysis as newer data become available, and thus, merits consideration for its application in food safety consumer research.

Adult↗