Plasma metabolite biomarkers of boiled and filtered coffee intake and their association with type 2 diabetes risk.

BACKGROUND: Habitual coffee intake has been associated with a lower risk of developing type 2 diabetes (T2D), but few studies used biomarkers to reflect intake and investigated different coffee brews, that is boiled and filtered, separately. OBJECTIVES: To identify plasma metabolites associated with boiled or filtered coffee intake and to examine their association with T2D risk in Swedish adults. METHODS: In a case-control study nested within the Västerbotten Intervention Programme, baseline plasma samples from 421 case-control pairs and samples from a subset of 149 pairs at a 10-year follow-up were analysed using untargeted LC-MS metabolomics. We identified metabolites associated with food frequency questionnaires (FFQ)-estimated coffee intake and assessed odds ratios of T2D. RESULTS: In total, 24 and 32 metabolites were associated with boiled or filtered coffee intake. We determined robust metabolite panels for highly specific prediction of boiled or filtered coffee. We observed an inverse association between the metabolite panel of filtered coffee and T2D risk. No association with T2D was observed for the panel of boiled coffee intake. Similar results were observed for FFQ-estimated coffee intake. CONCLUSIONS: We identified plasma metabolites specifically associated with boiled or filtered coffee intake, which might be used as selective biomarkers. Our study supports a protective role of habitual intake of filtered coffee on T2D development. The lack of association for boiled coffee intake might be due to the lack of a protective effect of boiled coffee or due to the limited number of boiled coffee consumers in this population, but it warrants further investigation.

Intracellular glutathione determines bortezomib cytotoxicity in multiple myeloma cells.

Multiple myeloma (myeloma in short) is an incurable cancer of antibody-producing plasma cells that comprise 13% of all hematological malignancies. The proteasome inhibitor bortezomib has improved treatment significantly, but inherent and acquired resistance to the drug remains a problem. We here show that bortezomib-induced cytotoxicity was completely dampened when cells were supplemented with cysteine or its derivative, glutathione (GSH) in ANBL-6 and INA-6 myeloma cell lines. GSH is a major component of the antioxidative defense in eukaryotic cells. Increasing intracellular GSH levels fully abolished bortezomib-induced cytotoxicity and transcriptional changes. Elevated intracellular GSH levels blocked bortezomib-induced nuclear factor erythroid 2-related factor 2 (NFE2L2, NRF2)-associated stress responses, including upregulation of the xCT subunit of the Xc- cystine-glutamate antiporter. INA-6 cells conditioned to increasing bortezomib doses displayed reduced bortezomib sensitivity and elevated xCT levels. Inhibiting Xc- activity potentiated bortezomib-induced cytotoxicity in myeloma cell lines and primary cells, and re-established sensitivity to bortezomib in bortezomib-conditioned cells. We propose that intracellular GSH level is the main determinant of bortezomib-induced cytotoxicity in a subset of myeloma cells, and that combined targeting of the proteasome and the Xc- cystine-glutamate antiporter can circumvent bortezomib resistance.

Impact of thearubigins on the estimation of total dietary flavonoids in the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

Thearubigins (TR) are polymeric flavanol-derived compounds formed during the fermentation of tea leaves. Comprising ∼70% of total polyphenols in black tea, TR may contribute majorly to its beneficial effects on health. To date, there is no appropriate food composition data on TR, although several studies have used data from the US Department of Agriculture (USDA) database to estimate TR intakes. We aimed to estimate dietary TR in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort and assess the impact of including TR or not in the calculation of the total dietary flavonoid intake. Dietary data were collected using a single standardized 24-h dietary recall interviewer-administered to 36 037 subjects aged 35-74 years. TR intakes were calculated using the USDA database. TR intakes ranged from 0.9 mg/day in men from Navarra and San Sebastian in Spain to 532.5 mg/day in men from UK general population. TR contributed <5% to the total flavonoid intake in Greece, Spain and Italy, whereas in the UK general population, TR comprised 48% of the total flavonoids. High heterogeneity in TR intake across the EPIC countries was observed. This study shows that total flavonoid intake may be greatly influenced by TR, particularly in high black tea-consuming countries. Further research on identification and quantification of TR is needed to get more accurate dietary TR estimations.

Dietary intakes and food sources of phytoestrogens in the European Prospective Investigation into Cancer and Nutrition (EPIC) 24-hour dietary recall cohort.

BACKGROUND/OBJECTIVES: Phytoestrogens are estradiol-like natural compounds found in plants that have been associated with protective effects against chronic diseases, including some cancers, cardiovascular diseases and osteoporosis. The purpose of this study was to estimate the dietary intake of phytoestrogens, identify their food sources and their association with lifestyle factors in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. SUBJECTS/METHODS: Single 24-hour dietary recalls were collected from 36,037 individuals from 10 European countries, aged 35-74 years using a standardized computerized interview programe (EPIC-Soft). An ad hoc food composition database on phytoestrogens (isoflavones, lignans, coumestans, enterolignans and equol) was compiled using data from available databases, in order to obtain and describe phytoestrogen intakes and their food sources across 27 redefined EPIC centres. RESULTS: Mean total phytoestrogen intake was the highest in the UK health-conscious group (24.9 mg/day in men and 21.1 mg/day in women) whereas lowest in Greece (1.3 mg/day) in men and Spain-Granada (1.0 mg/day) in women. Northern European countries had higher intakes than southern countries. The main phytoestrogen contributors were isoflavones in both UK centres and lignans in the other EPIC cohorts. Age, body mass index, educational level, smoking status and physical activity were related to increased intakes of lignans, enterolignans and equol, but not to total phytoestrogen, isoflavone or coumestan intakes. In the UK cohorts, the major food sources of phytoestrogens were soy products. In the other EPIC cohorts the dietary sources were more distributed, among fruits, vegetables, soy products, cereal products, non-alcoholic and alcoholic beverages. CONCLUSIONS: There was a high variability in the dietary intake of total and phytoestrogen subclasses and their food sources across European regions.

Validity of food frequency questionnaire estimated intakes of folate and other B vitamins in a region without folic acid fortification.

BACKGROUND/OBJECTIVES: B vitamins have been implicated in major chronic diseases but results have been inconsistent. This study evaluated the accuracy of dietary intakes of folate, vitamin B12, riboflavin and vitamin B6 as measured by the Northern Sweden Food Frequency Questionnaire (FFQ) against repeated 24-h recalls (24HR) and plasma levels, taking into consideration the MTHFR 677C>T polymorphism. SUBJECTS/METHODS: B vitamin intakes assessed by a semi-quantitative FFQ designed to measure the intake over the previous year were compared with those from 10 24HR, as well as to plasma levels of folate and vitamin B12, in randomly selected men (n=96) and women (n=99) aged 30-60 years. FFQ-based B-vitamin intakes were also compared with plasma levels of B-vitamins and with MTHFR 677C4T genotype in 878 men, aged 40-61 years. RESULTS: Intakes of vitamins B12 and riboflavin were similar, whereas folate and B6 intakes were 16-27% higher, as estimated by FFQ versus 24HR. Spearman correlation coefficients between the two methods ranged from 0.31 to 0.63 (all P

Variation in intakes of calcium, phosphorus, magnesium, iron and potassium in 10 countries in the European Prospective Investigation into Cancer and Nutrition study.

BACKGROUND/OBJECTIVES: Adequate mineral intake is important for the maintenance of bone health, cellular function and general metabolism, and possibly in the aetiology of cancer and other chronic diseases. This study aimed at investigating variation in intakes of selected minerals across 10 European countries participating in the EPIC (European Prospective Investigation into Cancer and Nutrition) study. METHODS: Nutrient intakes for 36 034 subjects, aged between 35 and 74 years, in 27 centres were obtained using standardized 24-h dietary recall software (EPIC-SOFT). Mean intakes of calcium, phosphorus, magnesium, iron and potassium were calculated by centre and weighted by season and day of the week and were also stratified by age group. The contribution of food groups to total nutrient intake was calculated. RESULTS: There was clear geographical variability in intakes, with differences ranging from 35% for magnesium to 90% for iron in men and 36% for potassium to 75% for calcium in women, and a twofold difference in sources of haem iron (meat and fish). There was a geographical gradient in iron intake, with higher intakes in Southern than in Northern Europe and also around a twofold north-south gradient in the contribution of fruits and vegetables to potassium intake. Compared with reference intakes, the majority of age groups and centres had intakes above the recommended levels. Dairy foods and products contributed the most to calcium and phosphorus intake in almost all centres. Cereals and cereal products contributed the most to magnesium and iron intakes, except in Greece and Germany. CONCLUSIONS: Intakes of minerals vary substantially throughout Europe, with some geographical variability in their food sources.

Plasma folate and total homocysteine levels are associated with the risk of myocardial infarction, independently of each other and of renal function.

OBJECTIVES: To investigate the relationship between plasma folate, vitamin B12 and total homocysteine concentrations, dietary intake of folate and vitamins B12, B6 and B2, and the risk of first acute myocardial infarction (MI). DESIGN: Nested case-referent study with up to 13 years of follow-up. SETTING: The population-based Northern Sweden Health and Disease Study, with 73 879 participants at the time of case ascertainment. SUBJECTS: A total of 571 MI cases (406 men) and 1569 matched referents. Of the cases, 530 had plasma samples available, and 247 had dietary B-vitamin intake data. RESULTS: Plasma concentrations of folate were inversely associated, and total homocysteine positively associated, with the risk of MI, independently of each other and of a number of established and novel cardiovascular risk factors, including renal function [multivariate odds ratio for highest vs. lowest quintile of folate 0.52 (95% CI 0.31-0.84), P for trend = 0.036, and homocysteine 1.92 (95% CI 1.20-3.09), P for trend = 0.006]. For plasma vitamin B12 concentrations, and vitamin B12, B6 and B2 intake, no clear risk relationship was apparent. Though not statistically significant, the results for folate intake were consistent with those for plasma concentrations. CONCLUSIONS: In this large prospective study of a population without mandatory folic acid fortification, both folate and homocysteine were strongly associated with the risk of myocardial infarction, independently of each other and of renal function. Although randomized trials of folic acid supplementation are needed to determine causality, our findings highlight the potential importance of folate, or sources of folate, in incident cardiovascular disease.

Children with Down Syndrome: oral development and morphology after use of palatal plates between 6 and 18 months of age.

OBJECTIVES: The aim of this study was to describe oral development and morphology in 18-month-old children with Down syndrome (DS) treated with palatal plates in combination with structured communication and speech training. The aim is further to describe the design of the palatal plates, compliance in their use and to give a brief report of their effect on oral motor function and speech. SAMPLE AND METHODS: Forty-two children with DS were followed from < or = 6 months of age until 18+/-3 months old. In addition to language intervention, and oral motor and sensory stimulation provided by speech therapists for all children with DS in Sweden, palatal plates provided by dentists are included in the training programme. In the evaluation, the children in the project were compared with two control groups of children matched for age; one group of children with DS who had not been treated with palatal plates, and one group of children with normal development. RESULTS: Compared to the children with normal development, both groups of children with DS had fewer teeth erupted and a lower prevalence of sucking habits. Deviant morphology of the tongue in the form of diastase, lingua plicata or a sulcus in the anterior third of the tongue was only seen in children with DS. All children with normal development had positive values for overjet compared to 53% of the children with DS. The palatal plates were used 2-3 times daily for a total mean time of 15 min. Compliance in use of the plates decreased with age, mainly due to eruption of teeth and subsequent loss of retention. Evaluation of oral motor function and speech show that the children with DS in the project had better motor prerequisites for articulation than the control children with DS. CONCLUSION: Palatal plate therapy did not affect oral parameters, i.e., eruption of teeth, types and prevalence of sucking habits, tongue morphology and symptoms of hypotonia. In combination with oral motor and sensory stimulation, palatal plate therapy had a positive effect on oral motor performance and prerequisites for articulation.

Hepatotoxicity induced by iron overload and alcohol. Studies on the role of chelatable iron, cytochrome P450 2E1 and lipid peroxidation.

BACKGROUND/AIMS: Clinical experience and studies with experimental animal models indicate a synergistic hepatotoxic effect of dietary iron overload and chronic alcohol ingestion. In order to elucidate the mechanism underlying this synergism, we examined the hepatic levels of ethanol-inducible cytochrome P450 2E1, glutathione and malondialdehyde, and the effect of iron chelation with desferrioxamine, in livers from rats treated with iron and/or ethanol. METHODS: Animals received diets with or without 2.5-3% carbonyl iron for 6-9 weeks, followed by an ethanol-containing diet or a liquid control diet for 5-9 weeks. Desferrioxamine was administered subcutaneously with mini-osmotic pumps. Alanine aminotransferase activity in serum and hepatic contents of glutathione and malondialdehyde were determined. The hepatic level of cytochrome P450 2E1 was determined with Western Blotting using a specific polyclonal antibody. RESULTS: The combination of iron and alcohol led to a marked increase in serum alanine aminotransferase activity as compared with all other treatment groups, and iron chelation with desferrioxamine reversed these increases. Treatment with alcohol alone led to slightly increased aminotransferases compared with controls. The level of cytochrome P450 2E1 was significantly elevated in microsomes isolated from ethanol-treated rats, but neither additional iron supplementation nor desferrioxamine influenced this level significantly. Glutathione contents were increased in the livers of animals treated with iron and/or ethanol. Malondialdehyde values were increased in iron-treated animals, whereas neither ethanol nor desferrioxamine altered malondialdehyde levels significantly. CONCLUSIONS: The toxic effects exerted by the combination of iron overload and chronic ethanol feeding on rat liver are dependent on a pool of chelatable iron. The hepatic level of cytochrome P450 2E1 is markedly induced by ethanol but not further altered by iron overload. Neither increased lipid peroxidation nor depletion of hepatic glutathione levels can explain the synergistic hepatotoxic effects of iron and ethanol in this model.

The major integral proteins of spinach leaf plasma membranes are putative aquaporins and are phosphorylated in response to Ca2+ and apoplastic water potential.

We show that homologs of the major intrinsic protein (MIP) family are major integral proteins of the spinach leaf plasma membrane and constitute approximately 20% of integral plasma membrane protein. By using oligonucleotide primers based on partial amino acid sequences for polymerase chain reaction and screening of a spinach leaf cDNA library, we obtained two full-length clones of MIP homologs (pm28a and pm28b). One of these clones, pm28a, was sequenced, and it encodes a protein (PM28A) of 281 amino acids with a molecular mass of 29.9 kD. DNA gel blots indicated that PM28A is the product of a single gene, and RNA gel blots showed that pm28a is ubiquitously expressed in the plant. In vivo phosphorylation of the 28-kD polypeptide(s), corresponding to PM28A and PM28B, was dependent on apoplastic water potential, suggesting a role in regulation of cell turgor for these putative aquaporins. In vitro, only one of the homologs, PM28A, was phosphorylated. Phosphorylation of PM28A occurred on Ser-274, seven amino acids from the C terminus of the protein, within a consensus phosphorylation site (Ser-X-Arg) for vertebrate protein kinase C. In vitro phosphorylation of PM28A was due to a plasma membrane-associated protein kinase and was strictly dependent on submicromolar concentrations of Ca2+.

Impact of medical and life-style factors on number of teeth in 68-year-old men in southern Sweden.

The aim of the present study was to investigate the impact of general health and life-style factors on the number of remaining teeth in 68-year-old men living in the city of Malmö, Sweden. The study included 483 men (participation rate, 78%). Poor self-assessed health, frequent medical attendance, diabetes, and oral dryness were related to fewer remaining teeth. Number of teeth was negatively correlated to concentrations of triglycerides and alkaline phosphatases in serum and to glucose in blood but positively correlated to serum urea. Various dietary variables including consumption of sucrose-containing products and nutritional quality were not related either to number of teeth or to prevalence of edentulousness. Smoking and high consumption of coffee or alcohol were associated with fewer remaining teeth. Multiple logistic regression analyses showed that social class, frequency of dental attendance, smoking, and serum concentrations of triglycerides and urea had an independent effect on number of teeth.

Can alpha-tocopherol and beta-carotene supplementation reduce adverse radiation effects on salivary glands?

In this study, we evaluated whether supplementation with antioxidant vitamins can reduce the adverse effects of irradiation on the salivary glands in the rat. Four groups of adult Sprague-Dawley rats were given a basic diet providing 0.6 mg alpha-tocopherol and no beta-carotene per day. In two groups the basic diet was supplemented with 3.4 mg alpha-tocopherol and 6 mg beta-carotene per day from 14 days before irradiation until 12 days after completed irradiation. One group of rats given basic diet and one group given supplemented diet were irradiated with 7 Gy daily for five consecutive days. Isoproterenol and pilocarpine-stimulated whole saliva was collected from all rats 2, 4 and 26 weeks after irradiation. Vitamin-supplemented irradiated rats had higher secretion rates on all three occasions compared with those of irradiated rats given basic diet. The changes in saliva composition seen in irradiated rats were less accentuated in vitamin-supplemented, irradiated rats. The proportions of acinar cells were significantly decreased both in parotid and submandibular glands 26 weeks after irradiation. Supplementation with alpha-tocopherol and beta-carotene did not alter the morphology of the glands.

Effect of saliva composition on growth of Candida albicans and Torulopsis glabrata.

Candida albicans and Torulopsis glabrata are the most prevalent yeasts in humans. The majority harbor C. albicans in the oral cavity, but only a few develop oral candidiasis. We have sought a possible relationship between indigenous salivary constituents, including antimicrobial and nutritive factors, and the growth rate and/or viability of inoculated fungi in glucose-supplemented sterilized saliva. Stimulated whole saliva was collected from 30 healthy donors. Saliva samples were sterilized, supplemented with glucose and inoculated with C. albicans or T glabrata. After incubation of the inoculates for 20 h, the number of viable cells were counted. All saliva samples were analyzed for different indigenous salivary components and Candida before as well as after sterilization. Besides a 4% reduction in calcium (Ca2+) and thiocyanate (SCN-) concentrations, sterilization did not affect the concentrations of saliva electrolytes, but the proteins were significantly reduced (19-85%). Indigenous candidal carriage (n=19) correlated with neither the growth of inoculated fungi nor any of the analyzed components in saliva. The growth of C. albicans and T. glabrata was similar at pH 5 but, at pH 6, C. albicans had a remarkably slower growth rate than T. glabrata. Statistical analysis showed that the 5-h growth of C. albicans at pH 5 was associated with water and electrolyte secretion, whereas the growth after 20 h was associated with variations in protein-glycoprotein content. The growth of T. glabrata was not related to variations in the salivary variables analyzed.

Kinetic studies of pea carbonic anhydrase.

Chloroplast carbonic anhydrase from Pisum sativum has been isolated. The kinetic properties of the enzyme have been studied and comparisons to the well characterised human carbonic anhydrase II made. Pea carbonic anhydrase was found to be dependent on a reducing agent in order to retain the catalytic activity. Oxidised, inactive, enzyme could be activated by the addition of a SH-agent. However, such activation gave only 60% of the activity of an enzyme kept in a reduced state all the time. The kinetics of CO2 hydration show an increase in kcat as well as in kcat/Km with pH, but the pH profile does not follow a simple titration curve. The pH dependence is more complicated and it seems as if there are several titratable groups affecting the activity. At pH 9 we obtain a turnover number of 4 x 10(5) s-1 and a kcat/Km value of 1.8 x 10(8) M-1 s-1 with reference to the subunit. We also find that the enzyme needs high concentrations of buffer to work at a maximal rate. Apparent Km values with respect to the total buffer concentration are found between 52-185 mM at neutral and high pH. At low pH the situation is complex with deviations from Michaelis-Menten kinetics. Chloroplast carbonic anhydrase from higher plants have been reported to have primary structures that are completely different from the enzyme from animals. In addition, we find the circular dichroic spectrum of pea carbonic anhydrase to be well distinguished from that of human carbonic anhydrase II. Despite those structural differences the kinetic parameters indicate that pea carbonic anhydrase is equally efficient as human carbonic anhydrase II in catalysing the hydration of CO2. However, the mechanism for proton transfer from the active site to the surrounding medium seems to differ between the two enzymes.

Population studies in northern Sweden. 18. Geographical covariation between hypercholesterolemia and Finnish genetic influence.

The population of northern Sweden shows a marked ethnic heterogeneity and a unique distribution of disorders with a monogenic or polygenic background, among them cardiovascular diseases. We have studied variations between 23 North Swedish subpopulations (regions) with respect to hypercholesterolemia and its possible determinants including dietary factors, obesity and the degree of Finnish genetic influence. A significant regional heterogeneity was found concerning hypercholesterolemia, obesity and high consumption of 'boiled' coffee. Hypercholesterolemia showed significant geographical covariations with Finnish genetic influence and consumption of 'boiled' coffee. The results are consistent with the hypothesis that in addition to environmental factors Finnish genetic influence contributes to the development of hypercholesterolemia and thereby to the increased rate of cardiovascular disease found in northern Sweden.

Processing of the chloroplast transit peptide of pea carbonic anhydrase in chloroplasts and in Escherichia coli. Identification of two cleavage sites.

The chloroplast transit peptide (cTP) of pea carbonic anhydrase was shown to be processed at two different sites, giving protein subunits of two sizes. The cleavage sites were identified and found to be localized immediately before and after a highly charged part, containing 8 acidic and 6 basic residues, of the cTP. Properties of pea carbonic anhydrase produced in Escherichia coli show that folding, oligomerization and catalytic activity do not depend on the presence of the acidic part or the rest of the cTP. The pattern of processing of the cTP in E. coli indicates that cleavage at site I is specific for a chloroplastic stromal peptidase and that cleavage at site I prevents processing at site II.

Coffee drinking and blood cholesterol--effects of brewing method, food intake and life style.

The strongest correlations between coffee consumption and serum cholesterol levels have been found in countries where people drink coffee brewed by mixing coffee grounds directly in boiling water (boiled coffee). In the present study of a population-based sample of 1625 middle-aged subjects (the Northern Sweden MONICA Study), approximately 50% of the participants were drinking boiled coffee, and 50% were drinking filtered coffee. Consumers of boiled coffee had significantly higher serum cholesterol levels than consumers of filtered coffee. Subjects who drank boiled coffee reported a higher intake of fat. A linear multiple regression analysis with serum cholesterol as the dependent variable confirmed that boiled coffee was an important independent determinant of cholesterol levels. We conclude that subjects who drink boiled coffee have higher serum cholesterol levels than those who drink filtered coffee, and that the most likely explanation for this finding lies in the type of brewing method.

Acute radiation effects on saliva composition in rats with different vitamin A levels in serum.

Irradiation of the head and neck often causes loss of salivary gland function which may lead to severe oral discomfort. The effects of a single dose of 25 Gy given to rats with different serum levels of vitamin A were studied. The salivary secretion rate as well as concentrations of protein, hexosamine, amylase and electrolytes, and the activities of two antibacterial glycoproteins were measured. At an adequate level of vitamin A in the diet, irradiation significantly reduced whole saliva secretion rate, and decreased the concentration of salivary sodium, calcium and hexosamine as well as the activity of a glycoprotein agglutinating a serotype c strain of S. mutans. Peroxidase, amylase and potassium were not significantly affected. The reductions seen at an adequate level of vitamin A were not reduced by supplementation of excess dietary retinol. The damage caused by irradiation was enhanced by vitamin A deficiency as seen in the reduced protein and hexosamine concentrations.

Selenium and vitamin E treatment of Duchenne muscular dystrophy: no effect on muscle function.

16 boys with Duchenne muscular dystrophy (DMD) were treated with sodium selenite and vitamin E for one year. One group of patients (10 boys) was examined using a battery of tests to assess muscular strength and function and cardiopulmonary function, and by CT scanning of 2 muscle groups over the 4 years prior to treatment. Six boys with DMD entered the study when the treatment was begun. Tests of muscular force and function, cardiopulmonary tests and CT-scanning were performed at the onset of treatment, and after 6 and 12 months. No beneficial effect on either muscular force or function was found during the treatment period. It is concluded that selenium and vitamin E in high doses do not improve muscle function in DMD.

Saliva concentrations of some selected proteins and glycoprotein markers in man after supplementary intake of beta-carotene.

Vitamin A has profound effects on cell biology, morphology and function of excretory cells. In the present study we investigated the effect of supplementation with beta-carotene (provitamin A) on the secretion of salivary glycoproteins and some antibacterial components. Eighty-nine men, drawn from a larger double-blind pilot study among Finnish men of a high socio-economic standard, participated in this study which lasted for 60 days. The men were allocated either to beta-carotene supplementation of 20 mg a day or to placebo treatment. At the end of the study samples of stimulated whole and parotid saliva were collected and examined for total protein as well as hexosamine, sialic acid, thiocyanate and the activity of salivary peroxidase. The secretion rate of whole saliva was calculated and the activities of lysozyme, a bacteria aggregating glycoprotein (BAGP) and secretory IgA were measured in parotid saliva. Significantly higher levels of beta-carotene, but not retinol, were found in serum and whole saliva in the beta-carotene group compared to the placebo group. Retinol or beta-carotene could not be detected in parotid saliva. No difference was found either in saliva secretion rate or in the composition of whole or parotid saliva between the beta-carotene and the placebo group.