RRR-α-tocopheryl succinate inhibits human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesis arrest

AIM:To investigate the effects of growth inhibition ofhuman gastric cancer SGC-7901 cell with RRR-α-tocopherylsuccinate(VES),a derivative of natural Vitamin E,viainducing apoptosis and DNA synthesis arrest.METHODS:Human gastric cancer SGC-7901 cells wereregularly incubated in the presence of VES at 5,10 and20mg.L^(-1)(VES was dissolved in absolute ethanol anddiluted in RPMI 1640 complete condition mediacorrespondingly to a final concentration of VES and lmL.L^(-1)ethanol),succinic acid and ethanol equivalents asvehicle(VEH)control and condition-media only asuntreated(UT)control.Trypan blue dye exclusionanalysis and MTT assay were applied to detect the cellproliferation.37kBq of tritiated thymidine was added tocells and [~3H]TdR uptake was measured to observe DNAsynthesis.Apoptotic morphology was observed byelectron microscopy and DAPI staining.Flow cytometryand terminal deoxynucleotidyl transferase-mediated dUTPnick end labeling(TUNEL)assay were performed to detectVES-triggered apoptosis.RESULTS:VES inhibited SGC-7901 cell growth in a dose-dependent manner.The growth curve showed suppressionby 24.7%,49.2% and 68.7% following 24h of VEStreatment at 5,10 and 20 mg·L^(-1),respectively,similar tothe findings from MTT assay.DNA synthesis wasevidently reduced by 35%,45% and 98% after 24h VEStreatment at 20 mg·L^(-1)and 48h at 10 and 20 mg·L^(-1),respectively.VES induced SGC-7901 cells to undergoapoptosis with typically apoptotic characteristics,including morphological changes of.chromatincondensation,chromatincrescent formation/margination,nucleus fragmentation and apoptotic body formation,typical apoptotic sub-G1 peak by flow cytometry andincrease of apoptotic cells by TUNEL assay in which 90%of cells underwent apoptosis after 48h of VES treatment at20 mg·L^(-1).CONCLUSION:VES can inhibit human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesisarrest,inhibition of SGC-7901 cell growth by VES is dose-and time-dependent.Therefore VES can function as apotent chemotherapeutic agent against human gastric carcinogenesis.

Effects of vitamin E succinate on the expression of Fas and PCNA proteins in human gastric carcinoma cells and its clinical significance

AIM: To investigate the effects of vitamin E succinate (VES) on the expression of Fas and PCNA proteins as well as its clinical significance in human gastric carcinoma, and to explore the mechanism of VES-induced inhibition of gastric carcinoma cell growth. METHODS: Immunohistochemical methods were used to detect Fas and PCNA expression both in human gastric cancer SGC-7901 cells treated with VES at different doses and in human gastric carcinoma tissues. RESULTS: After the SGC-7901 cells were treated with VES at 5, 10, 20 mg/L for 48 h, the positive rates of Fas expression were 16%, 27% and 48%, respectively, significantly increased compared to that of control group (P<0.05); while the positive rates of PCNA expression in groups treated with different doses of VES were 20%, 18% and 7%, respectively, which were significantly decreased compared to that of the control group (P<0.05). In human gastric carcinoma tissues, the Fas positive expression rate was 42.4%(25/59), which declined with the decrease in the degree of tumor differentiation (P<0.05) and with the existence of lymph node metastasis (P<0.001). While the PCNA positive expression rate was 91.5%(54/59), no relationship was observed between PCNA expression and clinicopathologic parameters. CONCLUSION: VES inhibited the growth of gastric cancer cells by indudng Fas expression and inhibiting PCNA expression. It is, therefore, considered that the expression of Fas and PCNA genes, through tumor cell apoptosis and proliferation, respectively, may be useful as a clinical predictive index in the application of VES to gastric carcinoma therapy, where as Pas may be of more value than PCNA.

Inhibition of conjugated linoleic acid on mouse forestomach neoplasia induced by benzo(a)pyrene and chemopreventive mechanisms

AIM: To explore the inhibition of conjugated linoleic acidisomers in different purity (75 % purity c9,t11-, 98 % purityc9,t11- and 98 % purity t10,c12-CLA) on the formation offorestomach neoplasm and cheopreventive mechanisms.METHODS: Forestomach neoplasm model induced by B(a)P in KunMing mice was established. The numbers of tumorand diameter of each tumor in forestomach were counted;the mice plasma malondialdehyde (MDA) were measuredby TBARS assay; TUNEL assay was used to analyze theapoptosis in forestomach neoplasia and the expression ofMEK-1, ERK-1, MKP-1 protein in forestomach neoplasm werestudied by Western Blotting assay.RESULTS: The incidence of neoplasm in B(a)P group, 75 %purity c9, t11-CLA group, 98 % purity cg,t11-CLA groupand 98 % purity t10, c12-CLA group was 100 %, 75.0 %(P＞0.05), 69.2 % (P＜0.05) and 53.8 % (P＜0.05) respectivelyand the effect of two CLA isomers in 98 % purity onforestomach neoplasia was significant; CLA showed noinfluence on the average tumor numbers in tumor-bearingmouse, but significantly decreased the tumor size, the tumoraverage diameter of mice in 75 % purity c9,t11-CLA group,98 % purity cg,t11-CLA group and 98 % purity t10, c12-CLAgroup was 0.157±0.047 cm, 0.127±0.038 cm and 0.128±0.077 cm (P＜0.05) and 0.216±0.088 cm in B(a)P group;CLA could also significantly increase the apoptosis cellnumbers by 144.00±20.31, 153.75±23.25, 157.25±15.95(P＜0.05) in 75 % purity c9,t11-CLA group, 98 % purity c9,t11-CLA group and 98 % purity t10,c12-CLA group (30.88±3.72 in BP group); but there were no significant differencesbetween the effects of 75 % purity c9,t11-CLA and twoisomers in 98 % purity on tumor size and apoptotic cellnumbers; the plasma levels of MDA in were increased by75 % purity c9,t11-ClA, 98 % purity c9,t11-CLA and 98 %purity t10,c12-CLA. The 75 % purity c9,t11-CLA showedstronger inhibition; CLA could also inhibit the expression ofERK-1 protein and promote the expression of MKP-1 protein,however no influence of CLA on MEK-1 protein was observed.CONCLUSION: Two isomers in 98 % purity show strongerinhibition on carcinogenesis. However, the inhibitorymechanisms of CLA on carcinogenesis is complicated, whichmay be due to the increased mice plasmaMDA, the inducingapoptosis in tumor tissues. And the effect of CLA on theexpression of ERK-1 and MKP-1 may be one of themechanisms of the inhibition of CLA on the tumor.

Polymorphism of Methionine Synthase Gene in Nuclear Families of Congenital Heart Disease

Objective To investigate the relation of methionine synthase (MS) gene variation with congenital heart disease (CHD) phenotype. Methods One hundred and ninety three CHD patients (94 males and 99 females) and their biological parents (nuclear families) in Liaoning Province were selected as the case group, and another 104 normal persons (60 males and 44 females) and their parents without family history of birth defects as the control group. For all subjects the polymorphism of MS gene A2756G locus was examined by PCR-RFLP method. Results In offspring of the control group the frequencies of MS genotype (+/ -) and allele (+) were 10.7% and 5.3%, without existence of homozygote. The MS genotype distribution and allele frequencies of CHD patients and their mothers were not significantly different from the control (P > 0.05). The frequency of allele (+) in case fathers (5.0 %) was apparently lower than that in the control (9.1%, P=0.060), and the odds ratio (OR) was 0.53 (95% CI: 0.25-1.09). There was no difference in parents' genotype combination between the two groups, and in genotype distribution among different types of CHD. Analysis of genetic transmission indicated that mutation allele (+) existed transmission disequilibrium in CHD nuclear families. The percentage of allele (+) transmitted from parents was lower than that allele (-) with OR 0.26 (95% CI: 0.11-0.60). Conclusion MS gene variation in parents is associated with occurrence of CHD in offspring, and mutation allele (+) in parents may be related with the decrease of CHD risk in offspring.

Relationship Between Polymorphism of Methylenetetrahydrofolate Dehydrogenase and Congenital Heart Defect

To investigate the relationship between G1958A gene polymorphism of methylenetetrahydrofolate dehydrogenase (MTHFD) and occurrence of congenital heart disease (CHD) in North China. Methods One hundred and ninety-two CHD patients and their parents were included in this study as case group in Liaoning Province by birth defect registration cards, and 124 healthy subjects (age and gender matched) and their parents were simultaneously selected from the same geographic area as control. Their gene polymorphism of MTHFD G1958A locus was examined with PCR-RFLP, and serum folic acid and homocysteine (Hcy) levels were tested with radio-immunoassay and fluorescence polarization immunoassay (FPIA). Results There existed gene polymorphism at MTHFD G1958A locus in healthy subjects living in North China. The percentages of GG, GA, and AA genotype were 57.98%, 35.57%, and 6.45% respectively, and the A allele frequency was 24.23%, which was significantly different from Western population. No difference was observed when comparing genotype distribution and allele frequency between the case and control groups, so was the result from the comparison between genders. The A allele frequency of arterial septal defect patients’ mothers (10.87%) was significantly lower than that of controls (28.15%) (P=0.014), with OR=0.31 (95% CI: 0.09-0.84), and no difference in the other subgroups. The percentage of at least one parent carrying A allele in arterial septal defect subgroup (43.48%) was significantly lower than that in controls (69.64%) (P=0.017), with OR=0.34 (95% CI: 0.12-0.92). The analysis of genetic transmission indicated that there was no transmission disequillibrium in CHD nuclear families. Their serum folic acid level was significantly higher than that of controls (P=0.000), and Hcy level of the former was higher than that of the latter with no statistical significance (P>0.05). Serum Hcy and folic acid levels of mothers with gene mutation were lower than those of mothers with no mutation. Conclusion No significant difference of genotype distribution and allele frequency existed between CHD patients and healthy population. MTHFD G1958A mutation in parents (particularly in mother) can decrease the risk of arterial septal defect in offspring. The possible mechanism of protection might be mutation, which can increase MTHFD enzyme activity, folic acid metabolism and homocysteine remethylation, and decrease Hcy level.

Inhibitory effects of c9, t11-conjugated linoleic acid on invasion of human gastric carcinoma cell line SGC-7901

AIM: To investigate the effect of c9, t1l-conjugated linoleic acid (c9, t11-CLA) on the invasion of human gastric carcinoma cell line and its possible mechanism of preventing metastasis.METHODS: Using reconstituted basement membrane invasion, chemotaxis, adhesion, PAGE substrate zymography and RT-PCR assays, we analyzed the abilities of invasion,direct migration, adhesion of intracellular matrix, as well as the activity of type IV collagenase and expression of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 mRNA in SGC-7901 cells which were treated with gradually increased concentrations (25, 50, 100 and 200μmol/L) of c9,c11-CLA for 24 h.RESULTS: At the concentrations of 200μmol/L, 100μmol/L and 50μmol/L, c9,tll-CLA suppressed the invasion of SGC-7901 cells into the reconstituted basement membrane by 53.7 %, 40.9 % and 29.3 %, respectively, in comparison with the negative control. Only in the 200 μmol/L c9,tll-CLA group, the chemotaxis of SGC-7901 cells was inhibited by 16.0 % in comparision with the negative control. C9,tll-CLA also could inhibit the adhesion of SGC-7901 cells to laminin, fibronectin and Matrigel, increase the expression of TIMP-1 and TIMP-2 mRNA, and reduce type IV collegenase activities in the serum-free medium supernatant of SGC-7901 cells.CONCLUSION: c9,t11-C:LA can inhibit the invasion of SGC-7901 cells at multiple procedures in tumor metastasis cascade, which may be associated with the induction of TIMP-1 and TIMP-2 mRNA expression.

Induction of Heme Oxygenase-1 in Human Hepatocytes to Protect Them From Ethanol-induced Cytotoxicity

Background/Aim We investigated the relationship between ethanol exposure and heme oxygenase (HO-1) in human hepatocytes in order to ascertain if induction of HO-1 can prevent ethanol induced cellular damage. Methods Dose-dependent (25-100 mmol/L) and time-dependent (0-24 h) ethanol exposure were used in the present study. HO-1 mRNA and protein expression were detected by PT-PCR and Western blot respectively. HO-1 activity was indicated by bilirubin and Fe2+ formation. Cytotoxicity was investigated by means of lactate dehydrogenate (LDH) and aspartate transaminase (AST) level in culture supernatants, as well as the intracellular formation of malondialdehyde (MDA), cellular glutathione (GSH) status and CYP 2E1 activity. Results We first demonstrated a dose-dependent response between ethanol exposure and HO-1 mRNA and protein expression in human hepatocytes. We further observed a time-dependent increase of HO-1 mRNA expression using 100 mmol/L ethanol starting 30 minutes after ethanol exposure, reaching its maximum between 3 h and 9 h. Being similar to what had been demonstrated with the mRNA level, increased protein expression started at 6 h after ethanol exposure, and kept continuous elevated over 18 h. In addition, we found that ethanol exposure to hepatocytes markedly increased HO-1 enzyme activity in a time-dependent manner measured as bilirubin and Fe2+ formation in human hepatocytes. Our results clearly showed that ethanol exposure caused a significant increase of LDH, AST, and MDA levels, while the antioxidant GSH was time-dependently reduced. Furthermore, we demonstrated that pre-administration of cobalt protoporphyrin (CoPP) induced HO-1 in human hepatocytes, and prevented an increase of MDA and a decrease of GSH. These effects could be partially reversed by zinc protoporphyrin (ZnPP), an antagonist of HO-1 induction. Conclusion HO-1 expression in cells or organs could lead to new strategies for better prevention and treatment of ethanol-induced oxidative damage in human liver.

ROS-related Enzyme Expressions in Endothelial Cells Regulated by Tea Polyphenols

Objective Elevation of reactive oxygen species (ROS), especially the level of superoxide is a key event in many forms of cardiovascular diseases. To study the mechanism of tea polyphenols against cardiovascular diseases, we observed the expressions of ROS-related enzymes in endothelial cells. Methods Tea polyphenols were co-incubated with bovine carotid artery endothelial cells (BCAECs) in vitro and intracellular NADPH oxidase subunits p22phox and p67phox, SOD-1, and catalase protein were detected using Western blot method. Results Tea polyphenols of 0.4 ug/mL and 4.0 ug/mL (from either green tea or black tea) down-regulated NADPH oxidase p22phox and p67phox expressions in a dose-negative manner (P<0.05), and up-regulated the expressions of catalase (P<0.05). Conclusions Tea polyphenols regulate the enzymes involved in ROS production and elimination in endothelial cells, and may be beneficial to the prevention of endothelial cell dysfunction and the development of cardiovascular diseases.

Effects of Spinach Powder Fat-Soluble Extract on Proliferation of Human Gastric Adenocarcinoma Cells

Four kinds of assays were used to study the effect of a fat-soluble extract of spinach powder (SPFE) on the proliferation of human gastric adenocareinoma cell line (SGC-7901) in vitro.These studies included: (Ⅰ) cell growth assay, (Ⅱ) colony forming assay, (Ⅲ) MTT colorimetric assay, and (Ⅳ) 3H-TdR incorporation assay. The concentrations of SPFE expressed as the level of β-carotene in the medium were 2×10-8, 2×10-7 and 2×10-6 mol/L β-carotene in assays (Ⅰ)～(Ⅲ), but 4×10- 8, 4×10-7 and 4×10-6 mol/L β-caretene in assay (Ⅳ) respectively. The results indicated that SPFE inhibited the prolifendion and colony forming ability of SGC-7901 cells. And in MTT assay, SPFE inhibited the viability of SGC7901 cells, but no inhibitory effect of SPFE was observed on the viability of lymphocytes in peripheral blood of healthy people. Finally, in the 3H-TdR incorporation test, both SPFE and β-carotene showed significant inhibitory effects on DNA synthesis in SGC-7901 cells, but SPFE was more effective than β-carotene.

Effects of cg,t11-conjugated linoleic acid on adhesion of human gastric carcinoma cell line SGC-7901

AIM: To investigate the effect of c9, t11-conjugated linoleic acid (c9,t11-CLA) on the adhesion of human gastric carcinoma cell line (SGC-7901).METHODS: SGC-7901 cells were at first treated with different concentrations (25, 50, 100, 200 μmol/L) of c9,t111-CLA and 1 mL/L ethanol (as a negative control) for 24 h.Using adhesion assay and Western blot, we investigated the ability of SGC-7901 cells to adhere to intracellular matrix and examined the expression of E-cadherin (ECD), α-catenin,intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) in these cells.RESULTS: The attachment rate to laminin of SGC-7901 cells treated with different concentrations of c9,t11-CLA (0,25, 50, 100, and 200 μmol/L) was 100.0±3.3, 95.7±4.0,89.2±4.6, 87.9±6.1, and 65.9±5.8, respectively. The attachment rate to fibronectin was 100.0±4.7, 96.8±3.8,94.5±4.1, 76.5±4.3, and 61.8±4.8, respectively. The attachment rate to Matrigel was 99.9±6.6, 91.4±6.8,85.5±7.4, 79.3±5.6, and 69.6±5.1, respectively. Besides,c9,t11-CLA could increase the level of ECD and α-catenin,and decrease the level of ICAM-1 and VCAM-1 in SGC-7901 cells.CONCLUSION: c9, t11-CLA can reduce the adhesion of human gastric carcinoma cells to laminin, fibronectin and Matrigel. c9,t11-CLA can increase the level of ECD and α-catenin, and decrease the level of ICAM-1 and VCAM-1 in human gastric carcinoma cells.

c-Jun N-terminal kinase is required for vitamin E succinate-induced apoptosis in human gastric cancer cells

AIM:To investigate the roles of c-Jun N-terminal kinase (JNK) signaling pathway in vitamin E succinate-induced apoptosis in human gastric cancer SGC-7901 cells. METHODS:Human gastric cancer cell lines (SGC-7901) were treated with vitamin E succinate (VES) at 5,10,20 mg/L. Succinic acid and vitamin E were used as vehicle controls and condition medium only as an untreated (UT) control. Apoptosis was observed by 4′,6-diamidine-2′-phenylindole dihydrochloride (DAPI) staining for morphological changes and by DNA fragmentation for biochemical alterations. Western blot analysis was applied to measure the expression of JNK and phosphorylated JNK.After the cells were transiently transfected with dominant negative mutant of JNK (DN- JNK) followed by treatment of VES,the expression of JNK and c-Jun protein was determined. RESULTS:The apoptotic changes were observed after VES treatment by DNA fragmentation.DNA ladder in the 20 mg/L VES group was more clearly seen than that in 10 mg/L VES group and was not detected following treatment of UT control,succinate and vitamin E.VES at 5,10 and 20 mg/L increased the expression of p-JNK by 2.5-,2.8- and 4.2- fold,respectively.VES induced the phosphorylation of JNK beginning at 1.5 h and produced a sustained increase for 24 h with the peak level at 12 h.Transient transfection of DN-JNK blocked VES-triggered apoptosis by 52%.DN-JNK significantly increased the level of JNK,while decreasing the expression of VES-induced c-Jun protein. CONCLUSION:VES-induced apoptosis in human gastric cancer SGC-7901 cells involves JNK signaling pathway via c-Jun and its downstream transcription factor.

Effects of Dietary Intervention on Hyperlipidemia in Eight Communities of Beijing, China

To examine the effect of community-based dietary intervention on hyperlipidemia. Methods A total of 180 hyperlipidemia individuals with TG>2.26 mmol稬-1(200 mg穌L-1)and/or TC>5.72 mmol稬-1 (220 mg穌L-1) were selected from 428 eligible subjects in eight communities of Beijing. They were randomly divided into intervention group (n=108) and control group (n=72). Dietary intervention was provided for the intervention group for 6 months. Information on dietary intakes, physical examinations and blood samples was collected. Serum lipids were assayed at baseline and endpoint of the study period. Results Respective decrease in dietary intake of total calories, fat, cholesterol and cooking oil by 13.62%, 24.75%, 24.40%, and 22.43%, in the intervention group was observed. The percentages of total calories from fat, carbohydrate and protein appeared to be desirable after study. Reduced body weight and BMI were also observed. There was a respective 5.61% and 7.06 % decrease in total serum cholesterol and low-density lipoprotein cholesterol in the intervention group, while no significant changes were found in the control group. Conclusions Community-based dietary intervention can effectively improve dietary patterns, control body weight, and decrease the levels of total serum cholesterol and low-density lipoprotein cholesterol.

Effects of Fat-soluble Extracts From Vegetable Powder and β-carotene on Proliferation and Apoptosis of Lung Cancer Cell YTMLC-90

Objective The aim of this investigation was to study the effects of fat-soluble extracts from vegetable powder (FEFVP) and P-carotene on the proliferation and apoptosis of cultured YTMLC-90 lung cancer cells. Methods The lung cancer cells were continuously exposed to a broad range of concentration of FEFVP and P-carotene. The proliferation was evaluated in MTT test. The induction of apoptosis was evaluated by morphological change, DNA fragmentation analysis, and DNA content analysis combined with flow cytometric analysis. Results Both FEFVP and P-carotene were found to inhibit cell proliferation and to induce morphologic changes consistent with apoptosis in YTMLC-90 cancer cells, including cellular shrinkage, chromatin condensation and nuclear fragmentation. DNA agarose gel electrophoresis showed DNA fragmentation 'ladder'. Flow cytometric analysis revealed decreased DNA content and the presence of a sub-G1 apoptotic peak. Conclusion These findings are consistent with the induction of apoptosis. Moreover, the effects of FEFVP are stronger than those of P-carotene. FEFVP inhibits the growth of YTMLC-90 probably via the induction of apoptosis cancer cells.

Potential role of p53 mutation in chemical hepatocarcinogenesis of rats

AIM: Inactivation of p53 gene is one of the most frequent genetic alterations in carcinogenesis. The mutation status of p53 gene was analyzed, in order to understand the effect of p53 mutation on chemical hepatocarcinogenesis of rats. METHODS: During hepatocarcinogenesis of rats induced by 3'-methyl-4- dimethylaminoazobenzene (3'-Me-DAB),prehepatocarcinoma and hepatocarcinoma foci were collected by laser capture microdissection (LCM), and quantitatively analyzed for levels of p53 mRNA by LightCyclerTM real-time RT-PCR and for mutations in p53 gene exons 5-8 by direct sequencing. RESULTS: Samples consisting of 44 precancerous foci and 24 cancerous foci were collected by LCM. A quantitative analysis of p53 mRNA showed that p53 mRNA peaked at an early stage (week 6) in the prehepatocarcinoma lesion, more than ten times that of adjacent normal tissue, and gradually decreased from week 6 to week 24. The expression of p53 mRNA in adjacent normal tissue was significantly lower than that in prehepatocarcinoma. Similar to prehepatocarcinoma,p53 mRNA in cancer was markedly higher than that in adjacent normal tissue at week 12, and was closer to normal at week 24. Direct p53 gene sequencing showed that 35.3%(24/68) (9 precancer, 15 cancer) LCM samples exhibited point mutations, 20.5% of prehepatocarcinoma LCM samples presented missense mutations at exon 6/7 or/and 8, and was markedly lower than 62.5% of hepatocarcinoma ones(P<0.01). Mutation of p53 gene formed the mutant hot spots at 5 codons. Positive immunostaining for p53 protein could be seen in prehepatocarcinoma and hepatocarcinoma foci at 24 weeks. CONCLUSION: p53 gene mutation is present in initial chemical hepatocarcinogenesis, and the mutation of p53 gene induced by 3'-Me-DAB is an important factor of hepatocarcinogenesis.

The Energy Expenditure and Nutritional Status of College Students——Ⅰ.The Energy Cost and the Total Energy Expenditure per Day

The energy cost of major activities was determined in healthy students. Among the 606 medical students, 319 were males and 287 were females. Their ages ranged from 18 to 24 years. Douglas' method was used to measure energy cost of each of a total of 42 activities, as well as that of the basal metabolic rates (BMR), resting metabolic rates (RMR) and the total energy expenditure per day under normal situations. The average RMR of male and female subjects were 0.669±0.033 and 0.656±0.030 kcal/sq.m/min respectively. The total energy expenditure per day of male students were 2706 kcal, and 2373 kcal for female students. The energy cost of single activities can be used as the basal data in studies of energy metabolism.

Preliminary Study on Aluminum Content of Foods and Aluminum Intake of Residents in Tianjin

Aluminum contents of 64 kinds mof foods in Tianjin were determined. The results showed that the aluminum levels in different kinds of foods varied greatly, and most foodstuffs from natural sources (including contamination from food processing) contained less than 10 mg/kg. Aluminum contents were higher in foodstuffs of plant origin, especially dry beans containing large amounts of aluminum naturally. Lower concentration of aluminum seemed to be present in foodstuffs of animal origin. It was estimated that the potential daily intake of aluminum per person from natural dietary sources in Tianjin was about 3.79 mg. This estimated figure of dietary aluminum intake was very close to the measured data from 24 daily diets of college students, which was 4.86±1.72mg. Considering all the potential sources of natural aluminum in foods, water and the individual habitual food, it would appear that most residents in Tianjin would consume 3-10 mg aluminum daily from natural dietary sources.