Identification of carcinogens in cooking oil fumes.

According to earlier studies, fumes from cooking oils were found to be genotoxic in several short-term tests such as the Ames test, sister chromatid exchange, and SOS chromotest. Fume samples from six different commercial cooking oils (safflower, olive, coconut, mustard, vegetable, and corn) frequently used in Taiwan were collected. Polycyclic aromatic hydrocarbons (PAHs) were extracted from the air samples and identified by high-performance liquid chromatography and confirmed by gas chromatography/mass spectrometry. Extracts of fumes from safflower oil, vegetable oil, and corn oil contained benzo[a]pyrene (BaP), dibenz[a,h]anthracene (DBahA), benzo[b]fluoranthene (BbFA), and benzo[a]anthracene (BaA). Concentrations of BaP, DbahA, BbFA, and BaA were 2.1, 2.8, 1.8, and 2.5 microg/m3 in fumes from safflower oil; 2.7, 3.2, 2.6, and 2.1 microg/m3 in vegetable oil; and 2.6, 2.4, 2.0, and 1.9 microg/m3 in corn oil, respectively. The authors constructed models to study the efficacy of table-edged fume extractors used commonly by Taiwanese restaurants. Concentrations of BaP were significantly decreased when the fume extractor was working (P<0.05) and the average reduction in percentage was 75%. The other identified PAHs were undetected. These results indicated that exposure to cooking oil fumes could possibly increase exposure to PAHs, which may be linked to an increased risk of lung cancer. The potential carcinogenic exposure could be reduced by placing table-edged fume extractors near cooking pots.

Mutagenicity and aromatic amine content of fumes from heated cooking oils produced in Taiwan.

According to toxicological studies, there are several unidentified mutagens derived from cooking oil fumes appearing in kitchens of Chinese homes where women daily prepare food. Data are limited to an analysis of aromatic amines from cooking oil fumes, which are known to be carcinogenic for bladder cancer. Fume samples from three different commercial cooking oils frequently used in Taiwan were collected and analysed for mutagenicity in the Salmonella/microsome assay. Aromatic amines were extracted from the samples and identified by HPLC and confirmed by gas chromatography/mass spectrometry (GC/MS). Extracts from three cooking oil fumes were found to be mutagenic in the presence of S-9 mix. All samples contained 2-naphthylamine (2-NA) and 4-aminobiphenyl (4-ABP). Concentrations of 2-NA and 4-ABP were 31.5 and 35.7 microg/m3 in fumes from sunflower oil, 31.9 and 26.4 mg/m3 in vegetable oil, and 48.3 and 23.3 microg/m3 in refined-lard oil, respectively. Mutagenicities of the three cooking oil condensates were significantly reduced (P<0.05) by adding the antioxidant catechin (CAT) into the oils before heating. Significant difference existed between the amounts of aromatic amines with and without adding CAT (P<0.05). These results indicate that exposure to cooking oil fumes in Taiwan might be an important but controllable risk factor in the aetiology of bladder cancer.

Genotoxicity of fumes from heated cooking oils produced in Taiwan.

Epidemiologic investigations of lung cancer among Taiwanese nonsmoking women have found that exposure to fumes from cooking oils may be an important risk factor. Fume samples from three different commercial cooking oils (lard, soybean, and peanut oils) often used in Taiwan for preparing Chinese meals were collected for genotoxicity analysis in SOS chromotest and sister chromatid exchange (SCE) assays. The induction factors of the SOS chromotest in Escherichia coli PQ 37 were dependent on the concentrations of lard and soybean cooking oil extracts without S9 mix. In addition, when CHO-K1 cells were exposed to condensates of cooking oil fumes for 12 h, SCEs showed a dose-related increase in extracts of lard and soybean oil fumes. This result provides experimental evidence and is in accordance with the findings of epidemiologic studies that women exposed to the emitted fumes of cooking oils are at an increase risk of contracting lung cancer.

Nitro-polycyclic aromatic hydrocarbon contents of fumes from heated cooking oils and prevention of mutagenicity by catechin.

According to earlier studies, fumes from cooking oils were found to be mutagenic and several polycyclic aromatic hydrocarbons (PAHs), (benzo(a)pyrene (B(a)P), benz(a)antracene (B(a)A), and dibenz(a,h)anthracene (DB(ah)A)) were identified. Fume samples from three different commercial cooking oils frequently used in Taiwan were collected and nitro-polycyclic aromatic hydrocarbons (NPAHs) were extracted from the samples and identified by HPLC chromatography. Extracts from three cooking oil fumes contained 1-nitropyrene (1-NP) and 1,3-dinitropyrene (1,3-DNP). Concentrations of 1-NP and 1,3-DNP were 1.1 +/- 0.1 and 0.9 +/- 0.1 micrograms/m3 in fumes from lard oil, 2.9 +/- 0.3 and 3.4 +/- 0.2 micrograms/m3 in soybean oil, 1.5 +/- 0.1 and 0.4 +/- 0.1 micrograms/m3 in peanut oil, respectively. The preventive effect of three natural antioxidants (gamma-tocopherol (TOC), lecithin (LEC), and catechin (CAT)) for the reduction of mutagenicity and amounts of PAHs and NPAHs of fumes from cooking oils were evaluated. Mutagenicity of cooking oil fumes occurred, and the concentration of B(a)P were significantly reduced (p < 0.05), by adding CAT into cooking oils before heating. B(a)A, DB(ah)A, and two NPAHs were not detected when the concentration of CAT was 500 ppm in all three cooking oil fumes. These results indicate that fumes of cooking oils contained PAHs and NPAHs that may be a risk factor for lung cancer among cooks and the carcinogens could be reduced by adding the natural antioxidant, catechin.

Prevention of exposure to mutagenic fumes produced by hot cooking oil in Taiwanese kitchens.

We evaluated the mutagens in fumes produced by heating three different cooking oils used in Taiwan to temperatures of 100 degrees C, 200 degrees C, and 300 degrees C, and constructed models to study the efficacy of fume extractors used commonly by Taiwanese women. Particulates of volatile emissions from lard (at 200 degrees C and 300 degrees C) and soybean oil (at 300 degrees C) were found to be mutagenic in the Salmonella/microsomal test with S9 mix, indicating that exposure of Taiwanese women to cooking oil fumes may be an important risk factor in the etiology of their lung cancer. Mutagenicity of lard and soybean oil fumes collected at 300 degrees C was obtained when a commonly used fume extractor was located at a usual distance of 70 cm above the oil surface, whereas the fume samples were not, or weakly, mutagenic in the Salmonella/ microsomal assay when the distance between fume extractor and oil surface was 60 cm or less. Reduction in mutagenicity was on average 1.2 +/- 0.5 revertants/cm (the percent reduction in mutagenicity was 46%), pointing to a possible cooking practice involving significant reductions in exposure to harmful oil fumes and, consequently, a decreased risk of lung cancer in Taiwanese housewives.

Mutagenicity and polycyclic aromatic hydrocarbon content of fumes from heated cooking oils produced in Taiwan.

According to epidemiologic studies, exposure of women to fumes from cooking oils appears to be an important risk factor for lung cancer. Fume samples from three different commercial cooking oils frequently used in Taiwan were collected and analyzed for mutagenicity in the Salmonella/microsome assay. Polycyclic aromatic hydrocarbons were extracted from the samples and identified by HPLC chromatography. Extracts from three cooking oil fumes were found to be mutagenic in the presence of S9 mix. All samples contained dibenz[a,h]anthracene (DB[a,h]A) and benz[a]anthracene (B[a]A). Concentration of DB[a,h]A and B[a]A were 1.9 and 2.2 micrograms/m3 in fumes from lard oil, 2.1 and 2.3 micrograms/m3 in soybean oil, 1.8 and 1.3 micrograms/m3 in peanut oil, respectively. Benzo[a]pyrene (B[a]P) was identified in fume samples of soybean and peanut oil, in concentrations of 19.6 and 18.3 micrograms/m3, in this order. These results provide experimental evidence and support the findings of epidemiologic observations, in which women exposed to the emitted fumes of cooking oils are at increased risk of contracting lung cancer.

Prevalence of betel quid chewing habit in Taiwan and related sociodemographic factors.

The prevalence of betel quid chewing habit in Taiwan was surveyed in a group of Chinese people from Kaohsiung city and in a second group from the aboriginal inhabitants of South Taiwan. In all 1299 participants constituted Group 1 (85.2% response rate) and 827 Group 2 (70.1% response rate). People were interviewed in their homes in house-to-house survey, according to a structured questionnaire developed and evaluated by the authors. Of the Kaohsiung inhabitants covering all ages and both sexes, 6% was a current betel chewer and 4% was an ex-chewer, whereas 42% of the aborigines aged over 15 yr was a current chewer and 1% an ex-chewer. Lifetime prevalence was 10%. Betel chewing enjoys islandwide popularity among the 20 million inhabitants of Taiwan; the number of current and ex-users was estimated at 2.0 million (95% CI 1.6-2.4 million). The betel quid was prepared in two different ways. In one, used mainly by aborigines, fresh areca nut was simply wrapped with betel leaf and in another, popular mainly among Chinese, a lengthwise piece of betel fruit and lime paste was sandwiched between two halves of an areca nut. A high proportion of chewers was also a smoker and drinker, but tobacco was not found to be chewed together with betel quid. Consumption varied between 14 to 23 portions per day, with individual frequencies ranging widely from 1 to over 200 portions a day. A statistical analysis of sociodemographic factors showed that lesser educated older men, blue collar workers, smokers and drinkers were the likeliest betel chewers.