Estimate of the maximal daily dietary intake of butylated hydroxyanisole and butylated hydroxytoluene in The Netherlands

Occurrence of synthetic phenolic antioxidants in foodstuffs from ten provinces in China and its implications for human dietary exposure

Synthetic phenolic antioxidants (SPAs) are widely used as food additives to delay the oxidation rate of oils and oil products. The concentrations and compositions of SPAs in Chinese residents' most popular daily foods and the resulting exposure risk of SPAs are not clear. Therefore, this study collected food samples in 13 food categories (n = 289) from 10 provinces in China. At least one of the SPAs was detected in approximately 99.7% of foodstuffs, and the concentration of ∑SPAs ranged from not detected to 7830 (geometric mean (GM): 296 ng/g wet weight). 2,6-2 tert butyl p-1,4-benzoquinone (BHT-Q) was the main transformation product, but SPAs in food tend to exist in the parent form. A significant difference between food categories was analyzed. The highest GM of ΣSPAs occurred in cereals and cereal products, which was approximately 8 times higher than that in beverages. The estimated daily intakes of ΣSPAs in Chinese preschoolers, school-age children, adults and elderly individuals were 22200, 9970, 7540 and 7700 ng/kg bw/day, respectively. The exposure risks of SPAs decreased with age. This is the first simultaneous analysis of SPAs in multiple provinces and multiple categories of foodstuffs.

Purification and structural characterization of a novel antioxidant and antibacterial protein from Arca inflata

A novel protein (J2-C4) with antioxidant and antibacterial activities was purified from the edible portion of Arca inflata. The purity of J2-C4 was measured to be 97.62% by RP-HPLC analysis, and the molecular weight was 20,537.0 Da by ESI-MS/MS. The isoelectric point of J2-C4 was determined to be 5.18 by IEF-PAGE. Secondary structure analysis of J2-C4 showed that it contained 34.9% α-helix, 15.0% β-sheet, 16.3% β-turn and 34.0% random coil by CD spectroscopy. The complete amino acid sequence of J2-C4 was identified by gel electrophoresis and LC-MS/MS together with transcriptome database analysis. Based on the alignment with NCBI BLAST database, J2-C4 showed 71% homology with a sarcoplasmic calcium-binding protein isolated from Crassostrea virginica. Therefore, J2-C4 was proposed to be a new sarcoplasmic calcium-binding protein-like protein in A. inflata. In vitro antioxidant assays showed that J2-C4 exhibited favorable scavenging activities on ABTS⁺ (EC₅₀ 145.80 μg/mL) and DPPH (EC₅₀ 455.62 μg/mL). J2-C4 exhibited antibacterial activities against Pseudomonas aeruginosa (MIC: 375 μg/mL), Escherichia coli (MIC: 187.5 μg/mL) and Methicillin resistant Staphylococcus aureus (MIC: 750 μg/mL). The results showed that J2-C4 might be developed as a potential food additive agent.

Changes in Quality Characteristics of Pork Patties Containing Antioxidative Fish Skin Peptide or Fish Skin Peptide-loaded Nanoliposomes during Refrigerated Storage

Marine fish skin peptides (FSP) have been widely studied due to their antioxidant and antimicrobial properties. We aimed to use a natural antioxidant, FSP, to replacing synthetic preservatives in a pork patty model, which is safer for human body. Moreover, nano-liposome technology can be applied for masking the fishy smell and improving the stability of this peptide. Therefore, in this study, the effects of FSP and FSP-loaded liposomes (FSPL) on pork patty were evaluated through the tests of thiobarbituric acid reactive substances (TBARS), color, cooking loss, texture, volatile basic nitrogen (VBN), and the pH value, during 14 d of refrigerated (4°C) storage. The results showed that all FSP-treated patties had lower TBARS values than control patties, which indicated an inhibitory effect of FSP on lipid oxidation. This effect in the patties depended on the FSP concentration. However, FSPL-treated patties showed significantly higher and undesirable TBARS values compared to the control, and this effect depended on the FSPL concentration. None of the physicochemical results showed remarkable changes except the pH and VBN values. Therefore, this study provides evidence that FSP has great potential to inhibit the lipid oxidation of pork patties and is capable of maintaining the quality and extending the shelf life. However, it is necessary to study the application of FSP treatments greater than 3% to improve the antioxidant effect on pork patties and search for other coating materials and technology to reduce the drawbacks of FSP.

Effect of Persimmon Peel (Diospyros kaki Thumb.) Extracts on Lipid and Protein Oxidation of Raw Ground Pork During Refrigerated Storage

The inhibition effect of persimmon peel extracts (PPE) (0.05(PPE-0.05), 0.1(PPE-0.1), and 0.2 g(PPE-0.2) per meat sample) on lipid and protein oxidation of pork patties during chilled storage for 12 days were investigated and compared to ascorbic acid (As-0.05) and butylhydroxytoluene (BHT) (BHT-0.01). The meat samples treated with PPE had greater (p<0.05) a* values comparing control in raw pork patties meat from day 4 of storage. The addition of PPE at all concentrations on meat samples effectively inhibited the formation of oxidation products as shown by decreasing conjugated dienes (CD), peroxide values (POVs), thiobarbituric acid reaction substances (TBARS), and carbonyl content during chilled storage for 12 d. The PPE-0.2 and BHT-0.01 had the lowest in decrease rate of free thiol content (0.24 and 0.22 times) during chilled storage. Therefore, results of this study suggest that PPE can be considered a potential antioxidant against lipid and protein oxidation of raw meat products.

2,6-Di-Tert-Butyl-Hydroxytoluene and Its Metabolites in Foods

2,6-Di-tert-butyl-hydroxytoluene (BHT, E-321) is a synthetic phenolic antioxidant which has been widely used as an additive in the food, cosmetic, and plastic industries for the last 70 y. Although it is considered safe for human health at authorized levels, its ubiquitous presence and the controversial toxicological data reported are of great concern for consumers. In recent years, special attention has been paid to these 14 metabolites or degradation products: BHT-CH₂ OH, BHT-CHO, BHT-COOH, BHT-Q, BHT-QM, DBP, BHT-OH, BHT-OOH, TBP, BHQ, BHT-OH(t), BHT-OH(t)QM, 2-BHT, and 2-BHT-QM. These derived compounds could pose a human health risk from a food safety point of view, but they have been little studied. In this context, this review deals with the occurrence, origin, and fate of BHT in foodstuffs, its biotransformation into metabolites, their toxicological implications, their antioxidant and prooxidant properties, the analytical determination of metabolites in foods, and human dietary exposure. Moreover, noncontrolled additional sources of exposure to BHT and its metabolites are highlighted. These include their carryover from feed to fish, poultry and eggs, their presence in smoke flavorings, their migration from plastic pipelines and packaging to water and food, and their presence in natural environments, from which they can reach the food chain.

Effect of butylated hydroxytoluene (E321) pretreatment versus L-arginine on liver injury after sub-lethal dose of endotoxin administration

Aim of this study was to compare the effects of L-arginine (L-arg) and food-antioxidant butylated hydroxytoluene (BHT) against oxidative stress of Escherichia coli endotoxin (LPS) in liver. Ninety Wistar albino rats were assigned in three groups. Rats received one of the following pre-treatment previous to 5mg/kg LPS intraperitoneally: saline, L-arg (NO donor, 100mg/kg) or BHT (250 mg/kg/day), for 3 days. At second, fourth and sixth hours, plasma nitrite-plus-nitrate, circulating liver enzymes, glutathione levels, superoxide dismutase, glutathione peroxidase activities were measured. The most remarkable liver injury was evident in BHT pre-treated animals at all time points compared to L-arg pre-treated rats. While BHT enhanced superoxide dismutase activities following LPS, glutathione decreased simultaneously compared to L-arg group. Although the risk associated with the use of BHT alone in subthreshold doses appeared to be low, higher risk of liver toxicity should be considered when over-consuming this food additive in endotoxemic settings.

Final report on the safety assessment of BHT(1)

BHT is the recognized name in the cosmetics industry for butylated hydroxytoluene. BHT is used in a wide range of cosmetic formulations as an antioxidant at concentrations from 0.0002% to 0.5%. BHT does penetrate the skin, but the relatively low amount absorbed remains primarily in the skin. Oral studies demonstrate that BHT is metabolized. The major metabolites appear as the carboxylic acid of BHT and its glucuronide in urine. At acute doses of 0.5 to 1.0 g/kg, some renal and hepatic damage was seen in male rats. Short-term repeated exposure to comparable doses produced hepatic toxic effects in male and female rats. Subchronic feeding and intraperitoneal studies in rats with BHT at lower doses produced increased liver weight, and decreased activity of several hepatic enzymes. In addition to liver and kidney effects, BHT applied to the skin was associated with toxic effects in lung tissue. BHT was not a reproductive or developmental toxin in animals. BHT has been found to enhance and to inhibit the humoral immune response in animals. BHT itself was not generally considered genotoxic, although it did modify the genotoxicity of other agents. BHT has been associated with hepatocellular and pulmonary adenomas in animals, but was not considered carcinogenic and actually was associated with a decreased incidence of neoplasms. BHT has been shown to have tumor promotion effects, to be anticarcinogenic, and to have no effect on other carcinogenic agents, depending on the target organ, exposure parameters, the carcinogen, and the animal tested. Various mechanism studies suggested that BHT toxicity is related to an electrophillic metabolite. In a predictive clinical test, 100% BHT was a mild irritant and a moderate sensitizer. In provocative skin tests, BHT (in the 1% to 2% concentration range) produced positive reactions in a small number of patients. Clinical testing did not find any depigmentation associated with dermal exposure to BHT, although a few case reports of depigmentation were found. The Cosmetic Ingredient Review Expert Panel recognized that oral exposure to BHT was associated with toxic effects in some studies and was negative in others. BHT applied to the skin, however, appears to remain in the skin or pass through only slowly and does not produce systemic exposures to BHT or its metabolites seen with oral exposures. Although there were only limited studies that evaluated the effect of BHT on the skin, the available studies, along with the case literature, demonstrate no significant irritation, sensitization, or photosensitization. Recognizing the low concentration at which this ingredient is currently used in cosmetic formulations, it was concluded that BHT is safe as used in cosmetic formulations.

A critical assessment of some biomarker approaches linked with dietary intake

In this review many examples are given of the complexities involved in using some biomarkers in relation to assessing the effects of dietary exposure, when there is frequently a need to determine changes following long-term low level exposure to dietary components. These range from understanding why the biomarker might be valuable and how best it can be measured, to the pitfalls which can occur in the interpretation of data. Analytical technique is considered in relation to folate and selenium, and flavonoid and carotenoid species are used to illustrate how the metabolism of a compound may alter the validity or adequacy of a marker. Vitamin A is discussed in relation to the difficulties which can arise when there are several biomarkers that may be available to assess exposure to one nutrient. Vitamin B12 is discussed in relation to the dietary choices made by individuals. Possible interactions and the role of measuring total antioxidant capacity is considered in some detail. In contrast to most nutrients, there is a marked lack of biomarkers of either exposure or effect for most non-nutrients. The role of biological effect monitoring is considered for dietary contaminants, fumonisins and polyhalogenated aromatic hydrocarbons. Aflatoxins are discussed to exemplify food contaminants for which the biomarker approach has been extensively studied. Finally some compounds which are deliberately added to foods and some which appear as processing contaminants are each considered briefly in relation to the requirement for a biomarker of exposure to be developed.

Estimates of the theoretical maximum daily intake of phenolic antioxidants BHA, BHT and TBHQ in Brazil

The theoretical maximum daily intakes (TMDI) of the phenolic antioxidants butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tertbutyl hydroquinone (TBHQ) in Brazil were estimated using food consumption data derived from a household economic survey and a packaged goods market survey. The estimates were based on maximum levels of use of the food additives specified in national food standards. The calculated intakes of the three additives for the mean consumer were below the ADIs. Estimates of TMDI for BHA, BHT and TBHQ ranged from 0.09 to 0.15, 0.05 to 0.10 and 0.07 to 0.12 mg/kg of body weight, respectively. To check if the additives are actually used at their maximum authorized levels, analytical determinations of these compounds in selected food categories were carried out using HPLC with UV detection. BHT and TBHQ concentrations in foodstuffs considered to be representive sources of these antioxidants in the diet were below the respective maximum permitted levels. BHA was not detected in any of the analysed samples. Based on the maximal approach and on the analytical data, it is unlikely that the current ADI of BHA (0.5 mg/kg body weight), BHT (0.3 mg/kg body weight) and TBHQ (0.7 mg/kg body weight) will be exceeded in practice by the average Brazilian consumer.

Estimates of the theoretical maximum daily intake of erythorbic acid, gallates, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in Italy: a stepwise approach

The three recent EU directives which fixed maximum permitted levels (MPL) for food additives for all member states also include the general obligation to establish national systems for monitoring the intake of these substances in order to evaluate their use safety. In this work, we considered additives with primary antioxidant technological function for which an acceptable daily intake (ADI) was established by the Scientific Committee for Food (SCF): gallates, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and erythorbic acid. The potential intake of these additives in Italy was estimated by means of a hierarchical approach using, step by step, more refined methods. The likelihood of the current ADI to be exceeded was very low for erythorbic acid, BHA and gallates. On the other hand, the theoretical maximum daily intake (TMDI) of BHT was above the current ADI. The three food categories found to be main potential sources of BHT were "pastry, cake and biscuits", "chewing gums" and "vegetables oils and margarine"; they overall contributed 74% of the TMDI. Actual use of BHT in these food categories is discussed, together with other aspects such as losses of this substance in the technological process and percentage of ingestion in the case of chewing gums.

Intake of butylated hydroxyanisole and butylated hydroxytoluene and stomach cancer risk: results from analyses in the Netherlands Cohort Study

Both carcinogenic and anticarcinogenic properties have been reported for the synthetic antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). The association between dietary intake of BHA and BHT and stomach cancer risk was investigated in the Netherlands Cohort Study (NLCS) that started in 1986 among 120,852 men and women aged 55 to 69 years. A semi-quantitative food frequency questionnaire was used to assess food consumption. Information on BHA or BHT content of cooking fats, oils, mayonnaise and other creamy salad dressings and dried soups was obtained by chemical analysis, a Dutch database of food additives (ALBA) and the Dutch Compendium of Foods and Diet Products. After 6.3 years of follow-up, complete data on BHA and BHT intake of 192 incident stomach cancer cases and 2035 subcohort members were available for case-cohort analysis. Mean intake of BHA or BHT among subcohort members was 105 and 351 microg/day, respectively. For consumption of mayonnaise and other creamy salad dressings with BHA or BHT no association with stomach cancer risk was observed. A statistically non-significant decrease in stomach cancer risk was observed with increasing BHA and BHT intake [rate ratio (RR) highest/lowest intake of BHA = 0.57 (95% confidence interval (CI): 0.25-1.30] and BHT = 0.74 (95% CI: 0.38-1.43). In this study, no significant association with stomach cancer risk was found for usual intake of low levels of BHA and BHT.

Inhibition of beta-carotene-15,15'-dioxygenase activity by dietary flavonoids

Beta-carotene-15,15'-dioxygenase is an enzyme responsible for providing vertebrates with vitamin A by catalyzing oxidative cleavage of beta-carotene at its central double bond to two molecules of retinal in intestinal cells. However, little data have been reported regarding regulation of the enzyme activity. We have evaluated the effects of antioxidants and dietary flavonoids on the beta-carotene dioxygenase activity in vitro using a pig intestinal homogenate as the enzyme source. 2,6-Di-tert-butyl-4-methylphenol (BHT), a synthetic antioxidant, strongly inhibited the activity at the level of 10(-6) M (a mixed-type inhibition), whereas butylated hydroxyanisole, nor-dihydroguaiaretic acid, n-propyl gallate, and curcumin were moderately inhibitory. Flavonoids such as luteolin, quercetin, rhamnetin, and phloretin remarkably inhibited the dioxygenase activity noncompetitively, whereas flavanones, isoflavones, catechins, and anthocyanidins were less inhibitory. The structure-activity relationship indicated that catechol structure of ring B and a planar flavone structure were essential for inhibition. The enzyme inhibition was also indicated in the cultured Caco-2 cells by the significantly reduced conversion of beta-carotene to retinol when incubated with BHT and rhamnetin at 2 microM and 5 microM, respectively. The results suggest that some dietary antioxidants derived from food sources modulate conversion of beta-carotene to vitamin A in intestinal cells.

Dietary antioxidants do not reduce fatty streak formation in the C57BL/6 mouse atherosclerosis model

Epidemiological studies and animal trials have suggested that dietary antioxidants protect against atherosclerosis. To test this hypothesis, C57BL/6 mice were fed atherogenic diets supplemented with either vitamin E or butylated hydroxytoluene (BHT). Three groups of 20 mice were fed for 15 weeks on diets containing 1% cholesterol and 0.5% cholic acid. The diet of two groups was supplemented with either 2% vitamin E or 1% BHT. The control group received no antioxidant supplements. The lowest mean serum cholesterol concentration was measured in mice supplemented with vitamin E. Mean serum HDL cholesterol concentrations were highest in the control group, which also had the highest ratio of HDL cholesterol to total cholesterol. Mice fed BHT developed a significantly greater area of aortic fatty streak lesions than the other two groups. However, despite having a more atherogenic lipoprotein profile, mice fed vitamin E developed a level of fatty streak formation similar to the control group. At the end of the trial, mice consuming the vitamin E- and BHT-supplemented diets had higher serum total antioxidant levels than the control mice. Because of changes to lipid metabolism caused by both vitamin E and BHT, the results of this study cannot be used to support the hypothesis that antioxidants confer protection against atherosclerosis. The results do, however, raise the possibility that other studies demonstrating an antiatherogenic action of vitamin E and BHT may have been influenced by their effects on lipid metabolism.

Measurement of synthetic phenolic antioxidants in human tissues by high-performance liquid chromatography with coulometric electrochemical detection

The antioxidants, 2-tert.-butyl-4-methoxyphenol (BHA) and its oxidative peroxidation product 2,2'-dihydroxy-3,3'-di-tert.-butyl-5,5'-dimethoxybiphenyl (di-BHA), 3,5-di-tert.-butyl-4-hydroxytoluene (BHT) and propyl gallate, were measured in plasma and tissue homogenates by HPLC and electrochemical detection, with a sensitivity down to 0.2 (BHA), 0.1 (di-BHA), 0.4 (BHT) and 1 (propyl gallate) ng ml(-1) of plasma or tissue homogenate. The data demonstrate that in man, at the current level of exposure to dietary antioxidants, significant amounts of BHA, BHT and propyl gallate are accumulated in the omentum. Furthermore, they provide the first evidence that the peroxidase-catalysed oxidation of BHA is operative in man.

Elevation of serum cholesterol levels in mice by the antioxidant butylated hydroxyanisole

The food antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are structurally related to the hypocholesterolemic drug probucol. The purpose of this study was to determine if BHA can lower serum cholesterol levels as is observed with probucol. Treatment of mice with 0.75% BHA in their feed for 10 days resulted in a significant (P < or = 0.01) elevation of serum cholesterol levels. This effect contrasts with the cholesterol-lowering effect of probucol. Further, the degree of cholesterol elevation was comparable to that observed in mice administered 3% cholesterol in their feed for 7 days. The enzyme acyl CoA:cholesterol acyltransferase (ACAT) was decreased significantly (P < or = 0.01) in liver microsomes from BHA-treated mice. In contrast, hepatic microsomal ACAT activity was increased significantly (P < or = 0.01) in cholesterol-fed mice. These results suggested that the increased serum cholesterol observed in BHA-treated mice was not accompanied by an increase in hepatic cholesterol levels. Indeed, hepatic microsomal cholesterol levels were reduced in BHA-treated mice, but were increased significantly (P < or = 0.01) in cholesterol-fed mice. These results demonstrate that the common food additive BHA elevates serum cholesterol levels by a mechanism that apparently involves the decreased uptake of cholesterol by the liver.