Nutritional Intake and Biomarker Status in Strict Raw Food Eaters.

Following a strict raw food diet (primarily based on fresh fruit and raw vegetables, waiving any consumption of heated or processed food) has the risk of undersupply of energy and certain macro- and micronutrients. In this cross-sectional study, we compared 16 non-smoking strict raw food eaters (5 women and 11 men, age 44.6 ± 12.3 years, duration of following the diet 11.6 ± 10.8 years) with the non-smoking participants (32 vegans, 27 omnivores) of the "Risk and Benefits of a Vegan Diet" (RBVD) study. We investigated body composition, dietary intake from 3-day weighed food records, and relevant fasting blood and serum parameters. Food choice and dietary behavior were very heterogenic in raw food eaters. They had lower mean values of BMI and percentage of body fat than the respective RBVD participants. The same holds true for energy supply and intakes of protein, carbohydrate, calcium and iodine. Serum levels revealed lower levels of HDL cholesterol, triglycerides, zinc, and vitamin D3. The raw food eaters with (n = 9) and without (n = 7) supplementation of vitamin B12 had median vitamin B12 levels of 399 and 152 ng/L, respectively. Accordingly, eight raw food eaters (50%) had homocysteine levels above 12 µmol/L. The study allows a close look at strict raw food eaters with respect to possible dietary deficiencies, but also provides insights into motivations and daily life.

Metabolites of 2- and 3-Monochloropropanediol (2- and 3-MCPD) in Humans: Urinary Excretion of 2-Chlorohydracrylic Acid and 3-Chlorolactic Acid after Controlled Exposure to a Single High Dose of Fatty Acid Esters of 2- and 3-MCPD.

SCOPE: Fatty acid esters of 2-monochloropropane-1,3-diol (2-MCPD) and 3-monochloropropane-1,2-diol (3-MCPD) are formed during the deodorization of vegetable oils. After lipase-catalyzed hydrolysis in the intestine, 2- and 3-MCPD are absorbed, but their ensuing human metabolism is unknown. METHODS AND RESULTS: The compounds 2-chlorohydracrylic acid (2-ClHA) and 3-chlorolactic acid (3-ClLA) resulting from oxidative metabolism of 2-MCPD and 3-MCPD, respectively, are identified and quantified in human urine samples. An exposure study with 12 adults is conducted to determine the urinary excretion of 2-ClHA and 3-ClLA. The participants eat 12 g of hazelnut oil containing 24.2 mg kg-1 2-MCPD and 54.5 mg kg-1 3-MCPD in the form of fatty acid esters. Average daily amounts of "background" excretion before the exposure are 69 nmol 2-ClHA and 3.0 nmol 3-ClLA. The additional mean excretion due to the uptake of the hazelnut oil amounts to 893 nmol 2-ClHA (34.0% of the 2-MCPD dose) and 16.4 nmol 3-ClLA (0.28% of the 3-MPCD dose). CONCLUSIONS: The products of oxidative metabolism of 2- and 3-MCPD, 2-ClHA, and 3-ClLA, are described for the first time in humans. Due to the lack of specificity, the metabolites may not be used as exposure biomarkers to low doses of bound 2- and 3-MCPD, respectively.

Urinary Excretion of 2/3-Monochloropropanediol (2/3-MCPD) and 2,3-Dihydroxypropylmercapturic Acid (DHPMA) after a Single High dose of Fatty Acid Esters of 2/3-MCPD and Glycidol: A Controlled Exposure Study in Humans.

SCOPE: 2- and 3-monochloropropanediol (2/3-MCPD) and glycidol are absorbed in the intestine after lipase-catalyzed hydrolysis of their fatty acid esters. METHODS AND RESULTS: In an exposure study with 12 non-smoking participants, the complete urinary excretion of the metabolite 2,3-dihydroxypropylmercapturic acid (DHPMA) and of 2/3-MCPD is measured on four consecutive days before and after consumption of 50 g glycidyl ester-rich palm fat or 12 g 2/3-MCPD ester-rich hazelnut oil. After controlled exposure, urinary excretion rates of 2/3-MCPD per hour strongly increase, followed by a decrease with average half-lives of 5.8 h (2-MCPD) and 3.6 h (3-MCPD). After consumption of hazelnut oil, mean excretion rates are 14.3% (2-MCPD) and 3.7% (3-MCPD) of the study doses. The latter rate is significantly higher (4.6%) after consumption of palm fat, indicating partial conversion (about 5%) of glycidol to 3-MCPD under the acidic conditions in the stomach. The average daily "background" exposure is estimated to be 0.12 and 0.32 µg per kg body weight (BW) for 2-MCPD and 3-MCPD, respectively. The relatively high and constant urinary excretion of DHPMA does not reflect the controlled exposure. CONCLUSION: Urinary excretion of 2- and 3-MCPD is suitable as biomarker for the external exposure to the respective fatty acid esters.

Vitamin and Mineral Status in a Vegan Diet.

BACKGROUND: In Germany, public interest in a vegan diet is steadily growing. There are, however, no current data on the macro- and micronutrient status of vegans. METHODS: In a cross-sectional study entitled "The Risks and Benefits of a Vegan Diet" (RBVD), we investigated the dietary intake, basic laboratory parameters, vitamin status, and trace-element status of 36 vegans and 36 persons on an omnivorous diet. Each group consisted of 18 men and 18 women aged 30-60. RESULTS: Nearly all the vegans and one-third of the persons on a mixed diet had consumed supplements in the previous 4 weeks. Vegans and nonvegans had similar energy intake but differed in the intake of both macronutrients (e.g., dietary fiber) and micronutrients (e.g., vitamins B12, B2, D, E, and K, as well as folate, iodine, and iron). There were no intergroup differences in the biomarkers of vitamin B12, vitamin D, or iron status. The ferritin values and blood counts indicated iron deficiency in four vegans and three non-vegans. Measurements in 24-hour urine samples revealed lower calcium excretion and markedly lower iodine excretion in vegans compared to non-vegans; in one-third of the vegans, iodine excretion was lower than the WHO threshold value (<20 µg/L) for severe iodine deficiency. CONCLUSION: Vitamin B12 status was similarly good in vegans and non-vegans, even though the vegans consumed very little dietary B12. This may be due to the high rate of supplementation. The findings imply a need to also assure adequate iodine intake in the population, especially among persons on a vegan diet.

Associations between Dietary Patterns and Bile Acids-Results from a Cross-Sectional Study in Vegans and Omnivores.

Bile acids play an active role in fat metabolism and, in high-fat diets, elevated concentrations of fecal bile acids may be related to an increased risk of colorectal cancer. This study investigated concentrations of fecal and serum bile acids in 36 vegans and 36 omnivores. The reduced rank regression was used to identify dietary patterns associated with fecal bile acids. Dietary patterns were derived with secondary and conjugated fecal bile acids as response variables and 53 food groups as predictors. Vegans had higher fiber (p < 0.01) and lower fat (p = 0.0024) intake than omnivores. In serum, primary and glycine-conjugated bile acids were higher in vegans than in omnivores (p ≤ 0.01). All fecal bile acids were significantly lower in vegans compared to omnivores (p < 0.01). Processed meat, fried potatoes, fish, margarine, and coffee contributed most positively, whereas muesli most negatively to a dietary pattern that was directly associated with all fecal bile acids. According to the pattern, fat intake was positively and fiber intake was inversely correlated with bile acids. The findings contribute to the evidence that, in particular, animal products and fat may play a part in higher levels of fecal bile acids.

Detection of N-Acetyl-S-[3'-(4-methoxyphenyl)allyl]-l-Cys (AMPAC) in Human Urine Samples after Controlled Exposure to Fennel Tea: A New Metabolite of Estragole and trans-Anethole.

Fennel and other herbs contain the secondary plant metabolites estragole and trans-anethole, of which estragole is carcinogenic in rodents. It is metabolically activated by cytochrome P450-catalyzed conversion to 1'-hydroxyestragole and subsequent sulfo conjugation to the genotoxic 1'-sulfoxyestragole. The current study followed the hypothesis that the reactive sulfate ester may be detoxified by glutathione conjugation, leading to the urinary excretion of a resultant mercapturic acid. We identified the assumed downstream metabolite N-acetyl-S-[3'-(4-methoxyphenyl)allyl]-l-Cys (AMPAC) in human urine samples after consumption of fennel tea. An isotope-dilution technique for its quantification by ultraperformance liquid chromatography-tandem mass spectrometry and [13C3,15N]AMPAC in urine samples was developed. The method was applied to determine the AMPAC concentration in urine samples following uptake of 500 mL of fennel tea containing 2.2 mg of estragole by 12 healthy participants (six females and six males). Before drinking the tea, the urinary AMPAC concentration was below the limit of detection. In most of the participants, the highest amounts of urinary AMPAC were found in the first-hour urine after exposure. The excretion by first-order kinetics (range of t1/2 = 0.78-1.54 h; mean ± SD: 1.13 ± 0.21 h) led to a nearly complete clearance within 8 h in all participants. The total AMPAC excreted was in the range of 93-1076 ng, reflecting pronounced interindividual variations of enzymes taking part in estragole metabolism. Importantly, AMPAC was also formed in one volunteer following oral uptake of a single dose of isolated trans-anethole, albeit to a much smaller extent compared to estragole. AMPAC may be of future use as a human biomarker for the internal exposure to the carbocation formed from either 1'-sulfoxyestragole or 3'-sulfoxyisoestragole, the reactive sulfate ester metabolites of estragole and trans-anethole, respectively.

The hemoglobin adduct N-(2,3-dihydroxypropyl)-valine as biomarker of dietary exposure to glycidyl esters: a controlled exposure study in humans.

Fatty acid esters of glycidol (glycidyl esters) are heat-induced food contaminants predominantly formed during industrial deodorization of vegetable oils and fats. After consumption, the esters are digested in the gastrointestinal tract, leading to a systemic exposure to the reactive epoxide glycidol. The compound is carcinogenic, genotoxic and teratogenic in rodents, and rated as probably carcinogenic to humans (IARC group 2A). Assessment of exposure from occurrence and consumption data is difficult, as lots of different foods containing refined oils and fats may contribute to human exposure. Therefore, assessment of the internal exposure using the hemoglobin adduct of glycidol, N-(2,3-dihydroxypropyl)-valine (2,3-diHOPr-Val), may be promising, but a proof-of-principle study is needed to interpret adduct levels with respect to the underlying external exposure. A controlled exposure study was conducted with 11 healthy participants consuming a daily portion of about 36 g commercially available palm fat with a relatively high content of ester-bound glycidol (8.7 mg glycidol/kg) over 4 weeks (total amount 1 kg fat, individual doses between 2.7 and 5.2 µg/kg body weight per day). Frequent blood sampling was performed to monitor the 2,3-diHOPr-Val adduct levels during formation and the following removal over 15 weeks, using a modified Edman degradation and ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Results demonstrated for the first time that the relatively high exposure during the intervention period was reflected in corresponding distinct increases of 2,3-diHOPr-Val levels in all participants, following the expected slope for hemoglobin adduct formation and removal over time. The mean adduct level increased from 4.0 to 12.2 pmol 2,3-diHOPr-Val/g hemoglobin. By using a nonlinear mixed model, values for the adduct level/dose ratio (k, mean 0.082 pmol 2,3-diHOPr-Val/g hemoglobin per µg glycidol/kg body weight) and the adduct lifetime (τ, mean 104 days, likely the lifetime of the erythrocytes) were determined. Interindividual variability was generally low. 2,3-DiHOPr-Val was therefore proven to be a biomarker of the external dietary exposure to fatty acid esters of glycidol. From the background adduct levels observed in our study, a mean external glycidol exposure of 0.94 µg/kg body weight was estimated. This value is considerably higher than current estimates for adults using occurrence and consumption data of food. Possible reasons for this discrepancy are discussed (other oral or inhalational glycidol sources, endogenous formation, exposure to other chemicals also forming the adduct 2,3-diHOPr-Val). Further research is necessary to clarify the issue.

Toxicology and risk assessment of acrolein in food.

Acrolein is an α,ß-unsaturated aldehyde formed by thermal treatment of animal and vegetable fats, carbohydrates and amino acids. In addition it is generated endogenously. As an electrophile, acrolein forms adducts with gluthathione and other cellular components and is therefore cytotoxic. Mutagenicity was shown in some in vitro tests. Acrolein forms different DNA adducts in vivo, but mutagenic and cancerogenous effects have not been demonstrated for oral exposure. In subchronic oral studies, local lesions were detected in the stomach of rats. Systemic effects have not been reported from basic studies. A WHO working group established a tolerable oral acrolein intake of 7.5 µg/kg body weight/day. Acrolein exposure via food cannot be assessed due to analytical difficulties and the lack of reliable content measurements. Human biomonitoring of an acrolein urinary metabolite allows rough estimates of acrolein exposure in the range of a few µg/kg body weight/day. High exposure could be ten times higher after the consumption of certain foods. Although the estimation of the dietary acrolein exposure is associated with uncertainties, it is concluded that a health risk seems to be unlikely.

Risks and benefits of dietary isoflavones for cancer.

A high intake of fruits and vegetables is associated with a lower risk of cancer. In this context, considerable attention is paid to Asian populations who consume high amounts of soy and soy-derived isoflavones, and have a lower risk for several cancer types such as breast and prostate cancers than populations in Western countries. Hence, interest focuses on soyfoods, soy products, and soy ingredients such as isoflavones with regard to their possible beneficial effects that were observed in numerous experiments and studies. The outcomes of the studies are not always conclusive, are often contradictory depending on the experimental conditions, and are, therefore, difficult to interpret. Isoflavone research revealed not only beneficial but also adverse effects, for instance, on the reproductive system. This is also the case with tumor-promoting effects on, for example, breast tissue. Isoflavone extracts and supplements are often used for the treatment of menopausal symptoms and for the prevention of age-associated conditions such as cardiovascular diseases and osteoporosis in postmenopausal women. In relation to this, questions about the effectiveness and safety of isoflavones have to be clarified. Moreover, there are concerns about the maternal consumption of isoflavones due to the development of leukemia in infants. In contrast, men may benefit from the intake of isoflavones with regard to reducing the risk of prostate cancer. Therefore, this review examines the risks but also the benefits of isoflavones with regard to various kinds of cancer, which can be derived from animal and human studies as well as from in vitro experiments.

Toxicological assessment of 3-chloropropane-1,2-diol and glycidol fatty acid esters in food.

Fatty acid esters of 3-chloropropane-1,2-diol (3-MCPD) and glycidol are a newly identified class of food process contaminants. They are widespread in refined vegetable oils and fats and have been detected in vegetable fat-containing products, including infant formulas. There are no toxicological data available yet on the 3-MCPD and glycidol esters, and the primary toxicological concern is based on the potential release of 3-MCPD or glycidol from the parent esters by lipase-catalyzed hydrolysis in the gastrointestinal tract. Although 3-MCPD is assessed as a nongenotoxic carcinogen with a tolerable daily intake (TDI) of 2 µg/kg body weight (bw), glycidol is a known genotoxic carcinogen, which induces tumors in numerous organs of rodents. The initial exposure estimates, conducted by Federal Institute for Risk Assessment (BfR) under the assumption that 100% of the 3-MPCD and glycidol are released from their esters, revealed especially that infants being fed commercial infant formula could ingest harmful amounts of 3-MCPD and glycidol. However, the real oral bioavailability may be lower. As this gives rise for toxicological concern, the currently available toxicological data of 3-MCPD and glycidol and their esters are summarized in this review and discussed with regard to data gaps and further research needs.

Toxicology and risk assessment of coumarin: focus on human data.

Coumarin is a secondary phytochemical with hepatotoxic and carcinogenic properties. For the carcinogenic effect, a genotoxic mechanism was considered possible, but was discounted by the European Food Safety Authority in 2004 based on new evidence. This allowed the derivation of a tolerable daily intake (TDI) for the first time, and a value of 0.1 mg/kg body weight was arrived at based on animal hepatotoxicity data. However, clinical data on hepatotoxicity from patients treated with coumarin as medicinal drug is also available. This data revealed a subgroup of the human population being more susceptible for the hepatotoxic effect than the animal species investigated. The cause of the high susceptibility is currently unknown; possible mechanisms are discussed. Using the human data, a TDI of 0.1 mg/kg body weight was derived, confirming that of the European Food Safety Authority. Nutritional exposure may be considerably, and is mainly due to use of cassia cinnamon, which is a popular spice especially, used for cookies and sweet dishes. To estimate exposure to coumarin during the Christmas season in Germany, a telephone survey was performed with more than 1000 randomly selected persons. Heavy consumers of cassia cinnamon may reach a daily coumarin intake corresponding to the TDI.