Evidence-Based Guideline of the German Nutrition Society: Fat Intake and Prevention of Selected Nutrition-Related Diseases.

As nutrition-related chronic diseases have become more and more frequent, the importance of dietary prevention has also increased. Dietary fat plays a major role in human nutrition, and modification of fat and/or fatty acid intake could have a preventive potential. The aim of the guideline of the German Nutrition Society (DGE) was to systematically evaluate the evidence for the prevention of the widespread diseases obesity, type 2 diabetes mellitus, dyslipoproteinaemia, hypertension, metabolic syndrome, coronary heart disease (CHD), stroke, and cancer through the intake of fat or fatty acids. The main results can be summarized as follows: it was concluded with convincing evidence that a reduced intake of total and saturated fat as well as a larger intake of polyunsaturated fatty acids (PUFA) at the expense of saturated fatty acids (SFA) reduces the concentration of total and low-density lipoprotein cholesterol in plasma. Furthermore, there is convincing evidence that a high intake of trans fatty acids increases risk of dyslipoproteinaemia and that a high intake of long-chain polyunsaturated n-3 fatty acids reduces the triglyceride concentration in plasma. A high fat intake increases the risk of obesity with probable evidence when total energy intake is not controlled for (ad libitum diet). When energy intake is controlled for, there is probable evidence for no association between fat intake and risk of obesity. A larger intake of PUFA at the expense of SFA reduces risk of CHD with probable evidence. Furthermore, there is probable evidence that a high intake of long-chain polyunsaturated n-3 fatty acids reduces risk of hypertension and CHD. With probable evidence, a high trans fatty acid intake increases risk of CHD. The practical consequences for current dietary recommendations are described at the end of this article.

Evidence-based guideline of the German Nutrition Society: carbohydrate intake and prevention of nutrition-related diseases.

The relative contribution of nutrition-related chronic diseases to the total disease burden of the society and the health care costs has risen continuously over the last decades. Thus, there is an urgent necessity to better exploit the potential of dietary prevention of diseases. Carbohydrates play a major role in human nutrition - next to fat, carbohydrates are the second biggest group of energy-yielding nutrients. Obesity, type 2 diabetes mellitus, dyslipoproteinaemia, hypertension, metabolic syndrome, coronary heart disease and cancer are wide-spread diseases, in which carbohydrates could have a pathophysiologic relevance. Correspondingly, modification of carbohydrate intake could have a preventive potential. In the present evidence-based guideline of the German Nutrition Society, the potential role of carbohydrates in the primary prevention of the named diseases was judged systematically. The major findings were: a high carbohydrate intake at the expense of total fat and saturated fatty acids reduces the concentrations of total, LDL and HDL cholesterol. A high carbohydrate consumption at the expense of polyunsaturated fatty acids increases total and LDL cholesterol, but reduces HDL cholesterol. Regardless of the type of fat being replaced, a high carbohydrate intake promotes an increase in the triglyceride concentration. Furthermore, a high consumption of sugar-sweetened beverages increases the risk of obesity and type 2 diabetes mellitus, whereas a high dietary fibre intake, mainly from whole-grain products, reduces the risk of obesity, type 2 diabetes mellitus, dyslipoproteinaemia, cardiovascular disease and colorectal cancer at varying evidence levels. The practical consequences for current dietary recommendations are presented.

Leptin plasma levels in the general population: influence of age, gender, body weight and medical history.

The polypeptide leptin exerts a multitude of regulatory functions. It has been implicated in the pathophysiology of inflammatory, metabolic and psychiatric disorders and has been found to be differentially expressed in men and women. Although a clear increase of leptin levels with age has been repeatedly observed in men, the association of leptin levels and age in women is an issue of scientific discussion. To investigate the association of age, gender, body mass index (BMI) and selected diseases with plasma levels of leptin in 551 adults randomly chosen from the Bavarian population, we assessed subjects' characteristics, lifestyle, and medical history including life time history of frequent diseases and performed blood sampling and standardized anthropometric measurements. Leptin plasma levels were measured using a Radioimmunoassay. Leptin levels were significantly higher in women as compared to men and this difference persisted even after controlling for differences in age or BMI. Leptin levels increased across the age groups in both men and women. Controlling for differences in BMI substantially attenuated the influence of age on leptin levels. In women, age was no longer significantly associated with leptin levels after controlling for BMI. With regard to medical history, hyperuricemia and gout were significantly associated with higher leptin levels, even after controlling for BMI, whereas subjects with high blood pressure or dyslipoproteinemia showed higher leptin levels only if the BMI was not considered as control variable. The BMI and its influence on the interrelations of gender, age and leptin should be considered when interpreting leptin levels.

Evidence for an association between genetic variants of the fatty acid desaturase 1 fatty acid desaturase 2 ( FADS1 FADS2) gene cluster and the fatty acid composition of erythrocyte membranes.

The present study gives further evidence for the recently found association between variants of the fatty acid desaturase 1 fatty acid desaturase 2 (FADS1 FADS2) gene cluster and PUFA in blood phospholipids and explores this association for cellular fatty acids in erythrocyte membranes. In a subgroup of adults participating in the Bavarian Nutrition Survey II, a cross-sectional population-based study conducted in Bavaria, Germany, allelic variation in three selected loci of the FADS1 FADS2 gene cluster was analysed and used for haplotype construction. Associations with plasma phospholipid PUFA (n 163) and PUFA in erythrocyte membranes (n 535) were investigated by regression analysis. All haplotypes of the original five-loci haplotypes of our previous study could be replicated. In addition, associations with serum phospholipid PUFA were confirmed in the present data set. Although less pronounced, associations between FADS1 FADS2 haplotypes and PUFA in erythrocyte membranes, particularly arachidonic and dihomo-gamma-linolenic acid, could be established. We provide the first replication of the association of the FADS1 FADS2 gene cluster with PUFA in blood phospholipids. For the first time, such associations were also shown for PUFA in cell membranes.

The association between dietary vitamin K intake and serum undercarboxylated osteocalcin is modulated by vitamin K epoxide reductase genotype.

Vitamin K acts as a cofactor during the gamma-carboxylation of vitamin K-dependent proteins. Undercarboxylated osteocalcin (ucOC) is a suggested biomarker of vitamin K status. The +2255 polymorphism of the vitamin K epoxide reductase gene (VKORC1) was shown to be associated with the recycling rate of the active form of vitamin K. We investigated the association between dietary vitamin K intake and serum ucOC and hypothesized that this association might vary by VKORC1 genotype. ucOC and total intact osteocalcin (iOC) concentrations were quantified using specific ELISA tests in serum samples of 548 male and female participants (aged 18-81 years) of the Bavarian Food Consumption Survey II. ucOC was expressed relative to iOC (ucOC/iOC ratio). Dietary intake of vitamin K (phylloquinone and menaquinones) was estimated from three 24 h dietary recalls using previously published food composition data. The association between dietary vitamin K intake and ucOC/iOC ratio was analysed using linear and non-linear regression models. Median intakes of phylloquinone/menaquinones were 83.4/37.6 microg/d in men and 79.6/29.8 microg/d in women, respectively. As expected, vitamin K intake was significantly inversely associated with the ucOC/iOC ratio. The ucOC/iOC ratio differed significantly across variants of the +2255 polymorphism in the VKORC1 gene. Stratification by VKORC1+2255 genotype revealed that only in carriers of the GG genotype (39 % of all participants) did the ucOC/iOC ratio significantly decrease with increasing intake of vitamin K. Thus, the results show that the inverse association between dietary vitamin K intake and serum ucOC depends on a functionally relevant allelic variant of the VKORC1 gene.

Challenges in harmonizing energy and nutrient recommendations in Europe.

At the present time, there is considerable diversity in the dietary reference values and recommendations used across Europe, both in terms of terminology and guideline values. Harmonization of dietary reference values would be beneficial in simplifying nutritional policy, trade, and public understanding of diet and health issues. However, this is not a simple task because of the differences in methodological approaches adopted and the assumptions made. In addition, there are genuine differences in diet, lifestyle and geography that may necessitate retaining variation in some dietary reference values between European nations. The complexities of harmonization were discussed at a recent symposium held under the auspices of the Federation of European Nutrition Societies (FENS). This provided overviews of the different terminologies currently in use, of the variations in reference values for children and adolescents, and of the disparities between different groups of countries in Europe. The symposium hosted by FENS provided a forum to exchange views and to consider the steps that will be needed if harmonization is to be realized in the future. A summary of the presentations and conclusions is presented here.

Supplementation of omega-3 fatty acids in parenteral nutrition beneficially alters phospholipid fatty acid pattern.

BACKGROUND: The clinical safety and the uptake of omega-3 polyunsaturated fatty acids (PUFA) into the serum phospholipids and erythrocyte membranes after administration of fish-oil-supplemented parenteral nutrition (PN) was investigated in colorectal surgical patients. METHODS: Forty patients undergoing colorectal surgery (n = 40) and with an indication for PN were enrolled in a prospective, double-blind, randomized study to receive an omega-3 PUFA-supplemented 20% lipid emulsion (Lipoplus; B. Braun Melsungen, Melsungen, Germany; test group, n = 19) for 5 days postoperatively. The control group received a standard 20% fat emulsion (Lipofundin MCT/LCT, B. Braun Melsungen, Melsungen, Germany, control group, n = 21). Clinical outcome parameters and safety were assessed by means of adverse events recording clinical parameters and hematologic analyses. The contents of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), as well as arachidonic acid (AA), in phospholipid fractions in plasma and in erythrocytes were analyzed preoperatively, on postoperative days 1, 6, and 10 using liquid gas chromatography. RESULTS: Both fat emulsions were well tolerated, and none of the adverse events was considered to be related to treatment. Postoperative infectious complications occurred in 4 patients of the omega-3 PUFA group vs 7 patients in the control group. As compared with the control group, the omega-3 PUFA group had significantly increased levels of EPA in the membranes of the erythrocytes in postoperative day 6 (2.0% +/- 0.9% vs 0.8% +/- 0.5% fatty acid methyl esters, [FAME]) and postoperative day 10 (2.1% +/- 0.8% vs 0.9% +/- 0.7% FAME, p < .05). Also, the EPA levels in the serum phospholipids were significantly higher than in the control group on the same postoperative days (7.0% +/- 2.6% vs 1.3% +/- 0.8% and 3.6% +/- 1.0% vs 1.0% +/- 0.4% FAME, p < .05). The DHA levels in the serum phospholipids were significantly higher in the omega-3 PUFA group compared with the control on postoperative days 6 and 10 (11.8% +/- 1.9% vs 8.4% +/- 1.5% and 11.2% +/- 1.6% vs 8.5% +/- 1.4% FAME, p < .05). AA levels were not significantly different in the both groups. CONCLUSIONS: Omega-3-fatty-acids-supplemented fat emulsions for parenteral administration are safe and very well tolerated. This study demonstrates that parenteral administration of omega-3-PUFA-enriched fat emulsions leads to increased incorporation of EPA and DHA into phospholipids in serum and erythrocytes, whereas AA levels remain unchanged. Thus, postoperative parenteral administration of omega-3-PUFA-enriched lipid emulsions could have an impact on the postoperative inflammatory response after abdominal surgery and could be used in standard postoperative care when PN is indicated.

Determinants and correlates of serum undercarboxylated osteocalcin.

BACKGROUND/AIMS: To assess dietary and nondietary determinants of serum undercarboxylated osteocalcin (ucOC) as a measure of vitamin K status. METHODS: UcOC and total intact osteocalcin (iOC) concentrations were determined by specific ELISA tests in serum samples of 231 male and 320 female participants (18-81 years) of the representative, cross-sectional Bavarian Food Consumption Survey II. Determinants of ucOC were investigated by analysis of variance, Spearman's rank correlation coefficients and logistic regression models. RESULTS: Mean ucOC serum concentration was 2.46 ng/ml in men and 2.34 ng/ml in women. Corresponding means of the ratio of ucOC to iOC (ucOC/iOC) were 0.28 and 0.29. Concentrations of ucOC and iOC, as well as the ratio of ucOC/iOC, strongly depended on the participant's age. UcOC was influenced by smoking status, sports activity, and the season when blood was collected. Dietary intake of the dominant vitamin K sources, green leafy vegetables and dairy products, as well as the plasma concentration of the carotenoid lutein were inversely associated with serum ucOC values. CONCLUSIONS: In studies using serum ucOC as a measure of vitamin K supply, determinants, especially age, need to be taken into account.

TNF-alpha, soluble TNF receptor and interleukin-6 plasma levels in the general population.

The cytokines tumor necrosis factor-alpha (TNF-alpha), soluble TNF receptors p55 and p75, and interleukin 6 (IL-6) are involved in host defense against several microbiological agents, in the process of inflammation and also in body weight regulation. In the present study, we sought to assess the influence of age, gender, smoking, and body mass index on plasma levels of TNF-alpha, TNF receptors, and IL-6 in more than 550 adult subjects randomly selected from the Bavarian population. None of the cytokine parameters had a normal distribution and all distributions were significantly skewed. The cytokine plasma levels investigated increased significantly with age, while gender had a relatively weaker influence on the plasma levels. Plasma levels of TNF-alpha, TNF receptors, and IL-6 correlated significantly with the BMI. The study provides insights into factors influencing the cytokine levels investigated in a randomly chosen study sample.

Plasma levels of tumor necrosis factor alpha and soluble tumor necrosis factor receptors in patients with narcolepsy.

BACKGROUND: Narcolepsy is a disabling sleep disorder characterized by excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis. Recent studies suggest that the immune system might play a pathogenic role pointing to a possible involvement of inflammatory cytokines. METHODS: We investigated a sample of 30 patients with narcolepsy in comparison with 120 sex- and age-matched and 101 sex-, body mass index (BMI)-, and age-matched randomly selected normal controls. In these groups, plasma concentrations of tumor necrosis factor alpha (TNF-alpha) and its soluble receptors p55 and p75 (soluble TNF receptor [sTNF-R] p55 and sTNF-R p75) were measured using commercial enzyme-linked immunosorbent assays. RESULTS: The narcoleptic patients showed a significantly higher BMI compared with controls of the same age. Soluble TNF-R p75 levels were consistently elevated in the narcoleptic patients compared with their sex- and age-matched (P = .001) as well as sex-, BMI-, and age-matched counterparts (P = .003). Female narcoleptic patients exhibited higher sTNF-R p55 levels compared with their sex- and age-matched controls (P = .01), but this difference disappeared when comparing patients with sex-, BMI-, and age-matched normal controls. Tumor necrosis factor alpha levels did not differ significantly between groups. CONCLUSION: Narcoleptic patients show increased plasma levels of sTNF-R p75, suggesting a functional alteration of the TNF-alpha cytokine system, further corroborating a possible pathogenic role of the immune system in this sleep disorder.

Preoperative oral supplementation with long-chain Omega-3 fatty acids beneficially alters phospholipid fatty acid patterns in liver, gut mucosa, and tumor tissue.

BACKGROUND: The uptake of omega-3 polyunsaturated fatty acids (PUFAs) into the liver, gut mucosa, and tumor tissue and plasma levels after preoperative administration of supplemented enteral nutrition was investigated in patients with malignancies of the upper gastrointestinal tract. The objective of the study was to evaluate the incorporation of preoperatively administrated PUFAs, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) into cell phospholipids. METHODS: Patients undergoing major gastrointestinal surgery (n = 40) were prospectively randomized to receive a PUFA-supplemented liquid oral diet 5 days preoperatively or an isocaloric control diet. The planned diet intake was 1000 mL/d providing 3.7 g of PUFA. The diet was given in addition to the usual hospital diet. The phospholipid fractions in plasma were analyzed on the day of surgery. Tissue samples of liver, gut mucosa (small intestine), and tumor were taken during surgery and homogenized. EPA and DHA content was analyzed using liquid gas chromatography. RESULTS: Both patient groups (PUFA group: n = 20; control group: n = 20) were similar in age, weight, and surgical procedures. As compared with the control group, the PUFA group had significantly increased levels of EPA in liver tissue (0.4 vs 1.3 weight %), gut mucosa (0.3 vs 1.0 weight %), and tumor tissue (0.3 vs 0.8 weight %). Also, the DHA levels in the PUFA group were significantly higher than the control group: liver tissue (4.1 vs 7.5 weight %), gut mucosa (2.1 vs 3.7 weight %) and tumor tissue (1.9 vs 4.2 weight %). CONCLUSIONS: This study suggests that administration of PUFA-enriched diets leads to increased incorporation of EPA and DHA not only in liver and gut mucosa tissue, but also in tumor tissue in patients with solid gastrointestinal tumors. Thus, preoperative administration of oral PUFA-enriched diets could have an impact on the postoperative inflammatory response after major abdominal surgery.

Estimated physical activity in Bavaria, Germany, and its implications for obesity risk: results from the BVS-II Study.

BACKGROUND: Adequate physical activity (PA) is considered as a key factor in the fight against the obesity epidemic. Therefore, detailed description of the actual PA and its components in the population is necessary. Additionally, this study aims to investigate the association between PA and obesity risk in a representative population sample in Bavaria, Germany. METHODS: Data from 893 participants (age 13-80 years) of the Bavarian Food Consumption Survey II (BVS II) were used. In each participant, three computer-based 24-hour recalls were conducted by telephone assessing type and duration of PA in the domains occupation, sports, other strenuous leisure time activities (of mostly moderate intensity) as well as TV/PC use in leisure time and duration of sleeping. After assigning metabolic equivalents (METs) to each activity, estimates of energy expenditure (MET*h) and total daily PA level (PALest.) were calculated. In a subgroup of adults (n = 568) with anthropometric measurements logistic regression models were used to quantify the impact of PA on obesity risk. RESULTS: Estimated average PA in women and men was 38.5 +/- 5.0 and 40.6 +/- 9.3 MET*h/d, respectively, corresponding to PALest. values of 1.66 +/- 0.22 and 1.75 +/- 0.40. Obese subjects showed lower energy expenditure in the categories sports, occupation, and sleeping, while the time spent with TV/PC during leisure time was highest. This is confirmed in logistic regression analyses revealing a statistically significant association between obesity and TV/PC use during leisure time, while sports activity was inversely related to obesity risk. Overall, less than 1/3 of the study participants reached the recommended PAL of >or= 1.75. Subjects within the recommended range of PA had an about 60 % (odds ratio = 0.43; 95% CI: 0.21-0.85) reduced risk of obesity as compared to inactive subjects with a PALest. <1.5. CONCLUSION: Based on the results of short-term PA patterns, a major part of the Bavarian adult population does not reach the recommendations (PAL>1.75; moderate PA of > 30 min/d). Despite the limitations of the study design, the existing associations between sports activity, TV/PC use and obesity risk in this population give further support to the recommendation of increasing sports activity and reducing sedentary behaviour in order to prevent rising rates of obesity.

Interactive effects of polyphenols, tocopherol and ascorbic acid on the Cu2+-mediated oxidative modification of human low density lipoproteins.

BACKGROUND: Only limited knowledge is available about any interactions between phenolic compounds and other antioxidants in inhibiting LDL oxidation. Many foods and beverages contain high levels of phenolic compounds; therefore, these compounds should not be considered in isolation from each other. AIM OF THE STUDY: The aim of this study was to examine the structure-antioxidant activity relationship of quercetin, caffeic acid, epicatechin, hesperetin and phloretin as well as alpha-tocopherol and ascorbic acid through their ability to interact with copper ions. METHODS: Isolated human LDL were incubated with single antioxidants or a combination of two and the kinetics of lipid peroxidation were assessed by measurement of conjugated diene formation (lag phase) via monitoring the absorbance at 234 nm after addition of copper ions. In addition, the degree of oxidation of the LDL protein moiety was followed by tryptophan fluorescence and carbonyl content measurements. RESULTS: Alpha-tocopherol and ascorbic acid showed a lower antioxidant activity in all test systems as compared to polyphenols at equimolar concentrations. Quercetin was the most effective compound in all three systems (p < 0.001 for lag phase and carbonyl content determination). A significant (p < 0.001) prolongation of the lag phase was found when combinations of ascorbic acid/quercetin, ascorbic acid/epicatechin, epicatechin/caffeic acid, and quercetin/epicatechin were tested as compared to the sum of the individual effects. Concerning the effects on LDL protein oxidation, the results from carbonyl content and the tryptophan fluorescence measurements showed that the combination of quercetin and caffeic acid revealed the strongest inhibitory effect (p < 0.001 carbonyl content; p < or = 0.002 tryptohan fluorescence) on protein oxidation which was higher than the effect of the single compounds. CONCLUSIONS: The results of the present study indicate that a combination of different antioxidants can be superior to the action of single antioxidants in protecting LDL lipid and protein moiety against oxidation. However, the substances may act by different antioxidative mechanisms, which are not necessarily complementary.

Plasma 7beta-hydroxycholesterol as a possible predictor of lung cancer risk.

Epidemiological data suggests a role of dietary cholesterol in the etiology of lung cancer without having a clear biological hypothesis. Although smoking as the outstanding risk factor for lung cancer may enhance lipid peroxidation reactions, this study was planned to assess smoking-independent associations between the extent of cholesterol oxidation and the risk for lung cancer. In the frame of a nested case-control study in European Prospective Investigation on Cancer-Heidelberg, six cholesterol oxidation products (COPs) were determined in plasma samples of 20 incident lung cancer patients obtained 1.9 +/- 0.6 years before diagnosis and in 40 matched (including smoking habits) controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by conditional logistic regression. Among all COP compounds tested, plasma 7beta-hydroxycholesterol was associated with lung cancer risk. The high crude risk estimate (OR approximately equals 5) became significant after adjustment for sports activity (OR = 6.83, CI = 1.08-43.01, 3rd versus 1st tertile). For the independent effect of 7beta-hydroxycholesterol, i.e., adjusted for other COP compounds, an OR of 8.08 (CI = 1.12-58.54, 3rd versus 1st tertile) was calculated (P = 0.04 for trend). Lung cancer risk adjusted for sports activity significantly increased by 26% (CI = 1.050-1.506, P = 0.01) per unit (1 nmol/mmol plasma cholesterol) of 7beta-hydroxycholesterol. No dietary factor had a significant effect in the regression model, but the dietary intake of meat, eggs, animal fat, cholesterol, and fruits (inversely) correlated with plasma COP concentrations. In this small study, plasma 7beta-hydroxycholesterol appeared to be a smoking-independent predictor of lung cancer risk and might therefore be used as a biomarker. Because of the rather high-risk estimate, research on possible intrinsic biological effects of this compound should be encouraged.

Fasting plasma concentrations of selected flavonoids as markers of their ordinary dietary intake.

BACKGROUND: Dietary flavonoids, especially flavonols, are discussed as potentially preventive agents in the etiology of diseases such as coronary heart disease, stroke, and cancer. However, their consideration in epidemiologic studies is hampered by difficulties in exposure assessment. AIM OF THE STUDY: By comparison with dietary intake estimates, fasting plasma flavonoid concentrations should be evaluated as possible biomarkers of the ordinary dietary intake. METHODS: 7-d dietary records were completed by 48 healthy female students. Flavonoid intake was estimated by means of available literature data on the flavonoid content of foods. Fasting plasma samples were taken at the end of the record period for flavonoid determination (HPLC). RESULTS: The mean intake estimates (7-d period) of quercetin, kaempferol, naringenin, and hesperetin amounted to 17.9, 4.7, 12.1, and 17.4 mg/d, respectively; the corresponding mean plasma concentrations were 22.9, 10.7, 8.2, and 22.2 nmol/l. For all four flavonoids significant correlations between 7d-intake results and fasting plasma concentrations (r = 0.30-0.46, p < 0.05) existed. As expected from the known short elimination half-life of some plasma flavonoids, distinctly higher correlation coefficients were found for the relationship between intake estimates for the last day before blood sampling and the fasting plasma concentrations (r = 0.42-0.64; p < 0.01). The intraindividual variation in fasting plasma flavonoid concentrations during ad libitum intake was found to be rather high (mean coefficient of variation between 82 and 91 %; n = 4). CONCLUSIONS: The flavonoid content in fasting plasma samples seems to be a suitable biomarker of short-term intake and a possible biomarker of the medium-term intake. Due to the high intraindividual variation the combined use of plasma flavonoid concentrations and dietary intake estimates may be the best choice in epidemiologic studies.

Nutrition, antioxidants, and risk factor profile of nonsmokers, passive smokers and smokers of the Prevention Education Program (PEP) in Nuremberg, Germany.

BACKGROUND: An elevated risk for coronary artery disease and lung cancer was reported for smokers and nonsmokers exposed to environmental tobacco smoke. Particularly in nonsmokers, in addition to the adverse effects of tobacco smoke, other factors which are associated with the exposure to environmental tobacco smoke may contribute to the health risks. We investigated both by questionnaires and biochemical analyses whether smokers influence the dietary habits of nonsmokers living in the same household. METHODS: The study population was a subgroup of the Prevention Education Program in Nuremberg: 817 adults aged 27-66 years were allocated to one of the four groups: Nonsmokers living with a nonsmoker (Group 1), nonsmokers living with a smoker (Group 2), smokers living with a nonsmoker (Group 3), and smokers living with a smoker (Group 4). RESULTS: The four groups did not differ in the body mass index, the concentration of lycopene, all-trans-retinol, and selenium in plasma. Plasma concentrations of high-density lipoprotein cholesterol, triglycerides, homocysteine, cobalamin, folate, beta-carotene, and alpha-tocopherol showed a gradient to unfavorable levels from Group 1 to Group 4. This trend was also reflected in the reported dietary intake of beta-carotene, alpha-tocopherol, ascorbic acid, fiber, and linoleic acid. CONCLUSIONS: Our data show that nonsmokers living with smokers indulge in less healthy dietary habits than nonsmokers living with nonsmokers. This has to be considered when evaluating the health risks of exposure to environmental tobacco smoke.

Dietary conjugated linoleic acid (CLA) intake assessment and possible biomarkers of CLA intake in young women.

OBJECTIVE: The habitual intake of the conjugated linoleic acid (CLA) isomer C18:2 c9t11 (rumenic acid, RA) was assessed and compared with plasma biomarkers. DESIGN: The newly developed food-frequency questionnaire (FFQ) comprised 46 food items and was validated by means of a 7-day estimated record (7-d ER). Additionally, the dietary intake results of the FFQ, 7-d ER, the last day (1-d ER) and the last two days (2-d ER) before blood sampling of the 7-d ER were compared to the content of C18:2 c9t11 in plasma phospholipids (PL) and triglycerides (TG) as possible biomarkers. SETTING: Metabolic unit of a university institute. SUBJECTS: Fifty-seven students completed both dietary instruments. From all participants fasting blood samples were taken. RESULTS: Mean daily intake of rumenic acid was 246 mg day(-1) and 323 mg day(-1) as measured by the FFQ and the 7-d-ER, respectively. The degree of correspondence between both assessment methods was acceptable; this is indicated by a total kappa value of kappa = 0.31 (P < 0.01) and a Pearson correlation coefficient of r = 0.46 (P < 0.01). Rumenic acid content in plasma triglycerides was twice as high as found in phospholipids. The correlation between the intake results gained with the 7-d ER and the plasma PL contents of C18:2 c9t11 was statistically significant; this was also true for the C18:2 c9tl 1 values in plasma TG compared with the intake results of one or two days before blood sampling. CONCLUSIONS: Regarding RA intake, the FFQ data revealed an acceptable degree of correspondence with the 7-d ER data but failed to show significant correlations to the potential biomarkers. However, with respect to the results of the 7-d ER, the RA content in plasma PL and TG are possible biomarkers of short-term and medium-term intake, respectively.