Frozen yogurt and ice cream were less healthy than yogurt,and adding toppings reduced their nutrition value: evidence from 1999-2014 National Health and Nutrition Examination Survey

It was hypothesized that frozen yogurt and ice cream would be less healthy than yogurt. We examined daily energy and nutrient intake from yogurt, frozen yogurt, and ice cream among US adults. In-person 24-hour dietary recall data (n = 6453) came from the 1999-2014 National Health and Nutrition Examination Survey. Regression analyses were performed to examine the differences in energy/nutrient intake from frozen yogurt and ice cream (with/without toppings) in comparison to yogurt. Approximately 5.3%, 0.9%, and 14.3% of US adults consumed yogurt, frozen yogurt, and ice cream on any given day, respectively. Among frozen yogurt and ice cream consumers, 29.7% and 14.8% added toppings to their consumption, respectively. Compared with yogurt, frozen yogurt consumption with and without toppings was associated with increased daily energy intake by 214.6 and 97.9 kj, respectively; whereas ice cream consumption with and without toppings was associated with increased daily energy intake by 427.2 and 343.5 kj, respectively. Compared with yogurt, frozen yogurt consumption was associated with a decreased intake of most vitamins/minerals under examination, but increased intake of sugar, total/saturated fat, cholesterol, fiber, and iron. Adding toppings to frozen yogurt further increased total and saturated fat intake. Compared with yogurt, ice cream consumption was associated with a decreased intake of multiple micronutrients, but increased intake of sugar, total/saturated fat, cholesterol, fiber, vitamins A and E, and iron. Adding toppings to ice cream further increased sugar intake. In conclusion, frozen yogurt and ice cream were less healthy than yogurt, and adding toppings made them even less desirable.     

Green tea or rosemary extract added to foods reduces nonheme-iron absorption

BACKGROUND: Phenolic compounds act as food antioxidants. One of the postulated mechanisms of action is chelation of prooxidant metals, such as iron. Although the antioxidative effect is desirable, this mechanism may impair the utilization of dietary iron. OBJECTIVE: We sought to determine the effect of phenolic-rich extracts obtained from green tea or rosemary on nonheme-iron absorption. DESIGN: Young women aged 19-39 y consumed test meals on 4 separate occasions. The meals were identical except for the absence (meal A) or presence (meal B) of a phenolic-rich extract from green tea (study 1; n = 10) or rosemary (study 2; n = 14). The extracts (0.1 mmol) were added to the meat component of the test meals. The meals were extrinsically labeled with either 55Fe or 59Fe and were consumed on 4 consecutive days in the order ABBA or BAAB. Iron absorption was determined by measuring whole-body retention of 59Fe and the ratio of 55Fe to 59Fe activity in blood samples. RESULTS: The presence of the phenolic-rich extracts resulted in decreased nonheme-iron absorption. Mean (+/-SD) iron absorption decreased from 12.1 +/- 4.5% to 8.9 +/- 5.2% (P < 0.01) in the presence of green tea extract and from 7.5 +/- 4.0% to 6.4 +/- 4.7% (P < 0.05) in the presence of rosemary extract. CONCLUSION: Phenolic-rich extracts used as antioxidants in foods reduce the utilization of dietary iron.     

Influence of nutritional knowledge on perceived healthiness and willingness to try functional foods

In order to assess the influence of nutritional knowledge on perceived healthiness and willingness to try functional foods, 104 consumers filled out a Nutritional Knowledge Questionnaire and answered a conjoint task. Participants had to evaluate 16 concepts consisting of combinations of carrier products (yogurt, milk desserts, pan bread and mayonnaise) and nutritional modifications (regular product, low-fat, enriched with antioxidants, and enriched with fibre). Three groups of consumers were identified with different level of nutritional knowledge. Highly significant differences were found in the healthiness evaluations of the clusters, which mainly depended on nutritional knowledge related to the links of diet and diseases. Highly significant differences in willingness to try functional foods were also found between the clusters. Whereas consumers with the lowest nutritional knowledge were not interested in consuming functional foods, the addition of fibre or antioxidants to healthy products increased the willingness of consumers with the highest level of nutritional knowledge to try the evaluated functional foods. These results suggested that lack of nutritional knowledge might limit the acceptance of functional foods and thus the use of health claims might be necessary to assure that consumers are aware of their health benefits.     

Postprandial metabolic events and fruit-derived phenolics: a review of the science

There is increasing evidence that the postprandial state is an important contributing factor to chronic disease. The role of fruit phenolic compounds to protect health and lower disease risk through their actions in mitigating fed-state metabolic and oxidative stressors is of interest and the topic of the present paper. Two main questions are posed: first, what is the role of plant foods, specifically fruits rich in complex and simple phenolic compounds in postprandial metabolic management; and second, does the evidence support consuming these fruits with meals as a practical strategy to preserve health and lower risk for disease? This review provides an overview of the postprandial literature, specifically on the effect of fruits and their inherent phenolic compounds in human subjects on postprandial lipaemia, glycaemia/insulinaemia and associated events, such as oxidative stress and inflammation. Among the identified well-controlled human trials using a postprandial paradigm, >50?% of the trials used wine or wine components and the remaining used various berries. Notwithstanding the need for more research, the collected data suggest that consuming phenolic-rich fruits increases the antioxidant capacity of the blood, and when they are consumed with high fat and carbohydrate 'pro-oxidant and pro-inflammatory' meals, they may counterbalance their negative effects. Given the content and availability of fat and carbohydrate in the Western diet, regular consumption of phenolic-rich foods, particularly in conjunction with meals, appears to be a prudent strategy to maintain oxidative balance and health.     

Apple as sugar substitute in cake

The reduction of sugar in food is important for healthy eating without drastically changing eating habits. Fruits can contribute to sweetener the flavor and it can also improve the fiber content and the bioactive compounds, contributing to turn the product healthier. The aims of this study were to evaluate apple as sugar substitute in cake and to analyze nutritional and sensorial aspects. The nutritional composition was evaluated based on the Brazilian Food Composition Table. The sensory analysis was conducted with 9-point hedonic scale. Apples’ puree replacing sugar turned the cake healthier due to the reduction on TEV, lipid and carbohydrates content. It also increased the dietary fiber. There were differences on color, flavor and texture between cakes mean acceptance, but the overall quality means were not statistically different showing the possibility of sugar cane exclusion. Flavor, texture and overall quality of modified samples presented good acceptance by the tasters.     

Wine modifies the effects of alcohol on immune cells of mice

Ethanol may be detrimental to immune cells due to the generation of free radicals during detoxification. If this is true, then alcoholic beverages that contain antioxidants, like red wine, should be protective against immune cell damage. We investigated this by giving mice either a red muscadine wine (Vitis rotundifolia), a cabernet sauvignon (Vitis vinifera), ethanol (all at 6% alcohol) or water in the water bottles as the sole fluid for 8 wk. Plasma antioxidant capacity was measured with alphaalpha-diphenyl-beta-picrylhydrazyl and was more than doubled in the mice that consumed wine compared to control mice that consumed water or ethanol. Cytochrome P450-2E1 levels and glutathione-S-transferase activity were modified in such a way as to be interpreted as protective. An immune response was elicited by an intraperitoneal injection of lipopolysaccharide. Later (24 h), natural killer cells and T-lymphocytes derived from the circulation were quantitated in the leukocyte fraction by flow cytometry. Ethanol consumption, as ethanol, significantly suppressed baseline cell numbers relative to the other groups. However, the mice that consumed the same amount of alcohol as wine had baseline cell numbers not different from the water-consuming controls. The lymphocyte response to lipopolysaccharide challenge was inhibited in the mice that consumed ethanol, but was normal in those that consumed the same amount of alcohol in the form of wine. We conclude that there are phytochemicals acting as antioxidants and impacting on the detoxification pathway in the wine that offset the detrimental effects of ethanol on immunity.     

Starch-based conditioned flavor preferences in rats: influence of taste, calories and CS-US delay

Six experiments examined the rat's preference for flavors associated with hydrolysed starch (Polycose) solutions. Hungry rats developed a preference for a flavor (CS+) mixed into a saccharin-sweetened 16% Polycose solution over a flavor (CS-) mixed in saccharin-water. The addition of acarbose, a drug which inhibits starch digestion, to the Polycose solution blocked the flavor preference. This finding indicates that it is the postingestive rather than the taste properties of Polycose that condition flavor preferences. Rats also developed a preference for a CS+ flavor that preceded the ingestion of a Polycose solution by 10 min. This flavor conditioning, however, was not obtained in all experiments. Some CS flavors may be more effective than others in producing conditioned flavor preferences over a delay. Preference conditioning over a delay was facilitated when the rats had previously learned that the taste of the US (Polycose) was not associated with rapid caloric repletion; this was accomplished by giving the rats prior exposure to a Polycose + acarbose solution. Rats with such pre-exposure learned to prefer a CS + flavor that preceded by 10 to 60 min the consumption of a Polycose solution (without acarbose). The results demonstrate that calorie-based flavor preferences can be conditioned over a delay, but conditioning is influenced by the nature of the CS and US stimuli used.     

Intakes of antioxidants in coffee, wine, and vegetables are correlated with plasma carotenoids in humans

The consumption of fruits and vegetables reduces the risk of major chronic degenerative diseases. The active compounds and the mechanisms involved in this protective effect have not been well defined. The objective of this study was to determine the contribution of various food groups to total antioxidant intake, and to assess the correlations of the total antioxidant intake from various food groups with plasma antioxidants. We collected 7-d weighed dietary records in a group of 61 adults with corresponding plasma samples, and used data from a nationwide survey of 2672 Norwegian adults based on an extensive FFQ. The total intake of antioxidants was approximately 17 mmol/d with beta-carotene, alpha-tocopherol, and vitamin C contributing <10%. The intake of coffee contributed approximately 11.1 mmol, followed by fruits (1.8 mmol), tea (1.4 mmol), wine (0.8 mmol), cereals (i.e., all grain containing foods; 0.8 mmol), and vegetables (0.4 mmol). The intake of total antioxidants was significantly correlated with plasma lutein, zeaxanthin, and lycopene. Among individual food groups, coffee, wine, and vegetables were significantly correlated with dietary zeaxanthin, beta-carotene, and alpha-carotene. These data agree with the hypothesis that dietary antioxidants other than the well-known antioxidants contribute to our antioxidant defense. Surprisingly, the single greatest contributor to the total antioxidant intake was coffee.     

Red wine is a poor source of bioavailable flavonols in men

Red wine is a source of polyphenolic antioxidants, of which flavonols such as quercetin are representatives. Red wine might therefore prevent LDL oxidation and atherosclerosis. However, data on the bioavailability of flavonols from wine are lacking. Therefore, we compared the bioavailability of flavonols, especially quercetin, from red wine with that from the major dietary sources, yellow onions and black tea. Twelve healthy men consumed 750 mL red wine, 50 g fried onions or 375 mL of black tea, each for 4 d in random order. These supplements provided similar amounts of quercetin (14-16 mg). There was a washout period of 3 d between each period of supplementation. The plasma quercetin concentration after the consumption of wine was lower than that after onions (P: < 0.05) and not different from that after tea. Urinary excretion of quercetin after wine did not differ from that after onions and was higher than that after tea (P: < 0.05). We conclude that flavonols from red wine are absorbed. However, because one glass of red wine provides fewer available flavonols than one portion of onions or one glass of tea, red wine appears to be a poorer source of flavonols than these other two sources.     

Bioaccessibility of folic acid and (6S)-5-methyltetrahydrofolate decreases after the addition of folate-binding protein to yogurt as studied in a dynamic in vitro gastrointestinal model

Milk products are only moderate sources of folate. Nevertheless, they are of interest due to their content of folate-binding proteins (FBP), which in some studies have been reported to increase folate bioavailability. The effect of FBP on folate bioavailability has been widely discussed. The aim of this study was to investigate the bioaccessibility of folic acid and (6S)-5-methyltetrahydrofolate (5-CH3-H4folate) from fortified yogurt using a dynamic in vitro gastrointestinal model (TIM). In addition, the effect of FBP on folate bioaccessibility and the stability of FBP added to yogurt during gastrointestinal passage were investigated. Folate bioaccessibility was 82% from yogurt fortified with folic acid and 5-CH3-H4folate. The addition of FBP to yogurt decreased (P < 0.05) folate bioaccessibility. The lowering effect of FBP was more pronounced in yogurt fortified with folic acid (34% folate bioaccessibility) than from yogurt fortified with 5-CH3-H4folate (57% folate bioaccessibility). After gastrointestinal passage, 17% of the FBP in yogurt fortified with 5-CH3-H4folate and 34% of the FBP in yogurt fortified with folic acid were recovered. No difference in folate bioaccessibility was found between folate-fortified yogurt and folate-fortified pasteurized milk (P = 0.10), whereas the lowering effect of FBP was (P < 0.05) greater in yogurt compared with pasteurized milk. In conclusion, based on the high bioaccessibility of folic acid and 5-CH3-H4folate, yogurt without active FBP can be considered to be an appropriate food matrix for folate fortification.     

Postprandial Improvement of Endothelial Function by Red Wine and Olive Oil Antioxidants: A Synergistic Effect of Components of the Mediterranean Diet

Objective: Consumption of olive oil may cause postprandial impairment of endothelial function, while acute ingestion of red wine seems to improve it. The purpose of the present study was to investigate the combined postprandial effects of two essential components of the Mediterranean diet, red wine and olive oil, on endothelial function.

Methods: Fifteen healthy subjects were enrolled in the study, which was comprised of 4 study days. Subjects were asked to consume a standard meal at each study day containing 50gr of olive oil and 250 ml of wine. Two types of wine (red and white; rich and poor in antioxidants respectively) and two types of olive oil (green and refined; rich and poor in antioxidants respectively) were used in a 2*2 design. Endothelium dependent, flow mediated dilatation (FMD) was measured with a B-Mode ultrasound device at fast and 1, 2 and 3 hours postprandially.

Results: Combined consumption of red wine and green olive oil (both rich in antioxidants) improved FMD postprandially (p = 0.002, ANOVA for repeated measures), which remained significant 1 hour (p = 0.002) and 2 hours (0.037) following the meal compared to fasting levels. No other combination of wine and olive oil caused any significant alteration on FMD.

Conclusion: Acute consumption of both red wine and green olive oil, rich in antioxidants, led to an improvement in the postprandial endothelial function in healthy subjects. These findings provide an additional favorable effect of components of the Mediterranean diet and of their antioxidant substances on endothelial function, at the postprandial state.     

The effect of grape-skin extract on oxidative status

Epidemiological studies indicate that moderate alcohol consumption, particularly wine, reduce the risk of CHD. The present study was designed to investigate the effect of grape-skin extract on markers of oxidative status. The study was designed as a randomised crossover. A diet with a low content of flavonoids was served with strict control of intake in two consecutive 1-week intervention periods to fifteen subjects (nine women, six men) divided randomly into two groups. During one of the weeks the subjects from either group consumed 200 ml grape-skin extract in water (1 mg extract/ml) at each of three daily meals (31.3 mg total phenolics, including 9.0 mg catechin). An increased activity of glutathione reductase and a borderline increase of glutathione peroxidase activity in erythrocytes were observed after grape-skin intervention, while the intervention had no significant effect on superoxide dismutase or catalase. Likewise, no effect was found on 2-aminoadipic semialdehyde (AAS) residues, a plasma protein oxidation product, or on malondialdehyde in plasma or in LDL, which are markers of lipoprotein oxidation. A marginal effect of grape-skin intervention was observed on plasma ascorbate levels. Intake of the experimental diet significantly reduced plasma vitamin C and plasma AAS in both groups. This effect was most pronounced in the particular week with no grape-skin extract addition. We speculate that grape-skin extract may have a sparing effect on vitamin C. The effects of the experimental diet may be partly ascribed to a low content of several fruit- and vegetable-related antioxidants like flavonoids and vitamin C and a relatively high content of carrot-derived antioxidants, such as carotenes.     

Characteristics of yogurt-like products prepared from the combination of skim milk and soymilk containing saccharified-rice solution

Yogurt-like products were prepared from a combination of skim milk and soymilk (100:0, 75:25, 50:50, 25:75, and 0:100) containing saccharified-rice solution by lactic fermentation of four different cultures. The ratio of skim milk and soy milk had no significant effect on titratable acidity, while the type and nature of culture used for fermentation affected the titratable acidity. Lower syneresis was observed in soy-based yogurt, and both the hardness and springiness of curd increased as the proportion of soymilk in the substrate increased. Skim milk-based yogurt had higher resistance to shear force with higher yield stress. The sensory quality of yogurt produced from mixed culture had higher preference compared with that produced from a single culture (Streptococcus thermophilus). There was no significant difference in texture and overall acceptability among yogurts produced from mixed substrates and skim milk-based yogurt.     

Effect of select antioxidants on malondialdehyde modification of proteins

To determine whether commonly used antioxidants alter malondialdehyde (MDA) modification of proteins, a known mechanism of free radical-related tissue injury, we studied the effect of adding 1 mg/mL of pycnogenol, 5 mM of alpha-tocopherol, 5 mM of ascorbate, and 0.2 mg/mL of an ethanol equivalent of red and white wine on MDA-protein content of endothelial cells in culture. The addition of pycnogenol but not of the other antioxidants was associated with significant reduction in MDA-protein content compared with controls (0.521 +/- 0.041 in arbritrary units versus 1.011 +/- 0.021, P < 0. 001). To determine whether the observed effect occurs distal to MDA generation, the effect of these antioxidants on the modification of bovine serum albumin with MDA generated in a cell-free system was studied. In this cell-free assay, pycnogenol but not the other antioxidants reduced MDA-BSA generation by approximately 50%. It is concluded that pycnogenol may reduce MDA modification of proteins at a step distal to MDA generation. This may be an additional mechanism of protective effects of pycnogenol against oxidative stress.     

酸牛乳抑制1,2-二甲基肼诱发小鼠大肠癌的实验研究

106只小鼠随机分成5组,每组18至23只。1～3组小鼠皮下注射1,2-二甲基肼(DMH),剂量20mg/kg体重,每周一次,连续20周。实验结束前,动物分别自由饮用自来水(第一组),水加嗜酸乳酸杆菌酸牛乳(第二组)及水加牛乳(第三组)。第4组和第5组为对照组,动物分别皮下注射1mM EDTA和蒸馏水。 27周诱癌期后,对照组小鼠未发生肿瘤。DMH处理动物中,第2组的结肠癌发生率为44.4％,比第1组(80％)和第3组(100％)明显降低(P<0.05)。此外,实验期间第2组动物的存活率(100％) 比第1组(80％)和第3组(74％)都高。结论是喂饲嗜酸乳酸杆菌(Shahani株)制备的酸牛乳能显著降低DMH诱发的小鼠癌肿和死亡率,而单纯牛乳则能增加。本研究的资料提示,食物中添加活嗜酸乳酸杆菌可能有助于预防结肠癌。     

Probiotic, as well as conventional yogurt, can enhance the stimulated production of proinflammatory cytokines

BACKGROUND: Lactic acid bacteria have been shown to stimulate the secretion of cytokines by lymphocytes and monocytes in a strain-dependent manner. Therefore, in this study, the effect of a daily intake of probiotic yogurt on cytokine production in young healthy women was compared with that of a conventional product. METHODS: For 2 weeks each, subjects consumed 100 g, then 200 g of either a probiotic or a conventional, commercially available yogurt, both containing Lactobacillus bulgaricus and Streptococcus thermophilus with additional Lactobacillus casei DN 114 001 in the probiotic product. Cytokine production in blood culture following stimulation with phytohaemmaglutinin and lipopolysaccharide was measured using Cytometric Bead Array and enzyme-linked immunosorbent assay. RESULTS: Stimulated production of tumour necrosis factor-alpha increased significantly following consumption of conventional or probiotic yogurt (+63% and +24% compared with baseline, respectively, P < 0.001). There was also a significantly higher production of interleukin (IL)-1beta in the conventional (+40%, P = 0.006) and of interferon gamma in the probiotic group (+108%, P < 0.05). IL-10 decreased following consumption of the probiotic product, but increased significantly after intake cessation (+129%, P < 0.001). No significant differences in cytokine responses between the conventional and the probiotic yogurt were observed. CONCLUSION: Both conventional and probiotic yogurt enhanced the stimulated production of pro-inflammatory cytokines.     

The addition of milk or yogurt to a plant-based diet increases zinc bioavailability but does not affect iron bioavailability in women

The addition of milk and milk-based products to the diets of individuals subsisting on plant-based diets was reported to have positive effects on nutritional status and functional outcomes such as growth, morbidity, and cognition. We examined the effect of the addition of milk or yogurt on the bioavailability of zinc and iron from a plant-based rural diet. The subjects were 48 Mexican women (30.9 +/- 5.7 y) who habitually consumed a plant-based diet. The women were assigned to 1 of 3 groups: 1) the typical rural Mexican diet, 2) that diet with milk added, or 3) that diet with yogurt for 13 d. Zinc absorption was measured after extrinsically labeling meals with (67)Zn and an i.v. dose of (70)Zn; iron absorption was measured by extrinsically labeling meals with (58)Fe and a reference oral dose of (57)Fe. Including milk and yogurt in the diet increased zinc absorption by 50 and 68%, respectively (P < 0.05). The 3 groups did not differ in the percentage iron absorption. The total amount of zinc absorbed was increased (P < 0.05) by 70% when milk was added to the meal and 78% when yogurt was added. The total amount of iron absorbed did not differ among the groups. The addition of milk and yogurt to a plant-based diet high in phytate increases zinc bioavailability without affecting iron bioavailability.     

Absorption of calcium from milk and yogurt

An increased prevalence of osteoporosis has been observed in lactase-deficient subjects. This association has been attributed to an avoidance of calcium-containing dairy products by lactase-deficient subjects and/or an adverse affect of lactose malabsorption on calcium absorption. Because the lactose in yogurt can be digested and absorbed by hypolactasic subjects, we tested the ability of lactase-deficient subjects and controls to absorb calcium from milk and yogurt. Subjects ingested 270 mg of Ca plus 45Ca in 250 g of milk or 147 g of commercial, unflavored yogurt, and blood radioactivity was assessed at intervals over 24 h. Based on the areas under the blood radioactivity curves, lactase-deficient subjects and controls absorbed calcium equally well from yogurt and milk. Lactase-deficient subjects absorbed 45Ca from both sources at least as well as did the controls. While we found no evidence to indicate that calcium in yogurt is better absorbed than calcium in milk, yogurt remains an excellent source of calcium because this fermented product is well tolerated by lactase-deficient subjects.     

An assessment of liking for sugars using the estimated daily intake scale

Sugar is often used in learning and conditioning studies as an unconditioned stimulus (US) to enhance liking for a flavor mixed with it. To use sugar as a US, participants are selected only if they like the taste of sugar based on their ratings of a sweetened water US during a preexposure trial prior to experimental procedures. This US-only trail introduces a potential sensory bias and can lead to participant attrition when such a trial is conducted the day prior to experimental procedures. The aim of the present study was to construct a brief scale, called the Estimated Daily Intake Scale for Sugar (EDIS-S), to measure a participant's exposure to sugar in their diet. It was hypothesized that exposure to sugar would be positively correlated with liking for sugar. As expected, an 11-item EDIS-S was reliable and significantly correlated with ratings of liking for a sweetened taste solution. Implications for the use of the EDIS-S as an assessment in many areas of research, and as a participant selection tool for conditioning studies are discussed.     

Acute smoking induces endothelial dysfunction in healthy smokers. Is this reversible by red wine's antioxidant constituents?

OBJECTIVE: Acute smoking causes endothelial dysfunction through impairment of nitric oxide (NO) production, or increased oxidative stress, but the exact mechanism still needs to be elucidated. In healthy non-smokers acute endothelial dysfunction caused by smoking one cigarette was counterbalanced by red wine's antioxidants. The aim of the present study is to investigate whether red wine's antioxidant substances could counteract the acute endothelial dysfunction induced by acute cigarette smoking in healthy smokers as well. METHODS: Twenty healthy volunteers (12 males) participated in a double-blind, cross-over study, comprised of three study days. All subjects either smoked one cigarette, or smoked and drank 250 ml of red wine, or smoked and drank 250 ml of dealcoholized red wine in each one of the study days. Flow mediated dilatation (FMD) was measured at fast and 30, 60 and 90 minutes after each trial. RESULTS: Smoking one cigarette induced a significant decrease in FMD (p < 0.001), which remained significant 30 (p < 0.001), and 60 (p = 0.003) minutes after the end of smoking. FMD remained statistically unchanged after consumption of either regular red wine, or dealcoholized red wine together with smoking. CONCLUSIONS: The observed endothelial dysfunction following smoking of one cigarette was counterbalanced by consumption of either red wine or dealcoholized red wine in healthy smokers. It is possible that acute endothelial dysfunction caused by smoking could be attributed to increased oxidative stress and red wine's antioxidants counteract these acute effects of smoke on endothelium.