Oxidative damage is involved in cardiovascular diseases. Intervention with alpha-tocopherol, ascorbic acid and beta-carotene does not appear to reduce pathogenesis. The purpose of this review is to ...describe alternative antioxidant mechanisms that may be involved.
Antioxidants with different chemical properties may recharge each other in an antioxidant network. The total antioxidant content of dietary plants may therefore be a useful tool for testing the "antioxidant network" hypothesis. Several berries, fruits, nuts, seeds, vegetables, drinks and spices have been found to be high in total antioxidants. Initial studies in animals and humans are supportive as to the beneficial effects of dietary plants rich in total antioxidants. Additionally, antioxidants and other plant compounds may also improve the endogenous antioxidant defence through induction of antioxidant and phase 2 enzymes. Dietary plants rich in such compounds include broccoli, Brussels sprouts, cabbage, kale, cauliflower, carrots, onions, tomatoes, spinach and garlic.
Although initial studies have indicated that antioxidants may reduce oxidative stress, human intervention studies do not support a beneficial effect of antioxidant supplements. Further research is needed to clarify whether other plant antioxidants, plants rich in a combination of antioxidants, or plant compounds that induce the endogenous antioxidant defence can reduce pathogenesis of cardiovascular disease and other oxidative stress-related diseases.
Although early studies suggested that coffee consumption might increase risk of some cancers, more comprehensive epidemiological and experimental data now generally indicate either neutral or ...beneficial effects. In this review, we summarize the current evidence for associations between breast, prostate, colorectal, and liver cancers and the consumption of coffee, and discuss the experimental evidence for potential chemopreventive mechanisms of coffee and coffee constituents. The epidemiological evidence consistently indicates that coffee protects against liver cancer, and also point toward protective effects for risk of colorectal cancers (with relative risks of 0.50 (95% CI: 0.42–0.59) and 0.83 (95% CI: 0.75–0.92), respectively, in the most recent meta‐analyses). There seems to be no association between the overall risk of breast and prostate cancer and coffee intake. However, for subgroups such as postmenopausal breast cancers, advanced prostate cancers, and breast and prostate cancer survivors, an inverse association with coffee intake is indicated. Potential mechanisms for chemopreventive effects of coffee phytochemicals includes inhibition of oxidative stress and oxidative damage, regulation of DNA repair, phase II enzymatic activity, apoptosis, inflammation, as well as having antiproliferative, antiangiogenetic effects and antimetastatic effects. The experimental evidence for effects of coffee and coffee constituents on each of these processes is discussed.
We have developed a food frequency questionnaire (FFQ) for the assessment of habitual diet, with special focus on the intake of fruit, vegetables and other antioxidant-rich foods and beverages. The ...aim of the present study was to evaluate the relative validity of the intakes of energy, food and nutrients from the FFQ.
Energy intake was evaluated against independent measures of energy expenditure using the ActiReg® system (motion detection), whereas 7-days weighed food records were used to study the relative validity of food and nutrient intake. The relationship between methods was investigated using correlation analyses and cross-classification of participants. The visual agreement between the methods was evaluated using Bland-Altman plots.
We observed that the FFQ underestimated the energy intake by approximately 11% compared to the energy expenditure measured by the ActiReg®. The correlation coefficient between energy intake and energy expenditure was 0.54 and 32% of the participants were defined as under-reporters. Compared to the weighed food records the percentages of energy from fat and added sugar from the FFQ were underestimated, whereas the percentage of energy from total carbohydrates and protein were slightly overestimated. The intake of foods rich in antioxidants did not vary significantly between the FFQ and weighed food records, with the exceptions of berries, coffee, tea and vegetables which were overestimated. Spearman's Rank Order Correlations between FFQ and weighed food records were 0.41 for berries, 0.58 for chocolate, 0.78 for coffee, 0.61 for fruit, 0.57 for fruit and berry juices, 0.40 for nuts, 0.74 for tea, 0.38 for vegetables and 0.70 for the intake of wine.
Our new FFQ provides a good estimate of the average energy intake and it obtains valid data on average intake of most antioxidant-rich foods and beverages. Our study also showed that the FFQs ability to rank participants according to intake of total antioxidants and most of the antioxidant-rich foods was good.
A plant-based diet protects against chronic oxidative stress-related diseases. Dietary plants contain variable chemical families and amounts of antioxidants. It has been hypothesized that plant ...antioxidants may contribute to the beneficial health effects of dietary plants. Our objective was to develop a comprehensive food database consisting of the total antioxidant content of typical foods as well as other dietary items such as traditional medicine plants, herbs and spices and dietary supplements. This database is intended for use in a wide range of nutritional research, from in vitro and cell and animal studies, to clinical trials and nutritional epidemiological studies.
We procured samples from countries worldwide and assayed the samples for their total antioxidant content using a modified version of the FRAP assay. Results and sample information (such as country of origin, product and/or brand name) were registered for each individual food sample and constitute the Antioxidant Food Table.
The results demonstrate that there are several thousand-fold differences in antioxidant content of foods. Spices, herbs and supplements include the most antioxidant rich products in our study, some exceptionally high. Berries, fruits, nuts, chocolate, vegetables and products thereof constitute common foods and beverages with high antioxidant values.
This database is to our best knowledge the most comprehensive Antioxidant Food Database published and it shows that plant-based foods introduce significantly more antioxidants into human diet than non-plant foods. Because of the large variations observed between otherwise comparable food samples the study emphasizes the importance of using a comprehensive database combined with a detailed system for food registration in clinical and epidemiological studies. The present antioxidant database is therefore an essential research tool to further elucidate the potential health effects of phytochemical antioxidants in diet.
Over the last quarter century, more than 532 genes have been put forward as regulatory targets of retinoic acid. In some cases this control is direct, driven by a liganded heterodimer of retinoid ...receptors bound to a DNA response element; in others, it is indirect, reflecting the actions of intermediate transcription factors, non-classical associations of receptors with other proteins, or even more distant mechanisms. Given the broad range of scientific questions continually under investigation, researchers do not always have occasion to classify target genes along these lines. However, our understanding of the genetic role of retinoids will be enhanced if such a distinction can be made for each regulated gene. We have therefore evaluated published data from 1,191 papers covering 532 genes and have classified these genes into four categories according to the degree to which an hypothesis of direct versus indirect control is supported overall. We found 27 genes that are unquestionably direct targets of the classical pathway in permissive cellular contexts (Category 3 genes), plus 105 genes that appear to be candidates, pending the results of specific additional experiments (Category 2). Data on another 267 targets are not evocative of direct or indirect regulation either way, although control by retinoic acid through some mechanism is clear (Category 1). Most of the remaining 133 targets seem to be regulated indirectly, usually through a transcriptional intermediary, in the contexts studied so far (Category 0).
Valid assessment tools are needed when investigating adherence to national dietary and lifestyle guidelines.
The relative validity of the new digital food frequency questionnaire, the DIGIKOST-FFQ, ...against 7-day weighed food records and activity sensors was investigated.
In total, 77 participants were included in the validation study and completed the DIGIKOST-FFQ and the weighed food record, and of these, 56 (73%) also used the activity sensors. The DIGIKOST-FFQ estimates the intake of foods according to the Norwegian food-based dietary guidelines (FBDGs) in addition to lifestyle factors.
At the group level, the DIGIKOST-FFQ showed good validity in estimating intakes according to the Norwegian FBDG. The median differences were small and well below portion sizes for all foods except "water" (median difference 230 g/day). The DIGIKOST-FFQ was able to rank individual intakes for all foods (r=0.2-0.7). However, ranking estimates of vegetable intakes should be interpreted with caution. Between 69% and 88% of the participants were classified into the same or adjacent quartile for foods and between 71% and 82% for different activity intensities. The Bland-Altman plots showed acceptable agreements between DIGIKOST-FFQ and the reference methods. The absolute amount of time in "moderate to vigorous intensity" was underestimated with the DIGIKOST-FFQ. However, estimated time in "moderate to vigorous intensity," "vigorous intensity," and "sedentary time" showed acceptable correlations and good agreement between the methods. The DIGIKOST-FFQ was able to identify adherence to the Norwegian FBDG and physical activity recommendations.
The DIGIKOST-FFQ gave valid estimates of dietary intakes and was able to identify individuals with different degrees of adherence to the Norwegian FBDG and physical activity recommendations. Moderate physical activity was underreported, water was overreported, and vegetables showed poor correlation, which are important to consider when interpreting the data. Good agreement was observed between the methods in estimating dietary intakes and time in "moderate to vigorous physical activity," "sedentary time," and "sleep."
The current concepts of human fetal-placental amino acid exchange and metabolism are mainly based on animal-, in vitro- and ex vivo models. We aimed to determine and assess the paired relationships ...between concentrations and arteriovenous differences of 19 amino acids on the maternal and fetal sides of the human placenta in a large study sample.
This cross-sectional in vivo study included 179 healthy women with uncomplicated term pregnancies. During planned cesarean section, we sampled blood from incoming and outgoing vessels on the maternal (radial artery and uterine vein) and fetal (umbilical vein and artery) sides of the placenta. Amino acid concentrations were measured by liquid chromatography-tandem mass spectrometry. We calculated paired arteriovenous differences and performed Wilcoxon signed-rank tests and Spearman's correlations.
In the umbilical circulation, we observed a positive venoarterial difference (fetal uptake) for 14 amino acids and a negative venoarterial difference (fetal release) for glutamic acid (p<0.001). In the maternal circulation, we observed a positive arteriovenous difference (uteroplacental uptake) for leucine (p = 0.005), isoleucine (p = 0.01), glutamic acid (p<0.001) and arginine (p = 0.04) and a negative arteriovenous difference (uteroplacental release) for tyrosine (p = 0.002), glycine (p = 0.01) and glutamine (p = 0.02). The concentrations in the maternal artery and umbilical vein were correlated for all amino acids except tryptophan, but we observed no correlations between the uteroplacental uptake and the fetal uptake or the umbilical vein concentration. Two amino acids showed a correlation between the maternal artery concentration and the fetal uptake.
Our human in vivo study expands the current insight into fetal-placental amino acid exchange, and discloses some differences from what has been previously described in animals. Our findings are consistent with the concept that the fetal supply of amino acids in the human is the result of a dynamic interplay between fetal and placental amino acid metabolism and interconversions.
BACKGROUND: Vitamin D status is known to be important for bone health but may also affect the development of several chronic diseases, including cancer and cardiovascular diseases, which are 2 major ...causes of death. OBJECTIVE: We aimed to examine how vitamin D status relates to overall and cause-specific mortality. DESIGN: The Uppsala Longitudinal Study of Adult Men, a community-based cohort of elderly men (mean age at baseline: 71 y; n = 1194), was used to investigate the association between plasma 25-hydroxyvitamin D 25(OH)D and mortality. Total plasma 25(OH)D was determined with HPLC atmospheric pressure chemical ionization mass spectrometry. Proportional hazards regression was used to compute hazard ratios (HRs). RESULTS: During follow-up (median: 12.7 y), 584 (49%) participants died. There was a U-shaped association between vitamin D concentrations and total mortality. An approximately 50% higher total mortality rate was observed among men in the lowest 10% (<46 nmol/L) and the highest 5% (>98 nmol/L) of plasma 25(OH)D concentrations compared with intermediate concentrations. Cancer mortality was also higher at low plasma concentrations (multivariable-adjusted HR: 2.20; 95% CI: 1.44, 3.38) and at high concentrations (HR: 2.64; 95% CI: 1.46, 4.78). For cardiovascular death, only low (HR: 1.89; 95% CI: 1.21, 2.96) but not high (HR: 1.33; 95% CI: 0.69, 2.54) concentrations indicated higher risk. CONCLUSIONS: Both high and low concentrations of plasma 25(OH)D are associated with elevated risks of overall and cancer mortality. Low concentrations are associated with cardiovascular mortality.
Physical activity (PA) monitoring is applied in a growing number of studies within cancer research. However, no consensus exists on how many days PA should be monitored to obtain reliable estimates ...in the cancer population. The objective of the present study was to determine the minimum number of monitoring days required for reliable estimates of different PA intensities in cancer survivors when using a six-days protocol. Furthermore, reliability of monitoring days was assessed stratified on sex, age, cancer type, weight status, and educational level.
Data was obtained from two studies where PA was monitored for seven days using the SenseWear Armband Mini in a total of 984 cancer survivors diagnosed with breast, colorectal or prostate cancer. Participants with ≥22 hours monitor wear-time for six days were included in the reliability analysis (n = 736). The intra-class correlation coefficient (ICC) and the Spearman Brown prophecy formula were used to assess the reliability of different number of monitoring days.
For time in light PA, two monitoring days resulted in reliable estimates (ICC >0.80). Participants with BMI ≥25, low-medium education, colorectal cancer, or age ≥60 years required one additional monitoring day. For moderate and moderate-to-vigorous PA, three monitoring days yielded reliable estimates. Participants with BMI ≥25 or breast cancer required one additional monitoring day. Vigorous PA showed the largest within subject variations and reliable estimates were not obtained for the sample as a whole. However, reliable estimates were obtained for breast cancer survivors (4 days), females, BMI ≥30, and age <60 years (6 days).
Shorter monitoring periods may provide reliable estimates of PA levels in cancer survivors when monitored continuously with a wearable device. This could potentially lower the participant burden and allow for less exclusion of participants not adhering to longer protocols.
BACKGROUND: Supplements containing ascorbic acid, α-tocopherol, or β-carotene do not protect against oxidative stress-related diseases in most randomized intervention trials. We suggest that other ...redox-active phytochemicals may be more effective and that a combination of different redox-active compounds (ie, antioxidants or reductants) may be needed for proper protection against oxidative damage. OBJECTIVE: We aimed to generate a ranked food table with values for total content of redox-active compounds to test this alternative antioxidant hypothesis. DESIGN: An assay that measures the total concentration of redox-active compounds above a certain cutoff reduction potential was used to analyze 1113 food samples obtained from the US Department of Agriculture National Food and Nutrient Analysis Program. RESULTS: Large variations in the content of antioxidants were observed in different foods and food categories. The food groups spices and herbs, nuts and seeds, berries, and fruit and vegetables all contained foods with very high antioxidant contents. Most food categories also contained products almost devoid of antioxidants. Of the 50 food products highest in antioxidant concentrations, 13 were spices, 8 were in the fruit and vegetables category, 5 were berries, 5 were chocolate-based, 5 were breakfast cereals, and 4 were nuts or seeds. On the basis of typical serving sizes, blackberries, walnuts, strawberries, artichokes, cranberries, brewed coffee, raspberries, pecans, blueberries, ground cloves, grape juice, and unsweetened baking chocolate were at the top of the ranked list. CONCLUSION: This ranked antioxidant food table provides a useful tool for investigations into the possible health benefit of dietary antioxidants.
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