Anette Karlsen

Effects of anthocyanins on cardiovascular risk factors and inflammation in pre-hypertensive men: a double-blind randomized placebo-controlled crossover study.

High intake of fruits and vegetables is associated with reduced cardiovascular risk. A number of fruits and vegetables are rich in anthocyanins, which constitute a subgroup of the flavonoids. Anthocyanins have demonstrated anti-inflammatory and anti-oxidative properties, and anthocyanin-rich interventions have indicated beneficial effects on blood pressure and other cardiovascular risk factors. We assessed whether a purified anthocyanin supplement improves cardiovascular metabolic risk factors and markers of inflammation and oxidative stress in prehypertensive participants, and whether plasma polyphenols are increased 1–3 h following intake. In all, 31 men between 35–51 years with screening blood pressure >140/90 mm Hg without anti-hypertensive or lipid-lowering medication, were randomized in a double-blinded crossover study to placebo versus 640 mg anthocyanins daily. Treatment durations were 4 weeks with a 4-week washout. High-density lipoprotein (HDL)-cholesterol and blood glucose were significantly higher after anthocyanin versus placebo treatment (P=0.043 and P=0.024, respectively). No effects were observed on inflammation or oxidative stress in vivo, except for von Willebrand factor, which was higher in the anthocyanin period (P=0.007). Several plasma polyphenols increased significantly 1–3 h following anthocyanin intake. The present study strengthens the evidence that anthocyanins may increase HDL-cholesterol levels, and this is demonstrated for the first time in prehypertensive and non-dyslipidemic men. However, no other beneficial effects in the short term were found on pathophysiological markers of cardiovascular disease.

Six carotenoids in plasma used to assess recommended intake of fruits and vegetables in a controlled feeding study

Background: There is a need for objective and universally applicable biomarkers for the intake of foods believed to affect human health.Objective: The purpose of this feeding study was to test whether plasma concentrations of carotenoids could be used to distinguish recommended consumption of mixed fruits and vegetables (five a day) from the current national intake of fruits and vegetables (two a day).Design: A strict crossover design was chosen to correct for observed interindividual variations in carotenoid response. A total of 40 healthy subjects were included in the study. After 1 week run-in period with no fruits and vegetables in the diet, one group was given two portions (300 g) of fruits and vegetables daily, while another group was given five portions (750 g) for 14 days. Following a 2 week wash-out period and 1 week run-in, the regimens were switched between the groups. Fruits and vegetables were combined to match a typical Norwegian diet.Results: Enhanced intake from two to five portions of mixed fruits and vegetables increased plasma concentrations of α-carotene (P=0.033) and lutein (P=0.051) in a crossover analysis. Analysis of data in the parallel part of the study revealed differences between the high and low intake for plasma concentrations of α-carotene (P=0.013) and β-carotene (P=0.016). A trend was also evident for plasma concentrations of lycopene (P=0.057) and lutein (P=0.076) in the parallel analysis. No effect of high vs low intake of fruits and vegetables was observed for plasma concentrations of β-cryptoxanthin, zeaxanthin, cholesterol and triacylglycerols.Conclusion: The study indicates that plasma concentration of α-carotene, β-carotene and lutein may be used to assess changes of fruit and vegetable intake corresponding to an increase from the present national intake in Norway to the recommended amount of five portions of fruits and vegetables daily.Sponsorship: Norwegian Research Council, National Nutrition Council, Throne Holst Foundation for Nutrition Research and Freia Chokoladefabriks Medisinske Fond.

Stability of whole blood and plasma ascorbic acid.

The objective of this study was to evaluate the impact of pre-analytical factors on the short and long term stability of ascorbic acid (AA), the main form of vitamin C in whole blood and plasma. The effects of various anticoagulants, acidification, storage temperature and time were tested. A recently developed fast and sensitive HPLC method was used to measure AA levels. AA baseline values observed in heparin plasma were significantly higher than values observed in EDTA, citrate and Stabilyte plasma, as well as in serum. pH and temperature were identified as additional critical pre-analytical factors during the short, medium and long term handling and storage. Thus, assessment of reliable and accurate AA status in biological samples demonstrates to be highly dependent on whether the initial conditions during sample handling are controlled. In conclusion, heparin tubes should be used for blood sample collection. As AA is rapidly degraded, sample collection should be followed by immediate centrifugation and plasma acidification. To avoid further degradation during sample handling, samples should be stored at −70°C without delay and analyzed within 80 days.

Blood cell gene expression associated with cellular stress defense is modulated by antioxidant-rich food in a randomised controlled clinical trial of male smokers

BackgroundPlant-based diets rich in fruit and vegetables can prevent development of several chronic age-related diseases. However, the mechanisms behind this protective effect are not elucidated. We have tested the hypothesis that intake of antioxidant-rich foods can affect groups of genes associated with cellular stress defence in human blood cells. Trial registration number: NCT00520819 http://clinicaltrials.gov.MethodsIn an 8-week dietary intervention study, 102 healthy male smokers were randomised to either a diet rich in various antioxidant-rich foods, a kiwifruit diet (three kiwifruits/d added to the regular diet) or a control group. Blood cell gene expression profiles were obtained from 10 randomly selected individuals of each group. Diet-induced changes on gene expression were compared to controls using a novel application of the gene set enrichment analysis (GSEA) on transcription profiles obtained using Affymetrix HG-U133-Plus 2.0 whole genome arrays.ResultsChanges were observed in the blood cell gene expression profiles in both intervention groups when compared to the control group. Groups of genes involved in regulation of cellular stress defence, such as DNA repair, apoptosis and hypoxia, were significantly upregulated (GSEA, FDR q-values < 5%) by both diets compared to the control group. Genes with common regulatory motifs for aryl hydrocarbon receptor (AhR) and AhR nuclear translocator (AhR/ARNT) were upregulated by both interventions (FDR q-values < 5%). Plasma antioxidant biomarkers (polyphenols/carotenoids) increased in both groups.ConclusionsThe observed changes in the blood cell gene expression profiles suggest that the beneficial effects of a plant-based diet on human health may be mediated through optimization of defence processes.

Molecular Nutrition Research—The Modern Way Of Performing Nutritional Science

In spite of amazing progress in food supply and nutritional science, and a striking increase in life expectancy of approximately 2.5 months per year in many countries during the previous 150 years, modern nutritional research has a great potential of still contributing to improved health for future generations, granted that the revolutions in molecular and systems technologies are applied to nutritional questions. Descriptive and mechanistic studies using state of the art epidemiology, food intake registration, genomics with single nucleotide polymorphisms (SNPs) and epigenomics, transcriptomics, proteomics, metabolomics, advanced biostatistics, imaging, calorimetry, cell biology, challenge tests (meals, exercise, etc.), and integration of all data by systems biology, will provide insight on a much higher level than today in a field we may name molecular nutrition research. To take advantage of all the new technologies scientists should develop international collaboration and gather data in large open access databases like the suggested Nutritional Phenotype database (dbNP). This collaboration will promote standardization of procedures (SOP), and provide a possibility to use collected data in future research projects. The ultimate goals of future nutritional research are to understand the detailed mechanisms of action for how nutrients/foods interact with the body and thereby enhance health and treat diet-related diseases.

Relative validity of fruit and vegetable intake estimated from an FFQ, using carotenoid and flavonoid biomarkers and the method of triads

The aim of the present study was to validate the intakes of fruit, juice and vegetables from an FFQ. In sub-study I (n 147), intakes from the FFQ were evaluated against 7 d weighed food records (WR) and plasma carotenoid concentrations, whereas in sub-study II (n 85), the intakes were evaluated against plasma carotenoid concentrations and amounts of flavonoids in 24 h urine samples. Relative validity was evaluated by comparing median intakes, estimating correlation coefficients and validity coefficients using the method of triads. In sub-study I, we observed no significant difference in daily median fruit intake between the FFQ and the WR, whereas the intake of vegetables was higher from the FFQ than from the WR. The correlations between intakes from the FFQ and the WR ranged from 0·31 to 0·58. In sub-study II, the intakes of fruit and vegetables correlated significantly with plasma carotenoid concentrations and urinary flavonoids. The validity coefficients for the intakes of fruit and vegetables from the FFQ ranged from 0·61 to 0·88 in sub-study I and from 0·60 to 0·94 in sub-study II. In summary, based on the associations observed between intakes from the FFQ and the biomarkers and the FFQ validity coefficients, the FFQ was found valid and suitable for ranking individuals according to their usual intake of fruit, juice and vegetables.

Homocysteine, Cysteine, and Related Metabolites in Maternal and Fetal Plasma in Preeclampsia

Homocysteine is associated with endothelial dysfunction and cardiovascular disease, and elevated concentrations of homocysteine have been found in preeclampsia. The purpose of this study was to investigate maternal and fetal concentrations of total homocysteine and related metabolites (including cysteine, choline, and betaine), and possible associations with infant birth weight. Women with preeclampsia (n = 47) and controls (n = 51), who underwent cesarean section, were included. Maternal plasma, umbilical vein, and artery plasma were analyzed. Median concentrations of homocysteine, cysteine, choline, and betaine were significantly higher in women with preeclampsia than controls, both in maternal and fetal plasma. There were no differences in folate and vitamin B12 concentrations between the groups, neither for maternal nor fetal samples. Maternal homocysteine concentration was a negative predictor for birth weight only in the preeclampsia group. Elevated homocysteine and cysteine concentration in maternal circulation in preeclampsia is reflected in the fetal circulation. The clinical significance of elevated homocysteine and cysteine concentrations in maternal and fetal compartments in preeclampsia remain to be explored, both regarding fetal growth and development of disease later in life.

Supplementation of a western diet with golden kiwifruits (Actinidia chinensis var.'Hort 16A':) effects on biomarkers of oxidation damage and antioxidant protection

BackgroundThe health positive effects of diets high in fruits and vegetables are generally not replicated in supplementation trials with isolated antioxidants and vitamins, and as a consequence the emphasis of chronic disease prevention has shifted to whole foods and whole food products.MethodsWe carried out a human intervention trial with the golden kiwifruit, Actinidia chinensis, measuring markers of antioxidant status, DNA stability, plasma lipids, and platelet aggregation. Our hypothesis was that supplementation of a normal diet with kiwifruits would have an effect on biomarkers of oxidative status. Healthy volunteers supplemented a normal diet with either one or two golden kiwifruits per day in a cross-over study lasting 2 × 4 weeks. Plasma levels of vitamin C, and carotenoids, and the ferric reducing activity of plasma (FRAP) were measured. Malondialdehyde was assessed as a biomarker of lipid oxidation. Effects on DNA damage in circulating lymphocytes were estimated using the comet assay with enzyme modification to measure specific lesions; another modification allowed estimation of DNA repair.ResultsPlasma vitamin C increased after supplementation as did resistance towards H2O2-induced DNA damage. Purine oxidation in lymphocyte DNA decreased significantly after one kiwifruit per day, pyrimidine oxidation decreased after two fruits per day. Neither DNA base excision nor nucleotide excision repair was influenced by kiwifruit consumption. Malondialdehyde was not affected, but plasma triglycerides decreased. Whole blood platelet aggregation was decreased by kiwifruit supplementation.ConclusionGolden kiwifruit consumption strengthens resistance towards endogenous oxidative damage.

Plasma antioxidant responses and oxidative stress following a soccer game in elite female players

We aimed to investigate markers of oxidative stress and levels of endogenous and dietary antioxidants in 16 elite female soccer players in response to a 90‐min game (average intensity 82±3% HRpeak). Blood samples were taken before, immediately and 21 h after the game. Plasma‐oxidized glutathione, the ratio of reduced to oxidized glutathione (GSH:GSSG) and lipid peroxidation measured by d‐ROMs were used as markers of oxidative stress. Plasma endogenous [uric acid, total glutathione (TGSH)] and dietary antioxidants (α‐tocopherol, ascorbic acid, total carotenoids and polyphenols) were analyzed using liquid chromatography and the Folin–Ciocalteu method. Exercise induced an acute increase (P<0.05) in GSSG, uric acid, TGSH, α‐tocopherol, and ascorbic acid. In parallel, the GSH:GSSG ratio and polyphenols decreased (P<0.05). GSSG, GSH:GSSG ratio, uric acid, TGSH, and ascorbic acid returned to baseline at 21 h, while polyphenols and α‐tocopherol remained altered. Total carotenoids increased above baseline only at 21 h (P<0.05). Lipid peroxidation, measured by d‐ROMs, remained unchanged throughout the study. Thus, intermittent exercise in well‐trained female athletes induces a transient increase in GSSG and a decrease in the GSH:GSSG ratio, which is effectively balanced by the recruitment of both endogenous and dietary antioxidants, resulting in the absence of lipid peroxidation measured by d‐ROMs.

Evaluation of energy and dietary intake estimates from a food frequency questionnaire using independent energy expenditure measurement and weighed food records

BackgroundWe 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.MethodsEnergy 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.ResultsWe 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. Spearmans 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.ConclusionsOur 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.