The flavanones naringenin and hesperetin exhibit estrogenic, anticarcinogenic and antioxidative properties. Orange juice and grapefruit juice contain high amounts of these compounds, and therefore their intake from the diet can be relatively high. No data are available regarding plasma concentrations or plasma kinetics of flavanones. The objectives of this study were to develop methods allowing the analysis of naringenin and hesperetin from plasma and urine and to study their plasma kinetics and urinary excretion. We also wanted to assess whether plasma or urine flavanone concentrations can be used as biomarkers of intake. Healthy volunteers ingested orange juice (five women and three men) or grapefruit juice (two women and three men) once (8 mL/kg). Eleven blood samples and urine were collected between 0 and 24 h after juice administration. Flavanones were analyzed by HPLC with electrochemical detection. Naringenin and hesperetin were bioavailable from the studied juices, but interindividual variation in bioavailability was remarkable. The resulting plasma concentrations were comparatively high, and the peak plasma concentrations (C(max)) were 0.6 +/- 0.4 micromol/L (means +/- SD) for naringenin from orange juice and 6.0 +/- 5.4 micromol/L for naringenin from grapefruit juice. The corresponding value for hesperetin from orange juice was 2.2 +/- 1.6 micromol/L. The elimination half-lives were between 1.3 and 2.2 h, and therefore plasma concentrations reflect short-term intake. The relative urinary excretion varied depending on the flavanone source and dose and was 30.2 +/- 25.5% and 1.1 +/- 0.8% for naringenin from grapefruit juice and orange juice, respectively, and 5.3 +/- 3.1% for hesperetin from orange juice. The considerable difference in the relative urinary excretion of naringenin from the two juices was most likely caused by dose-dependent renal clearance rather than differences in bioavailability (as indicated by the similar C(max)-to-dose ratios). The results indicate that urine flavanone concentrations are not good biomarkers of dietary intake. We conclude that because of the relatively high concentrations of flavanones in plasma after ingestion of orange juice or grapefruit juice, considerable health effects could ensue in individuals consuming them regularly.

The consumption of moderate amounts of berries resulted in favorable changes in platelet function, HDL cholesterol, and BP. The results indicate that regular consumption of berries may play a role in the prevention of cardiovascular disease.

In clinical trials, studying the effects of quercetin from rutin, bioavailability must be taken into consideration and plasma quercetin concentrations monitored. Whether our results apply to other glycosidic drugs as well, especially other rutosides, should be investigated.

This meta-analysis of observational studies suggests that elevated homocysteine is at most a modest independent predictor of IHD and stroke risk in healthy populations. Studies of the impact on disease risk of genetic variants that affect blood homocysteine concentrations will help determine whether homocysteine is causally related to vascular disease, as may large randomized trials of the effects on IHD and stroke of vitamin supplementation to lower blood homocysteine concentrations.

Serum uric acid levels are a strong predictor of cardiovascular disease mortality in healthy middle-aged men, independent of variables commonly associated with gout or the metabolic syndrome. Serum uric acid measurement is an easily available and inexpensive risk marker, but whether its relationship to cardiovascular events is circumstantial or causal remains to be answered.

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BackgroundVegetarian and vegan diets have become more popular among adolescents and young adults. However, few studies have investigated the nutritional status of vegans, who may be at risk of nutritional deficiencies.ObjectiveTo compare dietary intake and nutritional status of Finnish long-term vegans and non-vegetarians.MethodsDietary intake and supplement use were estimated using three-day dietary records. Nutritional status was assessed by measuring biomarkers in plasma, serum, and urine samples. Vegans’ (n = 22) data was compared with those of sex- and age-matched non-vegetarians (n = 19).ResultsAll vegans adhered strictly to their diet; however, individual variability was marked in food consumption and supplementation habits. Dietary intakes of key nutrients, vitamins B12 and D, were lower (P < 0.001) in vegans than in non-vegetarians. Nutritional biomarker measurements showed lower concentrations of serum 25-hydroxyvitamin D3 (25(OH)D3), iodine and selenium (corrected for multiple comparisons, P < 0.001), Vegans showed more favorable fatty acid profiles (P < 0.001) as well as much higher concentrations of polyphenols such as genistein and daidzein (P < 0.001). Eicosapentaenoic acid proportions in vegans were higher than expected. The median concentration of iodine in urine was below the recommended levels in both groups.ConclusionsLong-term consumption of a vegan diet was associated with some favorable laboratory measures but also with lowered concentrations of key nutrients compared to reference values. This study highlights the need for nutritional guidance to vegans.