Bioavailability of fatty acids from krill oil, krill meal and fish oil in healthy subjects--a randomized, single-dose, cross-over trial.

BACKGROUND: Krill contains two marine omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), mainly bound in phospholipids. Typical products from krill are krill oil and krill meal. Fish oils contain EPA and DHA predominantly bound in triglycerides. The difference in the chemical binding of EPA and DHA has been suggested to affect their bioavailability, but little is known on bioavailability of EPA and DHA in krill meal. This study was undertaken to compare the acute bioavailability of two krill products, krill oil and krill meal, with fish oil in healthy subjects. METHODS: A randomized, single-dose, single-blind, cross-over, active-reference trial was conducted in 15 subjects, who ingested krill oil, krill meal and fish oil, each containing approx. 1 700 mg EPA and DHA. Fatty acid compositions of plasma triglycerides and phospholipids were measured repeatedly for 72 hours. The primary efficacy analysis was based on the 72 hour incremental area under the curve (iAUC) of EPA and DHA in plasma phospholipid fatty acids. RESULTS: A larger iAUC for EPA and DHA in plasma phospholipid fatty acids was detected after krill oil (mean 89.08±33.36%×h) than after krill meal (mean 44.97±18.07%xh, p<0.001) or after fish oil (mean 59.15±22.22%×h, p=0.003). Mean iAUC's after krill meal and after fish oil were not different. A large inter-individual variability in response was observed. CONCLUSION: EPA and DHA in krill oil had a higher 72-hour bioavailability than in krill meal or fish oil. Our finding that bioavailabilities of EPA and DHA in krill meal and fish oil were not different argues against the interpretation that phospholipids are better absorbed than triglycerides. Longer-term studies using a parameter reflecting tissue fatty acid composition, like erythrocyte EPA plus DHA are needed. TRIAL REGISTRATION: NCT02089165.

Postprandial glucose, insulin and glucagon-like peptide 1 responses to sucrose ingested with berries in healthy subjects.

Berries are often consumed with sucrose. They are also rich sources of polyphenols which may modulate glycaemia after carbohydrate ingestion. The present study investigated the postprandial glucose, insulin and glucagon-like peptide 1 (GLP-1) responses to sucrose ingested with berries, in comparison with a similar sucrose load without berries. A total of twelve healthy subjects were recruited to a randomised, single-blind, placebo-controlled crossover study. They participated in two meal tests on separate days. The berry meal was a purée (150 g) made of bilberries, blackcurrants, cranberries and strawberries with 35 g sucrose. The control meal included the same amount of sucrose and available carbohydrates in water. Fingertip capillary and venous blood samples were taken at baseline and at 15, 30, 45, 60, 90 and 120 min after starting to eat the meal. Glucose, insulin and GLP-1 concentrations were determined from the venous samples, and glucose also from the capillary samples. Compared to the control meal, ingestion of the berry meal resulted in lower capillary and venous plasma glucose and serum insulin concentrations at 15 min (P = 0·021, P < 0·007 and P = 0·028, respectively), in higher concentrations at 90 min (P = 0·028, P = 0·021 and P = 0·042, respectively), and in a modest effect on the GLP-1 response (P = 0·05). It also reduced the maximum increases of capillary and venous glucose and insulin concentrations (P = 0·009, P = 0·011 and P = 0·005, respectively), and improved the glycaemic profile (P < 0·001 and P = 0·003 for capillary and venous samples, respectively). These results suggest that the glycaemic control after ingestion of sucrose can be improved by simultaneous consumption of berries.

Berries modify the postprandial plasma glucose response to sucrose in healthy subjects.

Sucrose increases postprandial blood glucose concentrations, and diets with a high glycaemic response may be associated with increased risk of obesity, type 2 diabetes and CVD. Previous studies have suggested that polyphenols may influence carbohydrate digestion and absorption and thereby postprandial glycaemia. Berries are rich sources of various polyphenols and berry products are typically consumed with sucrose. We investigated the glycaemic effect of a berry purée made of bilberries, blackcurrants, cranberries and strawberries, and sweetened with sucrose, in comparison to sucrose with adjustment of available carbohydrates. A total of twelve healthy subjects (eleven women and one man, aged 25-69 years) with normal fasting plasma glucose ingested 150 g of the berry purée with 35 g sucrose or a control sucrose load in a randomised, controlled cross-over design. After consumption of the berry meal, the plasma glucose concentrations were significantly lower at 15 and 30 min (P < 0.05, P < 0.01, respectively) and significantly higher at 150 min (P < 0.05) compared with the control meal. The peak glucose concentration was reached at 45 min after the berry meal and at 30 min after the control meal. The peak increase from the baseline was 1.0 mmol/l smaller (P = 0.002) after ingestion of the berry meal. There was no statistically significant difference in the 3 h area under the glucose response curve. These results show that berries rich in polyphenols decrease the postprandial glucose response of sucrose in healthy subjects. The delayed and attenuated glycaemic response indicates reduced digestion and/or absorption of sucrose from the berry meal.

Measuring the glycemic index of foods: interlaboratory study.

BACKGROUND: Many laboratories offer glycemic index (GI) services. OBJECTIVE: We assessed the performance of the method used to measure GI. DESIGN: The GI of cheese-puffs and fruit-leather (centrally provided) was measured in 28 laboratories (n=311 subjects) by using the FAO/WHO method. The laboratories reported the results of their calculations and sent the raw data for recalculation centrally. RESULTS: Values for the incremental area under the curve (AUC) reported by 54% of the laboratories differed from central calculations. Because of this and other differences in data analysis, 19% of reported food GI values differed by >5 units from those calculated centrally. GI values in individual subjects were unrelated to age, sex, ethnicity, body mass index, or AUC but were negatively related to within-individual variation (P=0.033) expressed as the CV of the AUC for repeated reference food tests (refCV). The between-laboratory GI values (mean+/-SD) for cheese-puffs and fruit-leather were 74.3+/-10.5 and 33.2+/-7.2, respectively. The mean laboratory GI was related to refCV (P=0.003) and the type of restrictions on alcohol consumption before the test (P=0.006, r2=0.509 for model). The within-laboratory SD of GI was related to refCV (P<0.001), the glucose analysis method (P=0.010), whether glucose measures were duplicated (P=0.008), and restrictions on dinner the night before (P=0.013, r2=0.810 for model). CONCLUSIONS: The between-laboratory SD of the GI values is approximately 9. Standardized data analysis and low within-subject variation (refCV<30%) are required for accuracy. The results suggest that common misconceptions exist about which factors do and do not need to be controlled to improve precision. Controlled studies and cost-benefit analyses are needed to optimize GI methodology. The trial was registered at clinicaltrials.gov as NCT00260858.

Safety aspects and cholesterol-lowering efficacy of chitosan tablets.

OBJECTIVE: The purpose of this study was to determine the effect of two different doses of chitosan on serum fat-soluble vitamin concentrations, cholesterol concentrations, and other safety parameters. METHODS: A total of 65 men and women consumed 0, 4.5, 6.75 g per day of chitosan or 6.75 g per day glucomannan for eight weeks in a parallel, placebo-controlled, single-blind study. Altogether, 56 participants completed the study. RESULTS: No differences were detected among the treatments in serum vitamins (vitamin A, vitamin E, 25-hydroxyvitamin D), carotenes (alpha- and beta-carotene), clinical chemistry or hematology measurements. The changes in the total and LDL-cholesterol concentrations among the study groups were not statistically significant. CONCLUSION: In the present study, the consumption of chitosan tablets was found to be safe, but there was no significant effect on cholesterol concentration.

Effect of alpha-linolenic acid-rich Camelina sativa oil on serum fatty acid composition and serum lipids in hypercholesterolemic subjects.

Camelina sativa-derived oil (camelina oil) is a good source of alpha-linolenic acid. The proportion of alpha-linolenic acid in serum fatty acids is associated with the risk of cardiovascular diseases. We studied the effects of camelina oil on serum lipids and on the fatty acid composition of total lipids in comparison to rapeseed and olive oils in a parallel, double-blind setting. Sixty-eight hypercholesterolemic subjects aged 28 to 65 years were randomly assigned after a 2-week pretrial period to 1 of 3 oil groups: camelina oil, olive oil, and rapeseed oil. Subjects consumed daily 30 g (actual intake, approximately 33 mL) of test oils for 6 weeks. In the camelina group, the proportion of alpha-linolenic acid in fatty acids of serum lipids was significantly higher (P <.001) compared to the 2 other oil groups at the end of the study: 2.5 times higher compared to the rapeseed oil group and 4 times higher compared to the olive oil group. Respectively the proportions of 2 metabolites of alpha-linolenic acid (eicosapentaenoic and docosapentaenoic acids) increased and differed significantly in the camelina group from those in other groups. During the intervention, the serum low-density lipoprotein (LDL) cholesterol concentration decreased significantly by 12.2% in the camelina oil group, 5.4% in the rapeseed oil group, and 7.7% in the olive oil group. In conclusion, camelina oil significantly elevated the proportions of alpha-linolenic acid and its metabolites in serum of mildly or moderately hypercholesterolemic subjects. Camelina oil's serum cholesterol-lowering effect was comparable to that of rapeseed and olive oils.

The effect of meat products enriched with plant sterols and minerals on serum lipids and blood pressure.

The purpose of the study was to investigate the effect of non-esterified plant sterol-enriched and mineral-enriched low-fat and low-salted meat products compared with control meat products, on serum total and lipoprotein lipids and blood pressure in subjects with mildly to moderately elevated serum cholesterol concentration. A randomised, placebo-controlled, single-blind, repeated measure design was used. Altogether 21 volunteers completed the study. The study began with a pre-trial period of 1-2 weeks, which was followed by three different test periods in the following order: meat products enriched with plant sterols (1.2 g/day), potassium, calcium and magnesium (MP1); meat products with no added plant sterols and minerals (control); and meat products with plant sterols (2.1 g/day), potassium, calcium and magnesium (MP2). Each test period lasted for 3 weeks. During the MP2 period, the serum total and low-density lipoprotein cholesterol concentration decreased 4.9+/-7.5% (P<0.05) and 4.6+/-11.3% (not significant), respectively, compared with the control period. No differences in the high-density lipoprotein cholesterol and total triglyceride concentrations or in systolic blood pressure and diastolic blood pressure were found among the test periods. In conclusion, the present study showed that frankfurters and cold cuts enriched with plant sterols from tall oil, potassium, calcium and magnesium, as part of habitual Finnish diet reduced the serum total cholesterol concentration in hypercholesterolemic subjects when the intake of sitosterols was 2.1 g/day, but not with the lower dose.