Synthesis of specific fatty acids contributes to VLDL-triacylglycerol composition in humans with and without type 2 diabetes

Chronic intake of fractionated yellow pea flour reduces postprandial energy expenditure and carbohydrate oxidation

Effects of dietary fibers on human postprandial energetics remain undefined. The objective of the present study was to explore effects of whole yellow pea flour (WPF) and fractionated pea flour (FPF) on postprandial energy expenditure, substrate utilization, and hepatic triglyceride synthesis rate. Using a crossover-diet controlled design, 23 overweight men and women received muffins containing WPF, FPF, and white wheat flour (WF) for 28 days, followed by 28-day washout periods. Subjects received 50 g/day WPF and WF. Given that FPF is approximately 84% fiber, the amount of FPF administered to volunteers was equivalent to the amount of pea-derived fiber in the WPF treatment. Four weeks of FPF consumption reduced (P=.007) total postprandial energy expenditure (333.0±3.6 kcal/330 minutes) compared with WF (349.3±3.6 kcal/330 minutes). When values were normalized to the level of food energy consumed, FPF (4.6±0.3%) decreased (P=.018) the thermic effect of food (TEF) compared with WF (5.7±0.3%). Carbohydrate oxidation tended to be lower (P=.075) with FPF (44.7±2.1 g/330 minutes) versus WF (51.2±0.1.9 g/330 minutes). WPF had no effect on total energy expenditure, TEF, or carbohydrate oxidation. Only after 370 minutes was cumulative oxidation of [1-(13)C]palmitic acid higher (P=.045) in the WPF group (0.96±0.05%) compared with FPF (0.81±0.05%). Neither treatment had any effect on hepatic triglyceride synthesis rate. In conclusion, chronic ingestion of different fractions of yellow peas imposes distinctive effects on postprandial energy expenditure and substrate utilization.

The serum fatty acids myristic acid and linoleic acid are better predictors of serum cholesterol concentrations when measured as molecular percentages rather than as absolute concentrations

BACKGROUND

The use of serum fatty acid biomarkers in nutritional epidemiology is increasingly common; however, there is an absence of scientific evidence to substantiate whether the measurement of fatty acids as molecular percentages (which is the conventional approach) or as absolute concentrations is more informative.

OBJECTIVE

To advance understanding about this fundamental concept, we examined the ability of serum myristic acid and linoleic acid, expressed as molecular percentages or as concentrations, to predict dietary fat and serum cholesterol concentrations.

DESIGN

A cross-sectional analysis of a population-based survey of New Zealand adults (n = 2732) was undertaken. The association of myristic and linoleic acids in serum cholesterol ester and phospholipid with dietary fat or serum cholesterol was assessed.

RESULTS

Intake of saturated fat, dairy fat, and polyunsaturated fat was predicted similarly with the use of both units of measurement. After adjustment for confounders, mean total cholesterol decreased by 0.18 mmol/L from the lowest to the highest quintile of serum cholesteryl-linoleate as a molecular percentage (P = 0.027). In contrast, mean total cholesterol increased by 1.09 mmol/L from the lowest to the highest quintile of serum cholesteryl-linoleate concentration (P < 0.001). The molecular percentage and concentration of serum cholesteryl-myristate were positively associated with total cholesterol (P < 0.001). Results for serum phospholipid fatty acids were similar.

CONCLUSION

Serum myristic acid and linoleic acid measured as molecular percentages, but not as concentrations, predict serum total cholesterol in a manner that distinguishes between the differential cholesterolemic effects of dietary saturated and polyunsaturated fats.