(OR10-04-25) Postprandial Lipid and Lipoprotein Profiles Following Low-Carbohydrate vs. Low-Fat Diets

Objectives: We examined postprandial plasma lipids and lipoproteins using NMR spectroscopy after a 2-week low-carbohydrate (LC) vs. 2-week low-fat (LF) diets in a random order crossover inpatient study.

Methods: Twenty adults aged 29.9 ± 1.4y (mean ± SEM) with BMI 27.8 ± 1.3 kg/m>sup>2 were admitted to the metabolic unit at the NIH Clinical Center as in-patients and were randomized to a LF (10% fat) or a LC diet (10% carbohydrate) for 2 weeks after which they were instantly provided the alternate diet for 2 weeks. At the end of each diet period, liquid mixed meal tests matching the prevailing diet were consumed in the overnight fasted state and serial blood samples obtained at 0, 60, 120, 180, 240, 300, and 360 minutes for postprandial plasma lipid and lipoprotein profiling using NMR spectroscopy.


Results: Fasting ApoB was greater after LC vs. LF (75 ± 6 vs. 54 ± 6 mg/dL; p = 0.001), whereas fasting TG was lower (70 ± 7 vs. 91 ± 7 mg/dL; p = 0.01). ApoB postprandial area under the curve (AUC) was greater after LC vs. LF (77 ± 6 vs. 53 ± 6 mg/dL; p < 0.001) but TG AUC did not differ (107 ± 10 vs. 103 ± 10 mg/dL; p = 0.65). Fasting ratio of TG:ApoB (1.0 ± 0.1 vs. 1.8 ± 0.1; p < 0.001) and AUC ratio of TG:ApoB (1.5 ± 0.1 vs. 2.0 ± 0.1; p < 0.001) were lower after LC vs. LF. Fasting small-low-density lipoprotein particles ([LDLP] 1040 ± 94 vs. 678 ± 94 nmol/L; p < 0.001), AUC small-LDLP (1050 ± 82 vs. 722 ± 82 nmol/L; p < 0.001), fasting medium-LDLP (298 ± 65 vs. 117 ± 65 nmol/L; p = 0.001), and AUC medium-LDLP (303 ± 53 vs. 83 ± 53 nmol/L; p < 0.001) were all greater after LC vs LF. However, fasting (p = 0.06) and AUC large-LDLP (p = 0.18) did not differ.

Conclusions: In this 2-week inpatient trial, a LC diet led to a greater total atherogenic lipid load, comprised of smaller and denser ApoB particles, compared to a LF diet.

Funding Sources: Intramural Research Program of the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health