TABLE 2.
Potential biomarker equations for fatty acids densities based on linear regression of log-fatty acid density values from the NPAAS-FS (2011–2014; n = 153) on log-transformed metabolomics concentrations, log-transformed established dietary biomarkers, participant characteristics and baseline FFQ measures1
| Coef | R2 (%) | CV-R2 (%) | |
|---|---|---|---|
| SFA density | |||
| Intercept | −4.426 | ||
| TG (TG 51:2, FA 15:0) (serum) | 0.288 | 21.8 | 12.7 |
| Baseline protein density (FFQ) | −0.391 | 21.0 | 12.2 |
| Carbohydrate density biomarker | −0.451 | 1.6 | 0.9 |
| Leisure physical activity (metabolic equivalent units/wk) | −0.004 | 6.0 | 3.5 |
| Sphingomyelin (SM 14:0) (serum) | 0.268 | 3.1 | 1.8 |
| Ceramides (CER 22:0) (serum) | 0.493 | 5.0 | 2.9 |
| Cholesterol ester (CE 12:0) (serum) | 0.045 | 2.7 | 1.6 |
| TG (TG 52:2, FA 20:0) (serum) | 0.115 | 1.8 | 1.0 |
| D-Talose (urine) | −0.038 | 0.7 | 0.4 |
| Energy intake (kcal) from DLW | 0.072 | 0.1 | 0.0 |
| Urinary nitrogen | −0.041 | 0.2 | 0.1 |
| TG (TG 51:2, FA 18:1) (serum) | −0.039 | 0.0 | 0.0 |
| Diacylglycerol (DAG16:0, 18:1) (serum) | 0.038 | 0.1 | 0.0 |
| Cholesterol ester (CE 15:0) (serum) | −0.016 | 0.0 | 0.0 |
| Total | 63.9 | 37.2 | |
| MUFA density | |||
| Intercept | −11.356 | ||
| Carbohydrate density biomarker | −0.463 | 25.7 | 14.9 |
| TG (TG 52:3, FA 18:0) (serum) | −0.410 | 7.7 | 4.5 |
| N-Acetylalanine (serum) (serum) | 0.314 | 8.3 | 4.8 |
| 1/3-Methylhistidine (serum) | −0.036 | 6.7 | 3.9 |
| Phosphatidylethanolamine (PE 18:1, 18.1) (serum) | 0.114 | 4.9 | 2.8 |
| Niacinamide (serum) | 0.085 | 3.6 | 2.1 |
| Phosphatidylcholine (PC 16:0, 20:2) (serum) | −0.141 | 2.8 | 1.6 |
| 3-Hydroxypropionic acid (serum) | 0.110 | 1.9 | 1.1 |
| Cholesterol ester (CE 20:1) (serum) | −0.155 | 2.0 | 1.1 |
| Lysophosphatidylethanolamine (LPE 18:1) (serum) | 0.103 | 1.7 | 1.0 |
| Urinary nitrogen | 0.069 | 0.5 | 0.3 |
| TG (TG 54:2, FA 18:1) (serum) | 0.082 | 1.1 | 0.6 |
| Diacylglycerol (DAG 18:1, 18.1) (serum) | 0.096 | 0.3 | 0.2 |
| TG (TG 52:3, FA 20:1) (serum) | −0.029 | 0.1 | 0.0 |
| Total energy (kcal) from DLW | 0.005 | 0.0 | 0.0 |
| Total | 67.2 | 38.8 | |
| PUFA density | |||
| Intercept | −3.353 | ||
| TG (TG 49:2, FA 16:1) (serum) | 0.239 | 30.3 | 21.2 |
| TG (TG 50:3, FA 16:1) (serum) | −0.345 | 0.0 | 0.0 |
| Cholesterol ester (CE 15:0) (serum) | −0.358 | 3.1 | 2.2 |
| TG (TG 50:2, FA 14:1) (serum) | −0.156 | 1.8 | 1.2 |
| Cholesterol ester (CE 18:1) (serum) | −0.586 | 14.9 | 10.4 |
| Total energy (kcal) from DLW | 0.375 | 1.4 | 1.0 |
| Hexosylceramides (HCER 22:0) (serum) | 0.397 | 4.6 | 3.2 |
| Urinary nitrogen | −0.158 | 1.8 | 1.2 |
| Cholesterol ester (CE 18:0) (serum) | −0.362 | 1.9 | 1.3 |
| TG (TG 52:1, FA 20:1) (serum) | −0.079 | 1.8 | 1.3 |
| Cholesterol ester (CE 22:4) (serum) | −0.153 | 1.2 | 0.8 |
| TG (TG 54:6, FA 22:5) (serum) | −0.068 | 0.4 | 0.3 |
| TG (TG 54:7, FA 18:3) (serum) | 0.043 | 0.2 | 0.2 |
| TG (TG 52:2, FA 20:1) (serum) | 0.012 | 0.0 | 0.0 |
| Cholesterol ester (CE 16:0) (serum) | 0.020 | 0.0 | 0.0 |
| Total | 63.2 | 44.2 | |
Abbreviations: NPAAS-FS, Nutrition and Physical Activity Assessment Study feeding study; R2, percent of variation explained.
In (TG X1:Y1, FA X2:Y2), X1 indicates total number of carbons and Y1 indicates total number of double bonds in the 3 fatty acid chains. X2 indicates number of carbons and Y2 indicates number of double bonds in the fatty acid chain. In (DAG X1:Y1, X2:Y2); (PE X1:Y1, X2:Y2), X1 and X2 indicate number of carbons and Y1 and Y2 indicate number of double bonds in the fatty acid chains. In (SM X:Y); (HCER X:Y); (CE X:Y); (CER X:Y); (LPE X:Y); (FFA X:Y); (LPC X:Y); (PC X:Y), X indicates number of carbons and Y indicates number of double bonds in the fatty acid chain.