The Distribution of Fatty Acid Biomarkers of Dairy Intake across Serum Lipid Fractions: The Prospective Metabolism and Islet Cell Evaluation (PROMISE) Cohort

Abstract

Circulating fatty acids (FA) derived largely from dairy consumption have most commonly been measured in total human serum or phospholipid (PL) fractions, and have been used as validated biomarkers of dairy intake in a growing number of epidemiological studies. Nevertheless, measurement and characterization of a wider spectrum of FA biomarkers of dairy across the four major serum lipid fractions is lacking. This study aimed to (1) quantify FA biomarkers of dairy in PL, triacylglycerol (TAG), cholesteryl ester (CE), and unesterified fatty acid (FFA) serum lipid fractions; and (2) identify potential demographic and metabolic factors that may modify the proportions of these FA across serum fractions. Baseline data from 444 adults in the PROMISE cohort were analyzed. FA biomarkers, 15:0, t16:1n‐7, 18:2‐c9,t11, and t18:1n‐7 were quantified from serum. Dairy intake was estimated using the validated Canadian Diet History Questionnaire. Our results show that t18:1n‐7 was the most abundant FA biomarker in all fractions except CE, where 18:2‐c9,t11 was the most abundant. Positive correlations within fractions, and across FA in the PL, CE, and FFA fractions were found, however, TAG FA were negatively correlated with the other fractions. PL and CE FA were positively associated with dairy intake, and negatively associated with markers of dysmetabolism while, in contrast, these markers were predictors of higher TAG dairy FA. This study is the first to demonstrate distinct proportions of dairy FA in different serum lipid fractions. PL and CE FA marked dairy intake in this cohort, while TAG FA appeared to be markers of dysmetabolism.

The lipidomic correlates of epigenetic aging across the adult lifespan: A population‐based study

“…However, the underlying mechanisms are largely unknown. Previous studies have suggested that circulating C15:0 could be regarded as a direct biomarker of dietary C15:0 intake (Gotoh et al, 2008 ; Hodson et al, 2008 ; Jenkins et al, 2017 ; Rezanka & Sigler, 2009 ; Santaren et al, 2019 ), whereas circulating C17:0 is a product of biosynthesis, which can be affected by and correlates with dietary substrate intake (Jenkins et al, 2017 ). Even‐numbered chain‐length saturated fatty acids are mainly derived from de novo lipogenesis, through which carbohydrates and alcohol are converted to fatty acids in the liver or adipose tissue.…”

Association of circulating branched chain fatty acids with insulin sensitivity and beta cell function in the PROMISE cohort

“…A known amount of heptadecanoic acid (17:0) in FFA, TG, PL, and CE form were added to serum, as an internal standard, prior to extracting total lipids according to the method of Folch (Folch et al, 1957). Thin layer chromatography G-plates were loaded with a portion of the total Santaren, 2019). BCFA standards were methylated and analyzed via GC-FID (iso14:0, anteiso14:0, iso15:0, anteiso15:0, iso16:0, iso17:0, anteiso17:0, and iso18:0 purchased from Larodan AB in Solna, Sweden).…”

Dairy product consumption is associated with a lowering of linoleic acid within serum TAG in adolescent females with overweight or obesity: a secondary analysis

“…The δ13C reporting unit is milliUrey (mUr). A 1 mUr change equals to a 0•1 % (or 1‰) change in 13 C: 12 C compared with a reference material. Therefore, a positive delta δ13C value is indicative of an increase in δ13C.…”

“…When compared to most vegetable oils and margarines, dairy fat contains very low amounts of the omega-6 polyunsaturated fatty acid (n-6 PUFA) linoleic acid (18:2n-6), the major dietary PUFA in the western style eating pattern (9). Some fatty acids have been proposed as markers of dairy intake such as 15:0 and 17:0 (10)(11)(12)(13)(14). Serum levels of these fatty acids have been associated with a lower risk of developing CVD (15) and type 2 diabetes (16) in adults.…”