The general population is encouraged
to increase omega-3 polyunsaturated fatty acid (n-3 PUFA) intake in order to optimize
health for preventative health care. Consumers are typically unaware that
different amounts, types, and structural forms of n-3 PUFA have different
efficacy. Therefore, the objectives of this study were to characterize
different sources of n-3 PUFAs and to determine whether consumption of these
oils influences renal fatty acid composition and renal health. Lipid classes
and fatty acid profile of corn (CO), flaxseed (FO), menhaden (MO), salmon (SO),
tuna (TO) or krill (KO) oils were determined by thin-layer and gas
chromatography. All dietary oils consisted of >65% triglyceride with the
exception of KO. KO and FO also contained phospholipids. FO was rich in the n-3
PUFA, alpha-linolenic acid (18:3n-3) whereas, the marine oils were rich in the
long-chain n-3 PUFAs (>18 carbons). Following characterization of the oil
sources, female Sprague-Dawley rats (age 28 d) were randomly assigned (n = 10/group) to be fed a high fat 12%
(wt) diet consisting of these different oil sources for 8 weeks. Rats fed MO,
TO, and SO had significantly higher renal eicosapentaenoic acid (20:5n-3) and
docosahexaenoic acid (22:6n-3) deposition and this in turn, modulated inflammatory
responses. Feeding rats MO, SO and TO reduced urinary excretion of 13,14-dihydro-15-keto
prostaglandin E2. Feeding rats TO and SO reduced (P ≤ 0.002)
nuclear factor kappa B activity and circulating TNFα (P < 0.05). In contrast,
rats consuming KO had heavier kidney weights (P < 0.001), total calcium content, and
histological evidence of renal calcification and tubulo-interstitial injury. This
was due to increased (P < 0.001) urinary
phosphorus excretion associated with the phospholipids content of KO. The study
results indicated that consumption of n-3 PUFAs influences renal health and the
effects varied depending on the n-3 PUFA source consumed.