THE EFFECTS OF DIETARY n-6/n-3 RATIO OF POLYUNSATURATED FATTY ACIDS ON THE PHYSICAL PARAMETERS OF FEMUR AND BIOMARKERS OF BONE METABOLISM IN RATS (original) (raw)
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British Journal of Nutrition, 2004
PUFA and their metabolites are important regulators of bone formation and resorption. The effect of PUFA on bone growth may be especially striking during the perinatal period. The aim of the present study was to investigate the effect of diets with different n-6:n-3 fatty acid (FA) ratios during the perinatal period on bone parameters in the adult offspring. During late gestation and throughout lactation, rat dams were fed an isoenergetic diet containing 70 g linseed oil (n-3 diet), soyabean oil (n-6þn-3 diet) or sunflower-seed oil (n-6 diet) per kg with n-6:n-3 FA ratios of 0·4, 9 and 216, respectively. The offspring were weaned onto an ordinary chow and followed until 30 weeks of age. Bone parameters were analysed using peripheral quantitative computerised tomography and dual-energy X-ray absorptiometry. Femur length and cortical cross-sectional bone area and bone mineral content were significantly higher in the n-6þ n-3 group than in the other groups. Cortical bone thickness in the n-6þn-3 group was increased compared with the n-3 group, but most cortical bone parameters did not differ between the n-3 and n-6 groups. The results suggest that regulatory mechanisms were influenced by the n-6:n-3 FA ratio early in life and not compensated for by the introduction of an ordinary diet after weaning. Diet: Bone mineral density: Fatty acids: Insulin-like growth factor-1 * Corresponding author: Dr Marina Korotkova, fax þ46 31 21 70 23, email Marina.Korotkova@cmm.ki.se
Applied Physiology, Nutrition, and Metabolism, 2010
Previous studies have suggested that high-fat diets adversely affect bone development. However, these studies included other dietary manipulations, including low calcium, folic acid, and fibre, and (or) high sucrose or cholesterol, and did not directly compare several common sources of dietary fat. Thus, the overall objective of this study was to investigate the effect of high-fat diets that differ in fat quality, representing diets high in saturated fatty acids (SFA), n-3 polyunsaturated fatty acids (PUFA), or n-6 PUFA, on femur bone mineral density (BMD), strength, and fatty acid composition. Forty-day-old male Sprague-Dawley rats were maintained for 65 days on high-fat diets (20% by weight), containing coconut oil (SFA; n = 10), flaxseed oil (n-3 PUFA; n = 10), or safflower oil (n-6 PUFA; n = 11). Chow-fed rats (n = 10), at 105 days of age, were included to represent animals on a control diet. Rats fed high-fat diets had higher body weights than the chow-fed rats (p < 0.001). Among all high-fat groups, there were no differences in femur BMD (p > 0.05) or biomechanical strength properties (p > 0.05). Femurs of groups fed either the high n-3 or high n-6 PUFA diets were stronger (as measured by peak load) than those of the chow-fed group, after adjustment for significant differences in body weight (p = 0.001). As expected, the femur fatty acid profile reflected the fatty acid composition of the diet consumed. These results suggest that high-fat diets, containing high levels of PUFA in the form of flaxseed or safflower oil, have a positive effect on bone strength when fed to male rats 6 to 15 weeks of age.
European Journal of Nutrition
Purpose Adipocytes and osteoblasts were derived from a common progenitor, and canola oil intake may have an adipogenic and osteogenic effect. Thus, our objective was to evaluate the effect on adipocyte, lipid profile, glucose homeostasis, and bone of canola oil as main lipid source on the diet during development. Methods After weaning, rats were divided into two groups (n = 10 per group): control (S) and experimental (C) diets containing 7 mL/100 g soybean or canola oil, respectively. At 60 days, body composition, liver and intra-abdominal fat mass, adipocyte morphology, serum analysis, femur and lumbar vertebras density by dual-energy X-ray absorptiometry and computed tomography were determined. Differences were considered significant with P < 0.05. Results C group showed the following: lower liver (−12%) and intra-abdominal fat mass (−19%) area of adipocyte (−60%), cholesterol (−33%), insulin (−22%), lower total body (−9%) and spine (−33%) bone mineral content and bone area (−7 and −24%, respectively), femur mass (−9%), width of the diaphysis (−6%), femur (−10%) and lumbar vertebrae bone mineral density (−9%), and radiodensity of femoral head (−8%). Conclusions The lower intra-abdominal adiposity could have more beneficial effects in a short term, since it can be associated with a better insulin sensitivity and lipid profile, than the small reduction in femur and lumbar vertebra density. However, it has to be considered the incremental effect of this reduction along the aging process.
An increase in dietary n-3 fatty acids decreases a marker of bone resorption in humans
Nutrition journal, 2007
Human, animal, and in vitro research indicates a beneficial effect of appropriate amounts of omega-3 (n-3) polyunsaturated fatty acids (PUFA) on bone health. This is the first controlled feeding study in humans to evaluate the effect of dietary plant-derived n-3 PUFA on bone turnover, assessed by serum concentrations of N-telopeptides (NTx) and bone-specific alkaline phosphatase (BSAP). Subjects (n = 23) consumed each diet for 6 weeks in a randomized, 3-period crossover design: 1) Average American Diet (AAD; [34% total fat, 13% saturated fatty acids (SFA), 13% monounsaturated fatty acids (MUFA), 9% PUFA (7.7% LA, 0.8% ALA)]), 2) Linoleic Acid Diet (LA; [37% total fat, 9% SFA, 12% MUFA, 16% PUFA (12.6% LA, 3.6% ALA)]), and 3) alpha-Linolenic Acid Diet (ALA; [38% total fat, 8% SFA, 12% MUFA, 17% PUFA (10.5% LA, 6.5% ALA)]). Walnuts and flaxseed oil were the predominant sources of ALA. NTx levels were significantly lower following the ALA diet (13.20 +/- 1.21 nM BCE), relative to the A...
The effect of polyunsaturated fatty acids on bone health
Reviews in Clinical Gerontology, 2011
SummaryThe essential polyunsaturated fatty acids (PUFAs) are divided into two classes, n-3 (ω-3) and n-6 (ω-6) and their dietary precursors are α-linolenic (ALA) and linoleic acid (LA), respectively. PUFAs are precursors of a wide range of metabolites, for example eicosanoids like prostaglandins and leukotrienes, which play critical roles in the regulation of a variety of biological processes, including bone metabolism.A large body of evidence supports an effect of PUFA on bone metabolism which may be mediated by regulation of osteoblastogenesis and osteoclast activity, change of membrane function, decrease in inflammatory cytokines, such as interleukin-1 (IL-1), interleukin-6 (IL-6), and tumour necrosis factor alpha (TNF-α), modulation of peroxisome proliferators-activated receptor γ (PPARγ) and influence in NO secretion and NO synthase.Animal studies have shown that a higher dietary omega-3/omega-6 fatty acids ratio is associated with beneficial effects on bone health. Human studi...
British Journal of Nutrition, 2003
The effect of polyunsaturated fatty acids (PUFA), in particular conjugated linoleic acid (CLA), on Ca and bone metabolism is unclear. In a 2 × 2 factorial design study, forty male 4-week-old rats were fed a control diet containing 70 g added fat (soyabean oil (SBO; n–6 PUFA-rich diet) or menhaden oil–safflower oil (MSO; n−3 PUFA-rich diet))/kg diet with 0 or 10 g CLA/kg for 8 weeks. Ex vivo prostaglandin E2biosynthesis by bone organ culture was significantly higher (P<0·001) in rats consuming SBO compared with MSO, irrespective of CLA. Addition of the CLA treatment to either diet further lowered (P<0·05) ex vivo prostaglandin E2 production. Neither PUFA type nor CLA altered circulating or femoral mRNA levels of osteocalcin (a marker of bone formation) or insulin-like growth factor-I (a mediator of bone metabolism). While urinary pyridinium crosslinks levels (markers of bone resorption) were unaffected by CLA irrespective of PUFA type, they were significantly higher (P<0·05)...
The Role of Omega-3 Polyunsaturated Fatty Acids from Different Sources in Bone Development
Nutrients
N-3 polyunsaturated fatty acids (PUFAs) are essential nutrients that must be obtained from the diet. We have previously showed that endogenous n-3 PUFAs contribute to skeletal development and bone quality in fat-1 mice. Unlike other mammals, these transgenic mice, carry the n-3 desaturase gene and thus can convert n-6 to n-3 PUFAs endogenously. Since this model does not mimic dietary exposure to n-3 PUFAs, diets rich in fish and flaxseed oils were used to further elucidate the role of n-3 PUFAs in bone development. Our investigation reveals that dietary n-3 PUFAs decrease fat accumulation in the liver, lower serum fat levels, and alter fatty acid (FA) content in liver and serum. Bone analyses show that n-3 PUFAs improve mechanical properties, which were measured using a three-point bending test, but exert complex effects on bone structure that vary according to its source. In a micro-CT analysis, we found that the flaxseed oil diet improves trabecular bone micro-architecture, wherea...
Pakistan Journal of Nutrition, 2012
The beneficial effects of polyunsaturated fats and omega 3 supplements in human and animal nutrition have been widely discussed and established though clinical and experimental studies. In this study the High-Fat (HF) diet rodent models were used to evaluate the effects high doses of two polyunsaturated fats omega-3 and omega-6 on metabolic parameters and histology of liver and kidney. Male and female Wistar rats were fed High-Fat (HF) diets containing Omega-3 fish oil supplements (HF-F) and Omega-6 corn oil (HF-C) at a level that was equivalent to three times the maximum safe daily dosage and the control group was fed with regular laboratory chow. Body weight and plasma parameters of glucose, cholesterol and triglycerides were measured after a 8 week diet course. Rats fed both the high fat oil based diets (HF-F, HF-C) reported a significantly higher body weight gain than the control group. Plasma triglyceride levels were significantly higher in the high fat diets being highest in the fish oil based diet. Both the high fat diets fed animals (HF-F, HF-C) showed pronounced hepatic micro vesicular steaosis and renal interstitial inflammation in comparison with the control in the histological studies. Thus this study demonstrated that high fat diets with polyunsaturated fats including omega-3 rich fish oil could induce dyslipidemia and obesity in rodent models reflecting signs of metabolic syndrome in the humans.
Prostaglandins, Leukotrienes and Essential Fatty Acids (PLEFA), 2013
Long-chain n-3 PUFA (LCPUFA) and palmitate (16:0) positioning in the triacylglycerol (TAG) of infant formula may affect calcium-uptake which could affect bone health. We investigated if a human milk fat substitute (HMFS) with a modified TAG structure holding 16:0 predominantly in the sn-2-position compared with a control (CONT) and if increasing n-3LCPUFA intake giving fish oil (FO) compared with sunflower oil (SO) would affect bone parameters in piglets in two sets of controlled 14d-interventions (n ¼12/group). We assessed this by dual-energy x-ray absorptiometry, and ex vivo peripheral quantitative computed tomography and mechanical strength. Bone mineral content (BMC) was higher in the FO compared to the SO-group (p¼ 0.03). Despite similar weight gain in HMFS-and CONT-groups, body fat accumulation was higher with HMFS (po0.001), and BMC, bone area (BA) and cortical BA in femur were lower (p¼ 0.002, p¼ 0.005, and p¼0.02, respectively), indicating importance of both n-3LCPUFA and 16:0 TAG-positioning in infant formulas.