An increase in dietary n-3 fatty acids decreases a marker of bone resorption in humans

Abstract

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) α-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 AAD (15.59 ± 1.21 nM BCE) (p < 0.05). Mean NTx level following the LA diet was 13.80 ± 1.21 nM BCE. There was no change in levels of BSAP across the three diets. Concentrations of NTx were positively correlated with the proinflammatory cytokine TNFα for all three diets. The results indicate that plant sources of dietary n-3 PUFA may have a protective effect on bone metabolism via a decrease in bone resorption in the presence of consistent levels of bone formation.

Associations of dietary polyunsaturated fatty acids with bone mineral density in elderly women

“…In our study, the ratio was clearly lower, on average 4, compared with the previously reported Polyunsaturated fat and bone mineral density R Järvinen et al Polyunsaturated fat and bone mineral density R Järvinen et al 8-10 (Weiss et al, 2005). In a clinical trial, both diets with linoleic:a-linolenic acid ratio of 1.6 and 3.5 resulted in significantly lower bone resorption markers than a diet with a ratio of 9.5, corresponding the average American diet (Griel et al, 2007). However, findings from recent prospective studies among the US citizens are controversial.…”

Long-chain polyunsaturated fatty acids: Selected mechanisms of action on bone

“…Much of the research has emanated from animal models fed diets with n-3 LCPUFA far in excess of that in the human diet [157]. Nonetheless, randomised clinical trials [39] and cohort studies [38,41,44] support an important role for LCPUFA in human bone health. At this time, more data is required to incorporate n-3 LCPUFA into guidelines for the attainment and maintenance of bone mass in humans.…”

“…Some human studies indicate that PUFAs can increase bone formation, affect peak bone mass in adolescents [38] and reduce bone loss as measured using bone mineral densitometry [39]. In contrast, some of the studies in humans did not find any effect on bone markers [40] while some showed reduction in bone loss by measuring deoxypyridinolines and N-telopeptide of Type I collagen in the urine [8,38,39,41]. Two studies found a positive correlation between monounsaturated fat in the diet and bone density [42,43].…”

Effects of single or combined administration of salmon calcitonin and omega-3 fatty acids vs. diclofenac sodium in sodium monoiodoacetate-induced knee osteoarthritis in male Wistar rats

“…Therefore, they tend not exacerbate the OA disease process [17]. No change in the plasma alkaline phosphatase activity was recorded in adult rats maintained on high dietary N-3 [18]. However, N-3 have also been noted to decrease [19], or increase [20,21] the bone formation process.…”