Platt, I.D., A.R. Jossea, C.W.C. Kendall, D.J.A. Jenkins, A. El-Sohemya, 2011. Postprandial effects of almond consumption on human osteoclast precursors—an ex vivo study. Metabolism Clinical and Experimental. 60: 923–929.
Consumption of almonds has been associated with increased bone mineral density, but the direct effects of almonds on bone cells are not known. We determined whether serum obtained following the consumption of a meal containing 60 g of almonds affects human osteoclast formation, function, and gene expression in vitro. Human osteoclast precursors were cultured in medium containing 10% serum obtained from 14 healthy subjects at baseline and 4 hours following the consumption of 3 test meals containing almonds, potatoes, and rice and balanced for macronutrient composition. Osteoclast formation was determined by the number of tartrate-resistant acid phosphatase (TRAP)+ multinucleated cells, and osteoclast function was assessed by measuring TRAP activity in the culture medium and calcium released from OsteoAssay (Lonza Walkersville, Walkersville, MD, USA) plates. The expression of cathepsin K, receptor activator of nuclear factor kB, and matrix metalloproteinase–9 genes was measured by real-time reverse transcriptase–polymerase chain reaction. Compared with serum obtained at baseline, serum obtained 4 hours following the consumption of the almond meal reduced osteoclast formation by approximately 20%, TRAP activity by approximately 15%, calcium release by approximately 65%, and the expression of cathepsin K, receptor activator of nuclear factor kB, and matrix metalloproteinase–9 by 13% to 23%. No effects were observed with serum obtained from the other test meals. Serum obtained 4 hours following the consumption of an almond meal inhibits osteoclast formation, function, and gene expression in cultured human osteoclast precursors, and provides evidence for a positive effect of almonds on bone health.
Bullo´, M., P. Amigo-Correig, F. Marquez-Sandoval, N. Babio, M.A. Martinez-Gonzalez, R. Estruch, J. Basora, R. Sola`, J. Salas-Salvado´, 2009. Mediterranean diet and high dietary acid load associated with mixed nuts: effect on bone metabolism in elderly subjects. J Am Geriatr Soc. 57:1789–1798.
Objectives: To analyze the effect of differing diet on the acid load content on bone metabolism. Design: Multicentric, randomized, single-blind, parallel-group clinical trial. Setting: Outpatient clinics. Participants: Two hundred thirty-eight elderly men and women aged 60 to 80 at high risk for cardiovascular disease were randomly assigned to three interventional groups: a recommended low-fat diet (control diet group), a Mediterranean diet supplemented with virgin olive oil, or a Mediterranean diet supplemented with mixed nuts. Measurements: Main outcomes were 12-month changes from baseline in bone formation and resorption markers and bone mass measured according to quantitative ultrasound scanning. Results: The baseline data on the anthropometric, bone densitometry, and biochemical variables did not differ between the three groups. Dietary potential renal acid load (PRAL) and daily net endogenous acid production (NEAP) at baseline did not differ between groups. After intervention, subjects allocated to the Mediterranean diet with mixed nuts had a significant increase of PRAL and NEAP. In comparison, subjects in the Mediterranean diet with nuts group had higher parathyroid hormone (PTH) levels (2.63, 95% confidence interval (CI) = -1.01–6.35, P=.02) and a nonsignificantly higher (0.31, 95% CI = -0.13–0.74, P=.14) urine free deoxypyridoxine:creatinine ratio, a marker of bone resorption, than the control group and the Mediterranean diet with virgin olive oil group. Conclusion: A Mediterranean dietary pattern associated with a high dietary acid load derived from consumption of mixed nuts does not seem to have a much greater effect on bone metabolism biomarkers, with the exception of PTH levels, than a Mediterranean diet without mixed nuts or a control diet in elderly subjects.
Papoutsi, Z., E. Kassi, I. Chinou, M. Halabalaki, L.A. Skaltsounis, P. Moutsatsou, 2008. Walnut extract (Juglans regia L.) and its component ellagic acid exhibit anti-inflammatory activity in human aorta endothelial cells and osteoblastic activity in the cell line KS483. British Journal of Nutrition. 99(4):715-22.
Epidemiological studies suggest that the incidence of CVD and postmenopausal osteoporosis is low in the Mediterranean area, where herbs and nuts, among others, play an important role in nutrition. In the present study, we sought a role of walnuts (Juglans regia L.) in endothelial and bone-cell function. As the endothelial cell expression of adhesion molecules has been recognised as an early step in inflammation and atherogenesis, we examined the effect of walnut methanolic extract and ellagic acid, one of its major polyphenolic components (as shown by HPLC analysis), on the expression of vascular cell adhesion molecule (VCAM)-1 and intracellular adhesion molecule (ICAM)-1 in human aortic endothelial cells. After incubating the cells with TNF-α (1 ng/ml) in the absence and in the presence of walnut extract (10–200 µg/ml) or ellagic acid (10-7–10-5 M), the VCAM-1 and ICAM-1 expression was quantified by cell-ELISA. We further evaluated the effect of walnut extract (10–50 mg/ml), in comparison with ellagic acid (10-9–10-6 M), on nodule formation in the osteoblastic cell line KS483.Walnut extract and ellagic acid decreased significantly the TNF-a-induced endothelial expression of both VCAM-1 and ICAM-1 (P < 0.01; P < 0.001). Both walnut extract (at 10–25µg/ml) and ellagic acid (at 10-9–10-8 M) induced nodule formation in KS483 osteoblasts. The present results suggest that the walnut extract has a high anti-atherogenic potential and a remarkable osteoblastic activity, an effect mediated, at least in part, by its major component ellagic acid. Such findings implicate the beneficial effect of a walnut-enriched diet on cardioprotection and bone loss.
Griel A.E., P.M. Kris-Etherton, K.F. Hilpert, G. Zhao, S.G. West, R.L. Corwin, 2007. An increase in dietary n-3 fatty acids improves bone health in humans. Nutrition Journal. 6:2.
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). Twenty-three subjects 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.