Therapeutic potentials and modulatory mechanisms of fatty acids in bone

Vegan Diet and Bone Health-Results from the Cross-Sectional RBVD Study

Scientific evidence suggests that a vegan diet might be associated with impaired bone health. Therefore, a cross-sectional study (n = 36 vegans, n = 36 omnivores) was used to investigate the associations of veganism with calcaneal quantitative ultrasound (QUS) measurements, along with the investigation of differences in the concentrations of nutrition- and bone-related biomarkers between vegans and omnivores. This study revealed lower levels in the QUS parameters in vegans compared to omnivores, e.g., broadband ultrasound attenuation (vegans: 111.8 ± 10.7 dB/MHz, omnivores: 118.0 ± 10.8 dB/MHz, p = 0.02). Vegans had lower levels of vitamin A, B2, lysine, zinc, selenoprotein P, n-3 fatty acids, urinary iodine, and calcium levels, while the concentrations of vitamin K1, folate, and glutamine were higher in vegans compared to omnivores. Applying a reduced rank regression, 12 out of the 28 biomarkers were identified to contribute most to bone health, i.e., lysine, urinary iodine, thyroid-stimulating hormone, selenoprotein P, vitamin A, leucine, α-klotho, n-3 fatty acids, urinary calcium/magnesium, vitamin B6, and FGF23. All QUS parameters increased across the tertiles of the pattern score. The study provides evidence of lower bone health in vegans compared to omnivores, additionally revealing a combination of nutrition-related biomarkers, which may contribute to bone health. Further studies are needed to confirm these findings.

Regulation of Osteoclast Differentiation and Activity by Lipid Metabolism

Bone is a dynamic tissue and is constantly being remodeled by bone cells. Metabolic reprogramming plays a critical role in the activation of these bone cells and skeletal metabolism, which fulfills the energy demand for bone remodeling. Among various metabolic pathways, the importance of lipid metabolism in bone cells has long been appreciated. More recent studies also establish the link between bone loss and lipid-altering conditions—such as atherosclerotic vascular disease, hyperlipidemia, and obesity—and uncover the detrimental effect of fat accumulation on skeletal homeostasis and increased risk of fracture. Targeting lipid metabolism with statin, a lipid-lowering drug, has been shown to improve bone density and quality in metabolic bone diseases. However, the molecular mechanisms of lipid-mediated regulation in osteoclasts are not completely understood. Thus, a better understanding of lipid metabolism in osteoclasts can be used to harness bone cell activity to treat pathological bone disorders. This review summarizes the recent developments of the contribution of lipid metabolism to the function and phenotype of osteoclasts.

The impact of a high fat diet on bones: potential mechanisms

High-fat diet led to bone loss via gut microbiota and fatty acid imbalances, immune disorder and adipose tissue accumulation inside and outside the bone marrow.

Healthy eating index-2015 and bone mineral density among adult Iranian women

This is the first study to examine the potential association of adherence to the healthy eating index-2015 (HEI-2015) and bone health. Findings suggest that better diet quality (i.e., a higher HEI-2015 score) is significantly associated with a small but clinically important increase in bone mineral density among adult Iranian women.

PURPOSE

The HEI-2015 is a multidimensional measure of diet quality used to assess how well people's dietary behaviors align with key recommendations of the 2015-2020 Dietary Guidelines for Americans for achieving a healthy dietary pattern. We examined the potential association of the HEI-2015 and bone mineral density (BMD) among adult Iranian women, hypothesizing that a higher HEI-2015 score is associated with greater BMD.

METHODS

Four-hundred sixteen participants (mean age 48.0 years; 64.7% premenopausal) participated in this cross-sectional study. Lumbar spine and femoral neck BMDs were measured via dual-energy X-ray absorptiometry. Dietary intakes were assessed using a valid and reliable food frequency questionnaire. The HEI-2015 score was calculated based on dietary intakes of 13 components emphasized or minimized in the HEI-2015. The higher the HEI-2015 score, the better the diet quality.

RESULTS

After adjusting for potential covariates in the multiple linear regression analysis, higher HEI-2015 scores were associated with greater lumbar spine and femoral neck BMDs (lumbar spine: standardized beta-coefficient [β] = 0.292; femoral neck: β = 0.192; both P < 0.001). Similar significant associations were found among premenopausal (lumbar spine: β = 0.337; femoral neck: β = 0.262; both P < 0.001) and postmenopausal women (lumbar spine: β = 0.198; femoral neck: β = 0.287; both P < 0.050). Overall, every 10-unit increase in the HEI-2015 score was associated with a 0.03 g/cm² higher multivariable-adjusted BMD at both lumbar spine and femoral neck (both P < 0.001).

CONCLUSION

Findings suggest that better diet quality, as indicated by a higher HEI-2015 score, is significantly associated with a small but clinically important increase in BMD among adult Iranian women.

Dual Effects of Lipid Metabolism on Osteoblast Function

The skeleton is a dynamic and metabolically active organ with the capacity to influence whole body metabolism. This newly recognized function has propagated interest in the connection between bone health and metabolic dysfunction. Osteoblasts, the specialized mesenchymal cells responsible for the production of bone matrix and mineralization, rely on multiple fuel sources. The utilization of glucose by osteoblasts has long been a focus of research, however, lipids and their derivatives, are increasingly recognized as a vital energy source. Osteoblasts possess the necessary receptors and catabolic enzymes for internalization and utilization of circulating lipids. Disruption of these processes can impair osteoblast function, resulting in skeletal deficits while simultaneously altering whole body lipid homeostasis. This article provides an overview of the metabolism of postprandial and stored lipids and the osteoblast's ability to acquire and utilize these molecules. We focus on the requirement for fatty acid oxidation and the pathways regulating this function as well as the negative impact of dyslipidemia on the osteoblast and skeletal health. These findings provide key insights into the nuances of lipid metabolism in influencing skeletal homeostasis which are critical to appreciate the extent of the osteoblast's role in metabolic homeostasis.

Therapeutic potentials and modulatory mechanisms of fatty acids in bone

Bone metabolism is a lifelong process that includes bone formation and resorption. Osteoblasts and osteoclasts are the predominant cell types associated with bone metabolism, which is facilitated by other cells such as bone marrow mesenchymal stem cells (BMMSCs), osteocytes and chondrocytes. As an important component in our daily diet, fatty acids are mainly categorized as long‐chain fatty acids including polyunsaturated fatty acids (LCPUFAs), monounsaturated fatty acids (LCMUFAs), saturated fatty acids (LCSFAs), medium‐/short‐chain fatty acids (MCFAs/SCFAs) as well as their metabolites. Fatty acids are closely associated with bone metabolism and associated bone disorders. In this review, we summarized the important roles and potential therapeutic implications of fatty acids in multiple bone disorders, reviewed the diverse range of critical effects displayed by fatty acids on bone metabolism, and elucidated their modulatory roles and mechanisms on specific bone cell types. The evidence supporting close implications of fatty acids in bone metabolism and disorders suggests fatty acids as potential therapeutic and nutritional agents for the treatment and prevention of metabolic bone diseases.