The incidence of osteoporosis and associated fractures is found to be lower in countries where the Mediterranean diet is predominant. These observations might be mediated by the active constituents of olive oil and especially phenolic compounds.
The intake of olive oil has been related to the prevention of osteoporosis in experimental and in in vitro models. Very few prospective studies have evaluated the effects of olive oil intake on circulating osteocalcin (OC) in humans.
The objective of the study led by Spanish researchers was to examine the longitudinal effects of a low-fat control diet (n = 34), a Mediterranean diet enriched with nuts (MedDiet+nuts, n = 51), or a Mediterranean diet enriched with virgin olive oil (MedDiet+VOO, n = 42) on circulating forms of OC and bone formation markers in elderly men at high cardiovascular risk.
Consumption of a Mediterranean diet enriched with virgin olive oil for 2 years is associated with increased serum osteocalcin and P1NP concentrations, suggesting protective effects on bone.
Age-related bone mass loss and decreased bone strength is an almost invariable feature of human biology, affecting women and men alike as an important determinant of osteoporosis and fracture risk. Nutritional factors are known to be involved in age-related bone loss associated with osteoblast insufficiency during continuous bone remodeling, in interaction with a combination of genetic, metabolic, and hormonal factors.
Epidemiological studies have shown that the incidence of osteoporosis in Europe is lower in the Mediterranean basin. The traditional Mediterranean diet, rich in fruit and vegetables, with a high intake of olives and olive products, mainly olive oil, could be one of the environmental factors underlying this difference.
Some reports have suggested that the consumption of olives, olive oil, and oleuropein, an olive oil polyphenol, can prevent the loss of bone mass in animal models of aging-related osteoporosis. Recent in vitro studies have shown that oleuropein, the main phenolic compound in olive leaves and fruit and a constituent of virgin olive oil, reduced the expression of peroxisomal proliferator-activated receptor-γ, inhibiting adipocyte differentiation and enhancing differentiation of mesenchymal stem cells into osteoblasts. In addition, the gene expression of osteoblastogenesis markers, runt-related transcription factor II, osterix, collagen type I, alkaline phosphatase, and osteocalcin, was higher in osteoblast-induced oleuropein-treated cells.
A protective effect of olive oil and oleuropein has also been observed in experimental models. Femoral failure load and diaphyseal bone mineral density were increased after consumption of oleuropein and olive oil in ovariectomized mice. In addition to its role as bone marker, osteocalcin has also been related to glucose homeostasis. Mice lacking osteocalcin displayed decreased β-cell proliferation, glucose intolerance, and insulin resistance when compared with wild-type mice. We are unaware of studies evaluating the effects of olive oil on circulating osteocalcin and its possible relationship with insulin secretion/resistance in humans. The objective of this study was to explore circulating bone formation and resorption markers in association with the intake of olive oil. For comparison, we also studied the effects of consuming nuts and the effects of a low-fat diet.
Published evidence suggests that olive oil phenols can be beneficial by preventing the loss of bone mass. It has been demonstrated that they can modulate the proliferative capacity and cell maturation of osteoblasts by increasing alkaline phosphatase activity and depositing calcium ions in the extracellular matrix. Further research on this issue is warranted, given the prevalence of osteoporosis and the few data available on the action of olive oil on bone.
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