Could following a Mediterranean diet help protect against osteoporosis? That’s what media reports of a 2012 study suggested. Can a diet rich in fresh vegetables and fruit, fish and olive oil really strengthen our bones and provide this protection?
What kind of study was this?
Researchers from various institutions in Spain, partly funded by their Government, carried out a long term randomized controlled study. NHS Inform described this as ‘a well conducted study.’
What did the researchers investigate?
The study looked at the long-term effects of three types of diet on the levels of osteocalcin protein in the blood in 127 elderly men with high cardiovascular risk. Higher osteocalcin levels have been well correlated with increase in bone mineral density. The three diets were a low-fat control diet, a Mediterranean diet enriched with nuts and a Mediterranean diet enriched with virgin olive oil.
Characteristics measured at the start of the study, including age, body mass index, lipid profile, bone formation and restoration marker levels, did not differ significantly across the three dietary groups.
What did the researchers find?
When measured after 2 years, the group consuming a virgin olive oil enriched Mediterranean diet had significantly higher concentrations of osteocalcin proteins in their blood, compared to the other two groups.
Thus, the researchers concluded that consumption of a virgin olive oil enriched Mediterranean diet for two years is associated with increased serum osteocalcin levels, suggesting protective effects on bone.
Were there any limitations to the study?
The research didn’t directly measure bone density or fracture rates. Instead it measured osteocalcin levels as an indicator of bone density.
The participants in the study were randomly selected from a larger trial aimed at examining the role of Mediterranean diets in the prevention of cardiovascular disease. They were all male and had all been diagnosed with cardiovascular risk factors (such as type 2 diabetes). Further research would be needed into the effects on women and on younger and healthier people.
All participants in the study received instructions to use olive oil in cooking, increase consumption of fruit, vegetables, pulses and fish, replace processed and red meat with white meat and avoid butter and cream. All participants received the same instructions but we can’t be sure how fully each followed them.
Correlation with previous studies?
Previous studies had shown that the incidence of osteoporosis in Europe was lower in the Mediterranean basin. The traditional Mediterranean diet could have been a factor here.
According to Dr Fernandez-Real, lead author of the study, “The intake of olive oil has been related to the prevention of osteoporosis in experimental and in vitro models.”
Despite the weaknesses identified, this study does correlate with epidemiological and experimental evidence, suggesting potentially promising results with regard to the general field of bone health.
This study therefore has important possible implications for ageing. In a country like the UK the number of fractures and osteoporosis cases is relatively high.
More research is needed (in particular into the effect on bone density and fracture rates). However, if this confirms the findings from the Spanish study, it would provide a practical means by which people could help prevent or delay osteoporosis – simply by supplementing their diet with more olive oil, fish, fruit and vegetables.
Published 03/12/12 Review date August 2015