Pinoresinol of olive oil decreases vitamin D intestinal absorption.

Enriching oils, such as olive oil, could be one solution to tackle the worldwide epidemic of vitamin D deficiency and to better fit with omega 3 (DHA) recommendations. However, data regarding the interactions occurring at the intestinal level between vitamin D and phenols from olive oil are scarce. We first determined the effect of polyphenols from a virgin olive oil, and a virgin olive oil enriched with DHA, on vitamin D absorption in rats. We then investigated the effects of 3 main olive oil phenols (oleuropein, hydroxytyrosol and pinoresinol) on vitamin D uptake by Caco-2 cells. The presence of polyphenols in the olive oil supplemented with DHA inhibited vitamin D postprandial response in rats (-25%, p<0.05). Similar results were obtained with a mix of the 3 polyphenols delivered to Caco-2 cells. However, this inhibitory effect was due to the presence of pinoresinol only. As the pinoresinol content can highly vary between olive oils, the present results should be taken into account to formulate an appropriate oil product enriched in vitamin D.

Olive oil and vitamin D synergistically prevent bone loss in mice.

As the Mediterranean diet (and particularly olive oil) has been associated with bone health, we investigated the impact of extra virgin oil as a source of polyphenols on bone metabolism. In that purpose sham-operated (SH) or ovariectomized (OVX) mice were subjected to refined or virgin olive oil. Two supplementary OVX groups were given either refined or virgin olive oil fortified with vitamin D3, to assess the possible synergistic effects with another liposoluble nutrient. After 30 days of exposure, bone mineral density and gene expression were evaluated. Consistent with previous data, ovariectomy was associated with increased bone turnover and led to impaired bone mass and micro-architecture. The expression of oxidative stress markers were enhanced as well. Virgin olive oil fortified with vitamin D3 prevented such changes in terms of both bone remodeling and bone mineral density. The expression of inflammation and oxidative stress mRNA was also lower in this group. Overall, our data suggest a protective impact of virgin olive oil as a source of polyphenols in addition to vitamin D3 on bone metabolism through improvement of oxidative stress and inflammation.