I stumbled on a neat study today:
Compared to a low fat control diet, a Mediterranean diet with olive oil "robustly" increased osteocalcin levels while a Mediterranean diet with nuts did not.
Vitamin K's primary benefits (e.g. to bone health and artery calcification) come from activating proteins like osteocalcin (via carboxylation).
Given this, does this study suggest olive oil, compared to nuts, better supports the use of vitamin K in the body? Or is the bit of vitamin K1 in olive oil enough to explain this effect?
asked byMscott (12682)
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on April 05, 2013
at 09:39 PM
Okay so I'm going to answer my own question here. One of the main olive oil polyphenols, oleuropein, may affect osteocalcin levels, but mostly results are mixed or not supportive of this. As far as olive oil itself it may increase osteocalcin but the effect small and difficult to tell.
The more interesting theory explaining the study may be partially related to the effect of O6 polyunsatuated fat compared to monounsaturated fat. This study is quite interesting:
It found that consuming corn oil (abbreviated CO) led to lower levels of the vitamin K1 and lower levels of the vitamin k dependent protein MGP and increased the percentage of uncarboxylated (not activated) osteocalcin compared to a lower pufa mixture of olive and sunflower oil (abbreviated O/SO). From the paper:
"It was noteworthy that the PUFA-rich CO diet induced a significant reduction in plasma K1 and TAG compared with both adjustment and O/SO diets. This is consistent with the carriage of K1 by TRL (6) and with the well-established capacity of diets rich in PUFA to reduce post-absorptive concentrations of plasma TAG (21), probably by reducing the post-prandial accumulation of TRL (22). The accompanying evidence of slight increases in undercarboxylation of FII and osteocalcin by the CO diet imply a lowered vitamin K status that may, however, be unrelated to the lowering of plasma TAG and K1. Possible explanations include a reduced intestinal absorption of vitamin K, a reduced extracellular or intracellular delivery of vitamin K to target proteins, an increased turnover rate of the vitamin, or an inhibitory effect on VKD ??-carboxylation".
And perhaps most interestingly:
"The possibility that the CO diet reduced the intestinal absorption of vitamin K is supported by in vivo studies in rats that showed that the PUFA linoleic acid (18:2) caused a marked decrease in the intestinal absorption rate of vitamin K1 (23). This inhibition was not seen with the MUFA oleic acid (18:1)".
So it may be that olive oil isn't synergistic with vitamin K, but rather linoleic acid is antagonistic.