This is some interesting information I found when studying olive oil as I may be increasing the amount of fats in my recipe. The study appears to call into question whether olive oil is beneficial or deleterious to heart health.
The study can be read here: http://content.onlinejacc.org/article.aspx?articleid=1126754
To sum it up, the study found that olive oil impaired the endothelial function. This constricted blood flow by 31%. This was only after the meal, not permanently. The study puts it this way:
“Olive oil, a staple of the Mediterranean diet, has been presumed to have vasoprotective properties. It appears, however, to have mixed effects on serum cholesterol, endothelial function, and coagulation. Being highly mono-unsaturated (72%), it has beneficial effects on serum lipoproteins 39-41. The major unsaturated fatty acids in olive oil are oleic acid (18:1n-9) and linoleic acid (18:2n-6) (42). A high-oleic and linoleic acid meal has recently been shown to impair FMD in comparison with a low-fat meal (28). Oleic acid decreases vascular cell adhesion molecule-1 expression in endothelial cells, but not as effectively as polyunsaturated fatty acids, including omega-3 fatty acids (43). Whether the 17% saturated fat content of olive oil impairs this action is unknown. In a clinical study, olive oil was shown to activate coagulation factor VII to the same extent as does butter (44). Thus, olive oil does not have a clearly beneficial effect on vascular function.”
The conclusion drawn from these results is not stated herein, however one of the doctors behind the study made the following comment. Though it does sound sensational, I included it to provide his take on the results:
“Contrary to our hypothesis, our study found that omega-9 (oleic acid)–rich Olive Oil, impairs endothelial function after eating. If you’ve been using olive oil because you think it’s healthy, it’s time to think again.”
The reason for this impaired endothelial function seems to be the same as in high saturated fat meals:
“a high fat meal blocks the endothelium’s ability to produce that all important nitric oxide, which is a vasodilator and critical to preserving the tone & health of our blood vessels. When olive oil constricts the blood vessels it’s because it’s blocking the production of nitric oxide.”
I understand that nutrition is not a perfect science and that there are few hard facts. I also realize that many studies have found olive oil to have beneficial effects on multiple heart disease risk factors, and that the study cited here was rather small. Still though, I find myself disappointed by this information. Do other studies merely show improvement over the Standard American Diet? Questions such as this are hard to answer and more research over the coming years will hopefully iron out such things. In the meantime there does appear to be hope for those such as myself who use a large proportion of olive oil in soylent.
The following is from a WebMD article that looked at the study results:
“Vogel’s own research, in fact, has shown that when olive oil is combined with foods rich in antioxidants, such as vegetables, the vessel-constricting effect disappears. All you have to do is combine olive oil with red wine vinegar, which is loaded with the same antioxidants found in wine, and it appears you can prevent the deleterious effect on blood vessels.”
So, at the end of the day it might be wise for those using olive oil as their principle fat source, particularly in a high-fat keto recipe, to look at adding a pinch of red wine or red wine vinegar. Also, though I haven’t looked into it yet, adding a small amount of nitric oxide might be very beneficial, even if you don’t use olive oil. It appears to be good for arterial health: