Nuts and Olive Oil to Prevent CVD
Jacob Schor, ND, FABNO
March 31, 2013
I’m looking for a few good recipes, those that combine large amounts of nuts and olive oil; recipes that taste good enough that it won’t be hard to alternate between them and get a good serving of olive oil, nuts or both on a daily basis.
This quest is inspired by the publication of a study in February 2013, “Primary Prevention of Cardiovascular Disease with a Mediterranean Diet” by Estruch et al. Their results have been hailed as definitive evidence that a Mediterranean Diet prevents cardiovascular disease. That’s not quite true but they certainly give us solid evidence that nuts and olive oil can be useful.
Gina Kolata, the New York Times’ sometimes enthusiastic health reporter, summarized Estruch’s study, “About 30 percent of heart attacks, strokes and deaths from heart disease can be prevented in people at high risk if they switch to a Mediterranean diet rich in olive oil, nuts, beans, fish, fruits and vegetables, and even drink wine with meals….”
Not exactly true but let’s take a moment to look at the study.
This was a large multicenter trial conducted in Spain. A total of 7,447 participants were assigned to one of three diets: a Mediterranean diet supplemented with extra virgin olive oil, a Mediterranean diet supplemented with nuts or a low fat diet. The researchers delivered either free extra virgin olive oil or mixed nuts every week to the participants assigned to the Mediterranean diet. The study participants were all at high risk for cardiovascular disease (CVD), many taking ACE inhibitors, diuretics, other antihypertensive agents, statins, and drugs to control diabetes.
One group following the Mediterranean diet was told to consume 4 Tablespoons/day of extra-virgin olive oil; the second group was told to eat just over an ounce of nuts per day. The ‘control group’ was instructed to follow a low-fat diet.
The researchers tracked the rate of major cardiovascular events (myocardial infarction, stroke, or death from cardiovascular causes). After only 4.8 years, 288 of the participants had had a cardiovascular event and the study was ended. This was because the control group was at higher risk than either of the experimental cohorts. The olive oil group had a 30% lower risk of having a cardiovascular event and the nut eaters had a 28% lower risk than the control group.
This sounds like solid evidence that the Mediterranean diet works.
While there are lots of studies that tell us the Mediterranean diet should lower heart disease this is the first really large clinical trial to test this idea.
In the past evidence in support has come from epidemiological studies, not randomized controlled trials. The 1999 Lyon Heart Study is one of the few other trials and reported that following a Mediterranean diet reduced rate of a recurrence in individuals who had suffered a first myocardial infarction.
This new Estruch clinical trial really only tells us that eating olive oil or nuts is helpful, not that being told to follow a Mediterranean diet does much good. That’s because despite all the counseling from dieticians, the study participants didn’t change their diets much. The only thing they did differently was to eat a bit more fish and beans, about a third a serving more of fish a week and a bit less than half a serving of beans per week. Not even the most enthusiastic supporter of the Mediterranean diet will argue that these slight shifts were enough to change disease risk. The assumption is that it was the nut or oil added to the diets that had the impact.
This study protocol of both encouraging a Mediterranean diet and supplementing with olive oil and nuts isn’t original.
In a 2011 paper Sánchez-Villegas et al reported that a similar protocol encouraging consumption of supplemental nuts along with adherence to a Mediterranean diet over a 3 year period significantly reduced plasma brain-derived neurotrophic factor (BDNF) levels by 78% [odds ratios (OR)=0.22; 95% confidence intervals (CI)=0.05-0.90) of low plasma BDNF values (<13 µg/ml) as compared to the control group].
Some earlier trials following this kind of protocol had greater success at getting people to change their diet. Apparently the worse the person’s diet is at the start of the study, the more likely they will improve it. Or you might say, the easier it is to do something so it’s better.
Estruch conducted an earlier smaller version of this new study that was published in 2006, in which only 772 people were divided into the same three protocol groups. Instead of tracking cardiovascular disease events, the researchers tracked biomarkers of cardiovascular disease risk for just three months. Those people in the Mediterranean diet with olive oil or with nuts groups had significant decreases in plasma glucose, systolic blood pressure, total cholesterol/HDL ratio, and the olive oil group alone had decreased c-reactive protein levels. In 2012 Urpi-Sarda reported similar results. In those people on a low fat diet these parameters increased.
We can certainly conclude that supplementing with nuts or olive oil is a good idea for those at risk for heart attack or stroke. We can’t say that telling a patient to follow a Mediterranean diet will make a difference. The odds are against them taking the advice to heart.
Thus we return to my quest for ways to increase olive oil and nut consumption. Ideally in foods that taste so good as to be irresistible.
New York Times Almond Cake
A delicious recipe using boiled oranges and lemons, almond flour and olive oil. The draw back is that you have to consume two of these cakes per week to get the olive oil you need or one cake a week to get the nuts. Perhaps this is not such a bad idea after all. I wonder how many more nuts one could add instead of the flour?
While all the recipes hint that extra virgin olive oil will be too strong in mayonnaise, if one can stand it, clearly it makes an easy way to consume lots of oil:
This contains the right ingredients, in good proportions. The problem again is quantity. Can you polish off this recipe in three days? Maybe:
Mediterranean diet recommendations
Olive oil 4+ Tbsp/day
Nuts 3+ servings/day
Fresh fruits 3+ servings per day
Vegetables 2+ servings per day
Fish 3+ servings per week
Legumes 3+ servings per week
Sofrito 2+ servings/week
Wine with meals (only for those who were habitual drinkers at start of study) 7+ glasses /week
Soda drinks <1/day
Commercial bakery goods <3 servings/week
Spread fats <1 serving/day
Red and processed meats <1 serving/day
Sofrito is a sauce made from tomato, onion and garlic with herbs, which are simmered together in olive oil
Gina Kolata Mediterranean Diet Shown to Ward Off Heart Attack and Stroke New York Times February 25, 2013
Estruch R, Ros E, Salas-Salvadó J, Covas MI, D Pharm, Corella D, Arós F, Gómez-Gracia E, Ruiz-Gutiérrez V, Fiol M, Lapetra J, Lamuela-Raventos RM, Serra-Majem L, Pintó X, Basora J, Muñoz MA, Sorlí JV, Martínez JA, Martínez-González MA; the PREDIMED Study Investigators. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet. N Engl J Med. 2013 Feb 25.
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