Neat Study; Limited Value:
“Primary Prevention of Cardiovascular Disease with a Mediterranean Diet” in the February 25th addition of the New England Journal of Medicine made the news lately. And for good reason; though one not noted in much of the media: the diet raised the cholesterol levels of the subjects who ate a ‘Mediterranean diet,’ more on this later, and at the same time lowered disease and death due to strokes and heart attacks.
All approximations to follow: now the effect was limited, though touted as ‘a 30% reduction’ by the same reasoning that statins have been sold; that is 3 fewer ‘events’ per 1000 person/years. Now this is ‘not nothing’; but modest though it is, it remains worth considering.
First off every participant was already on several medications for high blood pressure, high cholesterol, high triglycerides, high glucose; a long list. They were either Type II diabetic at the start or had at least 3 known risk factors like family history, current smoking, high cholesterol, low HDL, etc. I won’t rehearse the whole study.
The diet suggested restrictions of red and processed meat (an old trick known to prejudice dietary results related to red meat), soda drinks, commercially produced baked goods and sweets and spread fats. It advocated more fish, fowl, tree-nuts, peanuts, vegetables, fruits and so on; nothing wrong with any of that, of course. The tweak was whether additional extra virgin olive oil or nuts were added to the basic recommendations which already included these elements in the dietary recommendations.
So you had three categories: Med diet plus additional olive oil, Med diet plus additional nuts or ‘low fat’ diet. The competition was between two versions of the Med diet or the conventional ‘low fat’ diet; famed these many years as the best diet for your cholesterol. It did in fact result in a lower cholesterol level than the Med diet plus additional olive oil or the Med diet plus additional nuts. The Med diet plus additional nuts did best overall; more fat by the way.
So, why aren’t I ecstatic about the results as they, in broad outline, reflect the diet I’ve recommended for over 20 years? Well, the study population was at such statistically high risk we cannot really apply the advice across an entire population without a better understanding of how medication modifies genetic risk and liver response to diet types as opposed to those on no medication; in other words there is a long list of technical issues left unaddressed by the study. Let me expand my complaint about the meat advice; several studies that have separated whole red meat from processed meats have found the risk associated with that ‘category,’ note the scare quotes, derive from the processing and not from the meats themselves. Another complaint was the unfounded anthropology of how dairy fits into the ‘Mediterranean diet;’ dairy was, with no basis in science, fact, or history of the study itself, treated as a bad actor and discouraged. This old myth is hard to kill; it is a reportage meme that won’t go away: when dairy fat has been looked at in isolation through diet/food diaries or directly in blood levels it has been associated with lower cardiovascular risk. Dairy somehow retains the ‘stain’ of being ‘fat’ which the study pretty much should have dispelled anyway.
Still, you have to love a study that shows higher cholesterol associated with lower stroke and heart attack risk.
But wait, there were other problems with the study: alcohol for one. As ‘red wine’ is routinely associated with the Mediterranean diet it was urged on the Med diet participants. Now, my practice is somewhat unusual, I live and work in Silicon Valley after all, but fully 20% of my patients have serious, measurable problems with alcohol. By serious, I mean wine/beer raises triglycerides enough to shift LDL production into the small dense category, a bigger risk than any reduction associated with wine ingestion, or results in shifts in liver function enough that liver impairment, including fatty liver disease, becomes expressed. Thus the universal advice that 1-2 glasses of red wine per day is, to my way of thinking, ill advised; nearly criminal if it were not so much a part of institutional medicine’s character to try to make universal recommendations. Lions eat meat, cows love grass and institutional medicine gives universal advice with little or no sound evidence (see 40 years of ‘low fat’ diet advice if you doubt that). This is just another example of why if you don’t measure it you cannot know whether you are making things worse or better. Are you the one for whom the wine is a good or bad idea? I don’t know, you don’t either and following generic advice based on a study that, fairly, must be considered a near ‘breakthrough’ for institutional medicine is still a bad idea. Measure it; measure it first and change ‘it’ based on direct evidence not wisdom, conventional or otherwise.
Calcium, again: Long term calcium intake and rates of all cause and cardiovascular mortality: community based prospective longitudinal cohort study
BMJ2013;346doi: http://dx.doi.org/10.1136/bmj.f228(Published 13 February 2013)
Conclusion High intakes of calcium in women are associated with higher death rates from all causes and cardiovascular disease but not from stroke.
OK, you can readily see the above is just a ‘cut and paste’ from the British Medical Journal but it was so simple and clear. “Higher death rates” in the above refers to an almost doubling of the death rate. 2X! Wow. And, ladies, it was the supplements not the dietary intake. In fact in the category of the highest total calcium intake of diet vs. diet with supplements, the highest pure dietary calcium intake death rate was the lowest of the categories. Another study, not quite as alarming as this one, was completed in men and showed a similar effect held in men too. Now the calcium supplement literature is all over the map; but the only map it is ‘all over’ is the one associated with harm.
OK, enough for one newsletter.
Smile, Have Fun, God Speed,
Dr. Mike
