Suppose you were an idiot. And suppose you were a nutrition scientist. But I repeat myself.
Sorry, just couldn’t resist borrowing from Mark Twain. Let me try again.
Suppose you’re a nutrition scientist. And suppose you conduct a study, all the while expecting the results to support a hypothesis you already believe. But then — @#$%!! — the results undermine the hypothesis.
Oh, dear, what to do?
We saw one way to handle that sticky situation in our last episode: just don’t publish the results. Ancel Keys conducted a clinical study in which people who consumed vegetable oils instead of arterycloggingsaturatedfats!! had higher mortality rates – including higher mortality from heart disease. Keys didn’t like that result, so the data gathered dust for 40 years. Nice move, Ancel.
Here’s another way to handle results you don’t like: explain them away. I found a couple examples of that method while looking through my database of studies recently.
In one study, researchers looked for a link between consuming dairy fat and heart disease. Here are some quotes from a Brown University press release:
Dairy products can be high in harmful saturated fat but not necessarily in risk to the heart.
Okay, let’s stop right there. Take a moment and wrap your head around that sentence. Saturated fats are harmful. Why? Because according to the Lipid Hypothesis, they cause heart disease. But they don’t necessarily pose a risk to the heart.
A newly published analysis of thousands of adults in Costa Rica found that their levels of dairy consumption had nothing to do statistically with their risk of a heart attack.
To conduct the study, [researchers] Aslibekyan and Baylin analyzed data on 3,630 middle-aged Costa Rican men and women who participated in an epidemiological study between 1994 and 2004 by co-author Hannia Campos of the Harvard School of Public Health.
Ah, so it was an observational study. Perhaps the researchers would be justified in explaining away their own results.
The researchers looked not only at the subjects’ self-reported dairy intake, but also at measurements of dairy fat biomarkers, namely 15:0 and 17:0, in their bodies.
Whoops. Not just an observational study. They actually measured biomarkers that told them how much dairy fat the participants consumed. Let’s look at the results.
What they found is that the dairy intake of people who had heart attacks was not statistically different than the intake of people who did not. After breaking people into quintiles, based on their dairy consumption amount, there was no significant linear relationship between consumption and heart risk, even among the most voracious consumers. The highest consumption quintile consumed an average of 593 grams of dairy foods a day.
Once again, stop and wrap your head around that. We’ve been told for decades to stop consuming cream and butter because the saturated fats cause heart disease. But in this study of more than 3,600 people – a study in which researchers directly measured biomarkers of dairy fat consumption – there was no relationship between consuming those arterycloggingsaturatedfats!! and heart disease.
So how do we explain this result?
Rather than suggesting that the saturated fats in dairy products are harmless, Aslibekyan and co-author Ana Baylin, an adjunct assistant professor of community health at Brown, hypothesize that other nutrients in dairy products are protective against heart disease, for all but perhaps the highest dairy consumption quintile in their study. The potentially beneficial nutrients include calcium, vitamin D, potassium, magnesium and conjugated linoleic acid (CLA).
Well, there you have it: saturated fats cause heart disease, ya see, but people who consume a lot of saturated dairy fats — even the most voracious consumers — don’t have higher rates of heart disease because … uh … because something else in the dairy products is protecting their hearts!
Awesome. Coming soon: nutrition scientists decide there must be heart-protective substances in bacon, eggs and sausage that offset the heart-killing effects of the arterycloggingsaturatedfats!!
Here’s another example of explaining away embarrassing results. In a 2010 study, researchers randomly assigned subjects to one of three groups: no change (the control group), 60 grams of whole grains for 16 weeks, or 60 grams of whole grains for 8 weeks followed by 120 grams of whole grains for 8 weeks.
These are the markers of cardiovascular health the researchers measured, according to the abstract:
BMI, percentage body fat, waist circumference; fasting plasma lipid profile, glucose and insulin; and indicators of inflammatory, coagulation, and endothelial function.
If whole grains are the wunnerful, wunnerful, health-enhancing food we’ve all been told they are, the second group should have shown improvement those health markers, and the third group should be well on its way to immortality. So let’s check the results:
Although reported WG intake was significantly increased among intervention groups, and demonstrated good participant compliance, there were no significant differences in any markers of CVD risk between groups.
No significant difference in any markers. That would mean not one.
Oh dear … and here we have our beloved USDA telling us all we need to eat more whole grains. How do we explain this result? Here’s how:
A period of 4 months may be insufficient to change the lifelong disease trajectory associated with CVD.
Riiiiiiight. Four months of consuming large servings of whole grains doesn’t affect BMI, percentage body fat, waist circumference, fasting plasma lipid profile, glucose, insulin, or indicators of inflammatory, coagulation, or endothelial function. But those whole grains may still have a positive effect on the lifelong disease trajectory associated with CVD.
Yeah, that makes perfect sense.
Well, at least these studies were published. If Ancel Keys had conducted them, the data would still be sitting in a dusty attic somewhere.