Download 2016-04-15 Don`t Eat The Headlines

Preventive Medicine Column
April 15, 2016
Don’t Eat The Headlines
I can say with reasonable authority that the recent spate of wildly gyrating nutrition headlines did not
cause (m)any of the world’s leading nutrition experts to change what they eat.
To the best of my knowledge, none of my vegetarian colleagues renounced their leafy greens when
headlines suggested that vegetarianism, overnight, had become bad for us. No one I know not already
inclined to eat full-fat dairy suddenly broke out the whipped cream and went wild when headlines canonized
dairy fat. And I am aware of no one who stopped drinking daily mugs of corn oil when it got slapped with a
skull and crossbones by a new paper in the British Medical Journal, mostly because I don’t know anyone who
was chugging corn oil in the first place.
Remember hearing that tilapia was worse for you than bacon? This, too, was hyperbolic nonsense,
but as tends to be true of all such media distortions, it was based on something. It was based on the
recognition that an excess of omega-6 fat, and an imbalance in dietary fatty acids, is bad.
While the BMJ paper about corn oil is new, the study from which these data were disinterred was run
50 years ago, before that knowledge was established. The intervention did not test the effect of a switch to a
balanced array of vegetable oils, or even one very salutary oil such as olive, let alone a switch to wholesome
foods rich in beneficial oils, such as nuts, seeds, avocado, and fish. Rather, it tested something that nobody
expert in nutrition is recommending: an extremely high dose of omega-6, linoleic acid. Whether or not our
memory extends beyond today’s headlines seems forever in question, but we already got the memo that this is
a dubious proposition.
With all due respect to the BMJ authors, I personally found it a bit odd that they stated the following:
“A key component of dietary guidelines has long been to replace saturated fat with oils rich in linoleic
acid…” The current Dietary Guidelines for Americans, let alone the far better 2015 Dietary Guidelines
Advisory Committee Report, make no such recommendation. Searching for any mention of linoleic acid, I
found it only in the appendices in the context of descriptions and definitions, not in any of the actionable
guidance. While the current Dietary Guidelines do recommend limiting saturated fat intake, the replacement
encouraged is a balance of healthful oils, such as olive, and the fats found natively in nuts, seeds, avocado,
and fish.
More relevant, perhaps, are the first formal Dietary Guidelines in the U.S., released in 1980, and thus
most proximal to the era from which the BMJ data issue. These guidelines encouraged limiting fat intake
altogether, along with saturated fat in particular. They certainly did not encourage chugging corn oil. As an
aside, but an important one to the historical revisionists who pretend to have discovered the harms of excess
sugar in an epiphany yesterday morning, the 1980 Dietary Guidelines included explicit advice to limit sugar
intake in the proverbial (and in this case, literal) short list (#5, to be exact).
Headlines related to a recent dairy study in Circulation suggest we should dive head first into the first
fondue pot we find. In reality, there was a very modest association between certain, specific, and rather
esoteric fatty acids in dairy and a lower incidence of diabetes. There were many potential confounders.
Finally, the headlines related to the health effects of vegetarian diets were such a massive, absurd
distortion of the actual study that I thought I must be misreading one or the other. Consequently, I conferred
directly with the senior study author, Dr. Tom Brenna of Cornell, who confirmed my impression: this was
some of the most irresponsible journalism we had ever witnessed. Given what passes for journalism these
days, perhaps especially in the domain of diet and health, that’s really saying something.
Let’s turn now to the implications of all this, and then bring it to a close. We heard that vegetarian
diets were suddenly bad for us, and all the nutrition experts I know kept eating vegetables. We heard that
vegetable oil was suddenly bad for us, and nobody I know stopped chugging corn oil, because no one I know
had ever started. We heard about the relative advantages of full-fat dairy, but only those already inclined that
way chose to skim this as cream. None of this nihilism is because nutrition experts are impervious to the
challenges of evolving science. Quite the contrary, for any who deserve to be called expert in the first place.
Rather, it’s because they know that headlines are a stupefyingly poor representation of that science.
In other words, we didn’t get indigestion from the latest spate of hyperbolic headlines, because we
never swallowed them in the first place. And neither should you.
-fin
Dr. David L. Katz;www.davidkatzmd.com; author, Disease Proof; founder, True Health Initiative