I have a new feeling when it comes to feeding my boys: confusion. After years of thinking I was offering them a reasonably healthy diet to protect against pretty crummy genetics, I felt my confidence slip a few weeks ago.
That was when a meta-analysis of more than 70 prior studies found the amount of saturated fat people ate had no bearing on whether they developed heart disease. Drawing widespread media coverage, the report published in the Annals of Internal Medicine also raised doubts about advice to switch to so-called “good fats,” the unsaturated fats prevalent in vegetable oils, fish and nuts.
Consider this another in a long list of what to eat and what not to eat. You can read one study that says red wine is great for heart health, another that says to go on the wagon. Caffeine is good for you — or not. And dark chocolate is like a wonder drug, except when it’s not.
The study about saturated fats, however, seemed to undermine the major dietary advice of a generation. And it’s not something that I, as a mom of two young boys, can take lightly. The men in my family have had a close relationship with heart disease. My father died at 54 from a heart attack. His dad made it to his seventies before he died of heart disease, but my great-grandfather was only 45 when he had the big one.
As a consequence, I’ve tried to follow the rules from medical authorities, hoping to somehow inoculate my two boys, ages 4 and 7, against a shortened life span. After trusting advice to feed them low-fat milk and limit other saturated fats, I suddenly wasn’t so sure about anything.
It didn’t help my confusion that the experts seemed to be firing at one another, with organizations such as the American Hearth Association warning the study’s conclusions might be “deceptive” for people deciding what to eat, and sticking to the position that “saturated fat can hurt your heart while polyunsaturated fats may help it.”
It all made me wonder, do I go out and by full-fat milk, finally remember to bring home the salami my oldest has been begging for, and, as New York Times food columnist Mark Bittman opined, put the butter back in my grocery cart?
And what did this mean for my aspiration to counter my neighbor’s faith in a heavy meat approach with a Mediterranean-style diet blessed by the Harvard School of Public Health?
With my head seriously spinning, I set out to ask some experts, including some of the study’s authors and one of its strongest detractors.
Luckily, at least for my discomfort with uncertainty, they all seemed to agree the study was no green light to load up on saturated fat.
I was reassured by the study’s lead author and others that it still made sense to look to recommendations like the ones I had found on Harvard’s Web site that favor something akin to the Mediterranean diet (with fats from olive and other vegetable oils, fish and nuts, as well as plenty of fruits and vegetables, some whole grains, beans, poultry and limited red meat).
“What the findings mean is just knowing the saturated fat [content] does not give you information about the effect on health,” said one of the study’s authors, Dariush Mozaffarian, a cardiologist and epidemiologist at Harvard.
He faults the type of dietary guidelines that focus only on lowering saturated fat, particularly if people replace the calories with refined carbohydrates and other processed food. Compared with refined carbohydrates, saturated fat has a neutral effect on the overall profile of cholesterol and triglycerides in the blood, he said.
“White bread with low-fat deli turkey is not a healthy food. Low-fat frozen yogurt is not good for you.”
I’ll keep that in mind. Sorry boys.
Yet Stephen Daniels, chair of pediatrics at the University of Colorado School of Medicine, was less sanguine about the study’s impact on popular perception.
“It is very difficult if people now think it’s fine to increase their level of saturated fat intake,” he said, pointing to decades of evidence that diets high in saturated fat increase LDL, the type of lipoprotein that has been considered a strong predictor of heart disease.
The focus needs to be on the overall diet, rather than on one micronutrient, said Daniels, who also heads the American Academy of Pediatrics committee on nutrition.
“An approach that increases fruits and vegetables, which are under-consumed by children and adults in this country, including whole grains, low-fat dairy, mostly low-fat meats and poultry and including fish has been shown over and over to be helpful.”
But what about advice on the best fats to choose? Here’s where the going got complicated.
The study said there wasn’t “clearly supportive evidence” behind current guidelines backing high consumption of polyunsaturated fatty acids and low consumption of saturated fats. A corrected version shifted slightly to say Omega-3 fatty acids, which are commonly found in fish and nuts, were associated with lower risk of heart disease.
Walter Willett, who chairs the Harvard School of Public Health’s department of nutrition, faulted the study for creating confusion on unsaturated fats and containing “layers of problems.” In formal comments on the paper, he and several colleagues at Harvard said: “The conclusions … regarding the type of fat being unimportant are seriously misleading and should be disregarded.”
In an interview, he said a major conceptual flaw was that the study compared saturated fat to all other sources of calories, rather than specific replacements. As such it overlooked a large analysis of studies published several years ago that more narrowly examined replacing saturated fat with polyunsaturated fat and found a reduction in heart disease, he said.
“They never did that analysis.”
In casting doubt on monounsaturated fat, another of the so-called good fats, he added, the study failed to highlight that the monounsaturated fat consumed in the studies was from red meat and dairy sources, rather than plant sources such as nuts and olive oil.
This was all getting pretty far into the scientific weeds for me.
More than I’d like, my grocery store decisions about which milk to buy were now clouded by a line in the study, highlighted by news reports, suggesting a certain fatty acid in dairy might be helpful rather than harmful when it comes to heart disease. But the scientists I talked to said the evidence for that was still unsettled.
In the end, I could live with that uncertainty and take all of this as a reminder to pass on junk food and refined starches and of course eat more fruits and vegetables.
Now, if I could only convince the boys.
I realized I still had work to do when my four-year-old protested last week, “I didn’t have any junk food yet today!” — as if, I suppose, this was an unexpected injustice.
Maya Weber is a writer, artist and teacher living in Washington D.C.