“The new findings are part of a growing body of research that has challenged the accepted wisdom that saturated fat is inherently bad for you and will continue the debate about what foods are best to eat.”
– New York Times
The New York Times Well Blog posted an article recently called Study Questions Fat and Heart Disease Link. The article reports on a study in the Annals of Internal Medicine. This is a literature review of 75 different studies that examined the relationship between saturated fat and coronary disease. The study’s conclusion:
“Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats.”
Beyond the saturated fat factor, the discussion on cholesterol and the different types of low-density lipoproteins (LDLs) is pertinent and echos the information in this post. Note also the comments on carbs and sugar from Dr. Rajiv Chowdhury, lead author of the new study and a cardiovascular epidemiologist in the department of public health and primary care at Cambridge University:
“The primary reason saturated fat has historically had a bad reputation is that it increases low-density lipoprotein cholesterol, or LDL, the kind that raises the risk for heart attacks. But the relationship between saturated fat and LDL is complex, said Dr. Chowdhury. In addition to raising LDL cholesterol, saturated fat also increases high-density lipoprotein, or HDL, the so-called good cholesterol. And the LDL that it raises is a subtype of big, fluffy particles that are generally benign. Doctors refer to a preponderance of these particles as LDL pattern A.
The smallest and densest form of LDL is more dangerous. These particles are easily oxidized and are more likely to set off inflammation and contribute to the buildup of artery-narrowing plaque. An LDL profile that consists mostly of these particles, known as pattern B, usually coincides with high triglycerides and low levels of HDL, both risk factors for heart attacks and stroke.
The smaller, more artery-clogging particles are increased not by saturated fat, but by sugary foods and an excess of carbohydrates, Dr. Chowdhury said. ‘It’s the high carbohydrate or sugary diet that should be the focus of dietary guidelines,’ he said. ‘If anything is driving your low-density lipoproteins in a more adverse way, it’s carbohydrates.’”
NPR also reported on this research in Don’t Fear the Fat: Experts Question the Saturated Fat Guidelines. This article offers a timeline leading up to the current research:
“So, let’s walk through this shift in thinking: The concern over fat gathered steam in the 1960s when studies showed that saturated fat increases LDL cholesterol — the bad cholesterol — the artery-clogging stuff. The assumption was that this increased the risk of heart disease.
But after all this time, it just hasn’t panned out, at least not convincingly. When researchers have tracked people’s saturated fat intake over time and then followed up to see whether higher intake increases the risk of heart attacks and strokes, they haven’t found a clear, consistent link.
In fact, the new study finds ‘null associations’ (to quote the authors) between total saturated fat intake and coronary risk. And a prior analysis that included more than 300,000 participants came to a similar conclusion.”
Both articles include caveats and reservations by other researchers. Read the articles to see those. I’m not sure they’re anything but what’s been said in the past, and this new research seems like a strong basis to refute the old advice.
A Life Long Fight Against Trans Fats
Dr. Fred Kummerow is a researcher who has no reservations about consuming saturated fat. He was one of the first researchers to lead the charge against trans fats. The New York Times profiled Dr. Kummerow in A Lifelong Fight Against Trans Fats. He observed in the 1950s a link between the man-made trans fats and coronary disease. It took decades for the rest of the food science world to accept his findings. He’s 99 years-old and still working. Some of his findings on vegetable oil and cholesterol are worth considering:
“In the past two years, he has published four papers in peer-reviewed scientific journals, two of them devoted to another major culprit he has singled out as responsible for atherosclerosis, or the hardening of the arteries: an excess of polyunsaturated vegetable oils like soybean, corn and sunflower — exactly the types of fats Americans have been urged to consume for the past several decades.
The problem, he says, is not LDL, the ‘bad cholesterol’ widely considered to be the major cause of heart disease. What matters is whether the cholesterol and fat residing in those LDL particles have been oxidized. (Technically, LDL is not cholesterol, but particles containing cholesterol, along with fatty acids and protein.)
‘Cholesterol has nothing to do with heart disease, except if it’s oxidized,’ Dr. Kummerow said. Oxidation is a chemical process that happens widely in the body, contributing to aging and the development of degenerative and chronic diseases. Dr. Kummerow contends that the high temperatures used in commercial frying cause inherently unstable polyunsaturated oils to oxidize, and that these oxidized fatty acids become a destructive part of LDL particles. Even when not oxidized by frying, soybean and corn oils can oxidize inside the body.
LDL’s and Kummerow’s own eating habits are discussed:
If true, the hypothesis might explain why studies have found that half of all heart disease patients have normal or low levels of LDL.
“You can have fine levels of LDL and still be in trouble if a lot of that LDL is oxidized,” Dr. Kummerow said.
This leads him to a controversial conclusion: that the saturated fat in butter, cheese and meats does not contribute to the clogging of arteries — and in fact is beneficial in moderate amounts in the context of a healthy diet (lots of fruits, vegetables, whole grains and other fresh, unprocessed foods).
His own diet attests to that. Along with fruits, vegetables and whole grains, he eats red meat several times a week and drinks whole milk daily.
He cannot remember the last time he ate anything deep-fried. He has never used margarine, and instead scrambles eggs in butter every morning. He calls eggs one of nature’s most perfect foods, something he has been preaching since the 1970s, when the consumption of cholesterol-laden eggs was thought to be a one-way ticket to heart disease.
“Eggs have all of the nine amino acids you need to build cells, plus important vitamins and minerals,” he said. “It’s crazy to just eat egg whites. Not a good practice at all.”
(Contrast that statement with the recent news of a poorly designed study that suggested eating eggs were as bad as smoking.)
I’m glad to see this type of information getting out. I think the giant lumbering battleship that is our nutritional advice is slowly turning another direction. Real food trumps processed food every time it seems, even if it’s loaded with fat and cholesterol.