If you are not confused and maybe even exasperated over all the contradictions around food in recent years, we would be amazed. Doctors, just like the rest of us, are challenged by uncertainty. Medical students are eager learners. They often embrace what their mentors teach them with a great deal of enthusiasm. After all, they will be tested to see how well they mastered the infinite number of details that are thrown at them. That is especially true when it comes to dietary dogmas. When there is a flip-flop on saturated fat it leaves many health professionals confused and dismayed.
Cholesterol In Eggs? The Controversy Persists!
It has been hard for some physicians to accept the idea that what their mentors taught them could be wrong. There is no better example than dietary cholesterol. The accepted wisdom for decades was that consuming high-cholesterol foods like eggs would raise cholesterol in the body and increase the risk for heart disease.
The American Heart Association (AHA) recommended limiting egg consumption to no more than three a week! In 2002, however, the AHA moderated that restriction, and by 2013 it admitted that a low-cholesterol diet might not reduce dangerous LDL cholesterol in the body.
Since then, most studies have not found that eating eggs causes clogged arteries.
A review (Current Atherosclerosis Reports, July 2023) notes:
“A meta-analysis of 39 observational studies including nearly 2 million individuals found no association between the highest intake of eggs and CVD [cardiovascular disease] mortality, and similar findings were presented in another meta-analysis of 24 observational studies of over 11 million individuals that found no association between highest intake of eggs and CVD mortality.”
But wait, if you think that concludes the controversy, the same authors conclude that the egg question remains unsettled. Their summary states:
“Recent findings are inconsistent regarding the possible relationship between egg consumption and CVD mortality and morbidity.”
Of course, such a conclusion leaves both physicians and patients unsatisfied. The same can be said of other dietary dogmas.
Sat Fat Is Sinful…Or Is There A Flip-Flop on Saturated Fat?
For years, doctors and dietitians have had a mantra for healthy eating: Stay away from foods containing cholesterol and saturated fat; they will clog your arteries and lead to heart attacks. Even after the egg controversy seemed semi-resolved, most health professionals maintain that saturated fat is a killer.
It remains an article of faith. Most Americans believe this and are careful to avoid whole milk and other full-fat dairy products. The American Heart Association (AHA) warns on its website to substitute fat-free (skim or “light”) milk and low-fat yogurt or cheese. The latest research, however, contradicts the AHA (American Journal of Clinical Nutrition, Sept. 2021).
AHA Resists Flip-Flop on Saturated Fat:
America’s premier heart association wants everyone to shun dairy fat. That’s because the AHA believes the cholesterol and saturated fat in milk, yogurt, cheese and ice cream will raise blood levels of cholesterol. And high cholesterol will lead to heart disease and ultimately to heart attacks.
An awful lot of people believe this story. Tens of millions of Americans now buy low-fat or non-fat yogurt. Such products dominate the dairy section in most grocery stores. There are also lots of milk substitutes based on plants such as soybeans or almonds.
Eating Low Fat Dairy Products Doesn’t Lead to AHA-Expected Outcomes:
A randomized controlled trial compared consumption of low-fat and high-fat dairy products over 12 weeks (American Journal of Clinical Nutrition, Sept. 2021). The control group limited their intake of dairy products.
All of the participants in this trial had metabolic syndrome. This constellation of high blood sugar, elevated cholesterol, hypertension and a large waist puts people at high risk for heart disease and diabetes. These are considered prime candidates for heart attacks, so they are the perfect subjects for this controlled trial.
Cardiologists might be surprised by the results of this study because they contradict conventional wisdom. There were no differences between groups with respect to LDL, HDL or total cholesterol, triglycerides or free fatty acids.
Please hit the pause button in your brain. Let the words percolate through your synapses.
Better yet, read the authors’ observations in their own words:
“In this 12-wk RCT [randomized controlled trial] in individuals with MetS [metabolic syndrome], consuming 3.3 servings of full-fat dairy/d in the form of milk, yogurt, and cheese did not significantly affect the fasting lipid profile compared with consuming identical amounts of low-fat dairy or a diet limited in dairy. This included no significant difference in the cholesterol content of any of the 38 isolated plasma lipoprotein fractions, despite substantial differences between the 3 diets in the consumption of total fat and SFAs [saturated fatty acids].
“The results of this study challenge the hypothesis that consuming full-fat dairy products increases the risk of CVD through elevating total and LDL-cholesterol concentrations, as a result of their high SFA and cholesterol content.”
The researchers conclude:
“In men and women with metabolic syndrome, a diet rich in full-fat dairy had no effects on fasting lipid profile or blood pressure compared with diets limited in dairy or rich in low-fat dairy. Therefore, dairy fat, when consumed as part of complex whole foods, does not adversely impact these classic CVD [cardiovascular disease] risk factors.”
Another Flip-Flop on Saturated Fat:
Lest you think this is brand new research, here is a summary about saturated fat and heart disease published in the Annals of Internal Medicine (March 18, 2014). The authors reviewed data on 600,000 volunteers. They could not find convincing evidence that a diet rich in saturated fat leads to heart disease.
Of course this defied conventional wisdom. Many nutrition experts rejected the research. But let’s drill down a bit deeper into what they did almost a decade ago. The authors reviewed 72 studies, arguably the best research at that time. They examined the relationship between diet and heart disease.
The conclusion in doctorspeak:
“…we found essentially null associations between total saturated fatty acids and coronary risk in studies using dietary intake and in those using circulating biomarkers…In contrast, we found a possible inverse association between circulating margaric acid (an odd-chain saturated fatty acid that is moderately correlated with milk and dairy fat consumption and coronary disease, suggesting that odd-chain saturated fats, which reflect milk or dairy consumption, may have less deleterious effects in risk for coronary heart disease.”
We know that is a bit hard to unwind. You know that null = no association. So, they found no connection between saturated fat and clogged arteries. More challenging and a real flip-flop on saturated fat is the second sentence. It suggests an inverse relationship between dairy fat consumption and “coronary disease.” Inverse means opposite or contrary to what might be expected.
The researchers also noted that polyunsaturated fats low in cholesterol such as corn or safflower oil do not appear to protect people from heart attacks. This too contradicts the nutritional principles that have reigned in the U.S. for decades. This is all quite heretical.
The only culprits that stood out in this mass of data were trans fats. The researchers found a clear link between consumption of foods high in trans fats and heart disease.
Americans were once encouraged to consume margarine and shortening made of hydrogenated vegetable oil loaded with trans fats on the understanding that these low-cholesterol solid fats would be better for the heart than butter or lard. Such advice now seems to have been based more on belief than evidence.
The Flip-Flop on Saturated Fat Disappeared Without a Trace:
Here are the conclusions of the study in the Annals of Internal Medicine:
“In conclusion, the pattern of findings from this analysis did not yield clearly supportive evidence for current cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of saturated fats.”
Lest you think the Annals of Internal Medicine is some wackadoodle medical journal that is easily ignored, please reconsider. This publication was established in 1927 and is one of the premier journals in American medicine. It is published by the American College of Physicians (ACP) and according to Widipedia is:
“…one of the most widely cited and influential specialty medical journals in the world.”
Do Not Expect Experts to Do a Flip-Flop on Saturated Fat:
There have been lots of studies demonstrating that the old dietary dogma was flawed and yet the AHA has not changed its stand on cholesterol and saturated fat in foods. The Sydney Diet Heart Study ran between 1966 and 1973 in Australia. The results weren’t published for 40 years (BMJ, Feb. 5, 2013).
The researchers in this experiment assigned high-risk men to use either margarine or butter during that time. Men using safflower oil margarine were 60 percent more likely to die over the years of the study. The absolute risk of death from heart disease went from 10 percent on the butter-rich diet to 16.3 percent on the margarine-based diet.
Another trial pitting butter against margarine ran about the same time. The Minnesota Coronary Experiment involved more than 9,000 patients in mental institutions and a nursing home. The researchers had total control over the subjects’ diets. The test diets included one high in saturated fat and the other high in polyunsaturated fats from corn oil.
Like the Sydney Diet Heart Study, the results were not what the investigators expected. Perhaps that explains why the data were not published until much later (Atherosclerosis, Jan-Feb. 1989). Patients on the corn oil diet had less cholesterol in their blood, but they were just as likely to die from heart disease.
What About Saturated Fat in Meat?
Here are more analyses published in the highly regarded Annals of Internal Medicine (Oct. 1, 2019). Get the straight and skinny on this research in our overview at this link.
The French never bought the American prohibition on saturated fat. They were loathe to give up their Brie, Camembert, paté, boeuf bourguignon and chocolate soufflé. Cardiologists were puzzled by the “French paradox.” Despite such foods rich in saturated fat, French heart attack rates have been considerably lower than those in the U.S.
If there is a moral to this ongoing diet controversy, it is that high-fat dairy products do not appear to be as dangerous as doctors once thought. Despite the latest study and all the others that have gone before it, we do not expect the AHA or nutrition experts to change their thinking.
In recent years we have seen the pillars of dietary dogma collapsing. Here is a list:
Eggs:
Before, cholesterol-laden yolks were thought to clog your arteries and lead to heart disease.
Now, eggs are considered an excellent source of high-quality protein.
Coconuts and avocados:
Before, these foods were off limits because of high saturated fat content.
Now, they are considered OK with potential health benefits.
Nuts:
Before, these were high fat treats, thought to raise cholesterol, heart attack risk and cause weight gain.
Now, nuts are known to contain good fats and data prove people who eat nuts lower their risk of heart attacks!
Shrimp:
Before, shrimp were believed to be sinful, high in cholesterol and dangerous for those at risk of heart disease.
Now, they are considered a good source of protein and raise good HDL cholesterol.
Butter:
Before, butter was a no-no because it is high in sat fat and cholesterol.
Now, butter is better than margarine made from trans fats.
Salt:
Before, salt was bad, raising blood pressure and causing heart disease.
Now, data indicate that there is a sweet spot. Going too low on sodium increases the risk of death!
Coffee:
Before, people were told to lay off the java because it raises blood pressure and harms the heart.
Now, coffee is a known source of dietary antioxidants. It helps prevent diabetes and may partially protect against neurological diseases like Parkinson’s and dementia.
Chocolate:
Before, chocolate was frowned upon as fattening and bad for the skin. It was also viewed as contributing to indigestion and reflux by relaxing the lower esophageal sphincter. Chocolate was featured on many lists of foods that people prone to migraine should avoid.
Now, chocolate with more cocoa flavanols than sugar is known to relax blood vessels and lower blood pressure. It may help maintain good cognitive function and reduce the risks of stroke and heart attack. While some individuals may find that chocolate triggers reflux or a migraine, most people handle it without difficulty.
Whole Milk, Cream & High-Fat Yogurt:
Before, high-fat dairy foods were believed to contribute to heart disease and obesity.
Now, studies show that both kids and adults who consume high-fat dairy are actually skinnier than those who consume skim milk and low-fat dairy products. The new research (above) shows that saturated fat found in high-fat dairy does not cause heart disease.
The Bottom Line on Saturated Fat:
What are we to make of all the food confusion? If there is a take-home message from all this, it is that evidence trumps belief. For decades “experts” have made assumptions about various foods. Because egg yolks contained cholesterol, they decided that eggs caused heart disease, without any data to support that hypothesis.
When research actually revealed that eggs do not cause heart disease, there has been a begrudging retreat from the hard line advice to shun eggs. But old ideas die hard. There are still many health professionals who caution against eating foods like eggs, avocados, nuts and shrimp, despite data to the contrary.
What About Dairy Products?
We suspect that the evidence that full-fat dairy products don’t raise cholesterol in high-risk patients will be challenging for most health professionals to accept. After all, it contradicts everything we have been told about a heart-healthy diet for more than 50 years.
Accepting the data (American Journal of Clinical Nutrition, Sept. 2021) and the analysis of 72 studies involving more than 600,000 people would mean that our thought leaders and policy makers got it wrong. In such scenarios, many people would prefer to shoot the messengers and pretend that the data do not exist. The research is likely to disappear without a trace and some nutrition experts will pretend it never saw the light of day.
In case you think this is old news, a study published in the journal BMC Cardiovascular Disorders (July 21, 2023) comes to a similar conclusions. The authors introduce their study with this statement:
“The role of fatty acids in coronary heart disease (CHD) remains uncertain. There is little evidence from large-scale epidemiological studies on the relevance of circulating fatty acids levels to CHD risk.”
The researchers examined data from roughly 90,000 participants in the UK Biobank. Blood lipids were measured and people were followed up for about 12 years. High triglyceride levels were the bad actors rather than saturated fatty acids. What raises triglycerides? A diet that high in ultra-processed foods is a major culprit. That means simple carbohydrates and sugar! Fiber-rich foods lower triglyceride levels.
Real Food:
What should you do? We follow the advice of Robert Lustig, MD, author of the book Fat Chance: Beating the Odds Against Sugar, Processed Food, Obesity, and Disease and Michael Pollen, author of In Defense of Food, An Eater’s Manifesto. They make it very clear: “EAT REAL FOOD!”
If it comes in a package with a long list of unpronounceable chemical ingredients, think twice or three times! Grandmothers instinctively knew that food grown in the garden and prepared with love was better than anything produced in a factory. Joe’s mother always believed butter was better than margarine and it turns out she was right.
Your Opinion:
What do you think? We would love to get your response to this essay. How do you deal with the food flip-flops of the last several years regarding nuts, chocolate, coffee and coconut? What do you make of the saturated fat controversy? Share your comments below.
If you agree with the mantra to “Eat Real Food!” you may find our books, Recipes and Remedies from The People’s Pharmacy and Spice Up Your Health: How Everyday Kitchen Herbs &Spices Can Lengthen & Strengthen Your Life worth checking out. Here are links to all our publications.
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