Dietary Cholesterol and Inflammation from Abdominal Obesity

Michael Greger M.D. FACLM · June 21, 2023 · Volume 62

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The optimal intake of dietary cholesterol may be zero.

Discuss

Transcript

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

What are the implications of our fat cells accumulating high levels of cholesterol? In this video, I explore that question while also continuing to put a focus on the activities of the egg industry.

There is abundant evidence that dietary cholesterol increases cardiovascular disease risk. The misdirection of the egg industry focuses on fasting levels of LDL cholesterol, which are only raised by about 10 percent. However, the main effect of diet is on the post-prandial state, the after-a-meal state. For about four hours after a high-fat/high-cholesterol meal, there is oxidative stress, artery dysfunction, and arterial inflammation, which happen after eating more than 140 mg of cholesterol––which is less than a single egg. So, while the egg industry spends hundreds of millions trying to convince people dietary cholesterol is harmless, there are good reasons for limiting cholesterol intake in persons at risk for vascular disease. But wait, vascular disease, coronary heart disease, is our #1 killer of men and women; so, aren’t we all at risk? Yes, it is seldom understood that this essentially means all people in developed countries who expect to live a long life should cut down on eggs.

In response, the egg industry has experimented with ways to reduce the cholesterol content of eggs by, for example, feeding laying hens cholesterol-lowering statin drugs, or even techniques to reduce the cholesterol content in egg yolks once the egg is formed, using things like solvent extraction fingernail polish remover—acetone. However, such methods have not been scaled up due to reasons such as food safety.

Or, the egg industry can spend its time going after new plant-based competitors, like the company Eat Just. The USDA investigated allegations of misconduct by the American Egg Board, which is run by the federal government, like the allegation that Egg Board staff threatened the CEO of Eat Just in emails they exchanged about putting a “hit” on him. And indeed, they discovered emails included references such as, “Can we pool our money and put a hit on him?” and having “old buddies from Brooklyn pay him a visit.” What corrective actions did the USDA take? The American Egg Board has admitted to the inappropriateness of such comments and apologized, and the Egg Board staff and board members will be required to complete additional training regarding proper email etiquette and ethics.

Dietary cholesterol may also contribute to inflammation in your body fat that can spill over into your bloodstream. Body fat is a major site for cholesterol storage in humans. Your fat cells can accumulate high levels of free cholesterol, which cannot be broken down by cells, and is toxic at high concentrations. And, that may lead to macrophage accumulation. Here’s a fat biopsy. See those little blue dots? Those are dying macrophages, which are a type of immune cell that can spill their contents of inflammatory chemicals that are believed to result in many metabolic derangements that accompany obesity––including insulin resistance, systemic inﬂammation, and atherosclerosis. So, reducing excessive dietary cholesterol intake is suggested as a simple way to attenuate obesity-associated metabolic diseases.

Yeah, but has it actually been put to the test in people? We know dietary cholesterol promotes the swelling of fat cells and belly fat inflammation in monkeys, but that’s like research showing dietary cholesterol directly induces acute intestinal inﬂammation in both mice and zebraﬁsh. What are you supposed to do with that information? There just weren’t any human studies, until now.

Vegetarians consume significantly less cholesterol. Although eggs are the single largest source of cholesterol in the American diet, more than any of the individual types of meat, meat in general is the #1 overall source (with more cholesterol coming from chicken than from red meat).

Researchers took biopsies from the vegetarians, and not only did their fat average fewer than half the pro-inflammatory macrophages compared to biopsies taken from omnivores, the meat-eaters had 50 percent greater expression of tumor necrosis factor in their abdominal fat––which is a potent inflammatory marker, though there’s lots of stuff in meat besides cholesterol that could have contributed to the inflammatory state.

But what else do you need to know beyond the bump in heart disease risk? Pre-eminent Harvard Nutrition professor Mark Hegsted once wrote that if cholesterol were introduced as a new food additive, we would cite the evidence that it raises cholesterol and heart disease risk, and the conclusion would almost certainly be that cholesterol could not be considered safe at any level, because any intake level above zero increases the risk of our #1 killer disease.

Please consider volunteering to help out on the site.

Sources

Acknowledgements

Motion graphics by Avo Media

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

What are the implications of our fat cells accumulating high levels of cholesterol? In this video, I explore that question while also continuing to put a focus on the activities of the egg industry.

There is abundant evidence that dietary cholesterol increases cardiovascular disease risk. The misdirection of the egg industry focuses on fasting levels of LDL cholesterol, which are only raised by about 10 percent. However, the main effect of diet is on the post-prandial state, the after-a-meal state. For about four hours after a high-fat/high-cholesterol meal, there is oxidative stress, artery dysfunction, and arterial inflammation, which happen after eating more than 140 mg of cholesterol––which is less than a single egg. So, while the egg industry spends hundreds of millions trying to convince people dietary cholesterol is harmless, there are good reasons for limiting cholesterol intake in persons at risk for vascular disease. But wait, vascular disease, coronary heart disease, is our #1 killer of men and women; so, aren’t we all at risk? Yes, it is seldom understood that this essentially means all people in developed countries who expect to live a long life should cut down on eggs.

In response, the egg industry has experimented with ways to reduce the cholesterol content of eggs by, for example, feeding laying hens cholesterol-lowering statin drugs, or even techniques to reduce the cholesterol content in egg yolks once the egg is formed, using things like solvent extraction fingernail polish remover—acetone. However, such methods have not been scaled up due to reasons such as food safety.

Or, the egg industry can spend its time going after new plant-based competitors, like the company Eat Just. The USDA investigated allegations of misconduct by the American Egg Board, which is run by the federal government, like the allegation that Egg Board staff threatened the CEO of Eat Just in emails they exchanged about putting a “hit” on him. And indeed, they discovered emails included references such as, “Can we pool our money and put a hit on him?” and having “old buddies from Brooklyn pay him a visit.” What corrective actions did the USDA take? The American Egg Board has admitted to the inappropriateness of such comments and apologized, and the Egg Board staff and board members will be required to complete additional training regarding proper email etiquette and ethics.

Dietary cholesterol may also contribute to inflammation in your body fat that can spill over into your bloodstream. Body fat is a major site for cholesterol storage in humans. Your fat cells can accumulate high levels of free cholesterol, which cannot be broken down by cells, and is toxic at high concentrations. And, that may lead to macrophage accumulation. Here’s a fat biopsy. See those little blue dots? Those are dying macrophages, which are a type of immune cell that can spill their contents of inflammatory chemicals that are believed to result in many metabolic derangements that accompany obesity––including insulin resistance, systemic inﬂammation, and atherosclerosis. So, reducing excessive dietary cholesterol intake is suggested as a simple way to attenuate obesity-associated metabolic diseases.

Yeah, but has it actually been put to the test in people? We know dietary cholesterol promotes the swelling of fat cells and belly fat inflammation in monkeys, but that’s like research showing dietary cholesterol directly induces acute intestinal inﬂammation in both mice and zebraﬁsh. What are you supposed to do with that information? There just weren’t any human studies, until now.

Vegetarians consume significantly less cholesterol. Although eggs are the single largest source of cholesterol in the American diet, more than any of the individual types of meat, meat in general is the #1 overall source (with more cholesterol coming from chicken than from red meat).

Researchers took biopsies from the vegetarians, and not only did their fat average fewer than half the pro-inflammatory macrophages compared to biopsies taken from omnivores, the meat-eaters had 50 percent greater expression of tumor necrosis factor in their abdominal fat––which is a potent inflammatory marker, though there’s lots of stuff in meat besides cholesterol that could have contributed to the inflammatory state.

But what else do you need to know beyond the bump in heart disease risk? Pre-eminent Harvard Nutrition professor Mark Hegsted once wrote that if cholesterol were introduced as a new food additive, we would cite the evidence that it raises cholesterol and heart disease risk, and the conclusion would almost certainly be that cholesterol could not be considered safe at any level, because any intake level above zero increases the risk of our #1 killer disease.

Please consider volunteering to help out on the site.

Motion graphics by Avo Media

Doctor's Note

Didn’t the Dietary Guidelines remove cholesterol as a nutrient of concern? No, just the opposite: Dietary Guidelines: “Eat as Little Dietary Cholesterol as Possible”.

Even egg industry-funded studies show the cholesterol we eat raises blood cholesterol levels. Check out Does Dietary Cholesterol (Eggs) Raise Blood Cholesterol?

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