Joe Rogan - Does Saturated Fat Cause Heart Disease?

The discussion centers on the contentious relationship between dietary saturated fat, cholesterol, and heart disease. Dr. Joel Kahn advocates for reducing saturated fat, citing historical and contemporary studies linking it to increased heart disease risk. He references the governmental and scientific consensus on limiting saturated fat intake. Conversely, Chris Kresser challenges this stance, arguing that recent meta-analyses and randomized controlled trials show no clear link between saturated fat intake and heart disease, and he criticizes reliance on outdated observational studies. Both emphasize the importance of updated scientific research in shaping dietary guidelines.

• Prevalence of Heart Attacks:
  • Heart attacks were not common until the 1940s.
  • First described in medical literature in 1916.
  • Post-World War II saw an increase in heart attack cases, particularly among executives in Minneapolis.
  • Notable cases: Franklin Delano Roosevelt died of high blood pressure, and Eisenhower had a massive heart attack.

"It was felt so until the 40s it was not common to have a heart attack. Heart attacks were described in 1916 not to say they didn't happen but the first medical article that used the word myocardial infarction 1916."

• Government and Institutional Response:
  • National Institutes of Health began funding major studies like the Framingham study in 1958 to investigate heart disease.
  • The concept of "risk factors" was introduced, including smoking, blood pressure, cholesterol, and family history.

"That's when our government National Institutes of Health started funneling major money into studies like the Framingham study."

• Risk Factors for Heart Disease:
  • Smoking, high blood pressure, cholesterol, and family history were identified as risk factors for heart disease.
  • Diet was not initially considered a significant factor in heart disease.

"The idea had come up heart disease wasn't just aging heart disease could be explained by what's called risk factors."

• Introduction of Dietary Hypothesis:
  • Dr. Ancel Keys suggested dietary fat might be a factor in heart disease.
  • The hypothesis evolved, distinguishing between different types of fats: good fats (omega-3 fatty acids), polyunsaturated fats, and saturated fats.

"Dr. Ancel Keys PhD suggested dietary fat might be a factor. It was a hypothesis, it's his early stage epidemiology doesn't prove anything."

• Focus on Saturated Fat:
  • Saturated fat, found in foods like red meat, chicken, and pizza, became the primary focus.
  • Guidelines began to suggest limiting saturated fat intake to combat heart disease.

"The focus went on saturated fat in food which would make a chicken, red meat, pizza those are the highest sources."

• Global Consensus on Saturated Fat:
  • 21 international statements from organizations like the World Health Organization and the American Heart Association recommend limiting saturated fat intake.
  • There is no significant controversy among these organizations regarding the impact of saturated fat on heart health.

"There is no opposite whether it's a World Health Organization, the American Heart Association, American College of Cardiology, whether it's the Institute of Medicine says eat as little saturated fat as possible."

• Impact on Cholesterol Receptors:
  • Saturated fats reduce the number of cholesterol receptors on the liver, leading to higher cholesterol levels in the blood.
  • This increased cholesterol can contribute to artery blockage and heart disease.

"When you eat foods rich in saturated fat, receptors on your liver for cholesterol go down. Cholesterol has no place to go, cholesterol stays in the blood, bumps into your artery wall."

• Epidemiological Evidence:
  • Epidemiological studies, despite their flaws, support the link between saturated fat and increased cholesterol levels.
  • Control trials, like Clark 1997, show that adding saturated fat to the diet raises cholesterol levels on average.

"They did control trials, everybody just go read Clark 1997 395 it's called metabolic studies. Change the diet, see what happens. You add saturated fat, cholesterol skyrockets on average."

• Diet of Long-Lived Populations:
  • Populations with high longevity, like those in Italy, Greece, and Okinawa, consume diets low in saturated fats.
  • These diets are associated with lower rates of heart disease and longer lifespans.

"Populations that live over a hundred, these are called the pillars of longevity. They don't eat foods rich in saturated fat. They have a little, they don't eat a lot."

• Saturated Fat Content in Foods:
  • All foods contain a mix of fats, including polyunsaturated, monounsaturated, and saturated fats.
  • Some foods recommended by health agencies, like mackerel, contain significant amounts of saturated fat.

"Every food that we consume has all of the fats in it: polyunsaturated, monounsaturated, and saturated fat. Two tablespoons of olive oil have more saturated fat than a seven-ounce pork chop."

• Nature of Fat in Foods:
  • The complexity of fat composition in foods raises questions about the blanket recommendations to avoid saturated fats.

"Does it make sense that nature would include that you can eat mackerel and the polyunsaturated fats in it are good for you, but the saturated fat in it is bad for you?"

These comprehensive study notes cover the key themes, summaries, and verbatim quotes from the provided transcript, offering a meticulous and exhaustive overview of the discussion around cholesterol, saturated fat, and heart disease.

• Initial guidelines on dietary cholesterol and saturated fat were based on early research from the 1970s.
• Zoe Harcombe, PhD in nutritional research, reviewed evidence from the 1970s to 2016, finding no solid evidence supporting restrictions on saturated fat and cholesterol.
• Recent meta-analyses involving large participant groups found no link between saturated fat intake and cardiovascular disease.

"There never really was good evidence to suggest that dietary cholesterol and saturated fat are connected to heart disease."

• Early guidelines may have been based on insufficient evidence, leading to decades of possibly misguided dietary advice.

"People have started to look at this more recently and, for example, you have a meta-analysis of observational studies including about 350,000 participants recently that found no relationship between saturated fat intake and cardiovascular disease."

• Contemporary research challenges the long-held views on saturated fat and cardiovascular health.

• Comprehensive reviews and meta-analyses have been conducted, covering randomized controlled trials and observational studies.
• These studies found no clear support for guidelines that encourage high polyunsaturated fat consumption and low saturated fat intake.

"An exhaustive review of studies, something like 25 randomized controlled trials and almost 40 observational studies involving 650,000 participants concluded: 'Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of saturated fatty acids.'"

• The evidence base for current dietary guidelines is being questioned, suggesting a need for revised recommendations.

• Science evolves by continually challenging and falsifying hypotheses, which has led to changes in dietary guidelines over time.
• In 2010, the US federal government removed restrictions on total fat, and in 2015, restrictions on dietary cholesterol were also lifted.

"In 2010, the US federal government removed restrictions on total fat... In 2015, they removed the restriction on dietary cholesterol."

• These changes reflect a growing recognition that not all fats are harmful and that previous guidelines may have been overly restrictive.

• John Ioannidis, a renowned epidemiologist, has critiqued the field of nutritional research for its methodological flaws.
• Ioannidis argues that nutritional epidemiology often fails to adhere to good scientific principles and needs radical reform.

"Some nutrition scientists and much of the public often consider epidemiological associations of nutritional factors to represent causal effects that can inform public health policy and guidelines. However, the emerging picture of nutritional epidemiology is difficult to reconcile with good scientific principles. The field needs radical reform."

• These critiques highlight the need for more rigorous and scientifically sound research in nutrition.

• Early research from the 1950s and 1960s suggested a link between dietary habits and heart disease, focusing on animal fats and cholesterol.
• Migration studies showed increased heart attack risks among Japanese individuals who moved to the US, suggesting dietary changes as a potential factor.

"In 1959, you grew up in Japan, you have a cholesterol of 120, you almost never see a heart attack. You move to Hawaii, your cholesterol rises to 180, your heart attack risk triples. You move to Los Angeles, your cholesterol is now 210, you have ten times the heart attack risk that you had when you lived in Japan."

• These historical observations supported the initial hypotheses linking diet and heart disease, but modern research challenges these early conclusions.

• Nutrition is a critical factor in preventing medical conditions like strokes, heart attacks, and other chronic diseases.
• The content of one's diet plays a significant role, though it is not the sole factor in disease prevention.

"The importance here is do you have a stroke, heart attack, erectile dysfunction, lose a leg, or do you not? At least one factor in the development of these horrible medical problems that are 80% preventable is nutrition."

• While nutrition is crucial, it is one of many factors influencing overall health.

• Strong Relationship with Animal Fats and Proteins: Public research indicates a strong correlation between animal fats and proteins, particularly butter, and heart disease.
• Sugar vs. Saturated Fat: Studies manipulating dietary components show that increasing saturated fat significantly raises heart disease risk, while increasing sugar does not have the same impact.

"If you could hold sugar the same and increase dietary saturated fat, heart disease rockets. If you could hold saturated fat the same and increase sugar in these manipulations, coronary heart disease doesn’t increase."

• Increasing saturated fat has a more direct impact on heart disease compared to sugar.

"I’ve never scooped sugar out of a blocked artery. I scoop cholesterol out of blocked arteries. 20% of every blockage in a heart is cholesterol."

• Cholesterol directly contributes to artery blockages, unlike sugar.

• Controlled Feeding Studies: Studies feeding participants two to four eggs a day show no impact on blood cholesterol levels in 75% of cases. In hyper-responders, dietary cholesterol modestly increases LDL cholesterol but also increases HDL cholesterol without raising heart disease risk.
• Guideline Changes: Due to these findings, dietary guidelines have been updated to reflect that consuming dietary cholesterol does not increase the risk of heart disease.

"They’ve done controlled feeding studies where they fed people two to four eggs a day, and those show that in 75% of cases, it has zero impact on blood cholesterol levels."

• Most people do not experience an increase in blood cholesterol from dietary cholesterol.

"This is why the guidelines were changed on dietary cholesterol, as there is no evidence that consuming dietary cholesterol increases the risk of blood cholesterol in most people."

• Updated guidelines reflect the lack of evidence linking dietary cholesterol to blood cholesterol increases.

• Short-Term vs. Long-Term Studies: Short-term studies often show harm from saturated fat, but long-term studies indicate that eating saturated fat does not increase saturated fat levels in the blood.
• Meta-Analyses Findings: Meta-analyses of randomized controlled trials show that low-carb diets, high in saturated fats, do not increase LDL cholesterol but improve several cardiovascular risk factors.

"Longer-term studies have shown that on average, eating saturated fat does not increase saturated fat levels in the blood."

• Long-term studies provide a more accurate picture of the effects of saturated fat.

"Meta-analyses of 17 randomized controlled trials found that low-carb diets neither increase nor decrease LDL cholesterol but were associated with a decrease in body weight and improvements in several cardiovascular risk factors."

• Low-carb diets have various health benefits without increasing cardiovascular risk markers.

• Superiority for Weight Loss and Glycemic Control: Meta-analyses consistently show that low-carb diets outperform or match low-fat diets for weight loss and are superior for glycemic control and reducing insulin and triglycerides.
• Beneficial Effects Without Increased Risk: Low-carb diets have beneficial effects across multiple health markers without increasing cardiovascular risk markers.

"All 10 meta-analyses showed that the low-carb diet either outperformed in most cases or was on the same level as low-fat diets."

• Low-carb diets are effective for weight loss compared to low-fat diets.

"All of these meta-analyses found that low-carb diets are superior for glycemic control, for reducing insulin, for reducing triglycerides, and have beneficial effects across the board without increasing cardiovascular risk markers."

• Low-carb diets offer broad health benefits without increasing cardiovascular risks.

• Preference for High-Quality Evidence: Randomized controlled trials (RCTs) are considered the best form of evidence, and recent RCTs do not show harm from increased saturated fat consumption.
• Critique of Older Studies: Studies from the 1940s and 1950s are less reliable compared to modern RCTs, which provide more accurate and controlled data.

"We need to prefer randomized controlled trials over that kind of evidence for sure."

• RCTs provide more reliable and accurate evidence compared to older epidemiological studies.

"Why do you continue to go back to these studies from the 1940s and 1950s?"

• Emphasis on the need to rely on modern, high-quality studies for accurate conclusions.

• Controlled Environment Studies: Studies conducted in metabolic wards, where participants' diets are strictly controlled, show that increasing saturated fat intake consistently raises cholesterol levels.
• Consistency Across Individuals: While individuals start at different cholesterol levels, the increase in cholesterol from saturated fat is consistent across different people.

"You put people in a metabolic ward at the National Institute of Health, change their diet, and their cholesterol rises sure as can be."

• Controlled studies show a consistent rise in cholesterol with increased saturated fat intake.

"The change in cholesterol is consistent; you’re going to go up 20%, 20%, 20%. We start at different points, but the change is consistent."

• Regardless of starting levels, increasing saturated fat consistently raises cholesterol.

• In 2008, the International Dairy Council acknowledged a decline in global dairy consumption and sales.
• The Council decided to invest in influencing researchers and public recommendations to promote dairy.
• This initiative led to funding sympathetic researchers and influencing public opinion through strategic publications and campaigns.

"2008 Mexico City the National the International Dairy Council meet and they published their notes which is why we notice and they said we are losing the battle people are eating less dairy around the world and we are losing sales what we can do is influence researchers influence recommendations."

• The dairy industry's global initiative aimed to find researchers who would support dairy, leading to campaigns like the milk moustache campaign.

"They looked for sympathetic researchers that would change public opinion and that was right before the milk moustache campaign."

• Dr. Ronald Kraus, an MD from Berkeley, received funding from the dairy industry and published a meta-analysis in 2010, which questioned the link between saturated fats and heart disease.

"He publishes we call it a meta-analysis ... their conclusion is they could not find and verify that saturated fat in the diet butter eggs and cheese raises the risk of heart disease."

• The study was published in the American Journal of Clinical Nutrition but faced criticism and was countered by an editorial in the same journal.

"It's an American Journal of Clinical Nutrition that same journal is a is a editorial that destroys the study this is 15 reasons this is horrible epidemiology."

• Subsequent studies, such as the 2014 meta-analysis by Chowdhury, continued the trend, contributing to public confusion about dietary fats.

"A guy named Chowdhury publishes a similar analysis that is the reason that Time magazine put on the cover butter is back."

• The confusion serves the interests of the dairy industry by maintaining consumer habits despite contradictory scientific evidence.

"There is a quote from the tobacco industry that our product is confusion they didn't care about you know winning the battle when the public's confused they're just gonna keep on doing habits they have."

• Early studies from the 1950s to 1990s consistently showed that higher saturated fat intake increased cholesterol and heart disease risk.
• These studies formed the basis of dietary guidelines that still recommend limiting saturated fat.

"The best done studies in the world say you eat more saturated fat your cholesterol goes up more saturated fat Cornette heart disease goes up it was crystal clear and the guidelines set it the guidelines still say it."

• Despite new studies and meta-analyses, the core message of limiting saturated fats remains valid according to historical research.

"The same science from the 1950s in the 1940s today if it's in retrospect valid."

• Observational studies generate hypotheses rather than proving them, and they often suffer from various limitations.
• Randomized controlled trials (RCTs) are needed to confirm the findings of observational studies.

"Observational studies were never meant to prove a hypothesis they're meant to generate a hypothesis."

• The Bradford Hill criteria help assess causal relationships in observational studies, but nutrition research seldom meets these criteria.

"There are criteria called the Bradford Hill criteria which you can use and apply to observational studies to assess the chance that there's a causal relationship."

• Replication in RCTs is crucial; many observational study claims fail to replicate in controlled trials.

"There was one analysis that found that zero of fifty-two claims that were made in observational nutrition studies were replicated when they were tested later."

• Beta carotene is an example where observational studies suggested benefits, but RCTs showed increased cancer risk.

"Observational studies originally suggested that beta carotene an antioxidant that people with the highest intake of beta carotene had something like a 30% reduce risk of death ... when they started doing trials where they were giving people beta carotene supplements not only did it not improve their lifespan they got more cancer."

• Recent meta-analyses of RCTs have shown that low-carb, high-protein diets improve glycemic control and are effective for type 2 diabetes.

"We've got a 2013 meta-analysis of 20 randomized controlled trials that found that low carb high protein diets led to greater improvements in glycemic control compared to low-fat American Heart Association American diabetic Association diets."

• These findings challenge older observational studies and suggest a shift in dietary recommendations based on more robust evidence.

"We've got another meta-analysis of 25 randomized controlled trials just published in 2018 that found the same thing."

• The evolution of science involves replacing outdated observational evidence with findings from well-conducted RCTs.

"Science marches on we we learn more we change and now we've got randomized controlled trials that are replacing some of the observational evidence from the 50s and 60s and 70s."

• Dr. Harkins' paper highlights that the evidence from older observational studies was never strong, underscoring the need for current, rigorous research.

"In dr. Harkins paper you see that that evidence was never strong to begin with and this is what we should be looking at."