Category Archives: Fat and Oil

High-Fat Diet, Especially High Saturated Fat, Increases Risk For Breast Cancer In Large Multicountry Study

Several prominent news outlets have carried stories recently calling on us to eat more fat, especially more saturated fat, saying “fat is good for you.” Yet, in this large multicountry study, women who ate the most fat, and especially the most saturated fat, were more likely to develop breast cancer (BC) than women who ate the least:

Study: Dietary Fat Intake and Development of Specific Breast Cancer Subtypes, Journal of the National Cancer Institute, 9 April 2014

Press Release: Consuming a high-fat diet is associated with increased risk of certain types of BC, Journal of the National Cancer Institute, 9 April 2014

Researchers “prospectively analyzed data from 10,062 breast cancer (BC) patients from the EPIC study with 11.5 years of follow-up. The EPIC cohort study consisted of 337,327 women living in 10 European countries, which creates a heterogeneous cohort both in terms of geography-related dietary fat intake patterns and in terms of molecular subtype.”

The authors conclude, “a high-fat diet increases breast cancer risk and, most conspicuously, that high saturated fat intake increases risk of receptor-positive disease, suggesting saturated fat involvement in the etiology of receptor-positive breast cancer.”

News Summary: High-Fat Diet May Boost Breast Cancer Risk, Study Found Women Who Ate The Most Saturated Fat Were More Likely To Develop Tumors, HealthDay, 9 April 2014

One strength of the new study is its large numbers, said Mia Gaudet, director of genetic epidemiology at the American Cancer Society. The breast cancer subtypes linked with fat intake are common, she said. “The majority of breast cancers in the U.S. and Europe are ER-positive, PR-positive, HER2-negative,” she noted.

Lead author Sabina Sieri, PhD: It’s possible that the high-fat intake raises the levels of the body’s own estrogen, which can stimulate the growth of breast cancer cells.

Gaudet: “If you have a mainly plant-based diet, that is going to help you keep your fat intake low.”

So, dietary fat increases the risk for breast cancer. Yet Time Magazine’s Brian Walsh urges us to “Eat Butter” (7 grams of saturated fat in just 1 tablespoon) and New York Times’ Mark Bittman informs us that “Butter Is Back.” (“Butter is back, and when you’re looking for a few chunks of pork for a stew, you can resume searching for the best pieces — the ones with the most fat.”) Dietary fat has also been shown to increase the risk for prostate cancer. And we know it’s implicated in the development of insulin resistance and diabetes. There must be some other motive working to push fat besides public health.

Something That’s Red Is Invisible Against A Red Background

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When most of the participants in a study are consuming fat above a threshold that promotes disease, it will look like fat is not disease-promoting.

I often say that in studies comparing one group to another, you won’t detect a harmful effect of _____ if both groups are exposed to a level of ______ that is risk-producing. I said this recently about that saturated fat study (meta-analysis) that got so much attention in the media, and that spurred proclamations such as “Eat Butter” and “Saturated Fat Vindicated”:

“One way you can arrive at all your groups showing similar risk, which this study found, is when there isn’t much difference in consumption among your comparison groups. … Or when most of your participants are consuming saturated fat above a threshold where risk for CVD increases.”

As Jeff Novick pointed out:

“One major problem with this study is they did not look at any studies where the saturated fat intake was less than 7%, which is the level recommended by the [American Heart Association]. … Most of the diets had saturated fat intakes in the range of 10-15% (or more).”

I also said this in reference to the PREDIMED study. That was a big trial studying effects of the Mediterranean diet. It had three groups: “low-fat,” olive oil, and nuts. All the groups ate high-fat, even the “low-fat” group which ate 37% of their calories from fat! Not even the American Heart Association considers that low-fat. For perspective, a whole-food plant-based diet gets less than 15% of its calories from fat. The PREDIMED study found eating lots of olive oil was similar in CVD risk to eating “low-fat.” All groups suffered heart attacks at similar rates. All groups were exposed to a level of fat that was risk-producing.

I just saw a video that Dr. Greger posted about a month ago where he says essentially the same thing:

He cited this study:

Sick Individuals And Sick Populations, International Journal of Epidemiology, 2001

“If everyone smoked 20 cigarettes a day, then clinical, case-control and cohort studies alike would lead us to conclude that lung cancer was a genetic disease; and in one sense that would be true, since if everyone is exposed to the necessary agent, then the distribution of cases is wholly determined by individual susceptibility.”

Within a population, that is, within a group with similar characteristics, you may not see a big range of exposure to something, e.g. in the US, most people eat around 30-35% fat, not a big range. But when you compare populations with different characteristics…

But at the level of populations it is a different story: it has proved easy to show strong associations between population mean values for saturated fat intake versus serum cholesterol level and coronary heart disease incidence, sodium intake versus blood pressure, or energy intake versus overweight.

The reason we know that smoking increases the risk for lung cancer is because:

In the case of cigarettes and lung cancer it so happened that the study populations contained about equal numbers of smokers and non-smokers, and in such a situation case/control and cohort studies were able to identify what was also the main determinant of population differences and time trends.

In sum:

But to identify the causal agent by the traditional case-control and cohort methods will be unsuccessful if there are not sufficient differences in exposure within the study population at the time of the study.

There are some real gems in this paper…

Grateful patients are few in preventive medicine, where success is marked by a non-event.

That’s so true! You don’t really know if your behaviors are adding years to your life.

And this. I can’t believe he said this:

Harder to overcome than any of these, however, is the enormous difficulty for medical personnel to see health as a population issue and not merely as a problem for individuals.

Just about 100% of the people I know, even those in the public health community, harp on about individual behavior. You will never, ever be successful in disease prevention if you only intervene at the individual level. Social norms, peer pressure, environmental pollutants, occupational hazards, there are just too many things an individual is up against, and doesn’t control. You have to change the environment in addition to, perhaps more than, changing individuals’ behavior.

Greger is right when he says:

This is one of the most famous papers ever written in preventive medicine. It should be required reading for all medical students.

Back to the point I was making at the beginning of this post… If you want to know if something is harmful – smoking cigarettes, eating saturated fat, watching television – make sure you have a comparison group that isn’t doing it, or isn’t doing very much of it. Something that’s red is invisible against a red background.

National Dairy Council’s And Unilever’s Involvement In Saturated Fat Study

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Note that the study below, which is often cited to justify eating more saturated fat, but which has been taken to task, not least of which by the renowned Dr. Stamler, and in the very same issue where the study was published,¹ was supported by the National Dairy Council, and by Unilever, which owns several ice cream companies, including Breyers, Ben and Jerry’s, Good Humor, and Klondike. (Under “Author’s Notes” item #4.)

¹ Diet-Heart: A Problematic Revisit, Jeremiah Stamler, American Journal of Clinical Nutrition, March 2010.
Stamler infers that the authors’ intent was not to clarify the association between fat and heart disease, but to inject doubt.

Dr. Klaper: “Pouring Olive Oil On Food Does Not Suddenly Make It Heart-Healthy”

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This is an excerpt from the presentation by Dr. Michael Klaper given at the Healthy Lifestyle Expo in 2012. He addresses olive oil, saying, “pouring olive on food does not suddenly make it heart-healthy.”

Highlights:

Restaurant food is “salt, sugar, and fat.” Eat before you go.
The Greeks have the highest rate of obesity in Europe.
Olive oil is 14% saturated fat.
“Remember, your body is never not looking.”
“Excessive saturated fats (even olive oil) stiffen the walls of the arteries and make them less responsive to nitric oxide which dilates the vessels and increases blood flow to the organs.”
How to stir fry without oil: Saute in seasoned vegetable broth.
For salad dressing without oil: Blend vegetables, fruits, nuts, vinegars, etc., puree and pour over greens.

Dr. Vogel: “Olive Oil Depresses Endothial Function”

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Here’s Dr. Robert Vogel, the lead author of that last study¹ cited in my post, Olive Oil Shown To Promote Atherosclerosis, speaking to Dr. Henry Black in a Medscape interview last May:²

I can’t embed the video but I’ve linked it here.

Dr. Vogel: There is no question that what you do daily — whether it is what you eat, how you exercise, whether you watch television or videos, or whatever — affects your endothelial function, and it affects it very quickly. One of the things we demonstrated several years ago is that if you eat a noxious kind of meal, a fast-food meal, your endothelial function worsens considerably. You lose about 50% of your endothelial function within 2 or 3 hours.[1,2]

Dr. Black: How do you measure that?

Dr. Vogel: We measure brachial reactivity. This is a noninvasive ultrasound test that measures the size of an artery and then looks at arterial changes after a stimulus, which is blood pressure cuff occlusion.

Dr. Black: Is anything else potentially detrimental aside from the fat in a diet?

Dr. Vogel: Many things are possibly detrimental or beneficial, but we found that what most depresses endothelial function is saturated fat.

Dr. Black: What about the Mediterranean diet? What do we know about that?

Dr. Vogel: That is a very hot topic right now. The PREDIMED study[3] from Barcelona included 7500 patients and showed about a 30% reduction in cardiovascular events with a Mediterranean diet. Of interest, I think they wanted to prove that it was the olive oil that was beneficial, but they got the same results whether participants consumed high amounts of olive oil or high amounts of mixed nuts. So they did not show what I think they intended to show.

We have looked at olive oil.[4] We found that olive oil may be not as bad as lard, but it does depress endothelial function, and that is because it also has high saturated fat.

Dr. Black: But that is a surrogate. With the Mediterranean diet study, they actually had outcomes — something that is unusual in any diet study.

Dr. Vogel: This was the third and the best of the diet trials[3,5] because it was a prospective randomized trial of about 7500 folks. It was carefully controlled, and they looked at the cardiac events in an organized way. With a 30% reduction in cardiac events, which was statistically significant, I think we can be sure that a good diet does matter.

¹ The Postprandial Effect Of Components Of The Mediterranean Diet On Endothelial Function, Journal of the American College of Cardiology, November 2000
² Et Tu, Olive Oil? Fats and Endothelial Function, Medscape May 2013

Olive Oil Shown To Promote Atherosclerosis

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The following studies provide evidence for the atherosclerosis-promoting effect of olive oil, in monkeys, mice, and humans:

1. Hepatic Origin of Cholesteryl Oleate in Coronary Artery Atherosclerosis In African Green Monkeys, Enrichment By Dietary Monounsaturated Fat, Journal of Clinical Investigation, 1997

“[We observed in monkeys] that the amount of coronary artery atherosclerosis was similar in the monounsaturated and saturated fat groups, in spite of the significantly improved LDL cholesterol concentration and LDL/HDL cholesterol ratio in the former.”

2. Dietary Monounsaturated Fatty Acids Promote Aortic Atherosclerosis In LDL Receptor–Null, Human ApoB100–Overexpressing Transgenic Mice, Arteriosclerosis, Thrombosis, and Vascular Biology, 1998

Mice were fed one of 6 diets with different fatty acid content: saturated, monounsaturated (cis and trans), polyunsaturated (n-3 and n-6), and a control diet.

“The reduction in aortic atherosclerosis was not found when either cis or trans monounsaturated fatty acids were fed. Rather, just as much atherosclerosis was seen when cis monounsaturated fat diets were fed as when saturated fat was fed, and significantly more atherosclerosis was seen when the trans monounsaturated fatty acids were fed.”

This is an important outcome when one considers that monounsaturated fats, often in the form of olive oil, are widely promoted as being healthful and effective for protection against heart disease.

3. Effect Of Fat And Carbohydrate Consumption On Endothelial Function, Lancet, December, 1999

“Consumption of a meal high in monounsaturated fat was associated with acute impairment of endothelial function when compared with a [low-fat] carbohydrate-rich meal.”

4. The Postprandial Effect Of Components Of The Mediterranean Diet On Endothelial Function, Journal of the American College of Cardiology, November 2000

“Contrary to part of our hypothesis, our study found that omega-9 (oleic acid)-rich olive oil impairs endothelial function postprandially.

The mechanism appears to be oxidative stress because the decrease in FMD was reduced (71%) by the concomitant administration of vitamins C and E. Balsamic vinegar (red wine product) and salad reduced the postprandial impairment in endothelial function to a similar extent (65%).

In a clinical study, olive oil was shown to activate coagulation factor VII to the same extent as does butter (44). Thus, olive oil does not have a clearly beneficial effect on vascular function.”

The major unsaturated fatty acids in olive oil are oleic acid (18:1n-9) and linoleic acid (18:2n-6) (42). A high-oleic and linoleic acid meal has recently been shown to impair FMD in comparison with a low-fat meal (28). (That’s the study above by Ong et al.)

In terms of their effects on postprandial endothelial function, the beneficial components of the Mediterranean and Lyon Diet Heart Study diets appear to be the antioxidant-rich foods—vegetables, fruits … not olive oil. Dietary fruits, vegetables, and their products appear to provide some protection against the direct impairment in endothelial function produced by high-fat foods, including olive oil.”

Clearly, olive oil is not the heart-healthy food it’s made out to be. It truly is a feat of marketing that a food which has been shown over and over to impair artery function exists in peoples’ minds as an elixir. The Mediterranean diet, with its generous portions of fruits, vegetables, and whole grains, improves health not because of olive oil, but in spite of it.

Time Magazine: “Eat Butter”

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The cover of Time Magazine’s next issue is going to say “Eat Butter.” The associated cover story by Bryan Walsh is entitled “Ending The War On Fat.” I haven’t read the article, so I don’t know what he bases his claims on. But I have read thousands of studies in my lifetime, and “eat butter” is not my conclusion. My cover story would read “Don’t Eat Butter.”

Here’s the video that accompanied Time’s story. It’s emceed by Walsh. It’s going to tell you that everything you’ve been led to believe about fat is wrong. It’s wrong.
http://c.brightcove.com/services/viewer/federated_f9?isVid=1&isUI=1

Dr. McDougall addressed Time’s upcoming story here. Marion Nestle addressed it here. (Nestle says saturated fat consumption is down, and so are deaths from heart disease.)

There is an abundance of research that implicates consumption of saturated fat in the development of heart disease. I am curious how Walsh will present this. McDougall says that one particular study, paid for by the National Dairy Council, is often cited to justify the “eat butter” proclamation:

Meta-Analysis Of Prospective Cohort Studies Evaluating The Association Of Saturated Fat With Cardiovascular Disease, American Journal of Clinical Nutrition, March 2010

However, that study was taken to task, not least of which by the renowned Dr. Stamler, in the very same issue where the study was published:

Diet-Heart: A Problematic Revisit, Jeremiah Stamler, American Journal of Clinical Nutrition, March 2010

Stamler infers that the authors’ intent was not to clarify the association between fat and heart disease, but to inject doubt.

“… the authors seem to be dissociating themselves from prevailing national and international dietary recommendations to the general population for primordial, primary, and secondary prevention of CHD/CVD and the established major metabolic risk factors. But they are not explicit. Is that their intent?“

What are those prevailing recommendations?

“Specifically, do they disagree with the merits of heart-healthy fare on the basis of DASH-, OmniHeart-, Mediterranean-, East Asian–type eating patterns, which emphasize vegetables, fruit, whole grains, legumes/seeds/nuts, fat-free/low-fat dairy products, fish/shellfish, lean poultry, egg whites, seed oils in moderation, alcohol (if desired) in moderation, and portion size/calorie controlled and deemphasize red and processed meats, cheeses, ice cream, egg yolks, cookies/pastries/pies/cakes/other sweets/sweetened beverages, snacks, and salt/commercial foods with added salt. Estimated nutrient composition of this fare is as follows: total fat ≈20–25% of kcal, SFA 6–7%, MUFA 7–9%, PUFA 7–9%, cholesterol <100 mg/1000 kcal, total protein 18–25%, vegetable protein 9–12%, carbohydrate 55–60% (mostly complex), fiber 30–35 g/d, 50–65 mmol Na/d (2900–3770 mg NaCl/d), mineral/vitamin intake high (6). A vast array of concordant multidisciplinary research evidence is the sound foundation for these recommendations.”

Nothing has changed. Don’t eat butter.

Proposed Warning Label For Meat: “Eating Meat Contributes To Insulin Resistance And Diabetes”

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The California Senate just passed a bill requiring warning labels on sugar-sweetened beverages:

“Drinking beverages with added sugar(s) contributes to obesity, diabetes, and tooth decay.”

It’s a shame that sweetened beverages are being singled out. I would like to see a similar label on meat:

“Eating meat contributes to insulin resistance and diabetes.”

Why? Because meat-eating is a risk factor for developing diabetes:
Meat Consumption As A Risk Factor For Type 2 Diabetes, Nutrients, February 2014

Researchers evaluated studies that examined different amounts and types of meat consumption and the risk for developing diabetes. They found that meat-eaters had a significantly higher risk of developing diabetes compared with non-meat-eaters. Here’s a chart summarizing the results of one of the included studies, Type of Vegetarian Diet, Body Weight, and Prevalence of Type 2 Diabetes, Diabetes Care, 2009:

Mechanisms for meat’s effect on diabetes risk:

Effect on body weight – “Nearly all observational studies comparing meat-eaters with those who avoid meat show higher body weights among the former group, a finding mirrored in the results of intervention studies using meatless diets.”
Effect on visceral fat (fat around organs in abdominal area) – “Visceral adipose tissue is associated with insulin resistance as a result of increased proinflamatory cytokines.”
Effect on intracellular lipid (fat inside cells) – Impairs insulin action. This would involve, in part, the glucose transporter (GLUT4), which I discussed here.
Effect on iron balance – “Meat provides a substantial quantity of heme iron … a prooxidant that encourages the production of reactive oxygen species, which may damage body tissues, including insulin-producing pancreatic cells.” Even moderately elevated iron stores are associated with insulin resistance and type 2 diabetes.
Nitrates in processed meats – Nitrites and sodium are both linked to elevated diabetes risk.
Systemic inflammation – “A 2014 Harvard study reported that as total red meat consumption increased, so did biomarkers of inflammation.”
One they didn’t mention was presence of persistent organic pollutants (POPs): Animal Fat Is A Natural Reservoir For Environmental Pollutants. “There is now solid evidence demonstrating the contribution of POPs at environmental levels, to metabolic disorders … such as obesity and type 2 diabetes.”