I wrote a previous post, With Enough Butter Anything is Good. So while looking at my YouTube feed up comes a video by NoLabCoatRequired. In his post, he shows how science has seemingly accepted as fact, though unproven, that the Diet-Heart Hypothesis is correct. The basic question is this: does saturated fats (like butter) cause cholesterol to rise, and cause heart attacks; or put another way, is it safe to eat butter?
Because of how serious of a discussion this is, along with my word limit of ~3k max, per post, I have taken the unusual step to document everything. I have all the critical studies summarized in footnotes at the end, numbered 1 through 11. Then I have links to everything else, mainly research documents.
Per usual, I am just a cook so please speak with your medical and/or nutritional expert to decide what is right for your body.
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Dietary Saturated Fat Causes Problems?
Kitchn writes that American scientist Ancel Keys first proposed the correlation between cholesterol and cardiovascular disease in 1955, prompting the Seven Countries Study, which seemed to confirm this hypothesis. This was an indirect, observational study that other scientists questioned its conclusions, accuracy, and data relevance. Despite those concerns, in 1956, the American Heart Association announced that a diet high in animal fat and coronary disease were linked, and the U.S. government recommend a low-fat diet as the key to heart health.
Ancel Keys is also the originator of the Diet-Heart Hypothesis. Basically, the diet-heart hypothesis is the assumption that dietary cholesterol and saturated fat cause heart disease.
Diet-Heart Hypothesis May Not Be Fact
Has a Logic Error
The Diet-Heart Hypothesis states three things: Dietary saturated fat increases blood cholesterol. And elevated blood cholesterol leads to a heart attack. Therefore, dietary saturated fat increases the risk of having a heart attack.
The Seven Countries Study shows a possible correlation between higher elevated blood cholesterol and heart disease. But does not prove that dietary saturated fat causes increases in cholesterol, nor does it prove that increased cholesterol causes heart disease.
The logic error points that the argument to lower saturated fat is, at its base, faulty.
Lack of Proof
The ideas that dietary, saturated fat increases blood cholesterol and therefor leads to heart attacks is an accepted truth by many current scientists. So strong is this idea that many studies do not even question this conclusion, but start their work using that as a basic fact (7 below). When historical studies are shown as proof, researchers point to diet controlled, short-term studies that indicate when people are fed saturated fats, their cholesterol may increase, but not in all people (1 below).
Yet, nearly every high-quality observational study conducted, finds that saturated fat intake is not associated with heart attack risk (2, 3 below). If consuming saturated fats leads to high cholesterol, why are there no studies saying people consuming saturated fats are having more heart disease; in fact, they are saying there is either no correlation, or saturated fat might even be beneficial (10 below, 12). To quote one neurobiologist, it may be that in most instances, when researchers have looked for a relationship between habitual saturated fat intake and blood cholesterol, it has been very small or nonexistent (6 and 11 below, 13).
My Problems with Saturated Fat Studies
My intent in this section is to just show how, even just a cook with common sense, can come up with concerns about studies that may have not looked at all facts related to cooking in their variables.
Confounding Factors
SnapKitchen wrote, what I considered after reviewing the Seven Countries Study as well: It’s important to note that nutrition studies in humans generally tend to have limitations, but epidemiological studies, in particular, have even larger ones. Correlation doesn’t prove causation, and yet some epidemiological studies draw serious conclusions with data that may have other things affecting the outcome, also called confounding factors.
Unclear Factors
I am not a scientist, so you could ask who am I to question these studies. My response is I am a cook and can explain my concerns through that experience. For instance, one study combined butter and margarine, to compare to certain vegetable oils. But butter and margarine should not be combined since they are not the same thing (9 below, 14). Similarly, those studies also combine various vegetable oils, but each have different sources and processes, and too should not be combined (5 below). To me this invalidates the study. It should have studied each item alone rather than combine unlike items.
Variations of Butter
Additionally, since the milk output is based in part on the consumed animal feed, it is not clear if they used real butter, grass fed cow’s butter, or industrially corn-raised butter, or if the butter used was altered (8 below). Unless isolated and fed a specific diet, recording what people ate at home with just a check for butter or margarine or oils does not cut it.
Diets, Genetics + Microbiome
Another problem is that they do not consider the whole diet people may be eating, combined with our various physical genetics and microbiome. For example, the MayoClinic is clear that soluble fiber reduces low-density lipoprotein (LDL) cholesterol, so if I have a high saturated fat diet that also has high fiber does it change the results? Additionally, we know that genotype deciphers how lipids are metabolized and it is not clear to me that any of the studies considered this either. For instance, if I have genetically high cholesterol, does consuming butter or not make any difference?
Iron Cookware
Finally, the study discussed above states: dietary iron, and particularly the heme iron found in red meat, has been positively associated with myocardial infarction and fatal CHD [Coronary Heart Disease] in most but not all studies. Well, other studies show cooking in cast iron can add a significant amount of iron to our diet. Researchers found that spaghetti sauce cooked in cast iron skillets increased the iron content anywhere from 2mg to 5mg iron. So do we know what people in these various studies were cooking in, because studies show dietary iron elevates LDL-cholesterol. Or one contrary result is higher iron boosts heart health, but may lead to strokes.
So What About Cow’s Butter
Cows are a ruminant that chew cud and have four compartments: the rumen, the reticulum, the omasum and the abomasum. Drinking milk, cheese, yogurt, butter, etc. are all made from the milk they express. The quality of the milk, butter, and other products rely heavily on the quality of their feed, health of the animal, and the specific processing that occurs to make the products.
I have reviewed ~50 studies over the past week regarding butter and its impact on our health (4 below). Originally, I thought this would be a fairly easy post, given how clear the instructions are to avoid saturated fats like butter for health. But now I see the problems with those studies, and where the science hedges, or contradicts general wisdom. The problems exposed in these studies, is that the scientists are not cooks or farmers, and butter is not a simple piece of matter. The effect of butter on health is much more complicated.
Butter and Margarine
As an example of the complexity, consider butter and margarine. They both look similar, a yellowish, greasy fat that we can cook and bake with, and they may even have a similar taste.
However, butter is made from cow’s milk fat. When cream in that milk is vigorously churned, solids called butterfat, and liquids called buttermilk, start to separate. The solids combine into butter, and the left over liquid is buttermilk. Then the solid matter is squeezed to release buttermilk, rinsed, and worked some more; here is a link to the best explanation.
Butter has less human intervention, fewer processes (outside of the cow), and fewer ingredients on the label. To be sold commercially, butter must have at least 80% fat and the remaining 20% is water and milk proteins.
Margarine, an engineered product, was invented in France by Hippolyte Mèges-Mouries in response to Napoleon III’s call for a cheap alternative to butter for French workers and for his armies in the Franco-Prussian war (15). Then margarine was made from beef tallow and milk, but now it has oil, water, salt, and additional ingredients such as emulsifiers, flavors, and coloring.
I do not want to discuss margarine too much, that is another post, but Snopes describes the process as starting with the oils that are used in its creation would most likely have been extracted at high pressure with solvents. They say it is likely that some pesticide residue remains throughout the margarine process, even if monitored to meet legal levels. Then, there is a chemical process to raise the melting point of the added oils, to allow the margarine to stay solid while at room temperatures. And then “bleaching” process starts by using activated charcoal or clays to lighten the product.
What I Decided to Do
I will continue to consume butter, as I have not seen clear evidence that the consumption of saturated fats, in moderation and within a well balanced diet will cause heart disease (16). However, I have a preference to hedge my bets, so I want to consume only the best butter that is available to me.
I want organic, foraged and grass-fed, unsalted, European creamy butter. When compared to industrial butter:
- Grass-fed organic butter contains: VitA (17, 18, 19), VitK (20), VitD (20a), and VitE (21)
- Higher proportion of healthy unsaturated fatty acids (22, 23, 24)
- Higher in omega-3 fatty acids (25)
- Up to 500% more conjugated linoleic acid than regular dairy (26).
- Grass-fed cows produce milk lower in fat (27). Researchers write, cows that ate more grass produced more milk, but no extra fat, meaning that the fat concentration in the milk was lower.
- Additionally, according to a 2006 study, trained panelists reported that butter from cows with a higher-grass diet was likelier to melt in the mouth, a texture that many people find pleasant.
- Another study proved consumers appreciate grass-fed butter better because it looked, tasted, and had a better color than industry butter.
So my preference is to avoid margarine. If I mix butter with oil at home I will use Olive Oil or Avocado Oils. And I buy salt free butter, if I need salt I just add it to the butter when required.
My preferred butters.
- Kerrygold Pure Irish Butter, unsalted which is cultured, and with 82% butterfat (28) even though it is not certified organic, and there is supplemental non-grass feed, of which ~3% may be GMO (28a). Their cows are housed ~2 months per year due to winter weather.
- Costco’s Kirkland 95% grass fed salted butter from New Zealand in the green packaging.
- Vital Farms pastured-raised butter, unsalted, and with 85% butterfat, and likewise may have some GMO grains fed to the cows during winter indoor stints.
- Challenge Butter as they use milk from family-run, grass-only California farms
What you should do is your decision and should be discussed with your medical or nutritional expert. But to help I have attached several significant studies on this topic below so you can read them yourselves and see how confusing the results are.
— Patty
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Studies With Relevance to Butter and Saturated Fats
1 A 2009 study noted that coronary heart disease continues to remain one of the leading causes of death in the USA. They state that dietary factors known to influence the risk of coronary heart disease include: saturated fats, trans-fats, and polyunsaturated fatty acids. Although higher plasma levels of low-density lipoprotein cholesterol are associated with an increased risk of coronary disease, and lipid-lowering therapy has been shown to reduce the risk of cardiovascular disease, they claim that the relationhip between dietary cholesterol and the risk of coronary heart disease is not clearly understood.
2 The 2010 study, referenced in the YouTube video, reviewed 21 studies looking at summarizing the evidence related to the association of dietary saturated fat with the risks of coronary heart disease, stroke, and cardiovascular disease. The study reviewed research articles that conducted 5-23 years followup of 347,747 people; 11,006 of which developed coronary heart disease or stroke; which prior studies had associated with intake of saturated fats, like butter, eggs, and milk products. But this review of those studies found that they did not prove a correlation between the intake of saturated fat and illness, in fact they proved saturated was not associated with an increased risk of any of the diseases mentioned.
3 Then in 2015, one of the follow up studies reviewed historical research that consisted of observational studies associating cow’s saturated fat or Industrial trans-unsaturated fat with all causes of mortality. They concluded that saturated fats are not associated with all causes of mortality, however, trans fats are associated with all causes of mortality. They surmised that this is probably because of higher levels of intake of industrial trans fats than ruminant trans fats in our modern diet.
4 A 2016 study specifically looked at butter intake in 9 medical databases, for a total of 636,191 participants, looking at randomized clinical trials providing effects of butter intake on mortality, cardiovascular disease including coronary heart disease and stroke, or diabetes in adult populations. This systematic review and meta-analysis found a relatively small or neutral overall association of butter with mortality, cardio vascular disease, and diabetes.
5 In 2018 a study showed that for cardiovascular health the type of fat consumed is more important than the total fat consumed, we should eliminate industrially produced trans fats, replacing saturated fat with polyunsaturated fats is good but not when replaced with carbohydrates, controversies remain about long term health effects of specific plant oils and of high fat, low carbohydrate diets, and the focus of dietary advice must be on the consumption of foods and overall dietary patterns, not on a single nutrient.
6 A study in 2019 concluded, dairy product consumption (milk, cheese, butter, and other products) is not associated with risk of all-cause mortality. This was after they conducted an overview of existing systematic reviews and meta-analyses (from 4 databases, from inception to 2018) examining the association between dairy product consumption and all-cause mortality risk.
7 In 2020 another study decided to assess the effect of reducing saturated fat intake and replacing it with carbohydrate, polyunsaturated, monounsaturated fat and/or protein on mortality and cardiovascular morbidity. They found 15 randomized clinical trials that had 16 comparisons, with over 56,675 participants. After a rigorous review, scientists found that reducing saturated fat had little to no effect on all-cause mortality or cardiovascular mortality. There was little or no proof that reducing saturated fats effects non-fatal myocardial infarction or CHD mortality, cancer mortality, cancer diagnoses, diabetes diagnosis, HDL cholesterol, serum triglycerides or blood pressure. However, there might be some effect on total myocardial infarction, stroke and CHD events; but they cannot make that claim because the data was unclear due to low quality evidence. So, they concluded that greater reduction in saturated fat caused greater reductions in cardiovascular events.
8 An interesting study appeared in 2021 that reviewed butter that were sold to consumers and found that there was a known practice of butter adulteration. They found butter was cut with different brands of hydrogenated vegetable oils, Irish potato puree, banana pulps, melted tallow, wheat and maize dough, and buttermilk, as well as water. As would be expected, they found significant differences among the fatty acid profiles of pure butter and the adulterated butter.
9 Then a 2021 study identified and prospectively followed 521,120 participants aged 50-71 years for 16 years. During that time, 129,328 deaths were documented. The associations drawn were that intakes of butter + margarine were associated with higher total mortality, while intakes of canola oil + olive oil were related to lower total mortality. [The major problem with this study was combining butter and margarine.]
10 Recently, in 2022, Italian Researchers wrote that while dietary fats, and especially saturated fatty acid, have been blamed for being the culprit in the dramatic increase in obesity and its associated diseases. However multiple systematic reviews and recent meta-analyses do not support the association between saturated fatty acid and cardiovascular diseases. They studied 1,936 Southern Italians and found that the consumption of saturated fatty acids does not seem to be harmful to cardio-metabolic health and, on the contrary, may exert beneficial effects.
11 A 1963 study seems to be the oldest one that looked at cholesterol leading to heart disease. Animal fat intake ranged from 55 to 173 grams/day, and blood cholesterol ranged from 154 to 324 mg/dL, yet there was no relationship whatsoever between the two. In fact they wrote that diet thus does not seem to account for the wide range in cholesterol changes that was found.
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