Dr Walter Willett And Polyunsaturated Fats

I'm reading through all the transcripts from Mark Hyman's "Fat Summit". I get to Dr Willett's and what I'm reading there is basically the opposite of what so many others are teaching, like Asprey and Kresser and Sisson.  For those who don't know, Willett is one of academia's leading experts on nutrition, is the chair of the nutrition department at Harvard and probably has access to more academic studies on nutrition than anyone else alive. He's saying that the data is clear, that from a health (especially cardiac) perspective, polyunsaturated fats are much healthier than saturated fats, and that saturated fats have the same basic health impact as carbohydrates.  He also says that we need both omega 6 and 3 fatty acids and as long as we have sufficient levels of both, the ratio of them is basically meaningless.


 


Is anyone here familiar with his work enough to be able to credibly comment on his conclusions?  Soybean and canola oils are healthier than grassfed butter and coconut oil? High levels of omega 6s to 3s is just fine?


 


I started reading those transcripts expecting to see more data in support of the new wave of thinking on saturated fat, and with Willett's, got anything but.


Comments

  • Here are a couple of links:


     



     

    This paper is bound to cause confusion. A central issue is what replaces saturated fat if someone reduces the amount of saturated fat in their diet. If it is replaced with refined starch or sugar, which are the largest sources of calories in the U.S. diet, then the risk of heart disease remains the same. However, if saturated fat is replaced with polyunsaturated fat or monounsaturated fat in the form of olive oil, nuts and probably other plant oils, we have much evidence that risk will be reduced.

     



     

    Rather than adopting a low-fat diet, it’s more important to focus on eating beneficial “good” fats and avoiding harmful “bad” fats. Fat is an important part of a healthy diet. Choose foods with “good” unsaturated fats, limit foods high in saturated fat, and avoid “bad” trans fat.

     

    “Good” unsaturated fats — Monounsaturated and polyunsaturated fats — lower disease risk. Foods high in good fats include vegetable oils (such as olive, canola, sunflower, soy, and corn), nuts, seeds, and fish.

     

    “Bad” fats — trans fats — increase disease risk, even when eaten in small quantities. Foods containing trans fats are primarily in processed foods made with trans fat from partially hydrogenated oil. Fortunately, trans fats have been eliminated from many of these foods.

     

    Saturated fats, while not as harmful as trans fats, by comparison with unsaturated fats negatively impact health and are best consumed in moderation. Foods containing large amounts of saturated fat include red meat, butter, cheese, and ice cream.

     

    When you cut back on foods like red meat and butter, replace them with fish, beans, nuts, and healthy oils instead of refined carbohydrates.


     


  • the only argument I can make is how did they control for saturated fats? Did they just say all saturated fat is equivalent?  Grainfed butter vs grassfed? Grainfed beef vs grassfed. Coconut oil vs ice cream?


     


    If we're talking the typical saturated fat most americans consume, then I can absolutely see his results being produced. If we're talking about "clean", paleo and bulletproof-approved forms of saturated fats, do we have any actual data to support the hypothesis that these forms of fat do not increase the risk of cardiovascular disease?


     


    In other words, if I have a client whom I recommend to start on the Bulletproof Diet and they come back to me with Willett's work, how do I defend my position in a responsible, data-based way?


  • Chris masterjohn has talked on his Daily Lipid podcast about some of the larger studies that people use to argue that PUFAs are a good replacement for saturated fat and why he thinks they are flawed. I can't remember which specific episodes but probably one of the ones about heart disease. Might be a good starting point. Of course he contradicts some BP dogma too.


    But in the end, there are all sorts of "nutrition experts" who have researched/experienced more than most of us (more than Dave!) ever will but still contradict each other. Its like politics/religion and we're somewhat dependent on the priests of the various religions to interpret things outside our own n=1.
  • dazdaz today is a good day ✭✭✭
    edited July 2016

    the University of Glasgow have been doing some interesting stuff looking at oils, 


    rather than looking at cholesterol, they have been looking at urinary proteomic biomarkers. 



    from s4 ep3 of the BBC prog 'Trust Me, I'm a Doctor' 

     


    Dr Bill Mullen and his team there have developed a new way of measuring subtle changes in heart health that can happen over only a few weeks, by looking at changes in the patterns of proteins excreted in peoples’ urine: a technique known as proteomics.

    The changes they are measuring are of the disease itself – which they can pick up before there are any physical symptoms, so it is far more accurate a method than measuring something that is just supposed to be associated with the disease, such as cholesterol levels. 

    ... 

     


    In this experiment, there was no evidence that either rapeseed oil or sunflower oil improves heart health.

    Since rapeseed oil has a similar level of monounsaturated fats to olive oil, it suggests that the benefits of olive oil are not down to its high monounsaturated fat content.

    And since sunflower oil is high in polyunsaturated fats, it suggests that these by themselves also do not have a beneficial effect on our hearts.


    The team are continuing the experiment for a further 6 weeks to see whether an effect is seen in the longer term.

    & from the same guys at the University of Glasgow on Olive Oil 

     
    In this experiment, it seems that taking 20ml of raw olive oil – either extra virgin or ‘normal’ – can have a positive effect on our hearts.
    Because both extra virgin and ‘normal’ olive oil appeared to have exactly the effect, it seems that it is not the extra plant chemicals in extra virgin that are having the beneficial effect – instead it seems to be something about the oil itself – either the balance of monounsaturates, polyunsaturates and saturates, or perhaps its omega 3 and omega 6 oil content. 

     
    link to actual olive oil study   

    fake it till you make it

  • EdwardEdward
    edited January 2017

    @rmathes said:
    I'm reading through all the transcripts from Mark Hyman's "Fat Summit". I get to Dr Willett's and what I'm reading there is basically the opposite of what so many others are teaching, like Asprey and Kresser and Sisson.  For those who don't know, Willett is one of academia's leading experts on nutrition, is the chair of the nutrition department at Harvard and probably has access to more academic studies on nutrition than anyone else alive. He's saying that the data is clear, that from a health (especially cardiac) perspective, polyunsaturated fats are much healthier than saturated fats, and that saturated fats have the same basic health impact as carbohydrates.  He also says that we need both omega 6 and 3 fatty acids and as long as we have sufficient levels of both, the ratio of them is basically meaningless.

     

    Is anyone here familiar with his work enough to be able to credibly comment on his conclusions?  Soybean and canola oils are healthier than grassfed butter and coconut oil? High levels of omega 6s to 3s is just fine?

     

    I started reading those transcripts expecting to see more data in support of the new wave of thinking on saturated fat, and with Willett's, got anything but.

    Walter Willett is probably the most credible source on diet and lifestyle alive today. Since the 1980s, he's been taking on vested interests, from the US Department of Agriculture (and its guidelines) to the industries that try desperately hard to influence these guidelines, including the sugar industry and the meat and dairy industries. Both randomized control trials and prospective cohort studies support his conclusions that saturated fats should be replaced with unsaturated fats found in olive oil, canola oil, nuts and seeds.

    A 2015 systematic review and meta-analysis of randomized control trials by Cochrane found that replacing saturated fat with unsaturated fats reduces one’s risk of cardiovascular disease, concluding that permanent dietary reduction of saturated fat and partial replacement by unsaturated fat is beneficial: http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD011737/abstract

    A 2014 systematic review of randomized control trials and prospective cohort studies found convincing evidence that replacing saturated fats with polyunsaturated fats reduces risk of cardiovascular disease: https://www.ncbi.nlm.nih.gov/pubmed/25045347

    A 2010 systematic review and meta-analysis of randomized control trials found that replacing saturated fats with polyunsaturated fats reduces risk of heart disease. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2843598/

    A 2009 systematic review of prospective cohort studies, co-authored by Willett, found that replacing saturated fats with polyunsaturated fats reduces risk of heart disease: https://www.ncbi.nlm.nih.gov/pubmed/19211817

    To add to all of that, we've had more recent data which haven't yet been included in systematic reviews and meta-analyses.

    A study using data from a large randomized control trial, published just in 2015, found that replacing saturated fats with monounsaturated and polyunsaturated fats is beneficial for health. https://www.ncbi.nlm.nih.gov/pubmed/26561617

    A study pooling data from two prospective cohort studies, also published in 2015 by Willett and colleagues, found that replacing saturated fats with monounsaturated and polyunsaturated fats reduces the risk of cardiovascular disease. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4593072/

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