4 Common Myths in Nutrition : Fat, Salt, Cholesterol & Oils


This week, I had two conversations that led to this blog article. One was with a friend and co-worker who listens to me talk a lot and asked me why omega-3 fatty acids are important.  The other was having a conversation about why most seed oils are bad for your health. So, let's dig into what's based in science and research, and what is based on medical consensus by physicians.  

Myth #1: Saturated fat makes you fat and is bad

Saturated fats are found in animal products and tropical oils. Historically, these fats have been thought to increase disease risk. However, the fat composition of animals, such as cows, depends upon what the animals were fed. 

For example, cows that are grass-fed and grass-finished have an omega-6 to omega-3 fatty acid profile of 2:1, whereas conventional, grain-fed beef has a ratio of 5:1. Additionally, grass-fed beef is high conjugated linoleic acid, a type of fat which is known to have many health benefits. More recent study results show that ultra-processed, carbohydrate-rich, and sugary foods pose more risks.

You can learn more about myths vs. truths of saturated fats our podcast here. Additionally, this 2019 paper and this 2020 paper debunk the science behind the nutritional guidelines of minimizing saturated fat in your diet.

Myth #2: Salt causes hypertension

Another myth is that salt causes hypertension. The lastest studies highlight that low salt, not high salt, leads to early mortality, which I discuss in this blog.

Myth #3: Cholesterol causes your arteries to clog

And we all know that diets high in cholesterol clog your arteries, right?  This too is a myth that I talk about in this podcast with John Gildea and Martin Katz, and we discuss how dietary cholesterol does very little to influence your cholesterol numbers.

Myth #4: Seed oils are vegan and therefore good

Lastly, there tends to be this belief that vegans are healthier than people who eat meat. But this really depends upon what the vegans are eating and what the carnivores/omnivores are eating. I’ve discussed above why conventional meats are unhealthy. But what about the vegan diet?

While there is much to say, I highlight the omega profiles of nut-based oils, which can often be a central part of the vegan diet. It boils down to remembering that a diet high in omega-6 fatty acids is super pro-inflammatory, which is bad.

Soybean Oil:  7:1 (7 omega-6’s to 1 omega-3)) & is GMO (genetically modified, so it is sprayed with Roundup).

Corn Oil: 49:1 & is GMO

Sunflower Oil: Virtually all omega-6

Safflower Oil: Virtually all omega-6

Canola Oil: 2:1 & is GMO

Cottonseed Oil: 50:1 & is GMO

Grapeseed Oil: Virtually all omega-6

Hemp seed oil: 3:1

Walnut oil: 4:1

Flaxseed Oil: 1:4 which is the rare exception of a seed oil being higher in omega-3 than omega-6 fatty acids. Flaxseed oil goes rancid quickly and should be kept cold. The only brand I trust is Barleans. I blend two tablespoons of flaxseed oil with a half cup of low-fat cottage cheese, which makes the omega-3's more bioavailable.  

Coconut Oil: 80-90% saturated fat. Virtually no omega-3 or omega-6 fatty acids.

Avacado Oil: 70% monounsaturated fat.  15% polyunsaturated fat (mainly omega-6 fatty acids).  15% saturated fat.  The monounsaturated fat is thought to reduce bad cholesterol and reduce risks of heart disease and stroke.  It comes in unrefined, which can be used cold and refined, which has a smoke point of 500 degrees F.  

Olive Oil75% monounsaturated fat.  10% polyunsaturated fat (mainly omega-6 fatty acids).  15% saturated fat.  Given the potential to create free radicals, I would not suggest cooking with olive oil.

Besides being high in omega-6 fatty acids, most seed oils can also be unhealthy due to the following factors:

  1. Refinement and Processing: Highly refined seed oils can lose many of their natural nutrients during the manufacturing process. The refining process, which often is in the form of high heat, can also introduce trans fats and other unhealthy compounds. 
  2. Oxidation: Some seed oils are prone to oxidation, which can create harmful free radicals. These free radicals can damage cells and contribute to aging and diseases like cancer.  
  3. Potential Contaminants: The way some seed oils are processed might introduce or concentrate contaminants like pesticides or heavy metals.

What to do?

  1. Eat fish and supplement with fish oils. I started eating these sardines about once per week after seeing Joe Mercola eat them on his visit to our lab back in 2016. I also take three tablespoons of Carlson Cod Liver Oil and two caps of Viva Naturals omega-3 fish oil. The fish oil capsules are higher in EPA and DHA than the cod liver oil.
  2. Read labels. Especially non-organic processed foods, which are loaded with nut oils. If you see them on the label, put it back on the shelf!
  3. Avoid processed foods, because of #2 above. Weston A Price called processed foods “devitalized foods of commerce.” They are devitalized, because they have long shelf lives and don’t rot or get moldy. By contrast, whole foods, which have more nutrients, do tend to get moldy and rot. So, instead of crackers, grab a stalk of celery. Instead of a pastry, grab a fruit.  
  4. Cook with saturated fat. I use coconut oil.  Ghee is also a saturated fat that you can cook with.

If you want to learn more about the importance of omega-6 to omega-3 fatty acid ratios, this blog discusses a study looking at people with a low omega-3 fatty acid profile that have the same mortality rate as smokers.


3 Comment

What about avocado oil? We switched to olive oil. Avocado, or coconut oil or even butter.

Dave, This was really helpful. Thanks so much! There is only one chain restaurant we have found that does not use seed oils- True Food. We are headed to Texas and I have called around to different clean/organic/local restaurants and asked what oils they use- and all that I talked to use seed oils. True Food only uses avocado, oil and coconut.

So would flaxseed oil at 1:4 be somewhat good to consume, or does the high processing of it still make it not recommended for overall health?

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