Fats and Oils
Fats and Oils
Oil and fat is a super controversial dietary topic. Are they bad or are they good? We attempt to simplify and demystify what's best for you and your dog.
The history of dietary fats is dramatic, and expert opinions have swung from one extreme to another over the decades. It’s no wonder that there is so much confusion and controversy on the topic. In this newsletter we summarize our review of the literature and share which oils we use in our daily lives.
Disclaimer: We are not health care providers. This newsletter is for informational purposes only. Please consult a professional for healthcare advice for you and your pet.
Before we get into it here are our new recipes this week:
Plus, a balanced one you may have missed:
TLDR: Official recommendations of dietary fats have flip-flopped over many decades so they need to be treated with caution. Saturated fats are likely less harmful than previously thought, while dietary cholesterol (like from eggs) has minimal effect on blood cholesterol in healthy people. For dogs, neither cholesterol nor saturated fat is of concern because dogs rarely die from arteriosclerosis.
For polyunsaturated fats, research indicates that both dogs and humans benefit from lower ratios of omega-6 to omega-3 fatty acids. The easiest way to do this is to consume less seed oils and increase fish consumption. We use lots of olive oil, which is high in monounsaturated fatty acid, and some saturated fats like coconut oil or clarified butter for high temperature cooking. We also supplement with high-quality fish oil.
The dirty history of margarine and hydrogenated oils
William Proctor and James Gamble were brothers-in-law who worked together to create one of the largest candle and soap manufacturers in the world. As prices for lard and tallow were controlled by the meat packing monopoly, the duo sought a new way make their products and took steps to control the cottonseed oil market. By 1905, they owned eight cottonseed mills in Mississippi.
Within a few years, they developed an industrial process to turn liquid oils into solid fats, called hydrogenation. The end product resembled lard. Mindful that electrification would likely destroy the candle business, they wanted to sell their products as food. Only problem was that cottonseed oil was toxic, so they developed another process to remove this toxin, called gossypol, and voila…FOOD! Kind of…
Proctor & Gamble marketed this product aggressively. They claimed that it was healthier than lard and butter because it came from plants. This appeared to make sense, but it wasn’t true. To be fair, P&G didn’t know this at first, but when reports of increased heart disease, infertility and growth problems began, things changed. A barrage of academic papers and well funded “research institutions” began to publish studies that claimed trans fats were a healthier alternative to animal fats. As recently as 1986, the Center for Science in the Public Interest (CSPI) praised fast-food chains like Burger King and KFC for switching from tallow to trans fats for frying.
It wasn’t until the 1990s that it was widely accepted that trans fats were FAR MORE atherogenic (causing heart disease in people) than animal fats. And it wasn’t until 2018 that trans fats were banned. It took more than 20 years to ban something after scientists agreed it was bad, and more than 50 years from when people started noticing problems.
Why does everyone hate seed oils now?
If you’re on social media these days you probably hear a lot about seed oils and how they are bad. It’s tempting to make complex issues black and white, but the reality is that it’s complicated. Seed oils are high in polyunsaturated oils or PUFAs as they are often called. Polyunsaturated means that there are several double bonds along the chain of carbons that only connect to one hydrogen. See the image below.
Each carbon atom only has 4 places to bond with other atoms, kind of like arms. Saturated fats have hydrogens connected to every free arm of each carbon (except the last) and are more stable because of it. There is simply less space for the oxygen molecules to fit in. Polyunsaturated fats have several places where carbons hold each other with two arms…leaving one arm to fool around with other atoms, which it often does. This is similar to how iron will rust, but stainless steel does not.
Just like iron rusts and becomes junk, so too do polyunsaturated fatty acids. When they spoil, they turn into all sorts of nasty byproducts like aldehydes, hydroperoxides and epoxides that are exactly as scary as they sound. These byproducts can damage components of cells like DNA, proteins and organelles. They are also associated with chronic disease.
Which oils are high in PUFAs?
Safflower oil: up to 80% PUFA, mostly omega-6
Grapeseed oil: up to 75% PUFA, mostly omega-6
Sunflower Oil: 70% PUFA, mostly omega-6. In our recipes we opt for sunflower seeds, because the oils stay locked in the seed until they are cooked. The amount is lower and freshness greater.
Corn oil: 60% PUFA, mostly omega-6
Canola oil: 30% PUFA, has more balanced profile, but contains a toxin, erucic acid, that has been selectively bred to safe levels.
Which are the “good” and the “bad” oils?
The idea of good and bad is overly simplistic for most things, including oil. As we’ve discussed previously even water can be toxic. The issue is that the modern western diet is too high in omega-6 because it’s in many foods including chicken and beef. Industrial seed oils are very cheap making them an easy additive to processed foods.
Though PUFAs are reactive and can spoil, they are still essential for humans and dogs.
As we’ve discussed in previous newsletters, omega-3s are also PUFAs and are the most abundant fats in the brain. They form essential parts of cell membranes, and serve important functions as part of the inflammation signaling process.
Similarly, omega-6 are also essential but they are everywhere in our foods, so people eat too much of them. This is a problem because the ratio between omega-6 and omega-3 appears to affect health, similar to how the ratio of macronutrients affects health. Too much of one, or not enough of the other, produces subtle metabolic effects that cascade to cause health issues.
Imagine you’re building a house and you need a certain ratio of bricks to cement. If don’t have the right ratio, and you can’t wait to build the house, you’re going to cut corners. These substitutions affect the stability of the house. For example too many bricks and not enough cement makes for a very weak structure, while too much cement and no bricks means that you can only build a very small house.
What’s the right ratio?
The research on ideal human ratios is still emerging, so it’s even more unclear for dogs. But there is good evidence that a lower omega-6 to omega-3 ratio is better. One highly cited literature review puts the ancestral ratio of omega-6 to omega-3 for people at 1:1. Modern western diets are greater than 15:1 on average and researchers propose that this promotes cancer, heart disease and autoimmune diseases while a higher intake of omega-3 has suppressive effects.
In two separate studies on omega-6 to omega-3 ratio in dogs, results suggest that lower is also better. One study first fed a diet with the ratio of 25:1 then switched half of the subjects to a diet with a 5:1 omega-6 to omega-3 ratio. The researchers conclude that a lower ratio had a positive effect on immune response. Another study examined the response to a similar change in diet on atopic dogs (those prone to eczema and allergies) and found that nearly half were able to resolve their symptoms. Of those dogs that were unable to resolve their symptoms, the fatty acid profile was different than those dogs who responded, suggesting the difference is due to fatty acid metabolism.
Additionally, studies feeding exclusively sunflower oil (which is very high in omega-6) caused the pancreas to work harder compared to exclusively feeding olive oil. (Please note: feeding exclusively sunflower oil is VERY different than feeding a bit of sunflower seeds for vitamin E. Confusing, we know!) Though this does not mean that PUFAs cause pancreatitis, high levels of PUFA appear to strain the organ which could lead to increased incident of pancreatitis.
Is saturated fat bad? What about dietary cholesterol?
Just like the official recommendation on trans fats changed dramatically, so too did recommendations on dietary cholesterol for people. Many organizations still vilify eggs because of their high cholesterol content. However, the most up-to-date scientific stance is that dietary cholesterol has little impact on the cholesterol of healthy people. Harvard University recently more than doubled their guidelines on egg consumption from a few per week to one per day.
Similarly, saturated fat may raise LDL in people, but the impact to cardiovascular disease in healthy people is inconclusive. For most people at risk of heart disease, dietary changes alone are insufficient to adequately lower ApoB, the most artherogenic particles. The confusion likely stems from Ancel Keys, the originator of the lipid hypothesis and author of the Seven Countries Study. He showed evidence from seven countries that consumption of saturated fats and high cholesterol led to heart disease. But importantly he left out countries and cultures who had contradictory situations.
This “lipid hypothesis” was also supported by research funded by the Sugar Research Foundation. In the 1960s this group paid Harvard Scientist Dr. Mark Hegsted to publish a paper in the New England Journal of Medicine downplaying the role of sugar in heart disease while shifting the blame to dietary fats. According to the New York Times, Dr. Hegsted later became the head of nutrition at the USDA.
In the years since the Seven Countries Study was published, several studies have confounded this research, including Ancel Keys own research. The Minnesota Coronary Experiment was a landmark study because it was a huge double-blind study on dietary fats in people. Both the participants and the researchers were unaware of what type of intervention the test subjects received. Over 9,000 institutionalized patients in mental hospitals or nursing homes were given either a vegetable oil or a saturated fat. The outcomes showed that despite lowering cholesterol, vegetable oils did not result in a significant reduction in death from heart disease.
Despite the rigorous design of the study and wide anticipation of the results, the data was not published until 2016, after both Ancel Keys and his co-author passed on.
Our opinion is that saturated fat consumption is likely less problematic than purported in previous generations and is a perfectly fine in moderation, combined with healthier fats. For dogs, saturated fats are even less of an issue due to the fact that dogs rarely die from arteriosclerosis and their ancestral diet likely consisted of a high amount of animal fats.
Which oils do we use?
Our main cooking oils are light olive oil, butter, ghee, and tallow, and we eat a lot of raw extra virgin olive oil. Olive oil is high in the monounsaturated oil oleic acid which is linked with lower inflammation and heart health. Light olive oil has the same composition of extra virgin olive oil, but has the plant matter removed. This means it’s safer for low temperature cooking. For high temperature frying we prefer to use clarified butter, tallow or coconut oil because it is much more stable at high temperatures.
To lower our omega-6 to omega-3 ratio, we feed / eat lots of fish and supplement with high-quality fish oil for both ourselves and the pups. There is some concern that fish oils can go rancid, so we make sure to review the third-party tests and also always store it in the refrigerator.
That’s all for this week! Have a great long weekend.
All the best,
Joelle and The Precious Creatures Team