I write and talk a lot about the macronutrients, carbohydrate, protein and fat. After all, they do embody the foods we eat every day, and should be the ultimate “wheel house” for all nutritionists.
I keep coming across more functional and integrative physicians speaking out about the risks of seed oils in foods, believing they are strongly connected to the obesity epidemic and other chronic diseases. However, I don’t see the same response from the dietetic community. It seems only the minority are speaking out.
There is mounting evidence to support the connection of seeds oil consumption with oxidative stress and ill health. Certainly enough evidence to give you pause-actually, I paused a long time ago. I’m at the don’t include in the diet stage.
Unfortunately, even the term, “seed oils” can be confusing. Just remember, in order to get oils out of seeds, you must crush them, along with a few other steps…more on that in a moment. Even before the industrial processing these oils are not fit for consumption. The processing brings them to the just barely edible stage, at least from a taste perspective, certainly not from a health perspective. Since seed oils are so ubiquitous in our food supply, it seems that we should be paying more attention.
For the past two decades, sugar has been the food ingredient demon. Now, seed oils are on the radar. So, we have two major constituents of processed food, sugar and seed oil fats at the forefront, being critiqued for their contribution to rising chronic disease, inflammation and obesity. The mechanisms of how sugar and processed seed oils can damage health may be independent of each other or have overlapping pathways. And, of course, there are multiple other factors at play with obesity and chronic disease. Some historical context is important here.
Sugar has been around for thousands of years, at least the natural forms such as honey, maple syrup, and coconut sugar. But, Americans have been consuming excessive amounts of sugar and refined carbohydrates such as pasta, rice, breads, cookies, pastries, etc since the 1970’s and onward.
Many physicians and institutions have been quite vocal about sugar, including Eric Westman, MD, the Duke diabetes specialist, Robert Lustig, MD, the pediatric, obesity endocrinologist. Also, the Heart Association has strict guidelines about added sugar, limiting 100 calories (6 tsp) for women/day and 150 calories (9 tsp) for men/day.
Sugar consumption has decreased since 2000, (though still higher than the 1970s and earlier), yet, obesity rates and chronic disease keep escalating, seemingly undeterred by sugar reductions. Yes, U.S. sugar intake is still too high, but our obesity numbers over 50 years ago were not as high as they are today.
Enter the argument for seed oils. Unfortunately the nutrition community seems to be singularly focused on linoleic acid, the essential omega 6 fatty acid, that is present in seed oils, and not the multitude of other issues that accompany this PUFA. Cognitive dissonance, maybe. Seed oils have not always been in the food supply, like sugar, which in and of itself should cause us to pause. It’s a relatively new ingredient. Processed seed oils first entered the food mass market in the early 1900’s in the form of Crisco. Now the food supply contains vast quantities of seed oils from corn, safflower, soy, sunflower, and canola.
There is great debate over whether or not nature intended for humans to consume certain vegetables at all. Some believe the bitter flavor of vegetable seeds are a warning not to eat, unlike the seeds of certain sweet fruits. My understanding is that in terms of botany biology a fruit by definition are the parts of a plant that bear seeds and whose job is to continue the plant species by scattering those seeds for more reproduction. The rest of the plant -leaves, stems, and roots are vegetables. Regarding human biology, we have both, bitter and sweet taste buds. Some believe the bitter taste buds are only there to protect us. But, wait, so the sweet taste buds are only there to enjoy the flavor? I have a little trouble with the bitter and sweet argument. It doesn’t completely make sense, since some bitter foods such as dark chocolate and Brussel sprouts both are thought to have medicinal value. And if the presence of human bitter taste buds were only for protection, then why do some bitter foods taste good to some people. Added to this, others believe that the polyunsaturated fats and fiber in vegetable seeds are healthy, by virtue of omega 6’s being an essential fat, and therefore should be plentifully consumed by humans.
I believe truth lives on both sides. Nutrient and phytonutrient content of fruits and vegetables is part of a nutritionist’s criteria for determining their health value. And, yes, too bitter, may be a warning of toxicity. Most likely though, you would spit this food out. But, how about too sweet—some may say there is no such thing.
Regardless of this bittersweet debate, ha, ha, it is the processing of vegetable oils that gets us into trouble, and most who are examining this topic agree on this point. The industrial crushing of vegetable seeds is what make oils available for human consumption. This processing involves heavy machinery and many and varied chemicals to deodorize and sanitize the leftovers. Seed oils because of their PUFA are inherently unstable, especially with heat and makes them more likely to form trans fats and more volatile compounds, some that are carcinogenic. So, seed oils in processed foods are already oxidized fats—even before your might oxidize them a bit more with cooking, all contributing to significant oxidative stress in the body once you consume them— an inflammatory lightning rod when entering the body (to say nothing of the plastic bottles that they are stored and sold in).
When we think of what happens to dietary fat once it enters the body, it’s not just to please our taste buds. Dietary fat has so many roles, including providing the substrate to make hormones, as well as the main ingredient for cell wall membranes. The constitution of the cell wall membrane, meaning its stability, pliability and resiliency will determine how well it communicates with other cells. The right kind of fats help create cell walls that can do this. What happens when cell wall membranes can’t function? Well, they don’t communicate with other cells and they become limited in how they respond to environmental signaling. This has major downstream implications over the entire body.
What are the right kind of fats? Probably not industrialized seed oils. More likely, more stable fats such as unrefined coconut oils, grass-fed butter, ghee and high quality olive oil. These are fats that have been in the food supply for thousands of years. They are more stable under heat, and don’t require the major industrial manipulation with chemicals to achieve a healthy product.
How does the food industry get away with this you ask? Because amazingly, many are so bold to claim that their products are “heart healthy”, including canola and corn oil. My guess, mutual institutional “high fiving” enables this to occur. Good rule of thumb, always follow the money.
Not to be ignored, omega 6’s and 3’s are essential fatty acids that we must consume because we can’t make them. For the average American, the ratio of 6’s to 3’s is >20:1, too high. The ratio should be closer to < 5-1. It is highly likely that embedded in this disrupted ratio, the plentiful omega 6’s are masking benefit from the omega 3’s, as well as contributing their own risks. There is no actual RDA for these two essential fats, but for Omega 6s, some recommendations are about 1.2 mg for women/day and 1.7 mg for men/day, and for Omega 3’s, a minimum of 250 mg up to a maximum of 4-5000 mg/day. N=1 here.
Our need for omega 6’s is easily met by a varied diet of meats, eggs, fruits, veggies and a few nuts (without added oil). We don’t need omega 6’s in every food. Also, the amounts of processed seed oils in foods far outweigh the amounts of other exogenous toxins that we are exposed to.
So, back to the bird’s eye view. Some are back pedaling that the original metabolic sin is not sugar but rather seed oils, theorizing that it contributes to leptin resistance and insulin resistance, both of these lead to visceral fat accumulation and metabolic dysfunction. What is left out of this bird’s eye view is the role of the gut microbiome and genomic risks in triggering inflammatory pathways to spur on the metabolic dysfunction. We’re turning a corner in recognizing the role of the gut microbiome with insulin resistance, elevated LDL cholesterol and lipopolysaccharide (LPS) in the blood and CVD. Once a dysbiosis triggers elevated levels of LPS (endotoxin), then those inflammatory pathways can begin— triggering of toll like receptors in the liver, endothelium, adipose tissue, just one part of this complex dance.
The question some are raising- Do processed seed oils set the stage for a disrupted metabolism making it easier for excessive sugar to further inflammation, thereby requiring people to eat even lower carbohydrate than usual? Perhaps. I think excessive sugar can contribute to dysbiosis regardless, but maybe it would take more carb to cause this damage, if seed oil damage were not present. Insulin still has to respond to excessive carbohydrates, regardless of seed oils. Many questions here. But, I do believe that the two together, seed oils and excessive sugar and carbs ARE a perfect storm for ill health.
The other issue is that PUFAs are stored and utilized differently in the body than saturated fat. Although both PUFAs and saturated fat can be burned for fuel, sport nutrition researchers are well aware that muscles quite effectively burn saturated fat, especially in athletes. Not the message the Heart Association wants you to hear. Whereas, studies show that it can take up to two years to get rid of seed oils that are concentrated in your tissues.
Regarding low carb, I go back to my book, The Seductive Land of Carbs (2015). Everyone has a carbohydrate tolerance and your gut microbes give some indication of what that tolerance may be. Our focus should not necessarily be “low carb” for everyone, but lowER carb depending on how much a person consumes. Some people may just need to cut back by 25-50 grams a day, while making other changes.
And not to forget, regardless of some wanting to dismiss the role of sugar, and put it all on seed oils, the primary role of carbohydrate is to provide fuel for muscles and the brain. Largely, your requirement depends on your activity level. So if you are leading a sedentary life, chances are at some point, you may not be able to eat a “normal” amount of carbs or the amount you used to consume to maintain a healthy weight and metabolism. Again, N=1 here.
The ratio of macronutrients is so important for everyone. First and foremost, figure out protein needs based on ideal body weight, then hash out the carbs and fat, based on activity and the quality of foods consumed. Aim to leave out the seed oils. You won’t starve, there are plenty of options and more and more food products are coming out that taste good and don’t use seed oils. It is a lifestyle change. As with anything, the dose makes the poison but because of genetics and other factors, some people may be more at risk.
Back to the original point, we have two major constituents of processed food, sugar and seed oil fats at the forefront being critiqued for their contribution to rising chronic disease, inflammation and obesity. Each of these are ripe for discussion and education. My job as a RD and RN is to objectively research the risks and benefits so the public can make informed choices. Every dietitian on the planet should be discussing this with their patients.
Where Do You Begin: Three Key Diet Tips for the Long Haul The macronutrients). https://www.ifn.health/online-courses