are seed oils harming your health?

are seed oils harming your health?

Since the 1980s, seed oils (also known as vegetable oils) have often been touted as “heart healthy fats” that help lower “bad” low-density lipoprotein (LDL) cholesterol levels and decrease the risk of heart disease. Seed oils are extracted from the seeds of various plants, including soybean, canola, rice bran, safflower, cotton, corn, sunflower, and grape. The seed oils from these eight plants in particular are extremely high in polyunsaturated fatty acids (PUFAs) and can cause distress to the human body when consumed regularly.


Seed oils originally entered the marketplace in the 1870s. They were largely used in paints and plastics or to lubricate machinery. The emergence of petroleum, however, quickly left the seed oil industry without a substantial market in which to sell their products.

Fortunately, soap and candle manufacturer Procter & Gamble were seeking cheaper alternative materials for their soap around the turn of the century. At the time, all soap was comprised of animal fats—which were more expensive and timelier to produce. When petroleum replaced seed oils as America’s main fuel source, cottonseed oil was deemed as “toxic waste.” P&G utilized this unwanted seed oil to craft cheaper soaps and, eventually, cooking oil as well. They labeled this oil “Crisco” after chemically altering it to resemble lard.

P&G put more money into advertising their product than any company in history. They ran eight marketing strategies staffed by professional artists and writers. Their marketing strategies quickly made Crisco a staple in the American diet and soon paved the way for various other vegetable oils.

Image Source: Jeff Nobs, “What’s Driving Chronic Disease?”

health consequences

increased lipid peroxidation

Consuming excess PUFAs on a daily basis leads to the production of lipid peroxides, which are formed through the oxidation of PUFAs. Lipid peroxides harm cells by deactivating enzymes, breaking down proteins, and disrupting phospholipid structures (the cell’s protective walls). Over time, higher levels of lipid peroxidation can cause oxidative damage to various tissues in our body.

Growing research, much of which is suppressed, suggests that lipid peroxides may be linked to health issues like inflammation, cancer, neurodegenerative diseases, and eye and kidney problems.

In the words of Dr. Ray Peat,

“Most of the products of lipid peroxidation are toxic, as a result of their reactions with proteins, DNA, and the mitochondria. The age-related glycation products that are usually blamed on sugar, are largely the result of peroxidation of the polyunsaturated fatty acids.”

lipofuscin accumulation

Lipofuscin (sometimes called “liver spots”) is a type of cellular waste that results from the oxidative stress free radicals cause when they act on lipid peroxides. As lipid peroxidation increases, so does the formation of lipofuscin. This brown pigment appears as spots on the skin but also largely occurs inside the body and is not always visible externally. The spots indicate liver problems and the buildup of lipofuscin, which is involved in age-related neurodegeneration and is a significant risk factor for macular degeneration.

liver damage 

The type of fat we consume directly impacts our liver. A common liver disease known as liver fibrosis occurs when the liver is inflamed for extended periods of time. This can cause scar tissue to form in the organ, disrupting its normal function.

PUFAs are prone to oxidation and have toxic byproducts, which can cause direct damage to our liver. According to this study, saturated fats and healthy cholesterol protect against liver fibrosis, while PUFAs promote it.

hormonal imbalance

Seed oils are incredibly estrogenic and can cause significant damage to our hormones.

PUFAs are seen hindering protective steroid pathways (like progesterone production) and opening a route toward increased cortisol, estrogen, and aldosterone production.

Unchecked levels of estrogen can cause considerable long-term damage, even leading to infertility in men and a number of health problems in woman—including breast cancer.

gut damage

PUFAs are unnatural to the human body. When we ingest large amounts, they can make our gut more permeable, releasing increased quantities of particles into the bloodstream.

This, in turn, increases inflammation and can lead to the development of a leaky gut. PUFA consumption is also found to increase the risk of inflammatory bowel disease (IBD) and Crohn’s disease.

what is the best cooking oil?

EVOO is one of the healthier options when selecting a cooking oil. Olive oil contains an abundance of antioxidants, including vitamin E, which can directly combat damage caused by prolonged seed oil consumption.

While there are several types of saturated fats suitable for cooking at high temperatures, olive oil stands out due to its abundance of polyphenols, which help combat free radicals, providing holistic benefits to the body.

It’s important to note that the quality of your EVOO matters! EVOO is often adulterated with seed oils, so it’s crucial to choose a brand whose practices you know and trust.


There are numerous additional health risks beyond what is discussed here that are associated with the overconsumption of PUFAs—DNA damage, metabolic interference, immune suppression, brain damage, diabetes, heart disease, and skin cancer, each of which warrants an individual article in its own right.

This article, however, is not meant to evoke fear but rather to inform you so you can make the best decisions when it comes to your food and your health. It’s impossible to avoid certain foods entirely, and it’s far more important to maintain social connections than to obsess over perfection.

Improving your health is an ongoing process, and even small daily adjustments can make a difference. So, if you consume less-than-ideal food at times, don’t dwell on it—just move forward. That is truly the healthiest thing for your mind, body, and soul.
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