Updated: Apr 7, 2022
It's a puzzle. Despite extensive research on the dangers of excessive levels of linoleic acid in our diet and the resulting increase in heart disease risk, metabolic disease, hypertension, type-2 diabetes, macular degeneration, joint pain, and skin conditions such as eczema, we still do not have widely publicized advice to carefully control this intake. Linoleic acid is an Omega-6 polyunsaturated oil, sometimes referred to as industrial seed oil, or vegetable oil. Sometimes they are even marketed as "heart-healthy" fats and oils. @*#@*@!
From a chemical perspective, these polyunsaturated fats have molecules with multiple double bonds making them easily broken down and oxidized, creating novel polymers that are hugely unhealthy and a major source of inflammation within your body. The drivers of oxidation (becoming rancid) are higher temperatures, longer time, and light. Conversely saturated fats are very stable and therefore do not readily oxidize to form dangerous chemicals.
Back in the 1950’s through the 1980’s there has been a fear of saturated fat, which has now been shown to be unjustified. However, this fear, which was based on very poor research, encouraged people to move away from healthy animal fats to the “new” industrial seed oils. While this was happening, a very wealthy individual named Phil Sokolof in USA, convinced of health risks associated with fats and particularly coconut oils, created a media campaign to turn people away from this tropical oil towards industrial seed oils instead. A third factor in this diet change was the desire by the USDA (US dept. of agriculture) to support farm incomes during WWII and subsidies were provided for growing wheat and corn, lowering the costs of these ingredients.
Look in the supermarket, at the huge range of Omega-6 industrial seed oils on sale. They are usually labeled as vegetable oils, but you should easily spot the marketing trick. They are not made from vegetables at all. They include soybean oil, cotton seed oil, safflower oil, corn oil (a grain), peanut oil, sunflower seed oil, sesame oil, canola oil, etc. They are often packaged in dark bottles to minimize degradation by light and have added antioxidants to help prevent them going rancid (oxidizing) almost immediately.
The process of extracting them from seeds uses petroleum-based chemicals and high heat which makes it almost impossible for them to remain unoxidized before they reach the supermarket shelf. People buying them often keep them in their pantry for many weeks during which time they gradually become more and more rancid, so that when eaten, you could be putting dangerous compounds directly into your body.
Many highly processed foods contain these polyunsaturated oils because they are a cheap way to add fats to the food. Look in the ingredients list of processed foods for vegetable oil, soy oil, corn oil, hydrogenated or partially hydrogenated fats, etc.
The Sydney Diet Health Study (1966-1973) of 458 men, was an attempt to compare the consumption of saturated fats with polyunsaturated fats and to measure the impact on cardiovascular risk. The polyunsaturated fat group lowered the cholesterol level nicely, compared to the saturated fat group, but despite the lowered cholesterol, the rate of cardiovascular disease (CVD) and coronary heart disease (CHD) mortality of the polyunsaturated group significantly exceeded the saturated fat group. Here is their recently stated outcome:
“Advice to substitute polyunsaturated fats for saturated fats is a key component of worldwide dietary guidelines for coronary heart disease risk reduction. However, clinical benefits of the most abundant polyunsaturated fatty acid, omega 6 linoleic acid, have not been established. In this cohort, substituting dietary linoleic acid (omega-6 vegetable oils) in place of saturated fats increased the rates of death from all causes, coronary heart disease, and cardiovascular disease. An updated meta-analysis of linoleic acid intervention trials showed no evidence of cardiovascular benefit. These findings could have important implications for worldwide dietary advice to substitute omega 6 linoleic acid, or polyunsaturated fats in general, for saturated fats.”
A number of researchers including Bill Lands, a renowned veteran lipid researcher have focused on the Omega-6 consumption, particularly in USA. It has been known for some time that Omega-6 oils (linoleic acid) have a pro-inflammatory effect in the human body while Omega-3 oils have an anti-inflammatory effect. If these are kept in reasonable 1:1 balance, your natural antioxidant glutathione can mop up the free radicals created by the inflammation from the oxidizing of these oils. However, if these 2 oil groups get seriously out of balance, then the level of inflammation can drive very poor health outcomes. The modern diets of some younger people in USA can have levels of Omega-6 up to 40 x the Omega-3 level. This is a recipe for major health problems in their future. In the last 145 years the typical dietary consumption of “vegetable” oils in USA, has gone from near zero to 80 grams per day per person. This growth rate closely matches the growth of metabolic syndrome, macular degeneration, and diseases such as diabetes and heart disease.
While Omega-6 is an “essential” fat, the essential level required is extremely low at no more than 1% of your calorie intake, while typical western diet levels can now be as high as 6%. A high level of Omega-6, or a high ratio of Omega-6 to Omega-3 is a clear indicator that the diet is heavy on seed oils which are already oxidized (rancid) before consumption as a result of the manufacturing process. It is the oxidation that is unhealthy about the seed oil consumption and drives up inflammation.
What does the linoleic acid (Omega-6) do in the body? It displaces the saturated fats that human bodies have used over thousands of years. I read that it can take up to 2 years to get the linoleic acid out of tissues and replace it with the healthier traditional fats. Here are some of the health impacts:
- Excess linoleic acid increases inflammation, which is a key driver for heart attack risk, hypertension, cancer, metabolic syndrome, macular degeneration, and many other health problems.
- Skin cancers are on the rise and the levels of polyunsaturated fat under the skin have been rising at about the same rate as the rise in skin cancers. This does not prove causality but people converting back to higher saturated fat diets frequently comment on the reduction in sun burn and the ability to stay out there longer without any problems. Our ancestors spent countless hours in the sun and survived to proliferate without cancers, despite having no sun creams, and they had very low levels of Omega-6 fats.
- There is strong evidence of a link between migraines and higher linoleic acid consumption.
- The cellular uptake of linoleic acid can result in greater production of substances, such as NHE, implicated in Alzheimer’s disease, Parkinson’s disease, Cancer, Atherosclerosis and Liver diseases.
Where does this high level of Omega-6 Linoleic Acid come from:
1. Industrial seed oils as mentioned, used at home, or used extensively for frying at restaurants or squirted onto hot plates, pans, and woks which the food is cooked in directly.
2. Packaged ultra-processed foods with vegetable oils, such as sauces, spreads, and creams.
3. Canned food with oils such as soybean oil with canned fish.
4. Shortening and margarines made from vegetable oils.
5. Grain fed animals such as Chicken and Pork. These mono gastric animals take up linoleic acid from the grain they eat, then you eat that meat. In USA, corn fed chicken is particularly high in linoleic acid.
6. Feedlot finished beef, the corn fed to these animals pushes up the linoleic acid in meat and the longer the animal stays in the feedlot, the worse the ratio of omega-6 to omega-3.
7. Farmed fish are often fed meal, made from grains such as soy and corn, driving up their omega-6 level.
In a report titled “Historical perspectives on the impact of n-3 and n-6 nutrients on health” by Bill Lands, a Standard American Diet was compared with a Mediterranean Diet. Using a USDA derived omega 3:6 balance list of 538 “Key Foods” consumed by Americans during 2007–2008. They identified the top 10 foods with the worst impact in the Omega 3:6 Balance. The simple step of deleting these ten food items with the most negative Scores converted the diet to "almost" the healthy level of a Mediterranean diet.
The removed items in order from worst to best, were:
1. soybean oil,
3. tub margarine,
4. microwave pop- corn,
5. ‘‘Italian’’ salad dressing,
6. potato chips,
7. stick margarine,
8. vegetable shortening,
9. peanut butter,
10. tortilla chip snacks.
Deleting these foods not traditionally present in Mediterranean meals changed the American ‘‘Key Foods’’ list to one that fits closer to a ‘‘Mediterranean diet’’. Conversely, adding these items to a Mediterranean diet would ‘‘Westernize’’ it in a way that has been happening gradually in Mediterranean regions. Maybe you need to look at how you can avoid these foods.
It is not only humans that become less healthy with excess linoleic acid in the diet. Animal feed researchers learned that when corn oil or soybean oil was used as a butterfat replacer in veal calf rations, the animals generally got sick and died. They eventually recognized the need to include an antioxidant (vitamin E) in veal calf rations containing oils rich in linoleic acid.
I read that manufacturers of these Omega-6 oils are apparently aware of these problems and are quietly trying to breed crops which produce a higher level of oleic acid oils (as found in olive oils) and a lower level of Omega-6 from which to manufacture their seed oils in the future.
What ways can you reduce the high-risk outcomes of consuming high levels of linoleic acid now?
1. Switch from using the above-mentioned seed oils to using olive oils, coconut oil, tallow, lard, avocado oil, butter, or ghee. Any fat that is solid at room temperature is much better.
2. Avoid food in restaurants which is fried as it will almost certainly be fried in vegetable oils.
3. For baking use coconut oil, butter, and Ghee.
4. Take care not to burn oils and fats by keeping temperatures below the smoke point, as this increases the oxidation risk.
5. Dispose if any old polyunsaturated oils as they will be somewhat rancid already.
6. Keep nuts in sealed containers in the refrigerator as they can also contain these oils and will go rancid readily. Buy small quantities so that you do not store them at home for long.
7. If you can, choose to grind nuts at home as once ground, the oxidation process is accelerated.
8. Eat foods with high omega-3 levels such as cold-water fish, like Salmon and Sardines.
In August 2020, the USA college of Cardiologists released a paper in which the following conclusion was stated:
“Whole-fat dairy, unprocessed meat, and dark chocolate are Saturated Fat-rich foods with a complex matrix that are not associated with increased risk of heart disease. The totality of available evidence does not support further limiting the intake of such foods”
A clever move would be to reduce your health risk, by minimizing consumption of Omega-6 seed oils and instead, return to the traditional animal fats that have been the staple dietary fats of our ancestors for thousands of years.
For more information on taking back your health and using food as medicine, look at my blog at: www.takebackyrhealth.com, where there is also a link to my book.
Book Link: https://amzn.to/3uiehfv
Good Health, George Elder