It has been known for a few years that PUFAs oxidise readily and this in turn can cause detrimental health consequences. There is an opinion now though which has been gathering momentum, that the addition of PUFA’s in our diet should be curtailed completely. [R]
But, even if we consciously decide not to eat any PUFAs at all, we simply cannot help it, as most of what we eat will contain some to a certain degree.
Fatty acids are in practically everything we consume. Even the humble potato has a particular lipid profile;
An experiment was conducted to determine the fatty acid content of nine varieties of potatoes during several months of storage. Highly significant differences were found among varieties, storage periods and fatty acids…Eight fatty acids were determined quantitatively by gas chromatography as follows: linoleic, 41.3%; palmitic, 24.9%; linolenic, 19.4%; oleic, 6.6%; stearic, 5.4%; myristic, 0.6%; and two unknowns of 1.4% and 0.4%. [R]
The Dangers of Misinformation
All fats are not created equal, but just how dangerous can ignorance be? In a paper entitled “Jumping on the Omega 3 bandwagon” the authors point out that marketing companies have seen to profit from the public’s ignorance with regard to Omega 3 fats.
A current gap of many food labelling legislations worldwide allow products containing only ALA and without n-3 LC-PUFA to be marketed as “omega-3 source” and this misleading information can negatively impact the ability of consumers to choose more healthy diets. [R]
Vegetable sourced fatty acids are predominately PUFAs with these fats being mostly medium chain length Fatty Acids. Compared to animal fats, where there is a much wider spectrum of the acid groups, a much healthier diet is achievable.
You need to eat long chain EPA and to some extent DHA, as these omega 3 fats are essential for multiple bodily functions. These are important for a healthy brain.
The synthesizing process that converts fatty acids to essential EPA and DHA is more involved as the chains get smaller. So, EPA which is 20 carbon atoms with five double bonds long and DHA (22 carbon atoms) are readily metabolised. These are easily obtained from fish (see chart below).
Equivalent omega 3 FAs from vegetable sources are predominately 18 carbon atoms in length.
Problems occur with the ingestion of high amounts of polyunsaturated fatty acids. The process of digesting PUFAs is limited by the availability of enzymes in our bodies to perform this function. We are not evolved to process high amounts of PUFA.
Any surplus PUFAs not utilised will float around the body and risk peroxidising, thus causing damage and eventually settle in soft tissue.
Peroxidised PUFAs are linked to cancer and many other diseases. [R]
Short Chain Fatty Acids
Short chain fatty acids are saturated and have a hydrogen atom attached to the carbon atom. The term saturated relates to the molecule being filled with hydrogen.
Unsaturated chains do not have the hydrogen attachment so are liquid at room temperature.
The bodies enzymatic system for processing fatty acids can easily convert short chain saturated fats into energy.[R]
Varied Fat Intake
Good quality saturated fat along with a small amount of Omega 9 oleic acid can be obtained from coconut oil.
If the person does not eat meat, fish, or consume dairy, their diet is going to be lacking in essential EPA and DHA.
Do not expect to gain essential omega3 from seed oils. A review of present research shows that contrary to popular belief, omega3 in Flax and Walnut oils is not converted to EPA or DHA [R].
This chart shows what I consider the UN SAFE FATTY ACIDS. I would recommend to not eat these oils, or only eat small amounts rarely.
I have added Avocado to the unsafe list, which may surprise some. Certain varieties contain harmful substances that may damage liver and have been linked to cancer [R]. Avocado is a known gut irritant, not only for those with FODMAP sensitivity, but can also invoke an extreme reaction known as FPIES in young children [R]. Even though there is a high amount of oleic acid in Avocado, similar to olive oil, olive oil wins due to the lack of reported health concerns and its very low omega 6.
The noticeable difference between the safe fat list and the unsafe is the amount of saturated fat. In the SAFE FAT LIST there are also PUFAs, but the amount is minimal.
Animals such as cows and sheep are ruminants which means they digest vegetables (grass) more thoroughly, thus converting most of the PUFAs in their diet to saturated fat. Pigs and birds are not this way evolved so their fat may contain higher amounts of PUFAs depending on what they have been fed.
Modern food processing has presented a problem in that manufacturers can cheaply produce vegetable or seed based PUFA oils. Due to the ease at which this product can be made, the producers were very eager to present any positive attributes to consumers. Various studies were carried out and published that present the oils in a favourable light. Chris Masterjohn wrote an insightful article explaining why researchers race to find conclusions to answers they already know.
As the world is awash with vegetable PUFAs, it’s gong to take a long time for views to change. Any claims that unnatural oils are good for us need to be viewed with scepticism and even though the body can digest and process them to a certain degree. Only in healthy people will metabolism and synthesising work best.
If you are hypothyroid, then you can be sure you have not been digesting PUFAs efficiently. One of the major causes of hypothyroidism is a result of PUFAs roaming freely in the bloodstream causing free radicals. This in turn damages the mitochondria, slows metabolism and hinders thyroid actions.
Medium chain polyunsaturated fatty acids should be eradicated from your diet as much as possible. Even long chain polyunsaturated fatty acids which are considered essential to health, should be only be consumed once or twice per week. LCPUFAs are highest in fish.