Seed oils are now a part of our lives but they weren't in the past even as recent as 1865, we weren't consuming them in large amounts because they weren't a part of our lives but fast forward to today, we consume over 700 the calories we get from different seed oils.
A study back in 1979 mentioned that there was a decrease in the IQ level of children. Children around this time were said to be easily distractible, hyperactive, easily irritated, and frustrated. Another study showed that the IQ level has decreased over the years since the 1980s after lead was removed from gasoline which was the prior suspect. Evidence is coming up gradually and this evidence is pointing to our food with seed oil being the major suspect.
Its no doubt that we have bigger brains than our ancestors and there are several theories around how we became so smart with some saying we were able to feed on certain foods like wild potatoes to help feed our energy hungry brains calories but this theory is just as dumb as it sounds because there are a lot of food that could give us calories to feed our brains. Another theory looked at hunting as a reason for our growing brain as meat helped our brain with the nutrients and calories it needed.
Scientists at some point wanted to learn what type of fat was responsible for brain growth, and they learned that there were two types of fat responsible for growth which are Arachidonic acid (AA) and docosahexanoic acid (DHA). We can get AA from eating land animals and to get DHA, early humans would have eaten a lot of animal brains but better they ate a lot of seafood.
DHA has been seen to improve learning, attention, memory, and reduce ADHD symptoms. Another theory like the Aquatic ape theory says human ancestors were water-loving, and lived close to aquatic life which helped us get large amount of nutrients for our brain, and the environment also affects how the majority of our body has adapted. Although most scientists do not subscribe to this theory.
Back to IQ, Japan is said to be the country with the highest IQ compared to countries like the US and this can be attributed to the food they eat which is predominantly seafood. When DHA is heated, it is degraded but Japanese eat plenty of raw seafood.
Humans in contrast to animals like rhinos get Linoleic acid (LA). LA usually compete with DHA for space in the cell preventing DHA from getting into the cells. It has been seen that animals with big by Linoleic acid and low DHA have smaller brains, while animals with low Linoneic acid and high DHA have big brains, and lots of vegetable oils have Linoleic acid. Countries like Japan also sat half the vegetable oil countries like the United States eat.
So, do we say that our vegetable/seed oils are are responsible for reduced brain function and IQ?
REFERENCE
https://www.zeroacre.com/blog/the-history-of-vegetable-oils
https://www.sciencedirect.com/science/article/pii/S2666149722000469
https://hana-lebensmittel.de/aa-dha/
https://danonenutriciaacademy.in/expert-article/influence-of-dha-and-aa-on-neurological-and-visual-development-of-infants/
https://pmc.ncbi.nlm.nih.gov/articles/PMC8003191/
https://pmc.ncbi.nlm.nih.gov/articles/PMC6470942/
https://pmc.ncbi.nlm.nih.gov/articles/PMC6179509/
https://pmc.ncbi.nlm.nih.gov/articles/PMC7832089/
https://pmc.ncbi.nlm.nih.gov/articles/PMC10386285/
https://sigmanutrition.com/seedoils/
https://www.researchgate.net/publication/338337698
https://www.scirp.org/journal/paperinformation?paperid=60860