- Very little linoleic acid is converted to arachidonic acid
- Arachidonic acid also makes anti-inflammatory molecules
- Linoleic acid can be converted to anti-inflammatory molecules
Animal studies that have been done were looking at very high amounts and in unusual chemical circumstances.
The other thought is that linoleic acid is harmful because we are consuming more of it at a time where we have more obesity (and more metabolic illness).
Preagrarian & Agrarian
The truth is that these correlations do exist. We have had an evolution of fatty acids in the human diet. Before pre-agrarian times, people had very low total fat intake.
And, most to all of their fats came from nuts and seeds and animal/marine fats. At the time, those same animal fats were pretty lean (not the same as today).
Then, we pivot to agrarian times. This is where more of the food available came from grains (and less of it came from game meats).
At that point, as well, was the first use of concentrated oils. In some areas, then, fat intake went up, but total animal intake went down.
Pre-Industrial & Industrial
In pre-industrial and early-industrial times, diets remained relatively stable. Still consuming amounts of farmed foods, people generally ate less game meat.
The Last Few Decades
This is where we have seen the biggest shift.