Excess Linoleic acid
Linoleic acid is an omega 6 fatty acid, a polyunsaturated fat or PUFA. Along with n-3, the other type of PUFA, it is technically an essential fatty acid, but the actual requirement is so small it might be better considered a micronutrient. A hunter-gatherer or Paleolithic human might have had a total PUFA intake of 3% of calories. Modern north americans have a PUFA intake of around 15%, most of it due to n-6. The problem with this is twofold.
1) As n-3 and n-6 precursors compete for the same enzyme in the eicosanoid pathway, the excess of n-6 in the diet means that n-3 is outcompeted at the enzyme level. The result is a preponderance of inflammatory molecules. Increased cancer and inflammation are both likely related to this
2) Many are aware that 6:3 ratio is important, so they try to compensate by taking fish oil to balance the 6:3 ratio. This doesn’t really work too well – you can’t realistically eat that much fish, and if you take fish oil supplements, you now exacerbate the second and more important problem with excess n-6, which is your total PUFA intake. High total PUFA, especially including the highly unstable n-3, leads to oxidative damage to your cells. Your arteries, liver and other organs don't appreciate extra oxidative damage.
The way to correct the modern excess of n-6 or linoleic acid is to avoid the modern sources of it. Stop eating all temperate vegetable oils – cooking and frying oils like corn, soy, canola, flax, all of it. And go easy on the nuts and factory chicken. These are big sources of n-6, especially the nuts and nut oils.
