Original Post April 2016.  PUFAs stands for polyunsaturated fatty acids. These are very large molecules that are highly susceptible to oxidation, a dangerous process to body integrity. Vitamin E helps protect (or control) PUFAs from oxidation. Thus, vitamin E is a good anti-oxidant for preventing unsaturated fats from breaking down into dangerous forms. ref  Vitamin E accomplishes this action by giving up a part of itself. After this action, the remaining part of vitamin E is now inactive and gets eliminated out of the body.* If too many PUFAs are allowed to breakdown, they can become rancid and toxic in the body. In scientific language, they produce too many negative aldehydes with resulting production of irreversible protein modifications. Since vegetable oils (mainly omega 6) and fish oils (mainly omega 3) have greater amounts of PUFA than animal saturated fats like butter and lard, greater amounts of vitamin E and other anti-oxidants are used up by a diet high in vegetable oils and fish oils. Plus, remember, the body uses some free radicals that generate lipid oxidation of PUFAs for positive purposes so there is a balance point to maintain. ref ref ref

SIDEBAR: One class of fats is called MUFA, standing for monounsaturated fatty acids. These fats can be quite good for the health of the body, especially on limiting LDL cholesterol oxidation in arteries. ref  Here is an article listing good dietary sources

SENIORS HAVE A FASTER FAT OXIDATION RATE THAN YOUNG PEOPLE. THEREFORE, SENIORS REQUIRE MORE ANTIOXIDANTS LIKE VITAMIN E TO PROTECT AGAINST FISH AND VEGETABLE OILS OXIDATIVE DAMAGE.

This pretty much sums up the dietary changes over the last century, higher PUFAs, as well as some supplement changes, higher vitamin E found in vegetable oils. The cholesterol theory of heart disease is responsible for many of these changes. Now, the question that this generated: Yes, there is more vitamin E in vegetable oils so the diet did increase somewhat in vitamin E over this time period. BUT, was it enough to offset the extra demands from the increased need to protect PUFAs? Especially since vitamin E gets processed out of many commercial vegetable oils. And then, add in supplemental PUFA omega 3 fish oils which were found to help prevent heart disease ref, but are still in a highly unstable state and need protection. ref ref

THE QUESTION ABOUT PUFAs? 

Are PUFAs healthy or not? You need some, but definitely, they may not be healthy in larger amounts. That is, the typical amount in the Standard American Diet today. Read the last line in this scientific article here.

Support for those who want a non-fish plant source of omega 3 fatty acids. ref

Fish oil supplements need to be protected during their total life span. Quality manufacturing, proper handling during and after processing, and refrigeration helps. Quality is not always visible. Buy from companies that care about protection and freshness. Fish oil capsules should contain a natural preservative (anti-oxidant) like vitamin E. Only buy small sizes, 90 or 60per individual. And refrigerate, especially after opening. Plus, leave the cotton or dessicant pak in bottle if present.

Two good choices would be Nordic Naturals Omega 3 softgels (with 330 mg EPA and 220 mg DHA in 2 softgels). this is a non-concentrated fish oil. Or Barlean's Fish Oil 100 softgels. The higher concentrations go through extra processing steps which change the natural molecular figuration. article

*Vitamins E and C may be recycled back to active state by Alpha Lipoic acid. This next ref talks about the superior anti-oxidant of using the whole family of tocopherols rather than just d-alpha tocopherol alone. There are certain forms of radicals that the alpha tocopherol form of vitamin E does not touch, but some of the other vitamin E family members do.