Ted, on further research, a minuscule amount of omega 3 fatty acids are present in beef brain tissue. The top of the list is flax seed (a grain) followed by nuts and seafood - fish - mollusks. Wild caught salmon is very high with about one fifth of the amount in flax seed. The studies I have read use a 200 calorie standard as the base.
You are correct, of course, that Wikipedia is a very shallow source of information. It does rank head and shoulders better than uninformed opinion however.
I started off learning about nutrition by reading scientific papers. Even so, it took me a while to grasp what the scientists were saying because the words were foreign to me.
To understand my response one needs the following information provided by this link for Omega-3 data in foods.
Food Analysis: GI, GL, Fat Ratio, and Inflammation.
The data on food in that link are basically derived from the government's data bases that it has collected over the years. For another view look at Nutritiondata.com. You will note that on their Web site the essential fatty acid (EFA) ratio is provided down in the lower left hand corner of the data. You'll note that in the nutrition trade, EFAs are not measured in terms of calories, but in terms of relative weight. For instance, in milligrams per ounce or per gram.
Unfortunately Nutrition Data's data is wrong on grass-fed meats. How do I know, because there are hundreds of independent studies from universities and private labs that have been done plus I have paid for some reports myself and have even tested my body's own ratio! Grass-fed meats range between 0.8 : 1 up to 2 : 1. Unfortunately, there is some confusion surrounding what is actually grass-fed. And in some early meat studies the food researchers didn't know the real difference. The concept of raising cattle without any grain whatsoever seemed so foreign to some that they thought a critter raised on grass with grain supplementation is the same as grass only. No, it's not. But that's another long story.
When analyzing EFA balances don't look only at the absolute amounts of the EFAs. The key is the balance between the EFAs by weight in ALL of the foods ingested during a day. It only takes one way-out-of-balance food (i.e. some walnuts) to throw off the entire day's balance derived from properly balanced foods. And then each day is a new day. Note that the foods of man prior to the invention of grain farming and other agricultural pursuits are mostly balanced evenly. That means every meal is balanced and the milligrams (mg) of Omega-6 fatty acids will be the same as the mg of omega-3 fatty acids consumed by the body. When animals eat those foods their EFA balances will also be evenly balanced. Then their immune systems operate optimally. When the balance deteriorates to more than 4:1 omega-6 to omega-3 that is called the omega-3 deficiency and the occurrences of chronic diseases are measurable in laboratory mice. Most Americans are up around 20:1. That's why they are over weight, dependent of drugs and operations, and health care costs are so high. It also explains why being "over weight" is now considered a chronic disease rather than merely a condition of eating more than the body can use. I eat a lot and I weigh 150 pounds.
Think of the balance of EFAs to the body as similar to the balance between gas and air to an engine. They don't have to be out of balance by much before the engine runs rough or even stops running. EFAs are a small component of a body's entire chemical mass. But the balance of the tiny EFA component impacts brain and body function immensely because the EFAs become permanent components of the membranes of all cells. When the balance is wrong, the cells can misfire in their function over time. Think cancer for one. Studies substantiate that claim and they date way back!
The mob misinterprets the works of the scientific community about Omega-3 fatty acids. Some of the foundation work is by Artemis Simopoulos, M.D. She is a world authority on essential fatty acids and was nutritional adviser to the Office of Consumer Affairs at the White House. She is the former editor in chief of World Review of Nutrition and Dietetics. That's a scientific publication. Her work is legendary in the scientific community.
Here is one of her peer-reviewed reports that explains the importance of balance.
I can send sources and more sources of the scientific works. The science is well documented and has been on the same track since the late 1970s. And if you look around, you'll see that there are literally thousands upon thousands of health studies that incorporate omega-3 fatty acids and indicate improvements in health because more omega-3 fatty acids are included in the diet. But once again, it's the EFA ratio that counts which incorporates the omega-6 fatty acids, not just dumping in some Omega-3.
Not only have I experienced significant improvements in my health by eating like a caveman, but so have my customers -- at least the ones who follow the Real Diet of Man. Anyone who has eaten that way for 12 months or more has a ratio that is better than 4 : 1.
P.S. Flax seed is technically not a grain, but since it is a seed it is very similar. By some design, nature saw to it that it was an anomaly when it comes to Omega-3 fatty acids. Unlike all other grains, it is high in Omega-3 and low in Omega-6. That does not mean other grains are good though. So the point made is meaningless. In the same light, nuts are a horrible source for omega-3 fatty acids because they are a much larger source for Omega-6 fatty acids. It’s all in the balance.