Here are amounts of omega-6 (N6) and omega-3 (N3) fatty acids in some common foods:
If you're trying to hold your omega-6 intake at bay, lots of nuts and seeds probably won't help. But they're not the primary culprit in American's soaring N6:N3 ratio. Many processed foods and baked goods contain some form of omega-6-rich corn or soy oil.
Why Reduce Omega-6?
- Omega-6 (N6) fatty acids are precursors to pro-inflammatory compounds in the body. Inflammation is good, it protects against infection. But high levels of omega-6 (relative to omega-3) have been linked to a range of inflammation-based conditions. Think of illnesses with "-itis" at the end of them, e.g. arthritis, bursitis. A pro-inflammatory environment has also been linked to cardiovascular disease, diabetes, certain cancers, and mental health problems.
- Omega-3 (N3) fatty acids are precursors to anti-inflammatory compounds in the body. Here's the thing: N6 and N3 compete for the enzymes that convert them into more biologically active compounds. So, when you have a lot of omega-6 around, it may use proportionately more of those enzymes, leaving you with a pro-inflammatory environment.
The Institute of Medicine says that an Adequate Intake (AI) for N6 (linoleic acid) is about 10 to 15 grams a day. The AI for N3 (alpha-linolenic acid) is about 1 to 2 grams a day. AIs are estimates, and as always they vary depending on age, gender, life stage, activity level, so many things. There's thinking that an optimum N6:N3 ratio is closer to something smaller, 4:1 or less. Some of us are eating a ratio of 20:1 and higher.
N6 and N3 often occur together in foods. Many foods that are good sources of N3 are also good sources of N6. Walnuts are a good example. They're a respectable food, but eating lots of them won't go very far in improving N6:N3 ratio.
(Walnuts have more N6 than N3, in a ratio of about 4:1. You can click through to the Excel spreadsheet I made to generate this graph, where I have the N6:N3 ratio listed for each food, along with saturated fat and calories. Look at that almond ratio: 1689:1!)
Another thing I learned doing this - When it comes to omega-3 content, there's hardly a difference between grass-fed beef and conventional beef. And neither of them provide more than a few milligrams in the raw state, probably negligible amounts after being cooked. (NutritionData's figures are based on USDA's figures which may or may not reflect the state of modern livestock production.)
One more thing - Greens (Romaine, spinach, kale, broccoli, rapini, etc.) have proportionately more N3 than N6 (anything less than 1.0 in the Ratio column in my Excel sheet). Now that's a food where the more you eat, the more improved your ratio.