Omega 3 fatty acids are seen as a natural remedy for ADHD and dyslexia but can you get your Omega 3 and Omega 6 through a normal diet?
There are plenty of Omega 3 and Omega 6 supplements on the market, costing about £20 ($30) for a month’s supply. Not everyone can afford this so I’m going to attempt to identify what and how much you need to eat to get them naturally. As a basis I’m going to set as my target the same amount of omega 3 and 6 as the EyeQ supplements. These were used in a large scale trial in Durham, UK, that had significant results. In this trial children received 558 mg of EPA and 174 mg DHA (omega 3 oils) and 60 mg of LA (omega 6). [For more on the difference between EPA, DHA and LA see ALA to DHA: The Fish Oil Alphabet].
Getting Your LA
LA is Linoleic Acid, named after the Greek for the plant Flax, more commonly known as Linseed. Its name is not a coincidence because LA is prevalent in most vegetable oils. To get 60 mg of LA in your diet you would need to eat any of the following:
|Food||Grams Required||LA grams per 100 grams of food|
As you can see it is very easy to get LA into your diet. In fact the problem is that we have too much LA in our diet generally because LA interferes with our ability to process omega 3 fatty acids. A ratio of 2:1 omega 6 to omega 3 is recommend by some experts. Studies have shown that the average western diet can have between a 10:1 and a 18:1 ratios. The foods identified above also contain omega 3 ALA but have a relatively low, 4:1 or less, ratio.
There Is Something Fishy About EPA
EPA is an omega 3 fatty acid. The body can convert it from Alpha-Linolenic Acid (ALA, the omega 3 equivalent of LA) but the process has only a 5% – 10% efficiency, so at least 5.58 grams of ALA are need generate 558 milligrams of EPA. To get that much ALA you would need to eat about 10 kg of spinach a day, a feat best left to Popeye.
To avoid a diet fit only for a rabbit, we need to get our EPAs direct from our food:
|Food||Grams Required||EPA grams per 100 grams of food|
As you can see fish are the most practical way of getting your EPA with obvious advantages over eating 5.58 kg of beef or 10 kg of spinach a day. However there is a problem with heavy metals in fish. There is a certain irony that the food stuffs we most need to develop our brains are the ones most likely to be full of brain destroying heavy metals. Mackerel contains about 55 parts per billion (ppb) of mercury and tuna 118 ppb. The US FDA sets a safety level of 1000 ppb so a can of tuna is safe. A problem arises because mercury can accumulate in the body so a regular diet of tuna or mackerel may lead to dangerously high levels of mercury. The FDA guidance is no more than 2 meals of tuna a week for pregnant women and children.
End of the Line for DHA
The end result of our bodies processing of ALA is DHA and it is between 2% to 5% efficient. So 100 milligrams of ALA become 2 to 5 milligrams of DHA. Like EPA, DHA is common in fish:
|Food||Grams Required||DHA grams per 100 grams of food|
Making a Meal Of It
Getting the balance of omega 3 and omega 6 fatty acids in your diet without poisoning yourself with heavy metals is very difficult. It must also be noted that the amounts and ratios of omega 3 and 6 used by the Durham trial are educated guesses. Research on the best combinations has been very limited.
Ultimately the advice is the same as all nutritional advice. Eat a varied diet with lots of fresh vegetables, fruit and nuts. Have sensible sized portions of fish two or three time a week and avoid fatty, processed foods.
The LCP Solution
What can high-omega-3 foods do for you?
Vegetarian Society: Omega 3 Fats
The Essential Omega-6 and Omega-3 Fatty acids in Food [ PDF ]
Mercury and Fatty Acids in Canned Tuna, Salmon, and Mackerel [ PDF ]
Alpha-linolenic acid in the prevention and treatment of coronary heart disease [ PDF ]
What You Need to Know About Mercury in Fish and Shellfish