Are you confused about dietary fat? I wouldn’t blame you if you are! There’s so much misinformation floating around about fat – how much we need, what types, and what effects the various kinds of fat have on the human body.
So here’s a basic primer on fats, to cut through the confusion and help you make informed decisions about what types and sources of fat to include in your diet:
Of all the different kinds of fat produced in the human body, there are only 2 kinds we cannot make ourselves:
- The omega-6 fat linoleic acid, and
- The omega-3 fat linolenic acid.
Both these fats are polyunsaturated.
Our bodies can make monounsaturated fats (such as those predominating in olive and canola oil) and saturated fats (those predominating in coconut oil, butter and animal fat) out of other types of fat, so we have no dietary requirement for such fats.
But we have to consume linoleic and linolenic acid, pre-made, in our diet – that’s why these fats are called essential fatty acids.
The problem is, most people eat far too much omega-6 fat, mostly from vegetable oils used in processed foods and from animal foods, and insufficient omega-3 fat. While the ratio between these 2 types of fat was probably around 4:1 (i.e. 4 times as much omega-6 as omega-3 fat) in our evolutionary diet, that ratio is now around 10:1, or even 20:1 in people eating a diet primarily composed of processed foods.
This imbalanced ratio contributes to a host of physical and mental health problems including heart disease, inflammatory joint disease, depression and ADD/ADHD.
Plant sources of omega-3 fats include:
- Green leafy vegetables,
- Flaxseed/linseed;
- Chia seed;
- Hemp seed; and
- Walnuts.
The type of omega-3 found in plant food is alpha-linolenic acid (ALA), a short chain omega-3. The major omega-3 fats used in the human body are EPA and DHA, which are both long-chain omega-3 fats. Only about 5-10% of ALA is converted into EPA, while the conversion rate to DHA is unknown, but probably very low – although pregnant women are able to convert more ALA into DHA than non-pregnant women and males.
Our nearest relatives, the great apes, consume incredibly large amounts of leafy greens, and these wild greens are far higher in omega-3 fats than the cultivated greens we consume. Obviously, this was the diet of our ancient ancestors too.
If you’re taking in such large amounts of greens, the fact that you convert a relatively small proportion of the ALA into DHA and EPA becomes relatively insignificant. But without access to these wild greens, some of us may run the risk of producing insufficient amounts of long-chain omega-3 fats.
Most people know that cold-water fish such as salmon and tuna contain long-chain omega-3 fats, but virtually all fish and seafood are contaminated with either mercury, PCBs and/or dioxins, all of which are highly toxic in different ways. In addition, fish contains large amounts of the pro-inflammatory omega 6 fat arachidonic acid.
If you’re concerned about your intake of long chain omega 3 fats, the safest way of securing adequate amounts of them is to use an algal-sourced EPA/DHA supplement. After all, fish don’t produce omega-3 fats: they consume algae, or fish that in turn have consumed algae. Algae produce omega-3 fats via photosynthesis.
There are now several brands of omega 3 supplement derived from algae, with varying ratios of DHA to EPA. As these supplements are grown in tanks of purified water, they are free of the contaminants that plague fish oil.
Algal-derived EPA/DHA supplements are safe, effective and environmentally sustainable, while fish oil production is contributing to the catastrophic collapse of fish stocks throughout the world’s oceans.
2 Comments
Lisa
11/07/2010Thanks Robyn – I’m learning so much. Maybe you could turn your blog into a book one day 🙂
Omega-3 fats…
I found your entry interesting do I’ve added a Trackback to it on my weblog :)…
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