Once vilified, fats and oils are now celebrated. Hardly a day goes by without me seeing a post about the top ten uses for coconut oil or such. Honestly, I think the best part about virgin coconut oil is that it smells and tastes like coconuts. And refined coconut oil? It's a good cheap oil for soap, bringing lots of lather to your recipe. It's a good source of medium-chain fatty acids and has a good shelf life. However, it only has a small amount of Linoleic acid, one of the essential fatty acids (EFAs).
I recently finished reading Susan M. Parker's Power of the Seed, and I recommend it to anyone who wants to learn more. It's a pretty awful title, but it's a good book. It covers the chemistry and components of oils, plus it includes a lot of profiles (about 90, I believe) of various oils. There are several appendices that help present the information on the oils in various ways, including a saponification value chart, if you make soap). There are few recipes if you don't know where to start with all the oils.
A Little Science
There are two essential fatty acids- Linoleic Acid (LA) and alpha-Linolenic acid (LNA). They are called such because your body doesn't produce them, so you need to get them from other sources. They're both polyunsaturated fatty acids, meaning they have two or more double bonds in their carbon chains. Saturated fatty acids don't have double bonds and are less susceptible to oxidation. LA has 2 double bonds, and LNA has 3, so LNA has the shorter shelf life of the two.
LA is an omega-6 fatty acid, and LNA is omega-3. You've probably heard of omega-3, and maybe omega-6 and omega-9. All unsaturated fatty acids have omega names, and the number refers to the first double bond in from the free end (the omega) of the chain. For omega-3, this means means your first double bond occurs at the third carbon in the chain,counting in from the omega. Saturated fats do not have omega names, which probably makes them sad.
Eating Your Omega-3
It's not my place to give medical advice, so I'm going to discuss sources rather than health benefits. It's easier to get enough linoleic acid in your diet, but fewer foods have high percentages of LNA. You'll often see omega-3 supplements, sometimes in pill form or as a straight oil.
You might think of fish when you hear omega-3, and most of the supplements for omega-3 fatty acids are various of fish oils. Other than a brief time when I was four years old, I never liked fish, plus I went vegetarian when I was a teenager. So I do not recommend fish, because I think they're gross as a food and they belong swimming merrily in the water. And if you're an omnivore who doesn't like fish but is considering fish oil supplements, I have two words for you- fish burp. Some will claim not to cause fish burps, but do you really want to risk it?
If want to consume your omega-3 fatty acids through whole foods, there are a few plant sources that are high in LNA. Chia and flax seeds are excellent sources. You should store both in the refrigerator, and grind the flax before using. Hemp seed and walnuts also provide a fair amount of LNA. Several berry and fruit seed oils have a decent amount, but it'd be hard to eat enough fruit to get the proper amount of fat.
If you want to supplement, flax and chia seed oils are available in pill form. If you're vegetarian, check the ingredients, since some of the supplements use gelatin. While your body can produce DHA and EPA (more omega-3 fatty acids), it's not always very efficient, so there are supplements for those two fatty acids as well. DHA and EPA typically come from fish oil, but there are some vegan supplements out there. I think they're derived from algae. The best sources for GLA (an omega-6) are borage, evening primrose, and black currant seed oils. These also come in pill form, and again check the ingredients if you're vegetarian.
Omega-6 for Your Skin
In addition to eating LA and LNA, you should consider using oils with these fatty acids on your skin. Dry, damaged, or acneic skin often have low-levels of linoleic acid, so using oils rich in LA might help balance the skin. If you're not using a single oil, look for oil blends or lotions that contain LA-rich oils. Since they are more likely oxidize quickly, a blend will probably help with shelf life.
A few good oils with high percentages of LA include evening primrose, grape seed, hemp, walnut, and wheat germ. Safflower and sunflower are also good sources, but only if they're not the high-oleic hybrids. Popular skincare oils argan, rose hip seed, rice bran, and sea buckthorn also have decent amounts. The oils have different properties, so some may be better for your particular skin type.
Susan M. Parker, Power of the Seed: A Guide to Oils for Health & Beauty, Port Townsend, WA: 2014, Process Media. ISBN: 978-1-934170-54-0