Olive oil eases cholesterol. Poppy seed oil can bring body back to dry hair. Macadamia nut oil can help you lose weight. All of these headlines are actually news about unsaturated fatty acids and the important role they play in human health. But what is an unsaturated fatty acid, really?
Here are five things everyone needs to know about unsaturated fatty acids and human health.
1. A fat is "unsaturated" if can react with chemicals in the environment without being changed into an entirely different product.
Fatty acids are molecules made of chains of carbon atoms. Every carbon atom is capable of bonding with up to four other atoms, or making a double bond with another carbon atom.
In the unsaturated fatty acid structure, at least one carbon atom is double-bonded to another carbon atom. This means that the two carbon atoms can lock onto other substances without destroying the molecule (and creating lots of free radicals in the process). A saturated fatty acid, on the other hand, has a much greater tendency to "go bad" because all of its carbon atoms already connect to as many atoms as they can.
2. Unsaturated fat can be cis-or trans.
By now you have probably heard that trans- fats are always bad for you. That's not quite true. Conjugated linoleic acid (CLA), the weight loss fat, is actually a combination of trans- and cis- fats. But the thing to understand about trans- fat is in this kind of fat, hydrogen atoms appear on opposite sides of the carbon chain. They act like tiny arrows, helping the trans- fat molecule stick into the lining of a cell.
Cis- fats, on the other hand, have hydrogen atoms on the same side of the carbon chain, and they go right in to the cells that use them. Trans-fats can get stuck in the lining of cells and trigger a chain of reactions that lead to calcification or free radical attack or oxidation of unsaturated fatty acids, whereas cis- fats do not.
3. Unsaturated fats don't go bad because they contain natural antioxidants.
The unsaturated fats in sunflower oil, almond oil, walnut oil, flaxseed oil, and other nut and seed oils usually keep a long time. That's because they contain natural vitamin E that fights free radicals. The longer you keep an unsaturated fat on the shelf, the more its natural vitamin E has to fight free radicals that might make the oil spoil, and the less antioxidant content is left for you. It's always better to use unsaturated fats as fast as possible. And never store them in metal containers, because any unsaturated fat can react with metal to go rancid.
4. Unsaturated fats are usually liquids at room temperature. Saturated fats are usually solid at room temperature. (Visit Saturated vs Unsaturated Fats page for a comparison of two fats.)
Unsaturated vegetable oils are turned into saturated fats to make margarine and shortening. The problem with margarine, shortening, and similar saturated fats is that they are much more likely to cause cardiovascular disease. As a general rule, liquid oil is good, and solid fat is bad-although if you use fat for frying, then a solid fat, such as butter or lard, is actually more resistant to oxidation and going bad (as long as you just use it once).
5. Plant oils that are mostly unsaturated fat usually contain at least a little saturated fat.
Soybean oil is especially high in unsaturated fat and especially low in saturated fat, but it still contains about 15 per cent saturated fat. And saturated fat is not always bad. Coconut oil is about 77 per cent saturated fat, but most of the fat in coconut oil is lauric acid, which has a number of healing properties.