9 Fats
Although both animal and plant foods contain fats (or lipids), much of the fat consumed by North Americans comes from animal products in the form of meat, fatty fish, eggs, and dairy products such as butter, cream, cheese, and whole milk. Vegetable fats are found in vegetable oils and vegetable shortenings.
Fats are an essential nutrient and have many beneficial functions in the body. They supply a steady source of energy, regulate certain body functions, contribute to the feeling of “fullness” after eating, and absorb and transport fat-soluble vitamins. There are two main types of fat: saturated and unsaturated. Saturated fats come from animal and tropical plants sources while unsaturated fats come from plant sources and fish. Unsaturated fats are further divided into monounsaturated and polyunsaturated fats.
The classification of a fat depends on its atomic structure. Fat is composed of carbon and hydrogen atoms bound together in long chains. If the chain has as many hydrogen atoms as it can possibly have, the fat is said to be saturated. If there is room on the chain for more atoms of hydrogen, the fat is unsaturated. The difference in atomic structure means that at room temperature most saturated fats are solid and unsaturated fats are liquid. If there is one double space free of hydrogen atoms in the chain, the unsaturated fat is monounsaturated. If there are two or more double spaces free of hydrogen atoms in the chain, the fat is classified as polyunsaturated. The best sources of polyunsaturated fats are fish and most vegetable oils, including corn oil, safflower oil, and sunflower oil.
One way of viewing the difference between saturated and unsaturated fats is to consider the atomic structure of fat to be like a sponge. If the “sponge” can still hold more hydrogen atoms, the fat is unsaturated. Knowing the molecular structure of fat is not as important as knowing that saturated fats tend to have negative health effects; polyunsaturated fats are better for us than saturated fats, and mono-unsaturated fats may even be more beneficial. Another point to remember about lipids is that, in general, animal fats are saturated while most plant fats are unsaturated. However, lipids in tropical oils tend to be saturated fats. This means that cocoa butter, coconut oil, palm kernel oil, and palm oil are saturated oils. The best sources of polyunsaturated fats are fish and most vegetable oils including corn oil, safflower oil, and sunflower oil.
Fatty fish such as mackerel, tuna, salmon, trout, and herring are rich in special fatty acids belonging to the omega-3 group. There is some evidence that one of the omega-3 chemicals, eicosapentaenoic acid (or EPA for short), helps to prevent coronary heart disease, provides relief for arthritis victims, and may reduce the frequency and intensity of migraine headaches (Harvard Medical School Patient Education Centre, 2015). Inconsistent findings in nutritional research suggest there is some controversy a