Polyunsaturated fat in food

If a fat is polyunsaturated, there are two or more places among the carbon atoms of its fatty acids where there are fewer hydrogen atoms attached than in saturated fats.

Polyunsaturated fats are unstable and are also abundant in certain plant oils – particularly corn and soybean oils – as well as in seeds, whole grains and fatty types of fish like salmon and tuna.

Because of their instability polyunsaturated are highly susceptible to oxidization. Polyunsaturated oils are oxidized by frying, heating and exposure to light and air.

Some polyunsaturated fats are also known as essential fatty acids because human bodies need them but cannot make them from other nutrients.

Polyunsaturated fatty acids in the diet belong to either the (n-6) or (n-3) family. About 90% of all polyunsaturated fatty acid in the diet is linoleic acid, which is found in vegetable oils like sunflower oil, corn oil and soybean oil.

Foods containing high proportions of polyunsaturated fats are usually soft or oily. Polyunsaturated fats should not exceed 8% of total daily kcal.

Too much polyunsaturated fat can promote free-radical damage to cells, contributing to heart disease and cancer. When polyunsaturated oils turn rancid, they produce free radicals that attack the cholesterol, causing it to become oxidized as well. The result is that both the cholesterol and polyunsaturated fats in the lipoprotein become oxidized.
Polyunsaturated fat in food