Cholesterol

Understanding saturated, unsaturated, and trans fats

Understanding saturated, unsaturated, and trans fats

Eating low-fat foods doesn't mean we should lose fat completely, but we do need to educate ourselves on which fats should ideally be avoided and which ones are healthier for the heart. Let's be clear: we need fat in our diet.

As the most concentrated source of calories (nine calories per gram of fat compared to four calories per gram of protein and carbohydrates), it helps supply energy. Fat provides linoleic acid, a fatty acid essential for growth, healthy skin, and metabolism. It also helps absorb fat-soluble vitamins (A, D, E, and K). And, face it, fat adds flavor and satisfies, makes us feel fuller, keeping hunger at bay.

Although all fats have the same number of calories, some are more harmful than others: saturated fats and trans fats in particular.

Saturated fats

These fats are derived from animal products such as meat, dairy, and eggs. But they are also found in some plant sources like coconut, palm, and palm kernel oils. These fats are solid at room temperature. Saturated fats directly raise total and LDL (bad) cholesterol levels. Conventional advice says avoid them as much as possible.

Trans fats or hydrogenated fats

Trans fats are actually unsaturated fats, but they can raise total and LDL (bad) cholesterol levels while lowering HDL (good) cholesterol levels. Trans fats are used to extend the shelf life of processed foods, typically cookies, cakes, potato chips, and donuts. Any item that contains “hydrogenated oil” or “partially hydrogenated oil” probably contains trans fat. Hydrogenation is the chemical process that transforms liquid oils into solid fats.

The US Food and Drug Administration no longer recognizes artificial trans fats, or partially hydrogenated oils, as safe for health. Food companies were required to eliminate trans fats in their products by 2018 or demonstrate why they are safe to use in their food.

Unsaturated fats

Monounsaturated fats and polyunsaturated fats are two types of unsaturated fatty acids. They are derived from vegetables and plants.

  • Monounsaturated fats they are liquid at room temperature, but begin to solidify at low temperatures. This type of fat is preferable to other types of fat and can be found in olives, olive oil, walnuts, peanut oil, canola oil, and avocados. Some studies have shown that these types of fats can actually lower LDL (bad) cholesterol and maintain HDL (good) cholesterol.
  • Polyunsaturated fats they are also liquid at room temperature. These are found in safflower, sesame, corn, and cottonseed oils. This type of fat has also been shown to lower LDL cholesterol levels, but it can also lower your HDL cholesterol.

Omega-3 fatty acids

These include an "essential" fatty acid, which means that it is critical to our health, but that our bodies cannot manufacture it. Good sources of omega-3 fatty acids include flax seeds and walnuts. These fatty acids can reduce the risk of coronary heart disease and also improve our immune system.

So read food labels carefully and choose your fats wisely. And as a general rule of thumb, liquid fats are better for you than solid fats.

By Fiona Haynes
Original article (in English)

Video: Saturated fats, unsaturated fats, and trans fats. Biology. Khan Academy (October 2020).