Facts About Fat: the Good, the Bad, and the Ugly
Monounsaturated, Polyunsaturated, Saturated, and Trans Fat
May 25, 2009
Dietary fat plays an important role in human health. Dietary fats are carriers of fat-soluble vitamins, are essential for energy, and are a source of essential fatty acids, such as omega-3 and omega-6. Lack of essential fatty acids can lead to deficiency symptoms.
Why then, has dietary fat gotten such a bad rap? While not all fats are harmful, some types of fat can be. It is important for consumers to know the difference so that they consume the type of fats that are beneficial to human health and cut down on fats that cause harm.
Dietary fat falls into four categories: monounsaturated fat, polyunsaturated fat, saturated fat, and trans fat.
Monounsaturated Fat: Good
What are monounsaturated fats? Monounsaturated fats typically have one double-bonded unsaturated carbon in the molecule.
Health implications: Monounsaturated fats are considered beneficial when eaten in moderation because these fats lower cholesterol levels, thus reducing risk of heart disease. Additionally, monounsaturated fats contain the antioxidant vitamin E and other nutrients supportive of body cells.
What foods contain monounsaturated fat?
- Avocado
- Natural peanut butter
- Seeds and nuts
- Olive oil
- Seed and nut oils: peanut oil, sunflower oil, canola oil, sesame oil
* Recommendation: monounsaturated daily fat should not exceed 25-35% of total daily calories.
Polyunsaturated Fat: Good
What are polyunsaturated fats? Polyunsaturated fats have more than one double-bonded unsaturated carbon in the molecule.
Health implications: polyunsaturated fats render a beneficial effect by reducing cholesterol levels in the blood, thereby lowering risk of heart disease. Polyunsaturated fats contain essential fatty acids the human body cannot produce on its own, critical omega-6 and omega-3 that assist brain and body function.
Which foods contain polyunsaturated fats?
- Fatty fish (salmon, mackerel, trout, herring)
- Walnuts
- Sunflower seeds
- Vegetable oils: soybean oil, corn oil, safflower oil
* Recommendation: polyunsaturated daily fat should not exceed 25-35% of total calories.
Saturated Fat: Bad
What are saturated fats? Saturated fats are fats with carbon atoms saturated with hydrogen atoms.
Health implications: Saturated fats are harmful because saturated fats raise blood cholesterol levels, which in turn increases risk of heart disease or stroke.
What foods contain saturated fat?
- Meat
- Dairy products
- Palm oil
- Coconut oil
*The American Heart Association recommends no more than 16 grams of saturated fats per day.
Trans Fat: Downright Ugly
What are trans fats? Trans fats are largely man-made. Trans fats are created when hydrogen is forced into liquid vegetable oils to solidify them. Partially hydrogenated oils contain trans fats.
Trans fats are used commercially because these fats have a longer shelf life, contribute to texture and taste of processed foods, and are inexpensive. Restaurants fry foods with products containing trans fats because these fats last longer.
Health implications: While convenient, trans fats have an "ugly" side in relation to the havoc these fats render to the human body. Trans fats raise LDL cholesterol levels, while lowering cardio-protective HDL-cholesterol. This renders a double-whammy in relation to cardiovascular health.
Which foods contain trans fats?
- Hydrogenated margarine
- Hydrogenated vegetable shortening
- Foods that are fried in these oils (French fries, donuts) or prepared with products that contain trans fats (crackers, cookies, pastry, biscuits)
* The American Heart Association recommends consuming less than 2 grams of trans fats per day. Discounting the small amount of trans fats that are naturally found in some meat and dairy products, this leaves zero room for industrially produced products containing trans fats.
A good rule of thumb: Replace foods containing saturated and trans fats with foods containing polyunsaturated and monounsaturated fats.
Knowing the facts about the four types of fat helps consumers to make heart-friendly choices.
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