Tuesday, April 2, 2013

Types of Fats (2 of 6)

To jump start this blog, I will be doing a series on "Fats." I'm excited to begin this journey learning about fats because it's everyone's favorite topic and one that is highly controversial. 

Click here if you missed the the first post of this series (introduction and the modern views of fat).

Our body needs fat, especially saturated fat, to nourish the brain, heart, nerves, hormones, and every single cell. Saturated fats form a key part of the cell membranes throughout our body. Eating too many unsaturated fats, the kind found in polyunsaturated in vegetable oils, adversely affect the chemistry of those membranes. Knowing the different types of fats will help us understand the right kinds of fats our body needs and will enable us to understand food labels.

Types of fats:

1. Saturated Fats
- Found mainly in animal fats and tropical oils like coconut oil and in lesser amounts in all vegetable oils (and also made within your body, usually from excess carbohydrates)
- They are highly stable, thus they are less likely to go rancid when heated during cooking and form dangerous free radicals that can cause heart disease and cancer.

2. Monounsaturated Fats
- Found commonly in the oils of olive, sesame, almond, pecan, cashew, peanuts, and avocados. Our body can also make monounsaturated fatty acids from saturated fatty acids when it needs them for body functions.
- They are relatively stable and do not go rancid easily and hence can also be used in cooking.

3. Polyunsaturated Fats
- Our body cannot make these fatty acids and must be obtained from foods.
- They are highly reactive and when subjected to heat or oxygen, as in extraction, processing, and cooking, free radicals are formed. It is these free radicals, not saturated fats, that can initiate cancer and heart disease. As such, industrially produced polyunsaturated oils, such as corn, safflower, soy, and sunflower oils, should be strictly avoided. 

The Dangers of Trans Fats

Processed and packaged foods contain trans fats that are produced through partial hydrogenation where polyunsaturated fats are whipped with hydrogen to make them unnaturally solid at room temperature. This makes trans fats have a longer shelf life and decreases refrigeration requirements, making them the preferable option for the food industry to make packaged foods. And most fast-food chains use partially hydrogenated oils to fry foods.

Trans fats compromise many bodily functions, promote weight gain, and actually increase cholesterol and the risk of heart disease as they increase our LDL (bad cholesterol) and decrease our HDL (good cholesterol). They also inhibit the production of adrenal hormones that is needed to relieve anxiety or stress. Trans fats interfere with insulin receptors in the cells, causing insulin resistance (hence type II diabetes). 

Excess polyunsaturated oils make the cell walls "floppy," thereby contributing to wrinkles. These oils are invariably rancid and contain free radicals that damage cells and contribute to aging. (One type of trans fat, called an isomer, occurs in small amounts in butter, beef, and lamb fat. But this insomer does not cause health problems. It is actually converted into a substance called CLA, which protects against weight gain). 

In short, trans fats are the worst kind of fats. They are poison to our body. The best way to avoid trans fats is by not eating processed and packaged foods!

In the next part of this series, we will learn about the right kinds of fats and the wrong kinds of fats.

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