What you should know about FATS?

By Grace Wei Ern Quek, RDExcellence Healthcare Pte Ltd

For many who are managing their weight, fats seems like a taboo word. Yes, we always hear "Too much fat can kill". But what do you know? Certain fats are actually good for our body!

Besides cushioning our vital organs, giving us extra padding for shock and impact from falls/injuries, and keeping us warm during the cold weather, some fats known as essential fatty acids are vital for brain development, skin integrity and also for reduction of heart disease and stroke risks.

Types and sources

There are mainly two distinct types of fat: Saturated fats and Unsaturated fats.

Saturated fats mainly come from animal and animal products, such as meat, milk, eggs etc. There are however, a few exceptions. Saturated fats can also be found in coconut milk and palm oil. Besides cholesterol, saturated fat is notoriously known for the fat that clogs up arteries.

Additionally, it has also been shown that excessive consumption of saturated fats can also increase risk of certain cancers, especially colon, rectum, endometrial, breast and prostate cancers. Many nutrition experts and authorities recommend keeping saturated fat consumption to less than 10% of daily calories.

Unsaturated fats mainly come from fish and plant sources. Unsaturated fats are divided into: polyunsaturated fats (PUFAs) and monounsaturated fats (MUFAs). PUFAs are further categorized into Omega-3 and Omega-6 fatty acids. Omega-3 and Omega-6 fatty acids are known as "Essential fatty acids" (EFAs) as they are critical for good health and the body does not have the ability to manufacture such fats on its own.

Omega-6 fatty acids can be converted into arachidonic acids (ARA), one type of fat used to build the brain. Other benefits from consuming Omega-6 fatty acids include: lowering of blood pressure, reduction of inflammation and joint pains, regulation of nerve functions and skin support. Omega-6 fatty acids sources include seeds and oils, such as pumpkin, sunflower, safflower, sesame, corn, walnut and soybean.

Omega-3 fatty acids can manufacture other important fats for the brain as well, EPA (Eicosapentanoic acid) and DHA (Docohexanoic acid). Studies have shown that increased consumption of EPA and DHA sources can boost a few more IQ points! Omega-3 fatty acids have also been found to have a cholesterol-lowering effect, particularly on LDL (low-density lipoprotein) cholesterol, also known as "bad cholesterol". Unfortunately, it lowers the HDL (high-density lipoprotein) or "good cholesterol" as well.

Omega-3 fatty acids are also needed for the formation of new tissues, and hence play an important role in growth and development. Such fats also improve immune function, decrease inflammation and help maintain water balance. Sources of Omega-3 fatty acids include fish (e.g. salmon, tuna, mackerel, herring, and cod), walnuts, flaxseeds and pumpkin seeds.

Monounsaturated fats (MUFAs) are known to lower LDL cholesterol, without affecting HDL cholesterol. Some studies even indicate that increased consumption of MUFAs can help improve HDL cholesterol. In fact, researchers have found that the Mediterranean diet, a diet rich in monounsaturated fats, gives lower incidences of coronary heart disease. It is also believed that MUFAs can offer protection against certain cancers, such as breast and colon cancers. MUFAs are also abundant in Vitamin E, an antioxidant that protects against free radical damage. Free radicals are often associated with aging, development of cancers and heart disease. Rich sources of MUFAs include: avocado, olive oil, canola oil, hazelnuts, brazil nuts, almonds, walnuts, cashews, sesame seeds and pumpkin seeds.

Trans-fat

What is trans-fat? Trans-fat actually originates from healthier oils like vegetable oils (e.g. olive or canola) and fish oils, but through a process called hydrogenation where hydrogen bonds are added, the fat's configuration is altered to a "trans" state. Trans-fat is generally added to foods to extend shelf life and enhance flavor.

Besides saturated fat and cholesterol, there is scientific evidence to show that trans-fat also raises LDL cholesterol, thus increasing the risk of coronary heart disease. Essentially, it is best to avoid food products that are labeled with ingredients containing "partially hydrogenated or hydrogenated vegetable oils". Where can trans-fat be found? Virtually almost all processed foods, such as margarine, shortening, french fries, snack foods such as potato chips, and cookies contain high amounts of trans-fat.

Food preparation

Frying should be avoided as much as possible as it damages healthier oils like PUFAs and MUFAs. The high heat oxidizes the oil and generates free radicals that are harmful to the body. But if you do fry, which types of cooking oils on the market are then best suited for the job? Polyunsaturated fat sources, e.g. corn, sunflower, safflower and soybean oils, are not recommended for frying as they are chemically unstable, especially when exposed to heat.

Never fry at high heats with corn oil for it has a high tendency to produce foam and smoke.
But the use of tropical oils is the preferred choice when frying, e.g. palm oil, which is a major component in common vegetable oils. Even though palm oil is high in saturated fat, it has a good oxidative stability during frying, owing to its fat composition and vitamin E content. In terms of daily sautéing or stir-frying, canola and olive oils top the list.

Thus, it is recommended to have at least two different oils at home for different cooking methods. However, the answer does not lie in choosing the best oil among cooking oils that offer health benefits, but in using them sparingly. All cooking oils are still 100% fat and pack approximately 126 calories per tablespoon.

Natural fats or supplements?

Having listed the many benefits of certain fats such as Omega-3 fatty acids, some consumers may choose to obtain such fats in the form of supplements. However, studies indicate that extracted and artificially isolated nutrients may not exert the same benefits as wholesome foods. In fact, most nutrients work in synergy with other nutrients. By consuming a single nutrient, you may be missing out on other beneficial nutrients that are included in wholesome foods as well. Whole foods also offer lower risk of toxicity than supplements.

References:
"The intake of fried virgin olive or sunflower oils differentially induces oxidative stress in rat liver microsomes". British Journal of Nutrition. February 2002.
Holford, P. "New Optimum Nutrition Bible". Piatkus Books Ltd. 2004.
Mackay, S. "Techniques and Types of Fat used in Deep-Fat Frying - A policy statement and background paper prepared by the Heart Foundation of New Zealand". July 2000. http://www.nhf.org.nz/files/Food_Industry/deep_fat_frying_exec_summary.pdf