What is a fat?

Fat is substance made from molecules of hydrogen, carbon and a little oxygen. What kind of fat it is depends on the different combinations of these molecules. 

What are the Essential Fatty Acids:

Essential Fatty Acids (EFAs) are necessary fats that humans cannot synthesize, and must be obtained through diet. EFAs are long-chain polyunsaturated fatty acids derived from linolenic, linoleic, and oleic acids. There are two families of EFAs: Omega-3 and Omega-6. Omega-9 is necessary yet "non-essential" because the body can manufacture a modest amount on its own, provided essential EFAs are present. The number following "Omega-" represents the position of the first double bond, counting from the terminal methyl group on the molecule. Omega-3 fatty acids are derived from Linolenic Acid, Omega-6 from Linoleic Acid, and Omega-9 from Oleic Acid.

Essential fatty acids are necessary to make cell membranes and for many of the important hormones and other chemical messengers that tell your body what to do. 

Omega-3 and Omega-6 essential fatty acids are especially important for making prostaglandins in your body. Prostaglandins are hormone-like substances that regulate many activities in your body including inflammation, pain, and swelling (some cause swelling and others relieve it). They also play a role in controlling your blood pressure, your heart, your kidneys, your digestive system, and body temperature. They are important for allergic reactions, blood clotting and making other hormones. 

Fatty acids are also natural blood thinners; they can prevent blood clots, which can lead to heart attack and stroke. Essential fatty acids contain natural anti-inflammatory compounds that can relive the symptoms of arthritis and autoimmune diseases. In addition, a diet low in essential fatty acids could result in skin problems, such as dandruff, eczema, splitting nails and dull brittle hair. 

Fatty acids influence the structure of the cells lining the intestinal tract, as well as the "villi" through which absorption of nutrients takes place. They increase the thickness and surface area of the digestive-absorptive cells that line the inside of our intestine. This results in more effective digestion, better absorption of nutrients, less absorption of allergens, and better health.

More importantly, numerous studies have shown that compounds found in essential fatty acids can block tumor formation in animals, and test tube studies have documented that omega-3 fatty acids can inhibit the growth of human breast cancer cells. 

Your brain is actually 60 percent fat - and DHA (an Omega-3 essential fatty acid) is the most abundant fat in your brain. It's also the most abundant fat in breast milk, since babies need it to nourish their growing brains and eye development. This Omega-3 fat seems to be important mostly for connecting brain cells to each other and making sure the transmission of brain signals get through right. It is also found in high concentration in the retina of the eye. 

Low levels of this Omega-3 fatty acid have been linked to an increase in dementia, mood changes, memory loss, and visual problems. In a Swedish study, elderly patients with Alzheimer's disease were found to have lower levels of this than healthy older people. Studies done at Purdue University showed that children diagnosed with attention deficit hyperactivity disorder had lower levels of these essential fatty acids. 

The Unbalanced Essential Fatty Acids:

Omega-3 essential fatty acid is essential to human health but is lacking in most Western diets. The balance of Omega-6 essential fatty acid and Omega-3 essential fatty acid should be four or five Omega 6 to each Omega-3 for a good balance. We get ample amounts of Omega-6 in the typical Western diet. The ratio in this diet is between 10 and 20 to 1 in favor of Omega 6, far too high in Omega-6. This unbalance encourages overproduction of some prostaglandins (hormone like substances your body makes that control many activities in your body). The imbalance causes many health problems by getting you body hormones and chemicals out of whack. 

Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA)

"There has been a dramatic surge in interest recently, amongst the public and health professionals alike, of the health effects of omega-3 fatty acids derived from fish and fish oils - consisting of docosahexaenoic acid (DHA) plus eicosapentaenoic acid (EPA). DHA is required in high levels in the brain and retina as a physiologically-essential nutrient to provide for optimal neuronal functioning (learning ability, mental development) and visual acuity, in young and old alike. DHA plus EPA are both considered to have beneficial effects in the prevention and management of cardiovascular disease plus associated risk factors as well as other chronic disorders. Whereas considerable amounts of the plant-derived omega-3 fatty acid known as a-linolenic acid (ALA) is consumed daily in North America (approximately 2 g/day), the physiologically-essential nutrient, DHA, is consumed at much smaller levels (approximately 80 mg/day) while EPA is consumed at the level of approximately 50 mg/day in a typical North American diet.

DHA plus EPA are absent from plant food sources rich in ALA (such as flax, canola oil, and walnuts). Since the metabolic conversion of ALA to DHA/EPA (combined) by metabolism is very limited in humans, the most direct way of providing DHA plus EPA for the body is via their direct consumption. Current intakes of DHA are approximately 20% of the target (300 mg/day) suggested by an expert scientific group during pregnancy and lactation. The extremely low intake of DHA in young children (e.g., approximately 19 mg DHA/day on average for 3-yr. olds in North America) is also of particular concern. Current intakes of DHA/EPA (combined) of 130 mg/day are approximately 15% of the target (900 mg/day) officially recommended by the American Heart Association for those with coronary heart disease and 20% of the 650 mg/day advised by an expert scientific group for healthy individuals. In view of the widespread reluctance of the public to consume sufficient amounts of fish, functional foods containing DHA plus EPA will become increasingly important sources of these important nutrients in the coming years to support optimal brain/visual performance, for cardio care, and other health conditions for young and old alike."¹

Omega-3 (Linolenic Acid)

Omega-3s are a type of polyunsaturated fat. The Omega-3 (called ALA) found in plant sourced foods such as canola oil, linseeds and walnuts needs to be converted by the body to the long chain Omega-3s to be used effectively. Alpha Linolenic Acid (ALA - shorter chain) is the principal Omega-3 fatty acid, which a healthy human will convert into eicosapentaenoic acid (EPA), and later into docosahexaenoic acid (DHA). EPA and the GLA synthesized from linoleic (Omega-6) acid are later converted into hormone-like compounds known as eicosanoids, which aid in many bodily functions including vital organ function and intracellular activity. Unfortunately this conversion is very inefficient so it is desirable to include long chain Omega-3s in the diet as well. These are found in oily fish, other fish and seafood and to a lesser extent in meats and eggs.

Long chain Omega-3s are used effectively in the body. DHA is a major building block of the brain. The retina in the eye is very concentrated in DHA. Other vital organs such as the heart are rich in long chain Omega-3s.

Both EPA and DHA are transformed to other active substances in the body which have anti-inflammatory and protective roles.

Omega-3s are used in the formation of cell walls, making them supple and flexible, and improving circulation and oxygen uptake with proper red blood cell flexibility and function.

Omega-3 deficiencies are linked to decreased memory and mental abilities, tingling sensation of the nerves, poor vision, increased tendency to form blood clots, diminished immune function, increased triglycerides and "bad" cholesterol (LDL) levels, impaired membrane function, hypertension, irregular heart beat, learning disorders, menopausal discomfort, itchiness on the front of the lower leg(s), and growth retardation in infants, children, and pregnant women.

Found in Food:

Food sourced from animals contains long chain Omega-3s. Oily fish like salmon (>2000mg/100g), other fish like hoki (410mg/100g), Blue eye cod (300mg/100g), canned tune (230mg/100g), snapper (220mg/100g), saltwater barramundi (100mg/100g) and other fish. Regular size egg provide about 80mg/100g,

Flaxseed oil (flaxseed oil has the highest linolenic content of any food), flaxseeds, flaxseed meal, hempseed oil, hempseeds, walnuts, pumpkin seeds, Brazil nuts, sesame seeds, avocados, some dark leafy green vegetables (kale, spinach, purslane, mustard greens, collards, etc.), canola oil (cold-pressed and unrefined), soybean oil, wheat germ oil, and others.

Omega-6 (Linoleic Acid)

Linoleic Acid is the primary Omega-6 fatty acid. A healthy human with good nutrition will convert linoleic acid into gamma linolenic acid (GLA), which will later by synthesized, with EPA from the Omega-3 group, into eicosanoids.

Some Omega-6s improve diabetic neuropathy, rheumatoid arthritis, PMS, skin disorders (e.g. psoriasis and eczema), and aid in cancer treatment.

Although most Americans obtain an excess of linoleic acid, often it is not converted to GLA because of metabolic problems caused by diets rich in sugar, alcohol, or trans fats from processed foods, as well as smoking, pollution, stress, aging, viral infections, and other illnesses such as diabetes. It is best to eliminate these factors when possible, but some prefer to supplement with GLA-rich foods such as borage oil, black currant seed oil, or evening primrose oil.

Found in foods:

Flaxseed oil, flaxseeds, flaxseed meal, hempseed oil, hempseeds, grapeseed oil, pumpkin seeds, pine nuts, pistachio nuts, sunflower seeds (raw), olive oil, olives, borage oil, evening primrose oil, black currant seed oil, chestnut oil, chicken, among many others.

Avoid refined and hydrogenated versions of these foods.

Corn, safflower, sunflower, soybean, and cottonseed oils are also sources of linoleic acid, but are refined and may be nutrient-deficient as sold in stores.

Omega-9 (Oleic Acid)

Essential but technically not an EFA, because the human body can manufacture a limited amount, provided essential EFAs are present.

Monounsaturated oleic acid lowers heart attack risk and arteriosclerosis, and aids in cancer prevention.

Found in foods:

Olive oil (extra virgin or virgin), olives, avocados, almonds, peanuts, sesame oil, pecans, pistachio nuts, cashews, hazelnuts, macadamia nuts, etc.

One to two tablespoons of extra virgin or virgin olive oil per day should provide sufficient oleic acid for adults. However, the "time-released" effects of obtaining these nutrients from nuts and other whole foods is thought to be more beneficial than consuming the entire daily amount via a single oil dose.

Reference:

1. Extracted from http://www.dhaomega3.org/