Types of Oils & Fats
Oils are classified as Saturated, Monounsaturated or Polyunsaturated. Saturation refers to the carbon-hydrogen makeup of the oil. The more hydrogen atoms there are, the greater the degree of saturation and solidity of the oil. The greater the saturation of a fat, the longer it is able to remain stable (unaltered or unchanged). All oils contain all three types of lipids in varying percentages and are classified according to which type predominates.
Polyunsaturated oils include the Essential Fatty Acids (EFA’s) Omega 3 (linolenic acid), and Omega 6 (linoleic acid). The body cannot make these fatty acids and hence they are called “essential”: we must obtain EFA’s from the foods we eat. Polyunsaturates have a shorter shelf life, as they are less stable than other oils and are prone to rancidity, particularly those highest in Omega 3 which must be kept refrigerated. They should never be heated or used in cooking as they are damaged by heat. These oils do not solidify even when cold. Grain, Seed and Fish oils are mainly polyunsaturated. The Omega 3 and 6 oils are Long Chain fatty acids.
Omega 3 essential fatty acids are important for healthy nervous systems, cholesterol levels, brain function, are shown to reduce the incidence of Alzheimer’s disease and dementia, and can reduce inflammation. Highest quantities of Omega 3 fats are found mainly in Flaxseed oil and Walnut oil. Omega 3 converts into the Very Long Chain fatty acids EPA and DHA in the body, both of which are immediately available from marine plankton, algae, and fatty fish. In average, the North American intake of Omega 3 fatty acids has shrunk to one sixth of 1850 levels. Note: Those suffering from any type of bleeding disorder (thrombocytopenia, hemophilia) should consult a doctor before taking Omega-3, as it can hinder the body’s ability to clot blood.
Omega 6 (linoleic acid, LA) essential fatty acid is needed for the conversion in the body to Gamma Linoleic Acid (GLA) and ultimately to the Very Long Chain fatty acid DHLA, which produces prostaglandin, hormone-like molecules that help regulate inflammation and blood pressure, as well as heart, gastrointestinal and kidney functions. A deficiency of Omega 6 fatty acid is extremely rare in diets of those living in North America, although there is a lack of GLA. Although Omega 6 oils are abundant in the diet, many people have difficulty using LA due to an impairment in a critical enzyme known as Delta-6-Desaturase, or “D6D”. Without this enzyme, the body cannot convert LA into GLA. D6D function is impaired in many people partially due to lifestyle factors such as smoking, sugar and alcohol consumption, stress, vitamin deficiencies, as well as high levels of saturated fat and trans-fatty acids in the diet. Ironically too much LA in the diet can also interfere with the conversion from LA into GLA. Some oils contain naturally occurring GLA, but unfortunately these are not the Omega 6 oils most North Americans consume. Main sources of Omega 6 fats are Pumpkin seed, Sesame seed, Sunflower seed and Safflower oils. Foods rich in GLA include Evening Primrose, Black Currant, Borage and Hemp Oils and Spirulina. Including GLA rich sources in the diet assures the body gets this essential nutrient.
The Omega 6 and 3 Connection
North American diets tend to have too much Omega 6, particularly in relation to Omega 3 fatty acids. This imbalance contributes to long-term diseases such as heart disease, cancer, asthma, arthritis, and depression.
A healthy diet would have a 1:4 ratio (1 part Omega-3 to 4 parts Omega-6).
A typical American diet presents between 1:11 to 1:30 ratio ( 11 to 30 times more omega-6 than omega-3 fatty acids).
The Essential Fatty Acid blend oils that are available in natural foods stores have been developed to help offset the imbalance of EFA oils we consume. They focus on providing supplementary Omega 3 oils, and quality sources of GLA.
Most commercially available vegetable cooking oils are in the form of polyunsaturated Omega 6, which contain little to no Omega 3. Modern agricultural and industrial practices have also reduced the amount of naturally occurring Omega 3 in commercially available vegetables, eggs, fish and meat. This dietary imbalance has created a culture deficient in Omega 3 EFA’s, which is disruptive for many vital metabolic functions and optimal health.
|EFA Comparison in Foods|
|Food||Omega 3||Omega 6||Food||Omega 3||Omega 6|
|Hemp Seeds||7||21||Olive Oil||0.6||7.9|
|Pumpkin Seeds||3.2||23.4||Wheat Germ||0.5||5.5|
- Essential Fatty Acids are specific polyunsaturated oils required from the diet, in a certain ratio for optimal health.
- The North American diet contains high amounts of highly processed Omega 6 oils and very little GLA and Omega 3 oils.
- Enriching the diet with EFA oils or supplements focusing on quality sources of Omega 3 and GLA can help normalize the balance of these essential nutrients in the body.
- High quality polyunsaturated oils require refrigeration, have a short shelf life and are liquid at room temperature.
Monounsaturated fats are generally liquid at room temperature and either semi-congealed or solid when refrigerated. These oils are more stable and do not go rancid as easily as the polyunsaturated oils, hence they can be used in cooking. The non-essential fatty acids Omega 7 and 9 are in this group.
Monounsaturated fats lower LDL (low density lipo-protein or the so called “bad”cholesterol), while at the same time raising HDL (high density lipo-protein or the “good” cholesterol). The consumption of highly monounsaturated olive oil in Mediterranean countries is considered to be one of the reasons why these countries, which have an unusually high-fat diet, have a lower incidence of heart disease. The body makes monounsaturated fatty acids from saturated fatty acids.
Omega 7 is a non-essential fatty acid used in our most delicate body tissues, such as skin and mucous membranes that line the digestive and urogenital tracts. Sources include Macadamia Nut and Sea Buckthorn oils.
Omega 9 non-essential fatty acid promotes a healthy inflammation response. Sources include the oils of Avocado, Almond, Olive, Sesame, Oleic Sunflower and Safflower and Canola. Consuming more Omega 9 Oils over Omega 6s help to offset our consumption of Omega 6 oils in our diet, balancing our fatty acid profile to a ratio our bodies prefer.
- Monounsaturated oils are helpful for maintaining a healthy cholesterol balance.
- The Mediterranean diet, known for its high fat intake and low rates of heart disease is high in these oils.
Saturated fats are solid at room temperature and are very stable maintaining their integrity when used in cooking. There is some controversy regarding the health effects of this oil. For years saturated fats were blamed for obesity, high cholesterol, and heart disease, but new research points to these fats as being beneficial to the diet. Elevated triglycerides in the blood have been positively linked to proneness to heart disease, but these triglycerides may not come directly from dietary saturated fats. Studies show that they are made in the liver from excess sugars that have not been used in energy production. The body turns these sugars into hard fats that make platelets sticky, interfere with insulin, and with EFA metabolism. The source of these excess sugars is any food containing carbohydrates, particularly refined sugar and white flour. Also many studies have not differentiated between saturated and trans-fats (see definition below).
There are in fact more than a dozen different types of saturated fat but we predominantly consume only three: stearic acid, palmitic acid and lauric acid.
It’s been well established that stearic acid (found in cocoa and animal fat) gets converted in the liver to the monounsaturated fat called oleic acid (the predominant fat in olive oil), which has no effect on cholesterol levels. The other two, palmitic and lauric acid, do raise total cholesterol. However, since they raise “good” cholesterol as much or more than “bad” cholesterol, the risk of heart disease is actually lowered. Lauric acid is also the main saturated fat in coconut oil, which is a Medium Chain fatty acid or MCT (for Medium Chain Triglycerides). These can be absorbed quickly and easily, as they do not require energy for absorption. MCT can contribute positively to the immune system. Throughout the years, studies have shown that these fats can help in the process of excess calorie burning, weight loss and are useful for those who cannot consume other fats.
Dietary saturated fats actually improve the body’s utilization of EFAs and protect them from becoming rancid. The body makes saturated fatty acids from carbohydrates. In foods, they are found in animal fats and tropical oils. Butter, Ghee, Lard, Coconut and Palm Oils are all saturated oils.
- Saturated oils are not as harmful to human health as has been commonly thought for many years and actually have many health benefits.
- Solid at room temperature and highly stable, these fats make great cooking oils.
|Proportions of Fats in Common Cooking Oils|
|Clarified Butter (Ghee)||5%||30%||65%|
|*More recently developed oil, higher in oleic acid and therefore more|
|monounsaturated than the regular variety of these oils.|
Chart adapted from “Healing with Whole Foods” by Paul Pitchford
Other Fat Related Products
is a fatlike substance called a phospholipid. The liver produces it daily if the diet is adequate. It is needed by every cell in the body and is a key building block of cell membranes. Without lecithin cell walls would harden. Lecithin protects cells from oxidation and largely comprises the protective sheaths surrounding the brain. Lecithin lowers cholesterol by liquefying arterial plaque. Although it is a fatty substance, it is also a fat emulsifier (keeps fats dispersed and in a suspension). Hence, it supports the circulatory system. High in choline, it is useful for making the neurotransmitter, acetylcholine and has been touted as a memory enhancer by improving cognitive function.
It is composed mostly of B vitamins, phosphoric acid, choline, linoleic acid and inositol.
It is found in high concentrations in soybeans, wheat germ, and peanuts and in the unfiltered oils of these foods, as well as in egg yolks and oats.