Monounsaturated And Saturated Oils

Last month we learned about vegetable oils, and how most of them are unhealthy, highly-manufactured food products. Despite the claims that polyunsaturated vegetable oils are healthier than saturated fats, we learned that they are unhealthy due to their instability at high temperatures, which take place not only during the manufacturing process, but while cooking with them. The toxic substances produced are damaging to our health.

Before we get into a discussion of saturated and monounsaturated vegetable oils in more detail, let us look at the structure of fats to better understand the differences between various fats and their impact on our health. Fat molecules are made up of fatty acids—long chains of molecules, made up of carbon, hydrogen, and oxygen. There are about 16 different types of fatty acids; however, each fatty acid is slightly different in structure, and each has many jobs in our body. The carbon atoms are joined together with either a single bond or a double bond. If two carbon atoms are linked together by single bonds (C-C), they have the maximum amount of hydrogen atoms attached to them. In other words, they are “saturated” with hydrogen atoms. Along the full chain of the fatty acid, the more single bonds between carbons, the more hydrogen atoms are attached, and the more saturated the fat becomes. In some fatty acids, a pair of hydrogen atoms in the middle of the chain is missing, creating a gap that leaves two carbon atoms connected by double bonds (C=C) instead of single bonds. Because the chain contains fewer hydrogen atoms, it is said to be “unsaturated.” A fatty acid with one double bond is called “monounsaturated” because it has one gap; the rest of the carbon bonds are single-bonded. Fatty acids having more than one gap are called “polyunsaturated”. This is what the difference is between saturated, monounsaturated and polyunsaturated fats. In foods of animal origin, a large proportion of fatty acids are saturated. In contrast, in foods of plant origin, a large proportion of the fatty acids are unsaturated. Here is a diagram of the chemical bonds:

What are the implications of fats either being saturated or unsaturated? In saturated fats, when all the bonds between carbon atoms are single bonds, it creates chemical stability. These “non-reactive” fats were traditionally used for higher heat cooking. Unsaturated fats with missing hydrogen atoms create chemical instability. And, the more double bonds a fat contains, the more reactive it is to heat, light, and oxygen. If we look at a couple of examples, monounsaturated oleic acid (a type of fatty acid), contained in olive oil has only one double bond and is relatively stable, considered safe for medium-heat cooking. On the other hand, polyunsaturated linoleic acid—dominant in soybean and canola oil—has two double bonds, and is considered highly unstable, making the fat highly reactive to light, heat, and oxygen. As a result, these so-called polyunsaturated “good” fats (referred to this way by nutritionists and other health experts) should not be used in cooking. Because of their reactivity, at high heat, these fats generate unwanted free radicals and poisonous aldehydes, which cause cancer, raise blood pressure, contribute to heart disease, increase cholesterol (counteracting the claim that polyunsaturated oils lower cholesterol levels) and other health issues. These diseases occur because the body is depleted of healthy antioxidants as they are used to rid the body of the free radicals produced by these oils. Therefore, it is not just a matter of choosing oils that are healthy, but also whether they stay healthy when used in cooking.

Now we can understand more clearly as to why vegetable oils are classified as either saturated, monounsaturated, or polyunsaturated oils, and what each implies when we use these oils in cooking. All vegetable oils are a mix of fatty acid types. When we classify an oil as either saturated, monounsaturated, or polyunsaturated, we classify it by the most predominant fatty acid it contains. While we think of olive oil as monounsaturated, it, in fact, contains monounsaturated, polyunsaturated and saturated fatty acids. Oleic acid, a monounsaturate, merely predominates. Every vegetable oil has about 120 calories and 13 g of fat per tablespoon. What really makes the oils different is their composition: Each one has a unique ratio of saturated fat to monounsaturated fat (MUFA) to polyunsaturated fat (PUFA). This ratio determines whether the oil is a solid or a liquid, how well it can withstand high temperatures, and what effects it will have on the human body. Fatty acid viscosity (thickness) and melting temperature increases with decreasing number of double bonds; therefore, monounsaturated fatty acids have a higher melting point than polyunsaturated fatty acids (more double bonds) and a lower melting point than saturated fatty acids (no double bonds).  Because unsaturated fats they have a double bond somewhere in their chemical structure, it causes them to be bulkier when interacting with other unsaturated fat molecules. This results in these fats being fluid at room temperatures. Monounsaturated oils are liquid at room temperature; however, they become semisolid or solid when refrigerated. Saturated oils are often solid at room temperature.

The chart on the right indicates the percentage of each type of fatty acid in the most common vegetable oils. The type of fat in the highest percentage defines the oil as either saturated, monounsaturated or polyunsaturated:

Stability of oils during heating is tested in two ways. The first is the smoke point of the oil. This is the temperature at which the oil begins to break down and smoke. Once the smoke point is reached, the oil begins to burn, and you destroy essential nutrients. Overheating also produced harmful free radicals. The more refined an oil is, the higher will be the smoke point. This is not always a good thing, as the more refined an oil is, the more processing has taken place to produce it. The second test is the oxidative stability, how resistant the oil is to reaction with oxygen. Some polyunsaturated oils have higher smoke points, but they oxidize much easier than the other oils. The conclusion would be to use more saturated and monounsaturated vegetable oils in cooking, which tend to be more stable when heated, and are less refined. Let us examine whether using these oils are healthy, or just less damaging than polyunsaturated oils, but still unhealthy.

MONOUNSATURATED OILS

This class of vegetable oils, also known as Omega-9 fatty acids, includes olive, peanut, avocado, and canola. As we learned last month, although canola is considered a monounsaturated oil, because of the need to process the canola plant so extensively to extract the oil from it, canola oil is considered unsafe to use.

Olive oil especially is well known for its heart healthy effects and is believed to be a key reason for the health benefits of the Mediterranean diet. It contains 74% monounsaturated fatty acids. It has fats that contain predominantly only one double carbon bond; therefore it can be used in cooking as it is fairly resistant to heat and oxidation. It has a lower smoke point than some other oils; but, cooking on the average home stove, roasting in the oven or even sautéing or pan frying over medium heat does not affect the quality of olive oil. Therefore olive oil is a healthier alternative.

Olive oil can also be used cold in salads, etc. Olive oil, especially cold-pressed olive oil is processed without using heat, making it healthier than oils manufactured in high heat conditions. It contains much more nutrients and antioxidants, and is less refined. Keep olive oil in a cool, dry, dark place, to prevent it from going rancid. The composition of avocado oil is similar to olive oil, it is high in vitamin E; however, it can be expensive. It can be used for many of the same purposes as olive oil. You can cook with it, or use it cold. Peanut oil can also be used in higher temperature cooking; however, it can sometimes be chemically extracted. Pick varieties labeled “roasted,” “toasted,” or “expeller-pressed” to avoid this.

Research shows that diets with healthy amounts of monounsaturated fats have a host of health benefits, including:

  • Decreased risk for breast cancer.
  • Raises HDL (good) and lowers overall levels of cholesterol.
  • Lower risk for heart disease and stroke.
  • Weight loss.
  • Decreased blood pressure.
  • Less severe pain and stiffness for sufferers of rheumatoid arthritis
  • Reduced belly fat.
  • Are a great source of Vitamin E

Monounsaturated oils are considered the most healthy oils to use in cooking because of their health benefits and lack of harmful effects on our bodies.

SATURATED OILS

The group of saturated vegetable oils include coconut, palm, and palm kernel oils. Much of the saturated fats in plant-based oils can increase the “bad” cholesterol, but on the other hand they also increase the amount of “good” cholesterol. However, when it comes to high heat cooking, saturated fat oils, especially coconut oil, is your best choice. Close to 90% of the fatty acids in it are saturated, which makes it very resistant to heat. They do not product any free radicals, and do not oxidize to product harmful by-products.

Coconut oil is semi-solid at room temperature and it can last for months and years without going rancid. Coconut oil also has powerful health benefits. Coconut oil is composed of a special kind of saturated fat called a medium-chain fatty acid (MCFA). MCFAs are burned rapidly by the liver and used for energy instead of being stored as fat. There is increasing evidence that an MCFA contained in coconut oil—lauric acid—can actually improve cholesterol levels and help kill bacteria and other pathogens. The fats in coconut oil can also boost metabolism slightly and increase feelings of fullness compared to other fats. It also makes a great natural moisturizer, and can be substituted for butter. Make sure to choose virgin coconut oil as it is organic, it tastes good and it has powerful health benefits.

Palm oil has slightly less saturated fat than coconut oil. Red palm oil, the unrefined version also contains nutrients such as vitamin E, Coenzyme Q10 and the antioxidant beta-carotene. It also has a very long shelf life before it becomes rancid.

Dietary fat was never all good or all bad; and saturated fat is not now all good, after having formerly been all bad. It depends on the specifics, which in turn depend on the foods you choose. There is increasing evidence that not all saturated fats are equal in their health effects. Overall, saturated vegetable oils are much healthier than saturated fats found in animals. The saturated fats—notably palmitic and myristic acids, which are found in dairy, meat and many processed foods—can increase blood lipids, initiate plaque build-up, contribute to vascular disease and inflammation.

Overall, saturated vegetable oils are not considered as healthy as monounsaturated vegetable oils as they can raise, however they are healthier than polyunsaturated vegetable oils when used in proper amounts. The recommendation is to keep the use of saturated fats to 10% of the daily calories in one’s diet. This equates to 1–2 Tablespoons per day.

CONCLUSION:

Since all vegetable oils and foods contain a mix of fatty acids, we are almost never making pure comparisons of one type of fat to another; and for this reason, we might expect to see some overlap in positive or negative health effects. For example, if we say that if olive oil, which is mostly monounsaturated fat, is good for our health, we have to acknowledge that olive oil also contains some saturated fat when we make that conclusion. In the world of fats, “all good” vs. “all bad” is never really the case. However, most experts will agree that cooking with olive oil is the best  “compromise” available.

Choose wisely when you make all food selections—plant foods, and those which are closest to their natural state—and you will avoid a host of ailments arising from the wrong kinds of fat, to excesses of sugar, salt, starch and calories. By choosing wholesome foods, you construct a wholesome diet, as God intended, which will improve, not only your quality of life, but years of life. Vegetables, fruits, whole grains, walnuts, almonds, lentils, beans, seeds, olives, and avocados are all among the foods most decisively recommended for health promotion. Also, they all contain healthy fats that are not found in the more processed foods, including vegetable oils.