Nutrition of Fats and Oils: Good Fats to Poisonous Fats
Can Fats and Oils be Good for You?
Good fats?? It is hard to accept that fat can be good. Most of us grew up when fat was bad, low-fat was good, and no-fat was supposed to be the best. This picture has been shown to be wrong, we actually need fat, at least the good kinds of fat.
Fat is a broad category of organic compounds that help make up the body. Fat, oil, lipids are all similar terms. Lipid is the more scientific term for fat compounds. The term fat is often used generally and more specifically when the fat is solid at room temperature. Oil is the term used for fats that are liquid at room temperature. And the term fatty acid is used for a building block of a fat; these are a large part of what is absorbed into our blood within our intestines.
Fats are used to build the membranes of all cells. This is particularly critical for brain cells (called neurons), as a brain is around 70% fat by weight. Also, many vitamins also depend upon fat to dissolve and be absorbed by our cells and tissues. These include vitamins A, D, E, and K. A truly fat-free diet would be very unhealthy.
There are several ways to classify fats. Structure is great for chemists, but I prefer to consider fats by how they affect the body – great fats, good fats, and poisonous fats.
Great Fats: Omega-3 Fatty Acids
The research has been piling up - Omega-3 oils are great! We need them. In fact, their disappearance from our diets may help explain the epidemics of heart disease and degenerative brain diseases; possibly even cancer and obesity.
Omega-3 fatty acids are found in a number of plant food sources, including flax seeds and walnuts, and in low amounts in many green leafy vegetables. Another great source is from cold water fatty fish, including salmon, tuna, trout, sardines, and herring.
Fish oils are great because the omega-3 components are already built into compounds the body uses, DHA and EPA. The brain in particular needs these fatty acids to properly build the cell membranes, which are primarily made from these components.
Omega-3 fatty acids are often called essential because our body can not make these fats, so we must eat them in our diet. DHA and EPA are fats we make from Omega-3 fatty acids and are the actual fats used in our body, especially cell membranes (most of the brain). So if we eat DHA or EPA we get what we need, but if we at least eat enough Omega-3’s we should be able to make what our body needs.
The benefits are so important that most baby formulas and many other foods now have added DHA, EPA, ARA, or omega-3. They have been shown to increase the IQ in those children who received them during fetal development and the first year of life (Pediatrics March 2003; J. Clinical Nutrition October 1999; J Pediatrics October 2001). Eye development and function also improved.
Other strong evidence shows the incidence of Alzheimer’s reduces (or is delayed) along with other neuro-degenerative diseases. Omega-3 fats are also known to improve mood, reduce depression, and even lower episodes of bipolar disorder (manic depression). A very recent study found eating two servings of fish each week reduced Alzheimer’s by almost 60% (Archives of Neurology October 2006). A National Institutes of Health study claims 40% of death from heart disease and 95% of depression are due to deficiencies in DHA and EPA (Amer J Clinical Nutrition 2001 & 2002).
The heart benefits are so well documented that even prescription versions of fish oil are now available. People who ingest omega-3 fats and oils have dramatically lower risks for heart attacks and strokes. It should be noted that omega-3 oils do ‘thin’ the blood, and so anyone taking blood thinners must check with their physicians about how to add these important oils to their diet.
Additional benefits that the evidence points to probably includes reducing the development of arthritis, diabetes, vision problems, some cancers, reduction in menstrual cramping, and helping clear and improve the skin and hair.
One important note regarding Omega-3 fats and oils is that our diet needs to have as much of these as the more common Omega-6 type. Most Americans eat plenty of Omega-6 and the imbalance appears part of the disease process (Nutrition Health Conf 2006). Most vegetable oils, including corn, are primarily Omega-6 and so should be avoided or eaten in small quantities. Canola oil is an almost even balance and so is a good choice for cooking. Flax seed oil is so lightweight that it can not be used in cooking, but in foods that do not need heating, it is a great way to try to improve the balance.
Good Fats: Monounsaturated Fats (MUFA)
Monounsaturated oils and fats are known to be kind to the heart. They help increase the good cholesterol (HDL), lower the bad cholesterol (LDL), and basically are good for the body systems.
Olive oil (virgin and extra virgin) is the best known MUFA, and boasts chemicals that may fight breast and colon cancer. Olive oil is clearly a good choice for use. In one major study it was found to lower blood pressure.
Grape seed oil has also been found to have many of the same benefits as olive oil. Canola oil also contains MUFA, as do peanuts (and peanut oil), nuts, avocados, and olives themselves.
Okay Fats: Polyunsaturated Fats
Polyunsaturated fats have not been implicated in heart disease, but many contain high levels of Omega-6 fats, which unbalance the cells. This imbalance means the body can not produce essential fats in sufficient quantity. Omega-6 oils have been connected with dry and scratchy eyes and increasing the rate of prostate cancer cell growth.
Omega-3 fats are in this polyunsaturated group, but because they are so healthy, have been dealt with separately above. Sources of the polyunsaturated oils include soybean, corn, safflower, sunflower, and cottonseed oils.
Bad Fats: Saturated Fats and Bad Cholesterol
Saturated fats are those that are found in meats and dairy. Saturated fats are known to raise the levels of bad cholesterol, they appear to harm other heart protective mechanisms, and they damage the brain cells involved in memory, raising the risk of dementia.
It is important to note that some body fats are saturated and are used to make what our body needs, such as steroid hormones. The great thing is that we can make all we need from the good fat in our diet.
It is best to eat only lean meats, avoiding visible fat, chicken skin, and dark poultry meat. Whole milk dairy foods, including butter, ice cream, cream, sour cream, and full-fat cheeses, should be avoided or minimized in the diet. Lard and shortening from animal fats should not be used, substituting a polyunsaturated oil for high temperature frying.
Poisonous Fats: Trans Fats and Interesterified Fat
The U.S. government now says that trans fats are so bad they need to be on the label of foods. Cities, such as New York, are banning them from restaurant meals. Why are these widely used fats so scary?
A fat that is great for manufacturers has become one of the most commonly eaten fats by Americans – trans fats. These trans fats are often called hydrogentated or partially hydrogenated oils because they have undergone a process of adding hydrogen molecules under heat that has transformed their structure. Trans fats are great for manufacturers because the oil solidifies for products needing hardened fats, and the oil does not break down so the shelf life of food products is increased.
Unfortunately the same reasons that make trans fat good for shelf life make it bad for the body. The inability of heat and bacteria to break down trans fats also are indicative that these fats are extremely difficult to break down for the body to use in productive ways. It increases the amount of fat in the belly, and even causes extra fat cells to be created, probably in an attempt to try to have sufficient stored levels of needed types of fat. The body becomes starved for quality oils that can help build neurons, cells membranes, and other necessary structures.
Trans fats have been linked to raising bad cholesterol levels, lowering good cholesterol levels, increasing plaque buildup in the arteries, and causing inflammation throughout the whole body. This triggers a host of problems, from increasing diabetes and dementia, to triggering strokes.
Most restaurant and grocery store foods have either removed trans fats or reduced them significantly. It would be healthiest if they were eliminated completely. The other problem is that some food producers have substituted interesterified fats for the trans fat, but recent research indicates they may cause many of the same problems (Nutrition & Metabolism January 2007). They should also be completely avoided. You must read the ingredient list carefully to find out if these are being added to your food. Ingredient lists indicate if hydrogenated, partially hydrogenated, or interesterified fats have been included.
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