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Unhealthy and Healthy Fats
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| The Skinny on the Good, the Bad and the Adulterated | |||||
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Although well-intentioned and seemingly logical, the fat-free diet craze which began in the 1970's was based on a severe misunderstanding about dietary fat. It may have actually contributed to the current “diabesity” problem. Confident that, “as long as it was fat-free, it was okay,” many dieters compensated for lack of fat in the diet with sugar, often in unrestricted amounts. As people began to eat an abundance of fat-free ice creams, cookies, cereals, and breads, their insulin levels chronically soared. We now recognize that regular, excess insulin release can lead to insulin resistance and subsequent weight gain. We also know that low- or no-fat diets fats can cause depression, lethargy, and irritability due to deficiency of essential fatty acids.
Bottom line is, we need healthy fats; they should comprise approximately 30 percent of our daily caloric intake.
Fats are not only tasty, but satiating. By adding healthy fats to our meals, we may actually eat less overall. As fat is more calorically dense than carbohydrates and proteins (each gram of fat has 9 calories, while each gram of carbohydrate or protein has 4 calories), eating it can bring about a feeling of fullness. Additionally, as fat does not elicit an insulin response, eating it in moderation can actually make it easier for us to burn off our fat reserves and lose weight. Our bodies need fats to burn as fuel and for proper heart and brain function; the heart gets 60 percent of its fuel from fat. We also need fat to help us absorb fat-soluble vitamins like A, D, E, and K, as well as carotenoids.
The key to fats is good choices and moderation. Knowing which ones enhance health, and which ones deplete it, as well as in what amounts, puts us on the right track in choosing heart-healthy fuels for our bodies.
Which Fats are Healthy?
Our understanding of the healthiness or unhealthiness of fats is constantly evolving. Ten years ago, doctors and nutritionists told us that unsaturated fats (monounsaturated and polyunsaturated fats) were good and that saturated fats were bad. This is because our bodies convert most saturated fat into cholesterol, and, at the time, we thought high cholesterol was the root cause of cardiovascular disease. We have since learned that chronic inflammation and oxidized LDL cholesterol cause heart disease. Hence, we now consider fats which contribute to inflammation, rather than convert to cholesterol, unhealthy. We also are better aware that hydrogenated (unsaturated) fats, i.e. trans fats, are highly inflammatory and may underlie numerous health problems, like cardiovascular disease.
Fats can cause inflammation in several ways. They may, when digested, convert to pro-inflammatory chemicals. They may oxidize easily and cause inflammation because oxidation creates free radical activity. If in the presence of chemicals which cause it to oxidize, LDL cholesterol can indirectly cause inflammation. Whether a fat is inflammatory, then, depends on its chemical structure, specifically the type of fatty acids it contains:
· Monounsaturated fatty acids
· Polyunsaturated (include omega-3, omega-6 and omega-9) fatty acids
· Saturated fatty acids
· Hydrogenated, or trans, fatty acids (monounsaturated or polyunsaturated fatty acids with artificially added hydrogen atoms)
Generally, it’s best to eat more monounsaturated fats and omega-3 polyunsaturated fats than saturated fats, and to avoid hydrogenated, or trans, fats altogether.
Most foods contain a different combination of fats. Choose foods with fats that are primarily monounsaturated or contain omega-3 polyunsaturated fats because these fats are anti-inflammatory. Omega-6 polyunsaturated fats are tricky: they are inflammatory, but we need to ingest them in small amounts. Saturated fats can be inflammatory, in that they contribute to increased LDL cholesterol which can oxidize when in the presence of other substances, however, the body needs some dietary cholesterol. Saturated fats are also resistant to oxidation, making them good choices when consumed in small amounts.
Monounsaturated Fats:
As monounsaturated fats help reduce inflammation while not catalyzing insulin release, they help us lower our risk of heart disease. While olive oil is probably the best source of monounsaturated fat, we can also get it through foods like avocados, and various seeds and nuts. Monounsaturated fats are liquid at room temperature which is why the oil separates with freshly ground nut butters.
Olive oil is best consumed in uncooked form, since heat damages its health-enhancing compounds. For inevitable cooking, light or extra light olive oil is good for stir-frying or baking, while extra virgin olive oil works well for light sautéing, or drizzled on appetizers, salads, vegetables, etc. Try using monounsaturated olive oil in a spray bottle instead of polyunsaturated (canola-oil) non-stick cooking sprays.
Polyunsaturated Fats:
Polyunsaturated fats, also liquid at room temperature, are a double-edged sword when it comes to health. Those such as corn oil, safflower oil, and canola oil, were once the darlings of nutritionists because of their ability to lower LDL cholesterol. Unfortunately, they also lower HDL, the “good” cholesterol. Additionally, some polyunsaturated fats oxidize quickly in our bodies, making our cells more vulnerable to degenerative diseases like cancer, cataracts, Alzheimer’s disease, and cardiovascular disease.
Problem is, we need to consume some polyunsaturated fats because they contain essential fatty acids (EFAs). EFAs are “essential” because we don’t make them in our bodies, i.e. we must get them through the diet and possible supplementation. There are two major EFAs in polyunsaturated fats, alpha-linolenic acid (ALA) and linoleic acid (LA), which are also categorized as either omega-3s or omega-6.
While ALA, an omega-3, can help decrease inflammation, too much LA, an omega-6, can increase it. Our bodies convert LA to arachidonic acid (AA), a highly inflammatory polyunsaturated omega-6 fatty acid, which our bodies also produce in response to free radical activity. While necessary in small amounts, AA can be “too much of a good thing.” Excess AA can set into motion a cascade of biochemical events that raise blood pressure and can block arteries. The key to polyunsaturated fats, then, is to consume a balance of omega-3 and omega-6s (we will discuss EFAs in greater detail below).
Saturated Fats:
Saturated fats, such as butter, are found primarily in animal products such as meat, cheese, milk, full-fat yogurt and eggs. They are solid at room temperature and convert to cholesterol in the body. Plant sources of saturated fat, which do not convert to cholesterol, include palm and coconut oil. We need cholesterol in our bodies to maintain the integrity of cell membranes, produce cellular structures and hormones, and for digestion. While our bodies are able to generate about 85 percent of our cholesterol, we obtain the rest from dietary sources, like saturated fats.
The downside of saturated fats is that they can cause inflammation if our blood levels of LDL cholesterol are high and our blood also has too much homocysteine, ferritin (iron), and/or lipoprotein(a), or Lp(a). These three substances each increase risk of oxidation of LDL cholesterol, which can lead to dangerous unstable plaque in blood vessels. Reducing levels of these substances, then, can help reduce our risk of cardiovascular disease linked to saturated fat intake.
To prevent excess levels of homocysteine, we need to get enough B vitamins in our diets. While too much Lp(a) is usually genetically inherited, one can fight this predisposition by increasing vitamin C intake to help preserve arterial structure (prevent collagen loss). Donate blood to prevent high iron levels (for women, regular loss of menstrual blood helps serve this purpose).
For people who have a penchant for fatty meat, eggs, and dairy products, supplementing with coenzyme Q10, as well as fish oil, can help prevent oxidation of LDL cholesterol. Avoiding trans, or hydrogenated, fats like the plague will also help, as they cause LDL cholesterol to oxidize.
One of the benefits of saturated fats is that, unlike polyunsaturated (including trans) fats, they do not oxidize easily at high temperatures. Oxidation of fat itself, as opposed to LDL cholesterol, causes inflammation due to increased free radical activity and possible degenerative disease. Cooking with saturated fats like coconut oil, then will help prevent oxidation-related inflammation.
Animal sources of saturated fats, such as fatty meats and eggs, tend to also contain pro-inflammatory arachidonic acid (AA), an omega-6 polyunsaturated fatty acid. This may explain why high saturated fat intake has been linked to heart disease, hypertension, stroke, and diabetes, as well as cancer. As a general guideline, moderate saturated fat intake is okay if you stick to an otherwise healthy, non-inflammatory diet full of fresh fruits and vegetables.
Hydrogenated / trans Fats:
Hands down, hydrogenated / trans fats are the unhealthiest fats around. Trans fats are vegetable oils to which an extra hydrogen molecule has been artificially added. They are found in processed foods like margarine and commercial baked goods, as well as fried foods. While adding the hydrogen molecule makes these fats solid at room temperature and increases their shelf life, it does nothing to increase our shelf lives. Rather, consumption of trans fats severely increases inflammation in our bodies by causing free radical damage to cell membranes, and increasing blood levels of LDL cholesterol and lipoprotein a (Lp(a)), a toxic blood factor. Together, oxidized LDL molecules and Lp(a) are a deadly combination: they can cause buildup of plaque and formation of blood clots in arteries, which can result in heart attacks. Trans fats are also linked to increased risk of some cancers.
Read nutrition labels and avoid, at all costs, anything with the words “hydrogenated,” or “partially hydrogenated.” Also avoid fast foods. Trans fats are entirely absent in the fresh, natural diets of Mediterranean and Asian cultures (upon which the PAM, or Pan-Asian Mediterranean, diet is based). Substitute healthier fats like olive oil or sesame oil. More on Polyunsaturated EFAs: Omega 3s and Omega 6s
We must get two polyunsaturated fatty acids through the diet: linoleic acid (LA), an omega-6, and alpha linolenic acid (ALA), an omega-3. From LA, we get arachidonic acid (AA), which is necessary, albeit pro-inflammatory. From ALA, our bodies produce two other crucially important fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Omega-3s - EPA, DHA, and ALA:
Omega-3 fatty acids, which we need for brain function and normal growth and development, are anti-inflammatory and cardio-protective. They defend against heart attacks by preventing the formation and attachment of blood clots in our arteries, as well as the rupture of unstable arterial plaques. They also prevent spasms in blood vessels. Studies have also shown that higher omega-3 consumption, especially through dietary sources of EPA and DHA, is associated with lowered risk of heart disease.
EPA and DHA are omega-3s found in fish (and fish oil) that can help lower blood pressure and prevent arteriosclerosis (blood vessel damage due to thickened walls and loss of elasticity). Omega-3s stimulate both the production of chemical mediators which relax smooth muscles, and prostaglandins, hormones which prevent blood clots. Omega-3s are also vasodilative (they help keep blood vessels open so oxygenated blood can easily flow through), in that they block the effects of certain chemical mediators which raise blood pressure.
Research has also shown that fish and fish oils are great brain food. Omega-3s can help alleviate psychological problems including depression, bipolar disorder, and even suicidal tendencies. DHA, in particular, is critical for the development of the retina and the fetal brain, and is necessary for brain and male reproductive health.
It’s important to remember that fish may contain excessive amounts of mercury and other contaminants due to environmental pollution; the higher up the seafood chain, the greater the chance of toxicity. Try to find a pure, uncontaminated fish oil that contains both EPA and DHA, and/or eat small migratory fish like wild-caught Alaskan salmon, Atlantic halibut, and cod. Avoid eating farm-raised fish, which tend to contain greater levels of heavy metals in addition to insecticides and pesticides, as well as larger fish like shark, tuna, and swordfish. Eating fish three to four times per week, or supplementing with 1,000 mg of fish oil daily, can help us get the omega-3s we need for health maintenance.
Vegetarians and other people who don’t consume fish or fish oil can get the building blocks for EPA and DHA by consuming ALA. ALA is an omega-3 EFA that can be transformed in the body into small amounts of EPA and DHA. Ground flaxseed or flaxseed oil is a great source of ALA as well as fiber, which offers the added benefits of healthier skin, lower cholesterol, improved digestion, and a cleaner bowel. ALA is also found in walnuts, tofu, wheat germ, and green, leafy vegetables like spinach.
Omega-6s - LA:
In addition to omega-3s, we need also need omega-6s, which are essential for brain and reproductive health, as well as for bone, skin, and hair development. There are many different types of omega-6s. Some, like gamma-linolenic acid (GLA) found in evening primrose oil, are non-inflammatory. Others, like the essential linoleic acid (LA), can cause inflammation. LA tends to be the primary type of omega-6 we consume, perhaps due to its prevalence in meats and vegetable oils (e.g. sunflower, safflower, and soy), as well as in processed foods which contain these oils. From LA our bodies make pro-inflammatory AA. High LA consumption, in the absence of adequate omega-3 intake, is associated with oxidation of LDL cholesterol in the body, which can promote vascular inflammation. Omega 3 and 6 Balance: The Eicosanoid Perspective
Ideally, we should consume an equal amount of omega 3s and omega 6s to balance inflammatory activity. Generally, traditional Mediterranean diets reflect balanced EFA intake, while Western diets do not. Americans typically consume 14 to 25 times more omega-6s than omega-3s. Such imbalance is associated with the development health problems like cardiovascular disease, cancer, inflammatory and autoimmune diseases.
Our bodies break omega-3 and omega-6 fatty acids down to make eicosanoids, hormone-like substances which play roles in immune system response, blood pressure regulation, reproductive processes and regulation of the sleep/wake cycle. While eicosanoids generated from omega-3s are anti-inflammatory, those made from omega-6s promote inflammation. As a result, the former are commonly referred to as “good” eicosanoids, and the latter, “bad” eicosanoids.
While inflammation plays a necessary role in immunity, health can deteriorate when inflammation becomes chronic. Overproduction of “bad” eicosanoids due to overconsumption of certain omega-6 fatty acids can lead to chronic inflammation. We can limit inflammation by ingesting enough omega-3 fatty acids to balance “bad” eicosanoids with “good” ones.
A Word About Omega 9s
Omega 9s are a family of unsaturated fatty acids, which are not essential (i.e. the body produces them endogenously) nor do they contribute to either “good” or “bad” eicosanoid production. The oleic acid found in olive oil is an example of an omega-9.
Fats In a Nutshell
Fats can hurt or help us, depending on which kinds we ingest. Fats are crucial for growth, development, and heart and brain health, yet eating too much of the unhealthier types can cause unnecessary inflammation and otherwise compromise cardiovascular health. It’s important that we get approximately 30 percent of our daily calories from healthy, fats like monounsaturated and polyunsaturated omega-3s. Eating healthy fats can actually help us lose weight, as they promote satiety without provoking an insulin response. Regular ingestion of unhealthy fats can cause chronic inflammation, and ultimately degenerative conditions like heart disease and cancer. As a guideline, avoid excess omega-6 ingestion, minimize saturated fat intake and avoid, altogether, processed foods containing trans, or hydrogenated, fats.
For more information about fats and the PAM Diet, check out my books, Lower Your Blood Pressure in Eight Weeks, Reverse Heart Disease Now and The Healing Kitchen.
Additional References and Resources:
© 2012 Heart MD Institute, PA |
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Fats in a Nutshell:
Monounsaturated:
(+) Anti-inflammatory
(+) Do not oxidize easily
(-) Do not contain essential fatty acids
Sources: olive oil, avocado, some nuts and seeds
Polyunsaturated Omega-3s:
(+) Contain essential fatty acid (EFA): ALA
(+) Contain EPA and DHA
(+) Anti-inflammatory and cardioprotective
(-) Oxidize easily
Sources: fish / fish oil, walnuts, flaxseed, tofu, and green, leafy vegetables
Polyunsaturated omega-6 fats:
(+) Some contain LA, an essential fatty acid
(-) LA converts to AA, which is inflammatory in excess amounts; need to consume equal amounts of omega-3 and omega-6 fats to balance inflammatory potential
Sources: meat, vegetable oils (corn, safflower, sunflower)
Saturated fats:
(+) Convert to cholesterol in the body (animal sources)
(-) LDL cholesterol can oxidize in presence of high homocysteine, Lp(a), and ferritin levels
(+) Does not oxidize easily
Need to balance intake with other nutritious and anti-inflammatory foods
Sources: dairy and meat products, coconut and palm oils, chocolate
Hydrogenated / trans-fats
(-) Have artificially added hydrogen
(-) The worst!! Highly inflammatory
(-) Oxidize most easily
Sources: processed and fried foods
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