Selecting the Best Fats for Your Diet

Fat, protein, and carbohydrates are all essential macronutrients for optimal health and performance. Each provide a vital source of energy. However, it is dietary fat (also known as lipids) that provides the greatest source of energy. Fat provides nine calories per gram, whereas both carbohydrates and protein provide four calories per gram. Given this difference, a little bit of dietary fat goes a long way toward increasing total daily caloric intake. The current recommendation for total daily percentage of calories that one should consume from dietary fat ranges between 25 and 35 percent.

There continues to be great controversy over dietary fat and its role in health. Perhaps even greater than the question of how much total fat one should consume is what type of dietary fat is “health promoting” or “health antagonizing.” So, what is important to know when it comes to selecting the best dietary fats for optimal health? Is it focusing on total daily fat intake or the type of fat that we are eating? Well, although most studies haven't demonstrated greater benefit in body composition, athletic performance, or total body weight when total calories from fat exceeds the current recommendation, the actual focus when it comes to optimizing health is more related to the type of fat that we are adding to our diet. It is time to end the low fat myth because the actual total amount of fat consumed in our diet (high or low) isn’t really what links us to chronic disease. Instead, what is truly important is the type of fat that we're eating.

This article will provide a brief discussion over fat in its entirety and will address the following:

• Functions of lipids
• Structure of lipids and their biological importance
• Regulation of metabolism
• Lipids, lipoproteins, and cardiovascular disease risks
• Dietary sources
• Essential fatty acids including supplementation considerations
• Medium chain triglycerides and athletes
• Different types of dietary fats and oils
• Storage and rancidity of cooking oils

Lipid Functions

As already mentioned, fat is a vital macronutrient. It plays many essential roles in our body. Fat gives us energy and is essential for the absorption of the fat soluble vitamins (A, D, E, and K). Some fatty acids are essential (linoleic and α-linolenic fatty acids) because our body is incapable of synthesizing them. These essential fatty acids play a very vital role in specific bodily functions and must be acquired from dietary sources. Dietary fat slows gastric emptying during digestion, which is important in providing the feeling of fullness (or satiety) to help us know when it’s time to stop eating. Fats are also important for maintaining healthy skin and hair, maintaining a healthy reproductive system, and providing our body with insulation against physical trauma. Fat also aids in body temperature regulation and promotes healthy cell function, and certain fats function as antioxidants in the body.

Structure and Biological Importance

The property that sets lipids apart from other major nutrients is their solubility in organic solvents. If lipids are defined according to this property, which is generally the case, the scope of their function becomes quite broad. It encompasses not only dietary sources of energy and the lipid constituents of cell and organelle membranes but also the fat soluble vitamins, corticosteroid hormones, and certain mediators of electron transport, such as coenzyme Q.

There are many compounds that are classified as lipids, yet only a small number are important as dietary energy sources or as functional or structural constituents within the cell. Lipids have been grouped arbitrarily according to fatty acids, triglycerides, sterols and steroids, phospholipids, glycolipids, and ethyl alcohol. This grouping is more functional than structural. The following information will provide details on the difference in structure and biological function of the different lipids.

Fatty acids

Fatty acids as a class are the simplest of the lipids. Structurally, they are composed of a straight hydrocarbon chain terminating with a carboxylic acid group. Therefore, they create a polar hydrophilic end and a nonpolar hydrophobic end that is insoluble in water. It is fatty acids that are components of more complex lipids, which will be discussed later in this section. Fatty acids serve as a vital source of energy, furnishing most of the calories from dietary fat.

Fatty acids are found in foods and body tissues, and the length of their carbon chains varies from four to about 24 carbon atoms. One method of classification is based on the number of double bonds that are present in the carbon chain. The more carbon to carbon double bonds that are present in the chain, the more pronounced the flexibility or bending effect it has. The amount of bending plays an important role in the structure and function of cell membranes.

Based on this classification, fatty acids may be saturated, monounsaturated, or polyunsaturated. A saturated fatty acid (SFA) is a fatty acid that contains no double bonds in its carbon chain. It is what makes this type of fatty acid structurally rigid and inflexible. Saturated fats are solid at room temperature. A fatty acid that possesses only one double bond in its carbon chain is known as a monosaturated fatty acid (MUFA). MUFAs are liquid at room temperature but turn solid when chilled. A fatty acid that contains two or more double bonds in its carbon chain is known as a polyunsaturated fatty acid (PUFA). PUFAs are liquid at room temperature and when chilled.

Geometric Isomerism

Where a carbon to carbon double bond exists, there is also an opportunity for either a cis or trans geometric isomerism that affects the molecular configuration of the molecule. In cis isomerism, the molecule folds back, forming a U-like orientation whereas in trans isomerism, the effect is extending the molecule into a linear shape similar to that of a SFA. It is the cis isomerism that is the most naturally occurring isomerism in unsaturated fatty acids, although the trans form is naturally found in some fats and oils. However, the large majority of trans fatty acids are derived through a process known as hydrogenation. Hydrogenation is the process of reducing the double bonds of cis orientation to form a rearrangement to the trans form, which results in a more energetically stable fatty acid. This process is commonly used in making margarine and frying oils and is designed to solidify unsaturated fatty acids at room temperature and thus increase shelf life.

Trans fatty acids are of concern due to adverse nutritional effects, particularly their role in the development of cardiovascular disease. The requirement to label trans fatty acid content in food has encouraged food manufacturers to use processes that do not result in trans fatty acids in the finished product.

Fatty Acid Nomenclature

When looking at the fatty acid nomenclature, there are two systems of notation that have been developed to aid in a shorthand way of understanding the chemical structure of a fatty acid. Both systems are used regularly. The first method is known as the delta (Δ) system of notation. This method has been established to denote the chain length of fatty acids and the number and position of any double bonds that may be present. The delta (Δ) system counts from the carboxyl end (refer to Figure A for an example using linoleic acid).

Using the example of the linoleic acid, the notation would be 18:2 Δ^9,12. The first number represents the number of carbon atoms (in this case, the number is 18). The number following the colon refers to the total number of double bonds present. Finally, the superscript numbers following the delta symbol designate the carbon atoms at which the double bonds begin and starts from the carboxyl end of the fatty acid. In the example of linolenic acid, the superscript numbers tell you that the first double bond begins at carbon number nine counting down from the carboxyl end followed by a second double bond at the twelfth carbon atom in the chain.

The second system of notation is the omega (ω) system. This system of notation locates the position of double bonds on carbon atoms counted from the methyl or omega (ω) end of the carbon chain (refer to Figure B for an example using linoleic acid). In using the example of linoleic acid, this system notation is 18:2 ω-6. The substitution of the omega symbol with the letter n is commonly used. Just like the delta (Δ) system, the omega (ω) system of notation also uses the first number to designate the total number of carbon atoms in the chain (i.e. 18). The number of double bonds is given by the second number following the colon (i.e. 2), and the carbon atom number location of the first double bond is given by the number following the ω- or n-. This system of notation takes into account that when there is more than one double bond in a fatty acid chain, they will always be separated by three carbons. Thus, if you know the location of the first double bond, you can determine the location of the remaining double bonds.

Table 1.1 lists some naturally occurring fatty acids and their dietary sources using both the delta and omega system of notation. This table only lists the fatty acids that have a chain length of fourteen carbon atoms or more because these fatty acids are most important both nutritionally and functionally. For example, palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), and linoleic acid (18:2) together account for more than 90 percent of the fatty acids in the average U.S. diet. However, shorter chain fatty acids do occur in nature. For example, butyric acid (4:0) and lauric acid (12:0) occur in large amounts in milk fat and coconut oil, respectively.

Essential Fatty Acids

Many unsaturated fatty acids can be synthesized in the body. However, there are two unsaturated fatty acids that can’t be synthesized in the body and therefore must be acquired in the diet from plant foods. These types of dietary fats are known as essential fatty acids. The two essential fatty acids include linoleic acid (18:2 n-6) and α-linolenic acid (18:3 n-3). From linoleic acid, ϒ-linolenic (18:3 n-6) and arachidonic acids (20:4 n-6) can be formed in the body. Omega-6 and Omega-3 fatty acids are essential because the body lacks enzymes required for their synthesis. The enzymes required for their synthesis are only found in plants.

Omega-3 fatty acids are of particular nutritional interest due to their anti-inflammatory and hypolipidemic effects in the body. One omega-3 fatty acid of particular interest is eicosapentaenoic acid (20:5 n-3) because it is a precursor of the physiologically important eicosanoids. Eicosanoids are fatty acids composed of twenty carbon atoms and are derived from either omega-3 or omega-6 fatty acids. The differences in biological functions and recommended ratio of omega-6 to omega-3 will be discussed later in this article.

Eicosanoids include physiologically potent substances called prostaglandins, thromboxanes, and leukotrienes, all of which are formed from precursor fatty acids. Eicosanoids have a tremendous number of very specific functions occurring in almost every tissue in the body. The three eicosanoids that have received the most attention in research are thromboxane, the leukotrienes, and the prostaglandins. Prostaglandins along with the thromboxanes have been demonstrated to exhibit a wide range of physiological actions, including lowering blood pressure, diuresis, blood platelet aggregation, and immune and nervous system effects as well as gastric secretions and the stimulation of smooth muscle contraction to name several. Certain combinations of prostaglandins and thromboxanes may exhibit antagonistic effects and thereby act as a platelet anti-aggregating factor. Certain prostaglandins are responsible for elevation in body temperature and can cause inflammation and therefore pain. Leukotrienes have potent biological actions that may include contraction of respiratory, vascular, and intestinal smooth muscles.

Triglycerides

Triglycerides are another type of fat found predominantly in adipose tissue (but also inside muscle cells) and represent a highly concentrated form of energy. Triglycerides are thereby the storage form of fat in the body. Triglycerides account for nearly 95 percent of dietary fat consumed. They are structurally composed of three fatty acids attached to a glycerol molecule. The three fatty acids attached may all be the same (a simple triglyceride) or different (a mixed triglyceride).

Triglycerides exist as solid fats or as liquid oils at room temperature, depending on the nature of the component fatty acids. If they contain a high proportion of short chain fatty acids or unsaturated fatty acids, they tend to be liquid at room temperature. A triglyceride (TG) made up of saturated fatty acids of longer chain length has a higher melting point and exists as a solid at room temperature. When used for energy, fatty acids are released from storage in free form from their glycerol chain as free fatty acids (FFA) and are then transported by albumin to various tissues for oxidation. These FFA can then be used to provide energy through an oxygen requiring process known as beta-oxidation. Unlike carbohydrates, which can be metabolized aerobically (with oxygen) or anaerobically (without oxygen), fatty acids can only be metabolized into energy aerobically.

Sterols and Steroids

Sterols and steroids are a class of lipids characterized by a four-ring core structure, with cholesterol being the most common sterol. Cholesterol is only present in animal tissues. Many sterols other than cholesterol are found in plant tissues. Cholesterol serves as a precursor for many other important steroids in the body, including the bile acids, steroid sex hormones such as estrogen, androgens and progesterone, the adrenocortical hormones, and the vitamin D of animal tissues (cholecalciferol). The structural differences between these steroids are in the arrangement of double bonds in the ring system, the presence or absence of carbonyl or hydroxyl groups, and the nature of the side chain at the seventeenth carbon.

Nearly all tissues in the body are capable of synthesizing cholesterol. The liver accounts for about 20 percent of endogenous cholesterol synthesis. Among the extrahepatic tissues responsible for synthesizing the remaining 80 percent of cholesterol, the intestine is the most active. The rate of cholesterol production in the body includes the absorbed exogenous cholesterol as well as the endogenously synthesized cholesterol. Together, the cholesterol production rate approximates one gram per day. The average cholesterol intake is considered to be about 600 mg per day, only which about half is absorbed during digestion. Endogenous synthesis therefore accounts for more than two-thirds of the daily total cholesterol production in the body.

Lipoproteins

Lipoproteins are particles that are composed of lipids and protein. The ratio of lipid versus protein content in the lipoprotein determines its density. The more lipid content a lipoprotein contains, the less dense it is. In order of lowest (the most lipid) to highest density (having more protein than lipid) are chlyomicrons, very low density lipoproteins (VLDL), low density lipoproteins (LDL) and high density lipoproteins (HDL).

The protein portion of any lipoprotein is called the apolipoprotein. Apolipoproteins play a very important role in the structural and functional relationship among the lipoproteins. They tend to stabilize the lipoproteins in the aqueous environment of the blood, provide specificity that allows them to be recognized by specific receptors on cell surfaces, and aid in the regulation of the lipoproteins’ metabolic functions. The main function of lipoproteins are to transport fats, mainly cholesterol and TGs from tissue to tissue to supply the needs of different cells. Chylomicrons are responsible for transporting exogenous TGs from the intestine to mainly muscle and adipose tissues. LDL are synthesized in the liver and are responsible for carrying endogenous cholesterol from the liver where they are taken up by other tissues in the body. HDL are synthesized in the liver and are responsible for transporting excess endogenous cholesterol from the body’s tissues where they are then transported to be taken up by the liver. This is the reason why having a higher serum high density lipoprotein cholesterol level is considered protective against cardiovascular disease because HDL are responsible for removing excess cholesterol from the blood where it is delivered to the liver. From the liver, the cholesterol and cholesterol esters can then be utilized for energy or excreted into bile that is then utilized for digestion and absorption of dietary fat after ingestion of a fat containing meal.

Regulation of Lipid Metabolism

Fatty acids are a rich source of energy. On an equal weight basis, they surpass carbohydrates in this property. Many tissues are capable of oxidizing fatty acids by way of a mechanism called beta oxidation. The oxidation of fatty acids occurs within the mitochondrion. Short chain fatty acids can pass directly into the mitochondrial matrix. Long chain fatty acids and their CoA derivatives are incapable of crossing the inner mitochondrial membrane, so a transport system is necessary. The carrier molecule for this system is carnitine, which can be synthesized in humans from the amino acids lysine and methionine, and is found in high concentration in muscle.

The oxidation of fatty acids in the mitochondrion occurs through a cyclic degradative pathway by which two carbon units in the form of acetyl CoA are cleaved one by one from the carboxyl end. Summarized, the process of beta oxidation of a fatty acid produces a NADH that can go into the electron transport chain (ETC) to produce three adenosine tri-phosphates. The products of this reaction are acetyl CoA (which enters the TCA cycle for further oxidation) and a saturated CoA-activated fatty acid that has two fewer carbons than the original fatty acid. The entire sequence of reactions is repeated, with two carbons being removed with each cycle of this metabolic process.

The regulation of fatty acid oxidation is closely linked to carbohydrate status. Fatty acids formed in liver cells can either be converted into TGs and phospholipids or oxidized into energy. When a carbohydrate rich meal is consumed, glucose is used to meet the energy needs of cells. After energy needs are met, any additional glucose will first be stored in the cells in the form of glycogen through the metabolic process known as glycogenesis. After glycogen stores are met, if there is any excess glucose remaining, it is converted to TGs for storage in adipose tissue. Therefore, glucose rich cells do not actively oxidize fatty acids for energy. Instead, a switch to lipogenesis is stimulated, accomplished in part by inhibition of the entry of fatty acids into the mitochondrion.

Blood glucose levels can affect lipolysis and fatty acid oxidation by other mechanisms as well. For example, hyperglycemia triggers the release of insulin from the beta cells of the pancreas, which promotes glucose transport into the adipose cell and therefore promotes lipogenesis. On the other hand, hypoglycemia results in a reduced intracellular supply of glucose, thereby suppressing lipogenesis. Furthermore, the low level of insulin accompanied by the hypoglycemic state would favor lipolysis, resulting in subsequent release of free fatty acids from adipose tissue into the bloodstream. Low glucose levels also stimulate the rate of fatty acid oxidation, which may lead to the formation of ketone bodies as described below.

In addition to the direct oxidation of acetyl CoA in the TCA cycle, acetyl CoA may also follow other catabolic routes in the liver. One such pathway is through the formation of ketone bodies (acetoacetate, B-hydroxybutyrate, and acetone). Ketone bodies are formed when there is an accelerated fatty acid oxidation combined with low carbohydrate intake or impaired carbohydrate use. This process provides the liver with another way to distribute fuel to peripheral tissues. Such situations where ketone body production is elevated include someone with diabetes mellitus (DM), starvation, or simply a low carbohydrate diet. In these situations, as carbohydrate use diminishes, oxidation of fatty acids accelerates to provide energy through the production of TCA cycle substrates (acetyl CoA). This shift to fat catabolism, coupled with reduced oxaloacetate availability, results in accumulation of acetyl CoA. As would be expected, this process results in a large increase in accumulation of ketone body formation, resulting in the condition known as ketosis. Ketosis can be dangerous because it can disturb the body’s acid base balance.

Other than omega-3 (α-linolenic acid) and omega-6 (linoleic acid) fatty acids, which are essential fatty acids that must be obtained from the diet, the body is capable of synthesizing fatty acids from simple precursors in almost every cell of the body. This process is known as lipogenesis. This process involves the sequential assembly of a starter molecule of acetyl CoA. The synthesis of fatty acids, unlike that of beta oxidation, takes place in the cells' cytoplasm. The enzymes involved in fatty acid synthesis are arranged in a complex called the fatty acid synthase system located in the cytoplasm. The normal product of the fatty acid synthase system is palmitate (16:0). In turn, it can be lengthened by fatty acid elongation systems to stearic acid (18:0) and even longer saturated fatty acids. Elongation occurs by the addition of two carbon units at the carboxylic acid end of the chain.

Furthermore, by desaturation reactions, palmitate and stearate can be converted to MUFA, palmitoleic acid (16:1), and oleic acid (18:1), respectively. In the case of the essential fatty acids, once acquired through the diet, longer, more highly unsaturated fatty acids can be formed from it by a combination of elongation and desaturation of palmitate and linoleate. These elongation reactions produce fatty acids that are metabolized to biologically active compounds that play a significant physiological role.

Lipids, Lipoproteins and Cardiovascular Disease Risk

Atherosclerosis is a degenerative disease of the blood vessels. The principle contributors in the atherogenic process are cells of the immune system and lipids, primarily cholesterol and cholesterol esters. High levels of circulating lipids, in particular low density lipoprotein cholesterol, build up on the lumen of the blood vessel and are called fatty plaque. If this plaque continues to build up in the artery wall, the lumen of the blood vessel becomes progressively more occluded, resulting in restricted blood flow.

Ever since plaque was found to be composed primarily of lipids, an enormous amount of research has been underway to investigate the possible link between dietary lipids and the development of atherosclerosis. This presumed link is known as the lipid hypothesis. At center stage of the lipid hypothesis is the controversy over cholesterol. The measured effectiveness of dietary interventions are often measured by the extent to which the interventions raise or lower serum cholesterol. This reasoning is justified in that many studies have linked cardiovascular disease risk to chronically elevated serum cholesterol levels. Receiving the greatest attention is not so much total serum cholesterol but how the cholesterol is distributed between its two major transport lipoproteins, LDL and HDL. Research has continued to support findings that maintaining relatively low levels of LDL and high levels of HDL (a low LDL:HDL ratio) supports wellness. It is from this body of research that the concept of “good” and “bad” cholesterol emerged. The “good” form is cholesterol associated with HDL where the “bad” form is cholesterol that is transported as LDL. High density lipoprotein particles are anti-atherogenic. They also have antioxidant and anti-inflammatory properties.

The measurement of total cholesterol is often the focus of cardiovascular risk. The reason for the negative outlook of total cholesterol in connection with cardiovascular disease risk is the fact that cholesterol is a major component of fatty plaque. However, contrary to widespread belief, changing the amount of cholesterol in the diet has only a minor influence on blood concentration in most people. This is because compensatory mechanisms are engaged, such as high density lipoprotein activity in removing excess cholesterol and the down-regulation of cholesterol synthesis by dietary cholesterol. However, it is well known that certain individuals respond strongly and others weakly to dietary cholesterol. This phenomenon, which may have a genetic basis, is further complicated by the fact that considerable within person variability exists independent of diet, a fact that clearly confounds the results of inter-subject studies.

Research examining the impact of various kinds of fatty acids on cardiovascular disease risk has focused on how each type of fatty acid effects serum cholesterol levels. Early research has generally supported the conclusion that saturated fatty acids are hypercholesterolemic and PUFAs are hypocholesterolemic. MUFAs were assumed to be neutral, neither lowering nor increasing serum cholesterol levels. Current research focuses more on how particular fatty acids effect the ratios of LDL and HDL. Studies have shown MUFAs to be as effective as PUFA-rich diets in lowering LDL cholesterol and TGs without significant change in HDL. These findings support the importance of what type of fat we are eating more so than total fat consumed. It is important to note that although the type of fat consumed greatly affects serum cholesterol levels and cardiovascular disease risk, it is still important to maintain total fat intake at a healthy range. Modifying the source of fats consumed does not have a desirable impact on overall health when overall high fat intake is sustained.

The understanding of the role of dietary intake of lipids in cardiovascular disease risk has changed over the years. A large majority of studies have shown that consumption of total fat, saturated fatty acids, cholesterol and trans fat have a positive correlation with cardiovascular disease risk due to having a hypercholesterolemic effect or from unfavorable shifts in ratios of LDL and HDL. In addition, it has been widely found that consumption of MUFAs and PUFAs have shown a negative correlation with cardiovascular disease risk when adjustments are made for cholesterol and saturated fatty acids consumed. Of particular interest in this area is the negative correlation found with consumption of omega-3 fatty acids on cardiovascular disease risk.

Omega-3 fatty acids have been supported to exert anti-atherogenic properties by various mechanisms. One mechanism is that omega-3 fatty acids inhibit the aggregation of platelets thought to be caused by fatty acid displacement. A second mechanism is the fact that omega-3 fatty acids have anti-inflammatory effects and thereby reduce the release of pro-inflammatory cytokines from cells involved in fatty plaque formation. Lastly, findings demonstrate the effects of omega-3 fatty acids on significantly reducing serum TG concentration. However, in this situation, it has been shown that α-linoleate was less effective than EPA or DHA, and plant n-3 fatty acids were generally less effective than marine n-3 fatty acids in their capacity to reduce TGs.

The potential risk for cardiovascular disease is actually more complicated than what is implied by listing positive and negative correlates. It involves a combination of genetics, dietary factors, exercise, and other lifestyle factors. Despite the large body of research, the mechanism by which hypercholesterolemic fatty acids exert their atherogenic effects has not been conclusively defined.

Dietary Sources

Table 1.2 provides a list of common dietary fats, their associated food sources, their effects on health, and the recommended daily limit for each.

Omega-6 and Omega-3 Fatty Acids

As previously mentioned, these two types of fatty acids are known as essential fatty acids due to the fact that our body can’t synthesize them. They are thereby only acquired through dietary intake. The three physiologically significant omega-3 fatty acids include alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Clinical research supports that EPA and DHA help reduce the risk of developing cardiovascular disease. Fish oil in particular has been shown to lower levels of serum TGs and provide protective benefits against the development of atherosclerosis.

Omega-3 fatty acids have also been studied for their impact on athletic performance. Study findings have identified that omega-3 fatty acids aid in the facilitation of quicker recovery times, improved release of somatotropin (growth hormone), reduced inflammation associated with exercise exertion, improved cognitive reactivity and focus, and increased blood and oxygen flow to working muscles, which thereby supports aerobic endurance. Lastly, they have been shown to support increased efficiency of the body’s ability to utilize fat for energy.

The most biologically significant and essential omega-6 fatty acid is linoleic acid. Linoleic acid is also the most prevalent dietary source of omega-6 fatty acids. However, gamma-linolenic acid (GLA) can be found in primrose oil, borage oil, and black currant seed oil. It is from linoleic acid that GLA and arachidonic acid can be formed in the body. Along with omega-3 fatty acids, omega-6 fatty acids play a crucial role in brain function as well as normal growth and development. Omega-6 fatty acids also help stimulate skin and hair growth, play a role in the maintenance of healthy bones, and contribute to the maintenance of a healthy reproductive system.

Omega-6 fatty acids are known to be largely pro-inflammatory whereas omega-3 fatty acids are largely anti-inflammatory. For optimal health, it is very important to have a balanced ratio of omega-6 to omega-3 fatty acids. The recommended ratio of omega-6 to omega-3 fatty acids range from a 2:1–4:1 ratio, although some health educators advocate higher ratios of upwards of a ratio of 6:1–8:1. The average diet provides plenty of omega-6 fatty acids, so supplements are usually not necessary. The average American diet typically provides ten to thirty times more omega-6 fatty acids than omega-3 fatty acids. Excessive consumption of omega-6 fatty acids have been shown to interfere with the health benefits of omega-3 fatty acids. A higher than recommended consumption of omega-6 to omega-3 fatty acid intake shifts the body's physiological state in the tissues toward the pathogenesis of many diseases due to the pro-inflammatory effect of omega-6 fatty acids in the body.

Available Forms and Recommended Dosing for Omega-3 Fatty Acids

Dr. Fred Pescatore describes omega-3 fish oils as “the one supplement you absolutely must take.” The following studies are reported by Dr. Fred Pescatore on the benefits of supplementation with omega-3 fish oil:

• A new study published in the journal Heart showed that “raising your omega-3 intake to a level on par with people living in Japan could significantly protect against heart disease and artery stiffening.”
• A meta-analysis of seventy clinical trials “showed that boosting your intake of omega-3s can significantly reduce blood pressure. These effects applied to all subjects, but the benefits were greatest for subjects with untreated hypertension. Among this group, omega-3s cut systolic blood pressure by more than four points on average and diastolic blood pressure by more than three points.”

Omega-3 Fish Oil Recommendations

The American Heart Association recommends consuming two to three servings of fish high in omega-3 fatty acids each week for adequate intake of this fatty acid. Oral fish oil capsule supplements are available for those people who do not like the taste of fish. It is important to note that fish oil supplements will vary in amount of EPA and DHA.

When selecting a fish oil supplement, the dosing should be based on the amount of EPA and DHA rather than the total amount of fish oil. Suggested dosing for anti-inflammatory benefits range from one to two grams of EPA and DHA in an approximate ratio of 2:1. Supplementing with fish oil is generally safe as long as ingestion does not exceed three grams of EPA and DHA daily. If taking a fish oil supplement for a certain medical condition, it is best to talk to your health care provider to find out what dosage is safely recommended to provide the most benefit for that particular condition.

Other forms of omega-3 fatty acid supplementation are available in liquid form (such as flaxseed oil, walnut oil, krill oil, and fish oil) and should be kept refrigerated. Nut and seed oils, such as flaxseed oil, are provided in the form of ALA. Whole flaxseeds should be ground within 24 hours to preserve the active ingredients and then stored in a dark container and also refrigerated.

There are safety concerns about taking a fish oil supplement, especially when dosing exceeds three grams daily. One safety concern of supplementing with large doses of fish oil is the increased risk of bleeding even in those people who do not have a bleeding disorder. Anyone with a planned surgical procedure should stop taking the supplement at least two to three weeks prior to surgery to reduce this risk. Certain fish oil supplements may be high in levels of mercury, lead, and other heavy metals. Therefore, when choosing a fish oil supplement, it is recommended that you purchase from an established company who certifies that their products are free of heavy metals. Fish oil supplements should not be taken by those people who have an allergy to seafood. For sport caught fish, the U.S. Environmental Protection Agency (EPA) recommends that pregnant or nursing women eat no more than a single six-ounce meal per week and young children less than two ounces per week. For farm raised, imported, or marine fish, the FDA recommends that pregnant or nursing women and young children avoid eating types with higher levels of mercury (such as mackerel, shark, swordfish, or tilefish) and eat up to 12 ounces per week of other types of fish.

Medium Chain Triglycerides and Athletes

Medium chain triglycerides are triglycerides with fatty acid chains ranging from six to twelve carbons in length. Medium chain triglycerides aren't found in concentrated amounts naturally, but medium chain triglyceride (MCT) oil is available in many stores. Because it's a saturated fatty acid, it has a long shelf life.

Research into its use as a supplement for athletes is conflicting. One quality of MCT oil is that it is directly absorbed and carried to the liver where it can quickly be oxidized into usable energy. The metabolic transport and utilization seem to mimic that of carbohydrates rather than typical fat metabolism. Some studies have also shown evidence that MCT oil supplementation may improve blood cholesterol levels, which is of particular interest for anyone with a family history of heart disease.

Some research studies have demonstrated that supplementation with an MCT oil may lead to greater weight loss. One study demonstrated higher thermogenesis in individuals who supplemented with MCT oil after the long-term consumption of long chain triglycerides. The MCT oil produced a higher thermogenic response over that of the long chain TGs and this could potentially stimulate weight loss. MCT oil does provide limitations due to its contribution to total energy intake. Therefore, the maximum recommendation for most athletes is 30 grams during a single meal. In addition, it is important to mention that high doses of supplementation with MCT oil may cause gastrointestinal distress, including diarrhea.

Whether refined or not, all oils are sensitive to heat, light, and oxygen. Rancid oil has an unpleasant taste and its nutrient value is greatly diminished. To delay the development of a rancid oil, all oils should be kept in a cool, dry place. Oils may thicken but will return to a liquid state if they are kept at room temperature. To prevent the negative effects of heat and light, make sure that oils removed from cold storage are done so just long enough for use. Refined oils that are high in MUFAs typically have a shelf life of up to one year. Oils that are high in PUFAs typically are only good for six months. Extra virgin olive oil will last up to nine months after opening. Other MUFA oils will typically keep well for up to eight months when stored in the appropriate conditions while unrefined PUFAs will keep for only about half as long. Saturated oils, such as palm and coconut oil, will have much longer shelf lives and can be stored at room temperature. The fact that they lack PUFAs causes them to be more shelf stable.

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