Fundamentals of Human Nutrition/Lipids and Health
Section 6.5 Lipids and Health
There are two types of fats in our diet that are either good or bad. For instance, Saturated and trans fat can be harmful because it increases the risk of heart diseases. Tropical oils, high fat dairy foods, and fried foods are examples of both saturated and trans fat. The good fats are monounsaturated and polyunsaturated fats because they can actually decrease the risk of coronary heart diseases and lower blood pressure levels. The Dietary Guidelines for Americans 2010 states that people should “consume less than 10 percent of calories from saturated fatty acids by replacing them with monounsaturated and polyunsaturated fatty acids” (DGFA, 2010, p. X). Vegetable oil, fish, nuts, and lean meats are some examples of what one should consume to obtain a healthy diet. Obesity is one of the biggest leading factors in the United States. Over consumption of calories due to high fat intakes can cause someone to become overweight. They can also develop cardiovascular diseases due to their increase in blood pressure, blood cholesterol level, diabetes, and lack of physical activity. One type of cardiovascular disease is Atherosclerosis. Atherosclerosis will form a plaque inside the blood vessels and accumulate platelets, which can then lead to a coronary heart disease. Some ways to decrease the risk of developing a cardiovascular disease is by reducing total cholesterol, LDL cholesterol, and increasing HDL cholesterol instead. It is important to limit oneself in their intake of saturated fatty acids, trans-fatty acids, and foods high in cholesterol. Not only is improving diet a good option, but also adding some exercise on a daily basis. Exercising will help strengthen the heart and cardiovascular system. It will improve circulation, lower blood pressure, improve sleep, and reduce stress.
Any type of exercise can help decrease blood pressure, LDL cholesterol, and increase HDL cholesterol instead. In a study by Jens Bangsbo et al, it was found that “total plasma cholesterol and low-density lipoprotein cholesterol are lower after a period of recreational football training” (Bangsbo et al., 2015, p. 4). This is just an example of how exercising can be very beneficial in a style of living. It will not only give you energy, but it will also improve the body’s overall health. In this study, “ young and middle-aged men, training for 12 weeks led to a significant 15 % decrease in LDL cholesterol and a non-significant 8% increase in high density lipoprotein cholesterol levels” (Bangsbo et al., 2015, p. 4). Exercising is critical and can be a way to offset fat in the human body.
6.5.1 Cardiovascular Disease
Lipids are fats that play a major role in numerous functions of the body. They are necessary for supplying energy to the body and maintaining cell membranes, however, if consumed in excess, they can make an individual more susceptible to obesity and cardiovascular diseases (3). In order to ensure one is not taking in too much fat, one must look at the concentrations of each lipid in their blood, also known as their blood lipid profile (3). The following is the recommended blood lipid profile (3): Total cholesterol <200 mg/dL LDL cholesterol <100 mg/dL HDL cholesterol >60 mg/dL Triglycerides <100 mg/dL
Heart disease is the leading cause of death of adults in the United States (3). It is caused by a number of things, but lipids play a major role in increasing that risk. Although a certain amount of lipids is necessary, if an individual does not consume the recommended daily intakes, they are only hurting themselves. Cholesterol and triglycerides are two lipids that are essential to the body. Cholesterol helps construct cells and produce hormones, and is transported through our bloodstream by lipoproteins (2). The amount of cholesterol is then computed from triglycerides, low-density lipoproteins (LDL) and high-density lipoproteins (HDL) (2). An excess amount of LDL, or what is also known as the “bad cholesterol,” is a main contributor in the increased risk of cardiovascular disease (CVD) (2). A plethora of LDL is susceptible to oxidation which provokes inflammation and build up in the walls of the blood vessels and arteries, leading to blockage, heightened blood pressure and atherosclerosis, a form of heart disease (1,2). The higher the LDL, the higher the risk and likelihood of heart disease. While LDL has been found to drastically increase your risk for heart disease, HDL has been found to do the opposite. In fact, the higher the HDL, the lower the chance of CVD, because it directs the cholesterol to the opposite direction of the bloodstream (1).
Saturated and trans fats are common causes of an increased LDL. However, some saturated fats raise blood cholesterol levels more than others. Lauric, myristic, and palmitic acids raise the levels, but stearic acid appears to slightly or not at all effect them (3). Due to the two types of fats being found in similar food items, nutritionists will recommend one to consume foods with little to no saturated fats in order to reduce the risk altogether. Saturated fats have also been found to promote blood clotting, which has been found to advance CVD (3). High amounts of trans fat in the diet lead to a higher LDL and a lower HDL, another reason its highly recommended to limit the amount of the two of them in the diet (3).
Triglyceride, another fat, levels vary on the person, but if found to have elevated levels in the body, it can contribute to CVD (1). Dietary cholesterol has been found to only slightly or not at all raise blood cholesterol levels, however, it is still recommended to reduce it in your diet to lower the risk of heart disease (3). You can lower your risk for heart disease by reducing the amount of saturated and trans fats in meals, and avoiding foods with added sugar (2). Adding fiber, losing weight, and regularly participating in aerobic exercise will also contribute to lowering your risk by increasing HDL (2). One should strive to keep their blood lipid profile within the recommended concentrations in order to limit the chances of cardiovascular disease (3).
1. Cholesterol. Retrieved from http://www.world-heart-federation.org/cardiovascular-health/cardiovascular-disease-risk-factors/cholesterol/
2. Cholesterol. Retrieved from http://umm.edu/health/medical/reports/articles/cholesterol
3. Whitney, E., & Rolfes, S. (2013). The Lipids: Triglycerides, Phospholipids, and Sterols. In Understanding nutrition (14th ed.). Belmont, CA: Wadsworth.
6.5.3 Body Cholesterol and Triglycerides
While some fats in the body are essential for good health, others may be harmful. Two types of fats that can be beneficial for health are monounsaturated and polyunsaturated fats. It is suggested that these fats can lower bad LDL cholesterol, and increase HDL cholesterol, which therefore improves overall blood cholesterol levels (American Heart Association, 2015). On the other hand, saturated and trans fats can negatively impact ones health. In this case, it is recommended that a person eats more monounsaturated and polyunsaturated fats for good health altogether. Some sources of monounsaturated fats include oils such as olive, peanut, and canola oil. In addition, avocados, peanut butter, nuts and seeds all contain monounsaturated fats as well (Zeratsky, 2015). As for polyunsaturated fats, the best food source for omega-3 fatty acid is fish. Seafood is very rich in these good fats, and the best choices include salmon, tuna, and oysters (Harvard Health). Other omega-3 fatty acid food examples are flax seeds and walnuts.
There are some major benefits to eating monounsaturated and polyunsaturated fats. One example of a benefit is reduced risk of heart disease and stroke by reducing blood pressure (Harvard Health Publications, 2015). In addition, such fats can help build cell membranes and the covering of nerves, which is needed for blood clotting, muscle movement, and inflammation (Harvard Health Publications, 2015). Furthermore, it is essential to eat these types of fats because they provide the body with energy and help absorb vitamins and minerals.
In this case, the consumption of bad dietary fats like saturated and trans fat will ultimately lead to health consequences. For example, saturated and trans fat will increase the risk of heart disease by increasing the bad cholesterol. This in turn, leads to the buildup of plaque in the arteries, which could potentially result in a heart attack or even death (Zeratsky, 2015). Furthermore, other negative health effects of these bad dietary fats include risk of developing type 2 diabetes and some types of cancer (Zeratsky, 2015). For these reasons, people should begin to replace unsaturated and trans fats in their diet with the more healthy kinds to prevent these diseases. Some easy changes to the diet could be avoiding fried or packaged foods, and substituting unhealthy, hydrogenated oils with olive oil instead.
However, it is important to note that while these good fats are essential to ones health, it is wise to consume these in limited quantities and not go overboard. All fats are high in calories and too much of them can still wreak havoc on a person’s health. Therefore, it is crucial that people eat the good fats in moderation.
6.5.3 Body Cholesterol and Triglycerides
When you think of fats, most people think of something negative in terms of health. However, many people may not know that there are some fats that are essential for health. Actually, some fats can improve your overall health and are needed in the diet. These fats include monounsaturated fats and polyunsaturated fats which include omega-3 fatty acids. These types of fats have shown to have health benefits such as lowering blood cholesterol levels and lowering the risk for heart disease. These types of fat are essential fatty acids that need to be obtained through diet. One important function of these fats is for the fat soluble vitamins: A, E, D, and K to get into and around the body (Robinson, 2015). Each of these fats contributes to a higher level of high-density lipoprotein (HDL) cholesterol which can help clean out some of the bad cholesterol in the blood, and lower the risk for cardiovascular disease (Vann, 2010). Sources for monounsaturated fats and polyunsaturated fats: • Avocados • Olives • Nuts • Natural nut butters • Sunflower, Sesame, Pumpkin Seeds • Flax Seeds • Fish Oils (salmon, tuna, mackerel, herring, trout, sardines) So how do you know when a fat is a bad fat or a good fat? Since fats have more than twice the amount of kilocalories per gram than carbohydrates (9 kcal vs 4 kcal) eating too much of any type of fat can quickly increase your total kilocalorie intake. Now that you know the types of fats that are beneficial to health, we can look at the types of fats that are harmful to health. These types of fat are what we think of when we think of processed foods such as candy, chips, fast foods, etc. Saturated fats, and trans-fats are considered to be the “bad” fats. These types of fats will raise total blood cholesterol levels and contribute to clogged arteries. Saturated fats also raise low-density lipoprotein (LDL) cholesterol which can contribute to a higher risk of cardiovascular disease (Ward, 2008). Sources for saturated and trans-fats: • Cheese • Dairy Desserts • Red meats • Butter • Foods that are prepared with hydrogenated oils The most important thing to remember when thinking about the types of fat that you want to eat is that the quality and quantity of fats matter. Lowering the amount of saturated and trans-fats and increasing the amount of monounsaturated and polyunsaturated fats can be extremely beneficial for health (Fetters, 2015). Quantity also matters, keep in mind that the recommended daily allowance for fats is between 10-30% of your total daily amount of kilocalories.
Cholesterol is a thick, waxy, odorless substance found in the blood. The liver produces cholesterol and it can also be found in foods such as meat, eggs, fish, and dairy products. The body requires cholesterol to make cell walls and other essential body substances. Cholesterol cannot travel through the body by itself therefore, the liver packages it with triglycerides and other lipoproteins that deliver it throughout the body (University Health Service). Cholesterol in the body can vary depending on genetic makeup, age, sex, and can change over the course of one’s life. Cholesterol is essential to the body, but too much in the blood stream can be dangerous. Too much cholesterol increases the chances of stroke and heart disease. Low-density lipoproteins (LDL) can be bad if they are present in excess amounts. These LDLs can build up inside of the arteries causing damage to the arteries and potentially blood clots. The desirable LDL level in the blood is less than 100mg/dL (University Health Service) . A diet heavily consisting of cholesterol and saturated fat will increase the risk of plaque build up in the vessels. Ways to reduce risk of plaque build-up include: eating less than 200mg of cholesterol a day, eating 20-30 grams of fiber daily, and by eating fish high in omega-3 fatty acids (University Health Services). Triglycerides are a fat found in the body. The body converts calories that are not being used right away into triglycerides that are stored in the body’s fat cells. Triglycerides differ from cholesterol because triglycerides are unused calories that can provide the body with energy while cholesterol is used in important bodily function such as building cells and hormones (Mayo Clinic). If one eats more calories than they burn, they could be at risk for high triglyceride levels. Triglycerides have the potential to cause plaque build-up in the arteries and lead to heart disease. The normal triglyceride level in the blood is under 150 mg/dL and anything above 200 mg/dL put one at risk for increased risk of heart attack, stroke, and death (Triglycerides). It is recommended that anyone over the age of 20 should have their triglyceride levels measured by a blood test called a lipid panel (Triglycerides). If triglyceride levels are too high, they can be lowered by losing weight, eating healthier fats such as peanut oil and salmon, and exercising regularly. Sometimes triglyceride and cholesterol levels cannot be treated by lifestyle changes alone and require taking medications to keep the levels in the normal range.
6.5.4 Omega-3 Fatty Acids
Essential fats are exactly what they say they are - essential. Your body is not capable of producing these, so you must get them in your dietary intake (Harvard 2015). For humans, this includes the omega 3 (linolenic) and omega 6 (linoleic) polyunsaturated fatty acids (NAP, 2005).
To start this discussion, some key things should be noted about fatty acids in general. “Saturated” refers to fatty acids that contain no double bonds, “monounsaturated” refers to those with one double bond, and “polyunsaturated” refers to fatty acids that contain more than one double bond (Baggott, 1998). These two essential fatty acids, as mentioned, are polyunsaturated. The “omega” designation, followed by the number, refers to the amount of carbons away from the omega carbon (the methyl end) that the double bond is positioned (Baggott, 1998). So omega 3 fatty acids have a double bond between the third and fourth carbon from the tail of the chain, and omega 6 fatty acids have a double bond between the sixth and seventh carbon from the tail of the chain.
Next: function. Essential fats serve many general functions in the body that are unrelated to production of energy and energy metabolism. They are a key component of cell membranes that not only promote their integrity but also affect their cell receptors (Harvard, 2015). They make hormones that regulate blood clotting, the contraction and relaxation of arteries, and inflammation of tissues in the body (Harvard, 2015). They also regulate the function of genes by regulating DNA and RNA transcription and translation (Harvard, 2015). They perform these functions largely by being elongated and converted to nonessential fatty acids. For example, the omega 6 linoleic acid of 18 carbons is often converted to arachidonic acid of 20 carbons, an essential part of phospholipid membranes in human tissues.
Omega-3’s seem to be the most important in disease prevention and the most lacking in western diets (Harvard, 2015). In foods, these appear as alpha-linolenic acid and are later converted to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (NAP, 2005) in the body. These function to lower the risk of coronary heart disease and strokes by preventing arrhythmias, reducing atherosclerosis buildups, improving plasma concentrations, increasing HDL cholesterol, decreasing blood pressure, and reducing inflammation (NAP, 2005). They are found primarily in fatty, oily fish (Harvard 2015). The AMDR is currently set at 0.25g to 2.0g, (FAO/WHO, 2008) or about 0.7% of total energy intake (ISSFAL, 2015)
Omega-6’s, primarily found as linoleic acid (Christie, 2013) are more common in the west and thus less of a dietary concern, but still just as necessary. They have been shown to reduce LDL cholesterol, increase HDL cholesterol, and lower the risk of coronary heart disease (NAP, 2005). The reason these are found so commonly in western diets is due to their prevalence in vegetable oils, as well as fatty fish, walnuts, flax seeds, and dark green leafy vegetables (Harvard, 2015). A healthy intake is about 2% of the daily energy intake (ISSFAL, 2015).
While both omega 3 and omega 6 fatty acids are essential, the appropriate balance of both in one’s intake is particularly important. The hormones and physiological responses that they regulate tend to counter one another, thus a balance is necessary. In Western diets, omega-3’s tend to be deficient, with a ratio of 15:1 – 16.7:1, omega-6:omega-3 respectively (Simopoulos, 2002). This unbalance can promote many diseases, including heart disease, inflammatory diseases, and some cancers. (Simopoulos, 2002). A more desired ratio, somewhere around 4:1, may be beneficial in preventing cardiovascular disease mortality as well as other disease risks (Simopoulos, 2002). This ratio may vary, however it is clear that Western diets need to up the intake of these essential omega-3’s.
Essential fatty-acids are a necessary micronutrient in everyone’s diet cross-culturally to ensure proper and efficient function of the human body’s physiological processes.
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