Chapter 5 - The Lipids - Spotlight B - Lipids in Health and Disease - HNTR 1153

risk factors for CVD

- Age - Race (more common in African Americans) - Family history (genetics) -Dyslipidemia -High blood pressure -Sedentary lifestyle - Diet high in saturated and trans fats, cholesterol, sodium, and added sugar -Smoking -Obesity -Diabetes -Infection and inflammation

fatty acids

A chain of carbon atoms with hydrogen atoms and a methyl group attached to one end of the fatty acid and a carboxylic acid group attached to the other end; a subclass of lipids that are also components of triglycerides and phospholipids. They are a type of lipid with multiple functions. They are metabolized to provide energy, they regulate rates of gene expression, and they are the starting material used to synthesize several hormone-like compounds in the body. They are also the primary components of two other types of lipids, triglycerides and phospholipids. Fatty acids differ in length, so they are categorized by the length of their hydrocarbon chains, as well as in their degree of saturation (how many carbon atoms have their available bonds filled with hydrogen atoms).

hydrogenation

A chemical process by which hydrogen molecules are added to unsaturated fatty acids to make them more saturated and solid at room temperature. Until recently, too much of the fat we consumed had undergone a process of hydrogenation, which makes unsaturated fats more solid and stable by chemically adding hydrogen to each carbon atom, flanking a double bond on the fatty acid chain to make them more saturated. This renders them harder at room temperature and more resistant to becoming rancid (oxidation and/or decomposition that can occur in unsaturated fats, resulting in unpleasant taste and smell). One outcome of partial hydrogenation, however, is that the structure of some of the unsaturated fatty acids is converted from their natural cis configuration to another configuration known as trans.

metabolic syndrome

A cluster of risk factors associated with the development of cardiovascular disease and type 2 diabetes. To be given a diagnosis of metabolic syndrome, individuals must have at least three of the following problems: - excessive abdominal fat - high blood pressure - elevated levels of triglycerides in the blood - low levels of HDL - elevated blood glucose levels (either prediabetes or type 2 diabetes) The prevalence of metabolic syndrome is on the rise. Today, it affects more than 50 million adults in the United States and approximately 25% of adults worldwide.

dietary fat

A compound found in plant and animal foods that is essential as an energy source and necessary for absorption and transport of fat-soluble vitamins.

DASH (Dietary Approaches to Stop Hypertension) diet

A diet that has been shown to reduce cardiovascular disease, obesity, and diabetes—all conditions that are also associated with cognitive decline.

Mediterranean diet

A dietary pattern associated with cultures bordering the Mediterranean Sea; the pattern emphasizes whole grains, fruits, vegetables, legumes, nuts, seeds, fish, and olive oil and limits meat, saturated fat, and full-fat dairy products. Both the Mediterranean diet and DASH (Dietary Approaches to Stop Hypertension) diet have been shown to reduce cardiovascular disease, obesity, and diabetes—all conditions that are also associated with cognitive decline. Their study found that elderly individuals whose dietary patterns most closely resembled these diets experienced a much slower decline in cognitive function over a period of 10 years.

saturated fatty acids

A fatty acid molecule with no double bonds between the carbon molecules; all carbon binding sites not already bound to another carbon are saturated with hydrogen. These lipids are relatively solid at room temperature. They are typically highest (as a percentage of total fat) in animal products (such as meats and dairy), but they are also abundant in some vegetable oils (such as coconut oil, palm kernel oil, palm oil, and cocoa butter).

unsaturated fatty acids

A fatty acid with fewer than the maximum possible number of hydrogen atoms attached to the carbon chain. Because of this configuration, these lipids are generally liquid at room temperature. These fats are found most abundantly in plant foods, such as seeds, nuts, grains, and most vegetable oils.

monounsaturated fatty acids

A fatty acid with only one double bond between carbons in the carbon chain. Abundant in olive and canola oils and nuts.

polyunsaturated fatty acids

A fatty acid with two or more double bonds between carbons in the carbon chain. Abundant in corn, safflower, sunflower, sesame, and soybean oils.

High-Density Lipoproteins (HDLs)

A lipoprotein responsible for transporting cholesterol from the bloodstream and tissues back to the liver. These lipoproteins often are referred to as "good" cholesterol. Rather than delivering cholesterol around the body, HDLs pick up as much excess cholesterol as they can from cells throughout the body and take it back to the liver, which then uses the cholesterol to make bile acids, excretes it directly into bile, or recycles it. This action explains why high levels of HDL cholesterol are typically associated with a lower risk for heart disease.

Low-density lipoproteins (LDL)

A lipoprotein responsible for transporting primarily cholesterol from the liver through the bloodstream to the tissues. The primary carrier of cholesterol in the blood, transporting cholesterol to essentially all cells. They are often referred to as "bad" cholesterol, as elevated levels are associated with an increase in the risk of heart disease.

very low-density lipoproteins (VLDLs)

A lipoprotein responsible for transporting primarily triglycerides to adipose tissue, cardiac muscle, and skeletal muscles. They originate from the liver and carry lipids that have been synthesized there, as well as lipids the liver has removed from blood.

Phospholipids

A molecule that is both hydrophobic and hydrophilic and is required to form cell membranes. Lecithin, which can be found in egg yolks, liver, and some plant products, is a phospholipid. The hydrophilic (having an affinity for water) and the hydrophobic (tending to repel water) structure of phospholipids is key to their function.

Lecithin

A phospholipid manufactured by the liver and also found in many foods; a major constituent of cell membranes. It is the most abundant phospholipid in the body; frequently added to food products, such as salad dressings, as an emulsifier.

emulsification

A process that allows lipids—fats—to form stable mixtures with water. The physical process of breaking up large fat globules into smaller globules, thereby increasing the surface area that enzymes can use to digest the fat. Bile acids produced in the liver from cholesterol (and stored in the gallbladder) make emulsification possible. The molecular makeup of bile acids features a water-soluble and fat-soluble "face." These two-faced molecules surround small lipid droplets so that the lipids remain suspended in water instead of clumping together.

lipid panel

A series of blood tests (total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides) used to assess risk factors of heart disease. These tests determine the amount of lipids circulating in blood. A diet high in saturated fat and low in unsaturated fats increases total blood cholesterol, which can be harmful to our health, increasing the risk of not only dementia but also heart disease.

optimal HDL level

Above 40 mg/dL (above 60 mg/dL is desirable) HDLs bring cholesterol from tissues back to the liver, where it is processed and eliminated. Not surprisingly, low levels of HDL-C—less than 40 mg/dl in men and 50 mg/dl in women—are associated with an increased risk of CVD. Conversely, higher levels of HDL-C can be associated with a lower risk of heart disease, but only up to a value of about 60 mg/dl. So higher levels of HDL cholesterol have a limited ability to offset the risk of heart disease seen with increasing levels of LDL cholesterol. For this reason, calculating the ratio of LDL-C to HDL-C is not clinically useful, particularly in individuals with high LDL-C concentrations.

How many servings of fish does the American Heart Association recommend per week? What types of fish are recommended?

American Heart Association recommends at least two weekly servings of these fish, which provide omega-3 fatty acids, protein, vitamin D, and other key nutrients. The most heart health fish are oily, cold-water fish such as anchovies, sardines, trout, albacore tuna, and salmon. Research shows that the oil found in these fatty fish—rich in healthy fats—lowers triglyceride levels, blood pressure, and heart rate, so it's not surprising that eating fish regularly is associated with a lower risk of CVD.

lipoprotein lipase (LPL)

An enzyme that hydrolyzes triglycerides passing by in the bloodstream and directs their parts into the cells, where they can be metabolized for energy or reassembled for storage. As chylomicrons and VLDLs enter the capillaries of adipose tissue and skeletal and cardiac muscle, their triglycerides are broken down to glycerol and fatty acids by the enzyme lipoprotein lipase (LPL) that is present in the capillaries of these tissues. As chylomicrons and VLDLs are depleted of their triglycerides, they are transformed into smaller "remnant" lipoproteins, which increase the proportion of their lipid cargo that is cholesterol. The triglyceride-depleted chylomicrons are referred to as chylomicron remnants, and VLDLs are transformed into cholesterol-rich low-density lipoproteins (LDLs).

alpha-linolenic acid (linolenic acid)

An omega-3 polyunsaturated essential fatty acid found in walnuts, flax seeds, soy, canola oil, and chia seeds; modified in the body to produce eicosapentaenoic acid and docosahexaenoic acid. Intake of this essential fatty acid is low in the diets of most Americans, who consume only about one-tenth of essential fatty acids in this omega-3 form.

linoleic acid

An omega-6 polyunsaturated essential fatty acid found in seeds and vegetable oils. It is needed for normal growth and for synthesis of important hormonelike compounds called eicosanoids. This is the most abundant polyunsaturated fatty acid in our diet. The primary sources are cooking oils, salad dressings, nuts, and seeds.

food sources of triglycerides

Animal fats, vegetable oils, dairy Grains- naturally low in fat except when fat is added. Fruits and vegetables- low in fat except avocados and coconuts.

risk factors

Any characteristic, condition, or behavior that increases the likelihood of developing a particular disease.

Health risks associated with high cholesterol intake

As with heart disease, growing evidence links high levels of cholesterol in the blood to the development of Alzheimer's disease and other forms of dementia. In fact, several studies in midlife participants showed that those with higher levels of total cholesterol had an increased risk of developing dementia later in life compared to those with normal or low blood cholesterol levels. Animal studies offer further clues to the connection between cholesterol and AD. In these studies, a diet high in saturated fat and cholesterol has been shown to cause brain inflammation and lesions and impair memory. Another finding indicates that increased cholesterol accelerates the buildup of a sticky protein called amyloid beta, a characteristic of AD. Amyloid beta can assemble into cell pores or channels to accumulate into clumps in those cells, which travel to the brain and disrupt its function.

food sources of cholesterol

animal products (organ meats, eggs, butter)

Food sources of phospholipids

egg yolks, liver, soybeans, peanuts, wheat germ

What are the two sources of cholesterol?

food we eat and liver synthesis

Identify tropical oils and describe their health implications

We are currently seeing a fascination in the United States with coconut oil, a source of saturated fatty acids, as advertisements present it as a panacea of sorts. The purported benefits to heart health, however, are not supported by current scientific evidence. Several studies have found that it raises LDL cholesterol to the same degree as saturated fats from other sources, such as butter, beef fat, and palm oil. This is not particularly surprising as coconut oil contains more saturated fat than any other commonly consumed fat in the U.S. diet. Based on current evidence, the best overall strategy to protect your heart health is to replace saturated fatty acids with unsaturated ones and to emphasize vegetables, fruits, and whole grains in the diet.

Excellent sources of EPA and DHA

We can more efficiently boost EPA and DHA concentrations in our body by regularly eating fish, particularly fatty fish like salmon, albacore tuna, trout, and sardines, which are excellent sources of these fatty acids.

optimal LDL level

less than 100 mg/dL LDLs ferry cholesterol to all of the cells of the body. This cholesterol forms the root of the plaques that slowly constrict blood flow through the vessels that feed the heart and brain; the lower your LDL cholesterol level, the lower your risk of heart attack and stroke. If you have other risk factors for CVD, it's best to keep your LDL-C concentration below 100 mg/dl. (Some experts recommend levels closer to 70 mg/dl especially if other risk factors are present.) In some cases, diet and exercise may not suffice, in which case people also take medications that lower their total cholesterol and LDL-C concentrations.

optimal triglyceride level

less than 150 mg/dL

optimal total cholesterol levels

less than 200 mg/dL Blood cholesterol levels measuring less than 200 milligrams of cholesterol per deciliter of blood (mg/dl) are considered desirable. Yet the average cholesterol level for a U.S. adult is just under 200 mg/dl—meaning the average American has a borderline high level. It is of even greater concern that approximately 40% of adults have cholesterol levels that exceed 200 mg/dl. People with high levels of total blood cholesterol have approximately twice the risk of heart disease as those who do not. Normal triglyceride levels vary by age and sex, but anything above 200 mg/dl is considered elevated. High triglyceride levels are common in people with heart disease or diabetes and correlate with lower levels of HDL cholesterol, or "good" cholesterol.

short chain fatty acids

less than 6 carbons

food sources of fatty acids

vegetable oils, seeds, nuts, animal fats, and fish oils

Identify foods that are lower fat choices

vegetables, fruits, and whole grains

Which tropical oil is solid at room temperature? What does this tell us about this fat?

Coconut oil. It contains saturated fat.

Sterols

Complex lipids of interconnected carbon rings with side chains of carbon, hydrogen, and oxygen; precursors for synthesis of steroid hormones; plant sterols have a possible role in reducing high blood cholesterol; used as additives in some margarines and spreads. The most discussed sterol is cholesterol.

myocardial infarction

Damage to heart tissue caused by decreased blood flow to the coronary arteries. Commonly known as a "heart attack"

plaque

Deposits of cholesterol, triglycerides, and cell materials that accumulate within the arterial walls. As a result of artery wall inflammation, the lining of the blood vessel becomes more prone to develop a waxy accumulation of cholesterol and triglycerides, known as a plaque. Over time, plaque development, loss of elasticity, and thickening in the blood vessel walls may make it difficult for blood to flow through the vessel. This "traffic jam" increases the chances of forming blood clots that either block flow at that location or break off and travel through the bloodstream, blocking blood flow elsewhere, causing tissue damage and tissue death.

good vs bad cholesterol

HDL is referred to as "good" and LDL is referred to as "bad." The commonly held view of cholesterol as being either "good" or "bad," is potentially misleading. Cholesterol is necessary for numerous essential functions throughout the body, and because most cells in the body receive cholesterol transported by LDLs, even LDLs are necessary. However, when the LDL cholesterol level rises too high and the HDL cholesterol level drops too low, it is this ratio—meaning the amount of each relative to each other—of lipoproteins (HDL to LDL) that is "bad" because high LDL cholesterol increases the risk of cardiovascular disease. Clinical laboratory tests that monitor blood lipid levels typically measure amounts and types of lipids present in lipoproteins in blood and provide an indication of risk of heart disease.

hypertension

High blood pressure. A condition in which blood pushes with excessive force against artery walls—is correlated closely with the extent of atherosclerosis found in the arteries.

eicosanoids

Hormonelike signaling molecules synthesized from arachidonic acid and eicosapentaenoic acid. One of the most important functions of essential fatty acids is to provide parent compounds to produce the hormonelike eicosanoids. These compounds are released during injury and stress and regulate blood pressure, inflammation, body temperature, and even pain. Aspirin and similar pain medicines work by blocking the synthesis of prostaglandins, which are one class of eicosanoids. This reduction in prostaglandin synthesis has the effect of not only reducing pain, inflammation, and fever but also reducing blood clotting. Two polyunsaturated fatty acids that are directly used for eicosanoid synthesis are arachidonic acid and eicosapentaenoic acid (EPA), which are 20-carbon fatty acids made from linoleic and linolenic acids, respectively. The effect of an eicosanoid on body functions depends on the fatty acid from which it is made. Blood clotting and inflammation is promoted when there is excess production of eicosanoids from arachidonic acid (an omega-6 fatty acid), compared with those produced from EPA (an omega-3 fatty acid). Blood clotting and inflammation are decreased when the production of eicosanoids from EPA increases. Because of these opposing effects, it is desirable to have a proper balance of omega-6 and omega-3 fatty acids in the diet.

Explain the functions of fats (ways fats are useful) in foods and the functions of fat in the body.

When selected and consumed in appropriate proportions, fat confers some important health benefits, as some fats are essential nutrients. Dietary fats are also required for the efficient absorption and transport of fat-soluble vitamins (A, D, E, and K) and phytochemicals. Fat consumption contributes to satiety (the sensation of feeling full) in part by slowing gastric emptying, which keeps food in the stomach a little longer. This causes foods to be digested and absorbed over longer periods, which can improve blood glucose control following the ingestion of high-carbohydrate foods when fats are included. Having adequate fat stores is important as adipose tissue cushions, protects, and insulates the kidneys, heart, and other organs and serves as a storage site for fat-soluble vitamins. Furthermore, inadequate stores of fat can reduce fertility in both men and women.

Fish oil supplements

Many companies sell fish oil as a dietary supplement, but it is questionable whether the general population's supplementation with omega-3 fish oil yields the same health benefits as consuming whole fish. The American Heart Associate does support the use of fish oil supplements for reducing the risk of future cardiovascular events in individuals with prior heart disease. Whereas whole fish consumption is encouraged, some types of fish can have high levels of mercury and other environmental pollutants. Thus, it is prudent to limit consumption of certain species, such as shark, swordfish, king mackerel, and tilefish.

long chain fatty acids

More than 12 carbons

lipids

Organic compounds composed of a diverse group of compounds that contain carbon-hydrogen chains of varying length with a lower proportion of oxygen atoms than in carbohydrates—fats are a subclass of lipids; a structurally diverse group of naturally occurring molecules that are generally, not always, insoluble in water but are soluble in organic solvents Examples include fatty acids, triglycerides, sterols, and phospholipids. As a major component of cell membranes, lipids give those structures flexibility and integrity, and various lipids are required for the synthesis of some hormones and hormonelike substances. Although some use the term lipid interchangeably with fat, the word fat, more precisely, refers to triglycerides, which make up 95% of all lipids in our foods and 99% of the stored fat in our bodies.

omega-3 fatty acids

Polyunsaturated fatty acids that have the first double bond at the third carbon molecule from the methyl end of the chain; associated with a decreased risk of cardiovascular disease and improved brain function. These fatty acids are found in fatty fish, such as salmon, and in some oils, such as canola oil.

omega-6 fatty acids

Polyunsaturated fatty acids that have their first double bond at the sixth carbon molecule from the methyl end of the carbon chain.

List cooking methods and other ways to reduce the intake of dietary fats

Replace fats like butters with oils like olive oil.

Which two types of fat raise blood cholesterol levels?

Saturated fats and trans fats

AMDR for fat

To promote health and reduce the risk of chronic disease, the Acceptable Macronutrient Distribution Range (AMDR) for total fat has been set at 20-35% of our total calories.

Which class of lipids is the major storage form in the body?

Triglycerides (fat)

Calculate the percentage of fat in a diet or a food item when given grams of fat and total calories

1. Multiple grams of fat x 9 calories per gram 2. Divide calories from fat by total calories 3. Multiple by 100 Example: A muffin has 10g of fat and 180 total calories 1. 10g fat x 9 calories per gram of fat a 2. 90 calories / 180 calories = 0.50 3. 0.50 x 100 = 50% of calories in muffin are from fat

medium-chain fatty acids

6-10 carbons

eicosapentaenoic acid (EPA)

A 20-carbon omega-3 fatty acid that can be produced in the body by the metabolism of the essential fatty acid alpha-linolenic acid or provided in the diet by oily fish.

DHA (docosahexaenoic acid)

A 22-carbon omega-3 fatty acid that can be produced in the body from the essential fatty acid alpha-linolenic acid, which is also found in oily fish.

stroke

A cerebral event (damage to the brain) that occurs when blood vessels supplying the brain are damaged or blocked. Most cases of stroke result when a clot impairs the supply of blood to the brain.

lipid digestion

A small amount of fat digestion takes place in the mouth and stomach (via enzymes called lipases), but most occurs in the small intestine. However, because lipids are not water soluble, and therefore cannot mix with water, the fat tends to clump together in the small intestine's watery environment. The body's solution to that problem is emulsification. Emulsification aids digestion by breaking up large fat globules into much smaller droplets so that fat-digesting enzymes can operate efficiently. Bile acids produced in the liver from cholesterol (and stored in the gallbladder) make emulsification possible. The molecular makeup of bile acids features a water-soluble and fat-soluble "face." These two-faced molecules surround small lipid droplets so that the lipids remain suspended in water instead of clumping together. Lipases, produced by the pancreas and released into the small intestine, can now readily access the triglycerides suspended in these droplets and digest them into monoglycerides and free fatty acids.

Cholesterol

A sterol that is produced by the body and required for steroid hormone production and cell membrane function. It is a critical component of our cell membranes and is needed as a precursor (a compound that is used to synthesize another compound) for the synthesis of bile acids, vitamin D, and steroid hormones (such as estrogen and testosterone), but it does not provide any energy. It is synthesized in nearly every tissue in the body but in particularly large quantities by the liver. Approximately 75% of the cholesterol in blood is made in our body, which provides all the cholesterol needed for body functions. Although a dietary source of cholesterol is not required, we consume cholesterol in animal foods such as meats and dairy products. Indeed, the presence of cholesterol in cell membranes is one distinguishing characteristic between plant and animal cells; thus dietary cholesterol is found only in foods of animal origin.

Triglycerides

A storage form of fat, made up of three fatty acid chains attached to the three carbons on a glycerol molecule. These are the most abundant type of dietary lipid, providing a large portion of total food energy, and they are required for the efficient transport of certain fat-soluble vitamins (vitamins A, D, E, and K) through the body. All triglycerides are composed of a mix of short-chain, medium-chain, and long-chain fatty acids. They seldom contain exclusively one type of fatty acid. Because triglycerides consist of three fatty acids, they can provide essential fatty acids, the fatty acids our bodies need but cannot synthesize in sufficient amounts. Essential fatty acids must be obtained through our diet.

fat

A term for triglycerides, a subclass of lipids, that are the primary form of fat in our bodies and our food.

glycerol

A three-carbon compound that makes up the backbone of a triglyceride molecule.

Atherosclerosis

A type of cardiovascular disease characterized by the narrowing and loss of elasticity of blood vessel walls, caused by accumulation of plaque and inflammation of tissue. It is an inflammatory disease characterized by the accumulation of fatty plaque in the walls of arteries and blood vessels that generally develops over the course of several decades. This process is typically caused by the presence of elevated levels of cholesterol-rich low-density lipoproteins (LDLs) in the blood. As blood levels of LDL rise, they infiltrate the artery wall, where the LDLs are likely to become oxidized (by reacting with unstable oxygen-containing molecules). Oxidized LDLs cause injury to cells that line the vessel wall, and this initiates an inflammatory process that attracts white blood cells called macrophages inside the arterial lining. Other factors, such as smoking and hypertension, can also cause injury to the arterial wall and trigger inflammation. Inside the vessel wall, macrophages take up the oxidized LDLs in a rapid and uncontrolled fashion. These fat-laden macrophages (now called foam cells) die and deposit their accumulated lipids within the wall of the artery, promoting further inflammation.

Chylomicrons

A very large lipoprotein that transports triglycerides and other dietary lipids away from the small intestine, first in the lymph and then in the blood. Transports dietary fats and cholesterol from the intestines to muscles and adipose tissue. Originate in the small intestine and carry essentially all lipids consumed in our diet In the mucosal cells of the small intestine, triglycerides, other lipids, and hydrophobic substances of dietary origin are incorporated into a type of lipoprotein called a chylomicron. Unlike other lipoproteins, however, chylomicrons are too large to enter blood immediately after their formation, so they first enter the lymphatic system, which then delivers them into the bloodstream.

What to eat instead

Based on current evidence, the best overall strategy to protect your heart health is to replace saturated fatty acids with unsaturated ones and to emphasize vegetables, fruits, and whole grains in the diet. Although saturated fatty acids do, indeed, have the potential to raise total and LDL cholesterol levels, an important factor to consider is what people who cut back on saturated fatty acids eat instead. If people replace high-fat foods with lower-fat options that are high in carbohydrates, particularly refined starches, added sugar, and potatoes (which happens frequently), then they won't likely see any health benefits. Low-fat diets high in carbohydrates, particularly when low in fiber and high in sugar, actually increase triglyceride levels in the blood. And some recent analyses even suggest that certain sources of saturated fatty acids long thought to be contributors to CVD, such as those in dairy products, actually may not affect blood lipids levels or increase the risk of CVD as negatively as other sources. Research indicates that replacing saturated fats with monounsaturated fatty acids can improve blood lipid profiles and reduce the risk of heart disease, but not as effectively as what is seen when saturated fats are replaced with polyunsaturated fatty acids.

Heart Protective Diet

Based on current evidence, the best overall strategy to protect your heart health is to replace saturated fatty acids with unsaturated ones and to emphasize vegetables, fruits, and whole grains in the diet. (INFOGRAPHIC B.8) The Dietary Guidelines for Americans recommend limiting overall saturated fat intake to 10% or less of total daily calories. For those with increased risk for heart disease and high blood cholesterol levels, recommendations from the National Cholesterol Education Program (NCEP) of the National Institutes of Health are to keep calories from saturated fat under 7%. - low dietary cholesterol - include foods with plant sterols and stanols - sufficient soluble fiber - weight management - physical activity

DHA and brain health

Because fish is the primary source of DHA and EPA in the American diet, Morris and her team conducted a study that evaluated the effects of fish consumption and total intake of omega-3 fatty acids on risk of developing Alzheimer's disease. For the study, about 800 elderly individuals were followed for four years. The results of this study showed an impressive 60% reduction in AD among those who consumed even one fish meal a week compared to those who ate fish less frequently or never. Other studies have also shown that increased fish consumption is linked to a reduced risk of Alzheimer's disease. Total intake of omega-3 fatty acids and DHA were associated with lower risk of AD, although no specific protective benefit with EPA alone was found. Another research group studied the effects of DHA levels in blood on risk of developing AD and other forms of dementia. After a nine-year follow-up period, they found that patients with the highest levels of blood DHA showed nearly a 50% lower risk of developing dementia. Of note, levels of EPA in blood were not shown to affect dementia risk. It appears then that DHA plays a key role in protecting the brain from damage and in decreasing AD risk. DHA appears to reduce risk via several mechanisms, most notably by producing beneficial compounds that reduce inflammation in the brain and protect it from damage that may contribute to the cause of the disease. DHA added to animal models had been shown to increase enzymes that protect the brain from damage, reduce brain inflammation, and improve nerve function while decreasing brain damage due to restricted blood supply.

Modifiable risk factors for CVD

Behaviors that can increase risk of disease; these include smoking, sedentary behavior, obesity, excessive alcohol consumption, high blood pressure, and poor dietary habits. Appropriate diet and lifestyle choices may reduce our risk of CVD by about 80%.

cardiovascular disease (CVD)

Conditions that impair the heart, arteries, veins, and capillaries, which move blood throughout the human body. CVD is the leading cause of death around the world, accounting for approximately 31% of all deaths in 2014. Although we may often think of CVD as a disease that affects primarily affluent countries, this is not the case as 75% of deaths due to CVD worldwide occur in low- to middle-income countries. A major reason for this is that people in these countries are often diagnosed late in the course of the disease and often have less access to effective healthcare, so their death rates from CVD are higher than for individuals in developed countries. In the United States, CVD has been the number one cause of death for more than 100 years; today an estimated one in three Americans have some form of the disease. According to 2018 statistics from the American Heart Association, about 2300 Americans die of CVD every day, equating to an average of one death due to CVD every 36 seconds. It's not just a disease of old age either—about 2 in 10 deaths from CVD in the United States in 2016 occurred in adults younger than 65 years.

adipose tissue

Connective tissue composed primarily of adipocytes (fat cells) that is a storage site for energy (in the form of triglycerides) and fat-soluble vitamins and cushions and insulates the body.

Diet Strategies to Reduce the Risk of Heart Disease

Consumption of plant sterols Consumption of nuts Consumption of oily, cold-water fish Plant based diet Consumption of soluble fiber such as in whole grains Moderate alcohol consumption (1 drink per day for women, 2 drinks per day for men) Substituting unsaturated oils for saturated fats

trans fatty acid (trans fat)

Fatty acids created by adding hydrogen to liquid vegetable oils (partial hydrogenation) to make them more solid; associated with an increased risk of cardiovascular disease. These trans fatty acids raise levels of LDL cholesterol and lower levels of HDL cholesterol in blood, thereby increasing the risk of heart disease more than any other type of fat. As little as 1% of total calories from trans fats can increase the risk of heart disease, stroke, or sudden death from these conditions and other causes. Given the risks of trans fats, the U.S. Food and Drug Administration banned added trans fats (partial hydrogenated oils) from foods except in special circumstances. This ban went into effect on June 18, 2018, with Canada banning its use on September 15, 2018. Although a small amount of trans fat is naturally present in dairy products and beef, most of the trans fat we consumed prior to the ban had come from the partially hydrogenated oils used to extend the shelf life of processed foods or to increase the melting point of vegetable oils. Do not be alarmed, however, if you see fully hydrogenated oils in the list of ingredients, as all double bonds have been eliminated in full hydrogenation and consequently no trans fats are produced.

Name the four classes of lipids

Fatty acids, triglycerides, sterols (such as cholesterol), and phospholipids (such as lecithin).

MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) Diet

Includes green leafy vegetables, berries, beans, nuts, whole grains, poultry, and fish. The MIND diet also limits the intake of red meats, cheese, and sweets and reduces saturated fat by substituting olive oil in place of butter and margarine. To assess the effect of diet on the risk of AD, the Morris-led team devised a scoring method to determine how closely individuals' diets resembled the MIND diet. They examined the diets of about 900 individuals over about a five-year period and found that elderly individuals whose diets either highly or moderately adhered to the MIND diet were significantly less likely to be diagnosed with AD. More recently, the ability of the MIND diet to preserve cognitive function was examined in approximately 6000 elderly adults. This study found that seniors whose diets were closely aligned with the MIND diet were 35% less likely to exhibit poor cognitive performance and that those whose diets only moderately aligned with the MIND diet were 24% less likely to demonstrate poor cognitive performance. Similarly, another recent study found that among more than 7000 elderly women, those whose diets best resembled the MIND diet had a 34% lower risk of developing AD over an average follow-up period of about 10 years.

lipid absorption

Lacteals in small intestine absorb dietary lipids that are not absorbed by the blood capillaries. The products of triglyceride digestion (monoglycerides and free fatty acids), along with bile acids and other fat-soluble dietary substances, form structures called micelles that deliver dietary lipids to the surface of mucosal cells of the small intestine. Micelles then release the dietary lipids, which are absorbed by the mucosal cells. Once inside mucosal cells, fatty acids and monoglycerides (which, as their name implies, contain only one fatty acid chain) are reassembled into triglycerides.

Recommendations for saturated fat

Less than 10% of the total calories. Within our overall fat intake, it is recommended that we emphasize unsaturated fats over saturated fats when choosing foods and added fats.

Recommendations for trans fats

Limit consumption to less than 1% of total calories. Ideally, you should consume 0 grams per day.

What are the two essential fatty acids?

Linolenic acid (omega-3, for example) and linoleic acid (omega-6), which are required in the diet because they cannot be synthesized by the human body.

foam cells

Lipid-loaded white blood cells that have surrounded large amounts of a fatty substance, usually cholesterol, on the blood vessel walls.

Lipoproteins

Structures formed by the assembly of proteins and phospholipids that transport lipids in lymph and in blood. Because most lipids are not soluble in water, they cannot dissolve in the watery environment of the bloodstream and require carriers for transport in it. Lipoproteins are protein-containing spherical particles that act as the primary carriers of lipids in blood.

fatty streaks

The earliest lesion of atherosclerosis; can be seen as early as the second decade of life. They appear as a collection of lipid-laden macrophages (foam cells) in artery walls that can eventually progress to atherosclerotic plaques.

partially hydrogenated oils (PHOs)

The primary source of trans fat. As little as 1% of total calories from trans fats can increase the risk of heart disease, stroke, or sudden death from these conditions and other causes. The U.S. Food and Drug Administration banned added trans fats (partial hydrogenated oils) from foods except in special circumstances. This ban went into effect on June 18, 2018, with Canada banning its use on September 15, 2018. Although a small amount of trans fat is naturally present in dairy products and beef, most of the trans fat we consumed prior to the ban had come from the partially hydrogenated oils used to extend the shelf life of processed foods or to increase the melting point of vegetable oils. Do not be alarmed, however, if you see fully hydrogenated oils in the list of ingredients, as all double bonds have been eliminated in full hydrogenation and consequently no trans fats are produced.

Blood lipid levels for decreased CVD risk

↑ HDL level ↓LDL level < 200 mg/dl of blood cholesterol