6.8 – Lipids and Disease

Replace Saturated Fat with Unsaturated fat

In proper amounts, cholesterol is a compound used by the body to sustain many important body functions. In excess, cholesterol is harmful if it accumulates in the structures of the body’s vast network of blood vessels. High blood L.D.L. and low blood H.D.L. are major indicators of blood cholesterol risk. The largest influence on blood cholesterol levels rests in the mix of saturated fat and trans fat in the diet. According to the Harvard School of Public Health, for every extra 2 percent of calories from trans fat consumed per day—about the amount found in a midsize order of French fries at a fast-food establishment—the risk of coronary heart disease increases by 23 percent.¹ A buildup of cholesterol in the blood can lead to brittle blood vessels and a blockage of blood flow to the affected area.

How saturated is the fat in your diet? Saturated fat is not an essential nutrient in the diet and it is suggested to be a forerunner of cardiovascular disease. In the United States and other developed countries, populations acquire their saturated fat content mostly from meat, seafood, poultry (with skin consumed), and whole-milk dairy products (cheese, milk, and ice cream). Some plant foods are also high in saturated fats, including coconut oil, palm oil, and palm kernel oil.

This being said, there are a growing number of physicians and nutrition experts who disagree that saturated fat and cholesterol are “bad” at all. Because this is not the opinion of the American Heart Association, it will not be discussed further here but if you wish to read about the controversy, please click here and read an article by Jeff Volek, Ph.D., RD, and Stephen Phinney, MD, Ph.D. of Virta Health.

^{1 Harvard School of Public Health. “Fats and Cholesterol: Out with the Bad, In with the Good.” Section 2.02. Accessed June 21, 2019.}

Food Cholesterol’s Effect on the Blood Cholesterol

If left unchecked, improper dietary fat consumption can lead down a path to severe health problems. An increased level of lipids, triglycerides, and cholesterol in the blood is called hyperlipidemia. Hyperlipidemia is inclusive of several conditions but more commonly refers to high blood cholesterol and triglyceride levels. When blood lipid levels are high, any number of adverse health problems may ensue. Consider the following:

• Cardiovascular disease. According to the A.H.A., cardiovascular disease encompasses a variety of problems, many of which are related to the process of atherosclerosis. Over time the arteries thicken and harden with plaque buildup, causing restricted or at times low or no blood flow to selected areas of the body.
• Heart attack. A heart attack happens when blood flow to a section of the heart is cut off due to a blood clot. Many have survived heart attacks and go on to return to their lives and enjoy many more years of life on this earth. However, dietary and lifestyle changes must be implemented to prevent further attacks.
• Ischemic stroke. The most common type of stroke in the United States, ischemic stroke, occurs when a blood vessel in the brain or leading to the brain becomes blocked, again usually from a blood clot. If part of the brain suffers a lack of blood flow and/or oxygen for three minutes or longer, brain cells will start to die.
• Congestive heart failure. Sometimes referred to as heart failure, this condition indicates that the heart is not pumping blood as well as it should. The heart is still working but it is not meeting the body’s demand for blood and oxygen. If left unchecked, it can progress to further levels of malfunction.
• Arrhythmia. This is an abnormal rhythm of the heart. The heart may beat above one hundred beats per minute (known as tachycardia) or below sixty beats per minute (known as bradycardia), or the beats are not regular. The heart may not be able to pump enough volume of blood to meet the body’s needs.
• Heart valve problems. Stenosis is a condition wherein the heart valves become compromised in their ability to open wide enough to allow proper blood flow. When the heart valves do not close tightly and blood begins to leak between chambers, this is called regurgitation. When valves bulge or prolapse back into the upper chamber, this condition is called mitral valve prolapse.
• Obesity. Obesity is defined as the excessive accumulation of body fat. According to US Surgeon General Richard Carmona, obesity is the fastest growing cause of death in America. The H.H.S. reports that the number of adolescents who are overweight has tripled since 1980 and the prevalence of the disease among younger children has doubled.² Obesity has been linked to increased risks of developing diabetes and heart disease. To help combat this problem important dietary changes are necessary. Reducing the type and amount of carbohydrates and sugar consumed daily is critical. Limiting the intake of saturated fats and trans fats, increasing physical activity, and eating fewer calories are all equally important in this fight against obesity.

^{2 US Department of Health and Human Services. “Childhood Obesity.” Accessed June 21, 2019.}

What You Can Do

The American Heart Association published  2021 Dietary Guidelines to Improve Cardiovascular Health in November 2021. They emphasize many of the principles we discuss throughout this text as seen in the introduction. “The purpose of this latest scientific statement is to (1) emphasize the importance of dietary patterns beyond individual foods or nutrients; (2) underscore the critical role of initiating heart-healthy dietary habits early in life; (3) present common features of dietary patterns that promote cardiometabolic health; (4) discuss additional benefits of heart-healthy dietary patterns, beyond cardiovascular health; and (5) highlight structural challenges that impede the adoption of heart-healthy dietary patterns.”³

The guidelines emphasize the following recommendations:

• Eat a wide variety of fruits and vegetables.
• Remember that saturated fats are found in large amounts in foods of animal origin. They should be limited in our eating patterns. Polyunsaturated fats are generally obtained from non-animal sources. Monounsaturated fats are found in animal and plant sources and are found in most nuts, seeds, seed oils, olive oil, canola oil, and legumes. Current guidelines recommend replacing dietary saturated fats with unsaturated fats, either monounsaturated or polyunsaturated fats. Liquid plant oils (canola and soy oil)  are the best choice. Limit tropical oils ( coconut, palm, and palm kernel), animal fats ( butter and lard), and partially hydrogenated fats.
• Chose healthy sources of protein. Include mainly protein from plants such as legumes and nuts, fish and seafood,  and low-fat or fat-free dairy products.  if meat or poultry is desired, stick with lean cuts of meat and avoid processed meats.
• Choose whole-grain and high-fiber foods. Reduced risk for cardiovascular disease has been associated with diets that are high in whole grains and fiber. Fiber also slows down cholesterol absorption. The A.H.A. recommends that at least half of daily grain intake should originate from whole grains. The Adequate Intake value for fiber is 14 grams per 1,000 kilocalories. These amounts are based upon the amount of fiber that has been shown to reduce cardiovascular risk.
• Minimize intake of beverages and foods with added sugars, and choose foods with little or no salt.
• If you choose to drink alcohol, limit intake.
• Choose minimally processed foods instead of ultra-processed foods.
• Balance energy intake with expenditure to maintain a healthy weight. Get more exercise on a regular basis. Increasing your energy expenditure by just twenty minutes of physical activity at least three times per week will improve your overall health. Physical exercise can help you manage or prevent high blood pressure and blood cholesterol levels. Regular activity raises H.D.L. while at the same time decreasing triacylglycerols and plaque buildup in the arteries. Calories are burned consistently, making it easier to lose and manage weight. Circulation will improve, the body will be better oxygenated, and the heart and blood vessels will function more efficiently.

As you can see, these guidelines are very similar to the Dietary Approaches to Stop Hypertension (DASH), Mediterranean, Healthy U.S.-style, and the healthy vegetarian eating patterns.  Adhering to any one of these high-quality eating patterns would be an excellent choice to avoid cardiovascular disease.

^{3 2021 Dietary Guidance to Improve Cardiovascular Health: A Scientific Statement From the American Heart Association  https://doi.org/10.1161/CIR.0000000000001031  accessed Nov 17, 2021}