Lowering Your Cholesterol: Some Food for Thought
Cholesterol is a kind of fat called a lipid which is essential to life. It is a necessary part of every cell in our body and provides a protective layer for our internal organs. It is also part of the protective covering of our nerves and is used as a building block for many hormones in our bodies. Dietary cholesterol is found exclusively in animal products such as eggs, dairy, beef, pork, lamb, poultry and fish. The most concentrated sources are liver and other end-organ meats, egg yolk and shellfish.
Cholesterol is carried in our bodies in packages called lipoproteins. There are many kinds of lipoproteins, the two most common being low-density lipoproteins (LDL) and high-density lipoproteins (HDL). Your body needs both kinds of lipoproteins to maintain health. However, abnormal levels can result in a disruption of normal structure and function of various organs in your body.
LDL cholesterol is considered “bad” cholesterol because elevated levels are associated with an accumulation of cholesterol buildup in arteries resulting in cardiovascular disease. However, a certain amount of LDL is necessary to transport cholesterol to various tissues in your body. On the other hand, HDL cholesterol is considered “good” cholesterol as it transports cholesterol away from various parts of your body to the liver for it to ultimately be excreted. High HDL levels are associated with reduced risks of cardiovascular disease while low levels result in increased risks. Triglycerides are a type of fat in your bloodstream, providing energy to cells. Elevated levels of triglycerides are also associated with increased risks of cardiovascular disease.
Modern diets and physical inactivity can result in unhealthy disruptions in our lipid profiles. Foods which provided a majority of sustenance for 99% of human evolution (seasonal fruits and vegetables, nuts, honey, lean wild meat and wild fish) have given way to cereal-grains, milk products, refined sugars, sweeteners and fatty farm-bred meats as the primary energy sources fueling human activity. This is compounded by trends indicating a general global reduction in physical activity levels over the past several decades.
The U.S National Cholesterol Education Program (NCEP), the Canadian Cardiovascular Society and the British Hyperlipidemia Association all consider diet and life-style as the primary means of lowering cholesterol and reducing risks of coronary artery disease. However, the relative ineffectiveness of conventional dietary advice administered by health professionals to patients has resulted in pharmaceutical companies understandably attempting to fill this gap by spending billions of dollars developing medications targeted to correct lipid imbalances and reduce the associated risks of cardiovascular disease. Well-designed studies have clearly demonstrated impressive effectiveness and overall benefits of many of these medications in not only improving lipid profiles but also substantially reducing the risks of developing cardiovascular disease. However, their associated costs and side-effects clearly make diet and life-style the most prudent approach for most patients to achieve those goals.
Take, for example, a new study published in 2012 in the Archives of Internal Medicine which showed a relationship between the use of statins – a commonly prescribed class of cholesterol-lowering medications – and an increased risk of developing diabetes mellitus. While this does not imply that statins are unsafe or patients should discontinue taking their statin medications, it strongly suggests the importance of structured life-style changes – mainly through diet and exercise – as the primary means of lowering cholesterol in patients determined, by their physicians, to have a low to moderate risk of cardiovascular disease. In some cases, this approach can reduce or even eliminate the need for medications altogether in such patients.
Along these lines, the following are some proven life-style strategies that can help lower your cholesterol:
A majority of studies indicate that regular aerobic activity can lower triglycerides and raise HDL while only having minimal effects on lowering LDL. Experts recommend both an increase in structured physical activity as well as a reduction in time spent in sedentary physical activities outside the gym. Guidelines from the American Heart Association and the American College of Sports Physicians recommend a minimum of 150 minutes per week of moderate intensity aerobic physical activity or 20 minutes for 3 days per week of vigorous aerobic activity to maintain health. This is in addition to routine light physical daily tasks such as household chores, yard work, climbing stairs, walking, chasing after children in the yard, etc.
Nuts and seeds
Nuts and seeds were a normal part of the hunter-gatherer diets of our ancestors thousands of years ago. They are a rich source of healthy unsaturated fats as well as high quality vegetable protein, fiber and antioxidants. Studies consistently show that intake of nuts and seeds has cholesterol-lowering effects. Despite being a rich source of fats and calories, research has shown that their long-term consumption in the context of a healthy diet does not result in weight gain and may even result in weight loss when substituted for other foods high in saturated fats and carbohydrates.
The Adventist Health Study revealed that individuals who consumed nuts four or more times per week were significantly less likely to suffer from fatal and non-fatal heart attacks. A study published in 2010 in the Archives of Internal Medicine showed that a mean daily consumption of 2.4 ounces (67g) of nuts resulted in a 5.1% reduction in total cholesterol and a 7.4% reduction in LDL cholesterol. Another article published in 2009 in the American Journal of Clinical Nutrition reviewed twenty-eight studies involving flax seed and concluded that consumption of whole flax seed (not flax seed oil) also led to a significant reduction in total cholesterol and LDL levels.
Omega 3 fatty acids
These are polyunsaturated fatty acids, primarily from the sea. Direct sources are fatty fish (salmon, mackerel, and herring), fish oil, fortified foods and some algal oil supplements. Many studies have demonstrated that marine sources of these fatty acids are effective in reducing triglycerides. A study published in the American Journal of Clinical Nutrition in 2009 found that triglyceride levels were reduced by 11% while HDL cholesterol was increased by 4% with 2 servings (4 ounces) of salmon per week. In addition, fish oil capsule supplementation at approximately 4g per day (EPA + DHA) has been shown to reduce triglycerides by 25-30%.
Multiple studies have demonstrated the cholesterol-lowering effects of soy proteins when substituted for animal proteins. One study conducted by the Agency for Health care Research and Quality (AHRQ) reported that daily consumption of approximately 36 grams of soy protein was associated with a 2.5%, 3%, and 6% lowering effect of total cholesterol, LDL, and triglycerides respectively.
Fruits and vegetables
Studies show that there is a cholesterol-lowering effect when foods with high saturated fat and cholesterol are replaced with fruits and vegetables. There are numerous other benefits associated with the consumption of fruits and vegetables, making their inclusion in a regular diet mandatory for good health.
Phytosterols are cholesterol-like molecules found in all plant foods. They are absorbed only in trace amounts but inhibit the absorption of cholesterol in your intestine. The NCEP’s Adult Treatment Panel (ATP III) recommends an intake of 2 grams per day to reduce LDL cholesterol by 10%. Typical western diets supply anywhere from 150-400 mg per day of phytosterols. The richest sources of naturally occurring phytosterols are minimally processed whole grains, nuts, seeds, fruits, vegetables, and non-hydrogenated vegetable oils. Phytosterols are also available as capsule supplements and are added to some margarines at up to 1 gram per tablespoon. Keep in mind that although these are generally well tolerated, consuming phytosterols in the forms of supplements or additives can cause symptoms such as nausea, gas, diarrhea, or constipation. There is also some concern that long-term use can cause vitamin deficiencies.
Fiber is an indigestible component of plants. It can be classified into two kinds: soluble and insoluble. Soluble fiber forms a gel when mixed with liquid, while insoluble does not. Soluble fiber is generally believed to be more effective in reducing cholesterol. Common sources of soluble fiber are oat/oat bran, nuts, fruits, dried beans and peas, vegetables and psyllium husk. Clinical trials have shown the LDL-lowering effect of dietary fiber. The NCEP recommends the consumption of 10 – 25 grams per day of soluble fiber to help reduce LDL cholesterol. Studies have shown that adding 5-10 grams of soluble fiber to a diet low in saturated fat and total cholesterol can reduce LDL levels by up to 5%.
Although there is not a great deal of solid evidence supporting significant cholesterol lowering effects of whole grains, there is strong evidence that their regular consumption does reduce risks for cardiovascular disease when included in a well-balanced diet. Whole grains are a good source of fiber and other important nutrients.
Many studies before 1995 suggested that garlic may have a beneficial effect on cholesterol levels. However, better-designed studies which have been conducted more recently failed to show any significant beneficial effect of consuming raw garlic or garlic supplements on cholesterol levels. Nevertheless, regardless of the direct health benefits of garlic itself, its inclusion in plant-based recipes can make them more flavorful, increasing the likelihood they will be eaten.
While knowledge about specific foods is important, it is more practical and effective long-term to focus on eating patterns when thinking about cholesterol reduction and overall health. Many of the food groups that can help lower or maintain low cholesterol have overlapping and synergistic health benefits, making their regular and balanced consumption more advantageous to overall health and longevity. As a general rule, because plant foods (fruits, vegetables, nuts, seeds, beans and grains) do not contain cholesterol, dietary patterns which replace meats and other animal products with plant-based whole foods can effectively reduce cholesterol – in some cases even as effectively as medications – while offering numerous other benefits that no single medication on the market can currently offer.
Mediterranean dietary pyramid
The Mediterranean diet refers to dietary patterns in the early 1960s of the countries surrounding the Mediterranean Sea. This diet was singled out because scientists observed high life-expectancies and some of the lowest rates of cardiovascular disease in that region. It has been associated with lower rates of heart disease and LDL-cholesterol levels, resulting in many medical organizations encouraging its adoption. In general, it emphasizes:
- An abundance of food from plant sources.
- Using olive oil instead of unhealthy fats such as butter.
- Limiting red meat intake to only a few times per month.
- Eating fish and poultry twice weekly.
- Low to moderate consumption of low-fat dairy products (primarily yogurt and cheese).
Harvard School of Nutrition Healthy Eating Pyramid
This dietary pattern shares some similarities with the Mediterranean diet in that it encourages a diet rich in plant-based foods while restricting red meat, refined foods and sweets. It, however, has some differences which include:
- Less emphasis on dairy products.
- Discourages the consumption of potatoes and refined grains such as white bread, white pasta and white rice.
- Allows more flexibility for Asian cultural food preferences by allowing the intake of tofu as a protein source and including peanut, sesame, sunflower, canola and soybean oils as additional options to olive oil.
The portfolio diet
A study published in 2003 in the Journal of the American Medical Association showed that the daily consumption of a combination of foods known to lower cholesterol can lower your LDL as effectively as a first-generation statin medication. The diet used in this study is frequently cited in the medical literature and became known as the “Portfolio Diet.” In addition to emphasizing a base diet low in saturated fat and rich in fruits and vegetables, it also recommends the daily consumption of two grams of plant sterols, thirty grams (about 23) almonds, twenty grams of soluble fiber and fifty grams of soya protein.
Making dietary changes to reduce your cholesterol can seem daunting. Here are some things to keep in mind:
- Be patient with yourself and set realistic goals. Consider changing one item in your diet each week. For example, rather than having white bread or croissants for breakfast, try oatmeal or high fiber cereal with non-fat milk. Another option is to change your snacks to unsalted nuts, vegetables, or fruits instead of potato chips or candy bars.
- Do not get disappointed if you slip once in a while. It is more important that the sum effects of your long-term diet balance out.
- A healthy diet does not mean you have to go hungry all day; this would be unsustainable long-term. Rather, it means eating sufficient amounts of the right foods to keep you healthy and your hunger satisfied.
- If you choose to eat red meat, avoid fatty kinds such as “prime,” liver and processed meats.
- Reduce your intake of partially hydrogenated vegetable oils and palm oils.
Most physicians would agree that, when treating high cholesterol, diluting efforts towards life-style changes and replacing them with medications may not be in the best overall health interests of most patients. Remember, living and eating healthy may have greater effects on your long-term health than any medication.
Mediterranean diet: http://www.oldwayspt.org/mediterraneandiet
Healthy Eating Pyramid: http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/pyramid/