Diet for Dyslipidemia
OVERVIEW ㅡ Dyslipidemia refers to high blood levels of low-density lipoprotein cholesterol (LDL-C), triglycerides (TGs) or both, or low blood levels of high-density lipoprotein cholesterol (HDL-C), all of which contribute to the development of atherosclerosis. Causes may be primary (genetic) or secondary, which includes excessive dietary intake of saturated fat, cholesterol and trans fat. A modified diet can improve the lipoprotein and lipid levels of individuals with dyslipidemia and can help prevent and/or slow the progression of coronary heart disease (CHD).
Lowering total cholesterol and LDL-C decreases risk for fatal and nonfatal coronary events. The 2016 update of the Canadian Cardiovascular Society guidelines for the management of dyslipidemia for the prevention of cardiovascular disease in the adult has established target lipid values based on degree of risk of CHD.
- Moderate energy (caloric) intake to achieve and maintain a healthy body weight.
- Avoid trans fats; limit saturated fats to < 9% of daily total energy intake; replace saturated fats with polyunsaturated fats particularly from sources with mixed omega-3/omega-6 (e.g., soybeans oils) and monounsaturated oils particularly from plant sources (e.g., olive oil, canola oil, nuts and seeds).
- Increase daily fiber intake to > 30 g.
- Follow any of the following diets: Mediterranean, DASH, Portfolio (emphasizing cholesterol lowering foods such as soluble fiber, soy protein, plant sterols and nuts), vegetarian, low glycemic load, or a diet rich in legumes, nuts, fruits and vegetables, or total fiber.
TYPE OF FATS
TRANS FATS are formed from the partial hydrogenation of vegetable oils, which turns the oils into solids. Trans fats have been shown to raise LDL-C levels and decrease HDL-C levels. These fats are often listed as ‘partially hydrogenated oil’ on food labels and are often found in vegetable oil shortening, hard margarines, commercially prepared baked goods, potato and corn chips, crackers, microwave popcorn and deep-fried foods. The Heart and Stroke Foundation of Canada states that trans fats are at least 5 times more harmful than saturated fats and has appealed to Health Canada to introduce regulations to severely limit the trans fat content of foods.
CHOLESTEROL is primarily produced by the liver, but dietary cholesterol found in animal foods may contribute to elevated blood cholesterol levels. Foods that have high levels of dietary cholesterol include egg yolks and organ meats, but all animal products contribute to the cholesterol level of the diet. Every ounce of beef, lamb, pork, poultry and fish contains approximately 25 mg of dietary cholesterol, and 1 cup of milk contains 4–33 mg, depending on the fat content. Restricting dietary cholesterol intake can achieve a 1–3% reduction in LDL-C.
SATURATED FATS are the strongest contributor to elevated LDL-C levels. They are found primarily in animal foods (beef, chicken, pork, whole-fat dairy products, eggs and lard) and in some plant-based foods (coconut, palm and palm kernel oils and cocoa butter). Restricting saturated fat intake can achieve a 5–10% reduction in LDL-C. A large, prospective cohort study found that replacing 5% of energy intake from saturated fats with equivalent energy intake from polyunsaturated fats, monounsaturated fats or carbohydrates from whole grains was associated with a 25%, 15% and 9% lower risk of CHD, respectively. However, carbohydrates from refined starches or added sugars (e.g., sugar sweetened beverages or foods) have been positively associated with a risk of CHD and should not be used to replaced saturated fat.
UNSATURATED FATS include monounsaturated and polyunsaturated fats. Monounsaturated fats (MUFAs) include omega-7 (palmitoleic) and omega-9 (oleic). They have been shown to improve blood cholesterol levels and are found in avocados, nuts and vegetable oils (canola, olive, peanut, safflower, sesame and sunflower).
POLYUNSATURATED FATS (PUFAs) include both omega-3 and omega-6 fatty acids. Omega-3 fatty acids can lower triglycerides and help prevent clotting of blood. They are found in cold-water fish (mackerel, herring, sardines, salmon and trout), canola and soybean oils, nuts (walnuts, pecans, pine nuts), and seeds (flaxseed, sunflower seed). Omega-6 fatty acids lower LDL-C. They are found in vegetable oils (soybean, safflower, sunflower, corn), non-hydrogenated margarine, nuts (almonds, pecans, brazil nuts) and seeds (sunflower).
- Fat free: < 0.5 g fat per serving of stated size.
- Low fat: ≤ 3 g fat per serving of stated size.
- Reduced fat: modified to contain at least 25% less fat than a similar reference food.
- Light in fat: modified to contain at least 25% less fat than a similar reference food.
- Cholesterol free, as only animal products contain cholesterol.
- Partially hydrogenated fat, as trans fats are formed in the processing.
- Low fat, as fat may be replaced with refined carbohydrates (sugars) and the resulting product may be higher in calories.
REFERENCES
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Scandinavian Simvastatin Survival Study Group. Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian Simvastatin Survival Study (4S). Lancet 1994;344:1383-9. Available at: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(94)90566-5/fulltext
Anderson TJ, Grégoire J, Pearson GJ et al. 2016 Canadian Cardiovascular Society guidelines for the management of dyslipidemia for the prevention of cardiovascular disease in the adult. Can J Cardiol. 2016;32(11):1263-1282. Available at: https://www.onlinecjc.ca/article/S0828-282X(21)00165-3/fulltext
Estruch R, Rose E, Salas-Salvado J et al. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med 2013;368(14):1279-90. Available at: https://www.nejm.org/doi/10.1056/NEJMoa1200303?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200www.ncbi.nlm.nih.gov
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Malik VS, Hu FB. Fructose and cardiometabolic health: what the evidence from sugar-sweetened beverages tells us. J Am Coll Cardiol 2015;66:1615-24. Available at: https://www.sciencedirect.com/science/article/pii/S0735109715049074?via%3Dihub
Canadian Food Inspection Agency. Specific Nutrient Content Claim Requirements. Fat claims. Available at: inspection.gc.ca/food/labelling/food-labelling-for-industry/nutrient-content/specific-claim-requirements/eng/1389907770176/1389907817577?chap=4