Nutrition Questions

Answer and explanation: C – Saturated fatty acids

Dietary saturated fatty acids consistently raise serum LDL-C more than all other macronutrient classes aside from trans-fatty acids on a per-calorie basis (1,2). Saturated fatty acids suppress hepatic LDL receptor activity and increase LDL production rates through alterations in intracellular cholesterol regulatory pools, thereby increasing circulating LDL-C concentrations.(3) Saturated fatty acids are found in high concentrations in red and processed meats, full-fat dairy and creams, coconut and palm oils, and commercially processed baked goods (4). Unsaturated fats (both polyunsaturated and monounsaturated), which are found in higher concentrations in plant oils (such as olive oil), avocados, nuts/seeds, and fatty fish moderately reduce LDL-C levels when they replace saturated fats (5). Dietary cholesterol, found in animal products, typically has a smaller effect on serum LDL-C than saturated fatty acids on a per-calorie basis. (5). The 2026 ACC/AHA Dyslipidemia Guidelines emphasize that "focusing on healthy eating patterns that limit saturated fat while increasing unsaturated fat produces more consistent LDL-C lowering than restricting dietary cholesterol” (6). However, it is estimated that about 20% of the population may be genetically predisposed to hyper-absorption of dietary cholesterol and may therefore experience a greater increase in serum LDL-C than non-hyper-absorbers when consuming dietary cholesterol (7). While refined sugar may have a small positive association with LDL-C, the evidence is weak and refined carbohydrates as a whole do not have a significant effect on LDL-C (5).

1.           Belardo D, Michos ED, Blankstein R et al. Practical, Evidence-Based Approaches to Nutritional Modifications to Reduce Atherosclerotic Cardiovascular Disease: An American Society For Preventive Cardiology Clinical Practice Statement. American Journal of Preventive Cardiology 2022;10:100323.

2.           Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Saturated fat, carbohydrate, and cardiovascular disease. The American journal of clinical nutrition 2010;91:502-9.

3.           Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Saturated fatty acids and risk of coronary heart disease: modulation by replacement nutrients. Curr Atheroscler Rep 2010;12:384-90.

4.           Wambogo EA, Ansai N, Terry A, Fryar C, Ogden C. Dairy, Meat, Seafood, and Plant Sources of Saturated Fat: United States, Ages Two Years and Over, 2017-2020. The Journal of nutrition 2023;153:2689-2698.

5.           Schoeneck M, Iggman D. The effects of foods on LDL cholesterol levels: A systematic review of the accumulated evidence from systematic reviews and meta-analyses of randomized controlled trials. Nutrition, Metabolism and Cardiovascular Diseases 2021;31:1325-1338.

6.           Blumenthal Roger S, Morris Pamela B, Gaudino M et al. 2026 ACC/AHA/AACVPR/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Dyslipidemia. JACC;0.

7.           Senaratne J, Griffiths J, MacDonald K, Senaratne MP. Evidence for cholesterol hyperabsorbers and hyperproducers based on comparative low-density lipoprotein reductions achieved by ezetimibe versus statins. J Cardiopulm Rehabil Prev 2012;32:250-4.