Author: Michael Bernstein
Date: 3-30-25
The highest dietary sources of saturated fats are dairy fat and meat fat. During digestion, saturated fat is broken down into saturated fatty acids. There are multiple types of saturated fatty acids. Saturated fatty acids are differentiated from each other based on their chain length and the number of carbon atoms in the chain. There are three main types of saturated fatty acids including short-chain (< 6 carbons), medium-chain (6-12 carbons), and long-chain (> 12 carbons). Some of the most regularly consumed saturated fatty acids includes stearic acid (18 carbons), palmitic acid (16 carbons), myristic acid (14 carbons), and lauric acid (12 carbons). The chain length is important because it defines biological functions. Some of the ones of interest are the effects on blood lipids and lipoproteins. Saturated fatty acids have various effects on total cholesterol, HDL-C, LDL-C, and triglycerides. Clinical research from the 1960s to the early 2000s found that saturated fatty acids promote cardiovascular disease by increasing total cholesterol and LDL-C. The long-chain saturated fatty acids which are found predominantly in meat, butter, and cheese contribute to blood lipid abnormalities, which may increase the risk for cardiovascular disease. Short-chain and medium-chain saturated fatty acids, including butyric (4 carbons), caprylic (8 carbons), and capric (10 carbons), do not cause lipid abnormalities and do not increase the risk for cardiovascular disease. These are found in highest concentration in tropical oils such as coconut and palm oil, and they may be metabolized more like carbohydrates. MCT supplements, short for medium-chain triglycerides, are composed of various medium-chain saturated fatty acids extracted from coconut oil or palm oil. They bypass normal digestion and go straight to the liver where they are rapidly metabolized into ketones for energy. MCT supplements are popular for individuals following a ketogenic diet (Enkhmaa et al., 2018; Houston & Rountree, 2018; Rakel & Minichiello, 2023).
Some of the more recent research indicates that red and processed meat is associated with increased cardiovascular disease risk, whereas consumption of dairy is not. The reasons for this are not clear. Dairy has more medium-chain saturated fatty acids and contains other nutrients that may mitigate this risk. Red and processed meat contains heme iron, which could be harmful in high amounts. In general, full-fat dairy products such as milk, yogurt, and cheese are rich in nutrients and may be consumed without negatively affecting cardiometabolic risk. Individuals looking to lower their LDL-C may want to avoid red and processed meats, as well as butter. It should be mentioned that LDL-C contains subtypes, including small, dense LDL, which is more atherogenic than large, buoyant LDL, and these subtypes should be taken into account rather than just LDL-C alone. Nonetheless, saturated fats are more likely to become oxidized in the body which can lead to increases in LDL-C, endothelial dysfunction, and inflammation, which can cause atherosclerosis. A diet high in saturated fats is also associated with visceral fat which covers organs, as well as increased liver fat, which can lead to NAFLD. However, it should be mentioned that certain individuals have favorable genetics that allow them to convert potentially harmful long-chain saturated fatty acids into monounsaturated fatty acids or other compounds that aren’t as toxic. Another important point is that both the Mediterranean and DASH diets, which have been extensively studied, are low in saturated fat and have been shown to lower the risk of cardiovascular disease (Staff, 2023; Cloyd 2023; Hirahatake et al., 2020; Perfilyev et al., 2017; Houston & Rountree, 2018).
An article from the Harvard T.H. Chan School of Public Health stated that saturated fatty acids can cause cellular stress and can cause lipotoxicity, as well as metabolic syndrome, which can progress to type 2 diabetes. However, their negative effects can be mitigated by consuming them with unsaturated fats. Also, individual genetic differences may affect a person’s susceptibility to the adverse effects of saturated fats on metabolic disorder risk. A high-fat diet high in saturated fats could lead to increased nervous system inflammation through activating inflammatory pathways in the brain. This could lead to brain dysfunction and neurodegenerative diseases. Saturated fatty acids bind to TLR4 in the brain which triggers an inflammatory response that increases hunger and food intake, which can lead to obesity. On the contrary, there was a 2010 meta-analysis based off of 21 prospective cohort studies which found that there was no significant association of saturated fat intake with coronary heart disease, stroke, or cardiovascular disease. This challenges conventional thinking that saturated fat consumption is linked with coronary heart disease, stroke, and cardiovascular disease (Harvard T.H. Chan School of Public Health, 2019; Tan et al., 2019; Enkhmaa et al., 2018).
These are the National Health Guidelines for saturated fat intake:
- The 2015-2020 Dietary Guidelines for Americans (DGA) recommends that saturated fat should consist of less than 10% of total calories (U.S. Department of Agriculture, & U.S. Department of Health and Human Services, 2020).
- The 2014 Academy of Nutrition and Dietetics (AND) recommendations that for healthy adults that saturated fat consist of less than 7% of total calories (Enkhmaa et al., 2018).
- The 2013 American Heart Association (AHA) and American College of Cardiology (ACC) Guidelines for individuals that would benefit from lowering their LDL-C levels recommends saturated fat intake consist of 5-6% of total calories (Enkhmaa et al., 2018).
- The NIH National Cholesterol Education Program (NCEP), which issued the Adult Treatment Panel III (ATP III), recommends that individuals with lipid disorders such as high cholesterol should reduce their saturated fat intake to less than 7% of total calories (Enkhmaa et al., 2018).
The Institute for Functional Medicine has two food plans that allow for certain foods high in saturated fats. This includes the Cardiometabolic Food Plan, which allows for small amounts of butter and coconut oil. The Mito Food Plan, which aims to support healthy mitochondria and energy production, includes coconut oil. It mentions that rates of heart disease are low in the South Pacific where a lot of coconut oil is consumed. The medium-chain saturated fatty acids in coconut oil can potentially lower LDL-C and increase HDL-C levels. Coconut oil also has antioxidants that are thought to be beneficial for the immune system. In addition to this, coconut oil contains beta-hydroxybutyrate, which is a ketone that is considered “superfuel” for the brain (Institute for Functional Medicine, 2014; Institute for Functional Medicine, 2020).
Heptadecanoic acid is a long-chain 17 carbon saturated fatty acid and also one of four significantly measurable odd-chain saturated fatty acids which may have important health promoting effects in humans. I had first heard about this nutrient from John Bagnulo PhD, MPH on The Health Edge podcast. Heptadecanoic acid is mainly found in whole fat dairy products. Human studies have shown that consumption of whole fat dairy products may lower the risk for insulin resistance, metabolic syndrome, and type 2 diabetes. It is thought that heptadecanoic acid in these whole fat dairy products could be a key contributor to these benefits. Also, low serum heptadecanoic acid may be associated with high ferritin levels which increases the risk for metabolic syndrome. Increasing dietary heptadecanoic acid may lower ferritin levels, which may be protective against metabolic syndrome. Odd-chain saturated fatty acids are also known to increase membrane fluidity even more than PUFAs. This could improve the functioning of membranes. Improving neuronal membrane functioning could have implications for Alzheimer’s disease treatment. Odd-chain saturated fatty acids also have anti-carcinogenic properties as well. Heptadecanoic acid is found mainly in whole fat dairy products. The highest concentration is found in butter, followed by whole-fat yogurt, whole-fat milk, and then 2% fat milk. Butter contains 10 times more than whole-fat yogurt, the second-highest source. While heptadecanoic acid shows promise, human studies are needed to confirm its health benefits (Venn-Watson et al., 2015; Jenkins et al., 2015).
References:
Byambaa Enkhmaa, Prasanth Surampudi, Erdembileg Anuurad, & Lars Berglund. (2018, September 11). Lifestyle Changes: Effect of Diet, Exercise, Functional Food, and Obesity Treatment on Lipids and Lipoproteins. Nih.gov; MDText.com, Inc. https://www.ncbi.nlm.nih.gov/books/NBK326737/
Rakel D, Minichiello V. Integrative Medicine. Fifth Edition. Amsterdam, Netherlands: Elsevier Ltd.; 2023.
Staff, E. (2023, January 17). Loving Your Heart: Cholesterol and You – Tufts Health & Nutrition Letter. Tufts Health & Nutrition Letter. https://www.nutritionletter.tufts.edu/healthy-heart/cholesterol/loving-your-heart-cholesterol-and-you/
Cloyd, J. (2023, May 1). A Functional Medicine Protocol for Coronary Artery Disease. Rupa Health. https://www.rupahealth.com/post/a-functional-medicine-protocol-for-coronary-artery-disease
Hirahatake, K. M., Astrup, A., Hill, J. O., Slavin, J. L., Allison, D. B., & Maki, K. C. (2020). Potential Cardiometabolic Health Benefits of Full-Fat Dairy: The Evidence Base. Advances in nutrition (Bethesda, Md.), 11(3), 533–547. https://doi.org/10.1093/advances/nmz132
Perfilyev, A., Dahlman, I., Gillberg, L., Rosqvist, F., Iggman, D., Volkov, P., Nilsson, E., Risérus, U., & Ling, C. (2017). Impact of polyunsaturated and saturated fat overfeeding on the DNA-methylation pattern in human adipose tissue: a randomized controlled trial. The American journal of clinical nutrition, 105(4), 991–1000. https://doi.org/10.3945/ajcn.116.143164
Fats, stress, death: Uncovering the toxic effects of saturated fatty acids on cells | Harvard T.H. Chan School of Public Health. (2019, April 4). Harvard T.H. Chan School of Public Health; HSPH. https://hsph.harvard.edu/news/fats-stress-death-uncovering-the-toxic-effects-of-saturated-fatty-acids-on-cells/
Tan, B. L., & Norhaizan, M. E. (2019). Effect of High-Fat Diets on Oxidative Stress, Cellular Inflammatory Response and Cognitive Function. Nutrients, 11(11), 2579. https://doi.org/10.3390/nu11112579
U.S. Department of Agriculture, & U.S. Department of Health and Human Services. (2020). Dietary guidelines for Americans 2020-2025: Executive summary.
Institute for Functional Medicine. (2014). Cardiometabolic Food Plan. https://www.ifm.org/
Institute for Functional Medicine. (2020). Mito Food Plan. https://www.ifm.org/
Venn-Watson, S. K., Parry, C., Baird, M., Stevenson, S., Carlin, K., Daniels, R., Smith, C. R., Jones, R., Wells, R. S., Ridgway, S., & Jensen, E. D. (2015). Increased Dietary Intake of Saturated Fatty Acid Heptadecanoic Acid (C17:0) Associated with Decreasing Ferritin and Alleviated Metabolic Syndrome in Dolphins. PloS one, 10(7), e0132117. https://doi.org/10.1371/journal.pone.0132117
Jenkins, B., West, J. A., & Koulman, A. (2015). A review of odd-chain fatty acid metabolism and the role of pentadecanoic Acid (c15:0) and heptadecanoic Acid (c17:0) in health and disease. Molecules (Basel, Switzerland), 20(2), 2425–2444. https://doi.org/10.3390/molecules20022425
* The content provided by this article is for informational purposes only. These statements are not intended to diagnose, treat, cure, or prevent any disease. This article is not intended to provide personal medical advice, which should be obtained from a medical professional.
