Dietary fats help us to feel satiable. When we eat real foods with saturated fats such as meat, eggs and dairy, we receive the proper proportion of protein and fats. Our ancestors had eaten like this for centuries with very rare incidences of heart diseases. When Dr Weston A. Price visited the Maasai back in 1935, the local government hospital doctor told him that most tribes were disease-free. (Ref A) Most of them had no dental caries or malformed dental arch. But ever since the recommendation to replace saturated fats with carbohydrates and polyunsaturated fats, heart disease became the No 1 killer in the world now. So is it the carbohydrates or the polyunsaturated fats that caused the rapid rise in heart disease? Or it is both?
The recommendation to replace saturated fats with unsaturated fats in our diet came about due to earlier studies which indicated some reductions in risks of cardiovascular disease (CVD) but not overall mortality. Some of these studies are listed at the end of this page (Ref B).
There are many studies in the last decade which show that saturated fats do not increase the risk of CVD. These studies are listed at the end of this page (Ref C).
The main argument against saturated fats is that consuming too much of it will raise cholesterol, specifically LDL, which in turn increases the risk of cardiovascular disease (CVD). However, it has been shown that total cholesterol and LDL are poor predictors of CVD. A better predictor is Total Cholesterol / HDL ratio or Triglycerides / HDL ratio. Read more about this in my section on Cholesterol.
Saturated fats increase both LDL and HDL and thus the Total Cholesterol / HDL ratio remains more or less the same. This means the risk of CVD is not changed. Moreover, it was shown that the type of LDL that was increased is the bigger ‘good’ pattern A type. (Ref D)
A recent editorial in the British Journal of Sports Medicine written by Dr Aseem Malhotra specifically mentioned that saturated fat does not clog the arteries. It contains a very good illustration on the root cause of coronary artery plaque and how a high fat diet and exercise, i.e., lifestyle interventions, can reduce the risk of CVD. You may read the editorial at this link https://bjsm.bmj.com/content/51/15/1111
Saturated fats that exist in real foods are considered healthy because they pose no risk of CHD and may offer protective benefits to the body. If this is not the case, all of us would not be around now because our ancestors ate meats and real foods that contain saturated fats. Animal fats like butter and lard are good sources of fat-soluble vitamins A, D and K.
If you have cut down on your saturated fats because of all the confusion and misleading guidelines, you may safely return to them and be free from worrying about their ill effects. If you are still not convince about the benefits of saturated fats, check out Weston A Price Foundation’s wealth of information on fats here. https://www.westonaprice.org/know-your-fats/
Those who are going for skim or low-fat products should change to full-fat dairy products instead. A study showed that full-fat dairy foods are inversely and independently associated with metabolic syndrome in middle-aged and older adults. Another study showed that full-fat dairy products may be associated with lower insulin resistance in Japanese adults. And lastly, a study found that a greater intake of high-fat dairy products prevents weight gain in middle-aged elderly women who were initially normal weight. (Ref E)
In summary, Saturated fats are an important component for our body functions. Saturated fats raise blood cholesterol but not the harmful, small dense LDL cholesterol that gets into arteries. You may increase your fats intake if you are on a low-carb (< 10% total calories) diet. The body will use the fats for energy to replace the loss in energy from the decrease in carbs intake. A low-carb high fat diet will increase your HDL and LDL. But your LDL will most likely be the big fluffy good ones (pattern A), as discussed in my section on Cholesterol.
References (I have extracted the conclusions from each publication for your easy reference)
(Ref A) Mann, G. V., Shaffer, R. D., Anderson, R. S., Sandstead, H. H., Prendergast, H., Mann, J. C., … & Isaac, S. M. (1964). Cardiovascular disease in the Masai. Journal of atherosclerosis research, 4(4), 289-312. https://doi.org/10.1016/S0368-1319(64)80041-7
Extracted Summary An investigation in the field of 400 Masai men and a number of women and children in Tanganyika showed little or no clinical or chemical signs of atherosclerosis. Despite a long continuous diet of only meat and milk, men have low serum cholesterol and no signs of arteriosclerotic heart disease. The reasons for this difference, with the common belief that animal fats lead to coronary disease, have been investigated. The authors admit that some independent protective mechanism, such as lack of emotional stress or extensive body movement, can play a role. They prefer the conclusion that diet fats are not responsible for the development of coronary diseases.
(Ref B) (SFA – Saturated Fatty Acid; PUFA – Poly-Unsaturated Fatty Acid; MUFA – Mono-Unsaturated Fatty Acid)
- Jakobsen MU, O’Reilly EJ, Heitmann BL, et al. Major types of dietary fat and risk of coronary heart disease: a pooled analysis of 11 cohort studies. Am J Clin Nutr. 2009;89(5):1425‐1432. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2676998/
Conclusion: The associations suggest that replacing SFAs with PUFAs rather than MUFAs or carbohydrates prevents Coronary Heart Disease over a wide range of intakes.
- Mozaffarian D, Micha R, Wallace S. Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials. PLoS Med. 2010;7(3):e1000252. Published 2010 Mar 23. https://www.ncbi.nlm.nih.gov/pubmed/20351774/
Conclusion: These findings provide evidence that consuming PUFA in place of SFA reduces CHD events in RCTs. This suggests that rather than trying to lower PUFA consumption, a shift toward greater population PUFA consumption in place of SFA would significantly reduce rates of CHD.
- Michas, G., Micha, R., & Zampelas, A. (2014). Dietary fats and cardiovascular disease: putting together the pieces of a complicated puzzle. Atherosclerosis, 234(2), 320-328. https://www.sciencedirect.com/science/article/abs/pii/S0021915014001622
Highlights: (a) Cardiovascular risk can be modestly reduced by decreasing SFA and replacing it by a combination of PUFA and MUFA. (b) Animal product intake (unprocessed red meat, egg, dairy) is not necessarily associated with increased cardiovascular risk. (c) Nut and olive oil intake is associated with reduced cardiovascular risk.
- Hooper, L., Martin, N., Jimoh, O. F., Kirk, C., Foster, E., & Abdelhamid, A. S. (2020). Reduction in saturated fat intake for cardiovascular disease. Cochrane database of systematic reviews, (5). https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD011737/full (We include 15 randomised controlled trials (RCTs) (17 comparisons, ˜59,000 participants))
Conclusion: The findings of this updated review are suggestive of a small but potentially important reduction (17%) in cardiovascular risk on reduction of saturated fat intake. Replacing the energy from saturated fat with polyunsaturated fat appears to be a useful strategy, and replacement with carbohydrate appears less useful, but effects of replacement with monounsaturated fat were unclear due to inclusion of only one small trial. This effect did not appear to alter by study duration, sex or baseline level of cardiovascular risk. Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturated fats. The ideal type of unsaturated fat is unclear.
- Rizos, E. C., Ntzani, E. E., Bika, E., Kostapanos, M. S., & Elisaf, M. S. (2012). Association between omega-3 fatty acid supplementation and risk of major cardiovascular disease events: a systematic review and meta-analysis. Jama, 308(10), 1024-1033. https://jamanetwork.com/journals/jama/article-abstract/1357266
Conclusion: Overall, omega-3 PUFA supplementation was not associated with a lower risk of all-cause mortality, cardiac death, sudden death, myocardial infarction, or stroke based on relative and absolute measures of association.
- Ramsden, C. E., Zamora, D., Leelarthaepin, B., Majchrzak-Hong, S. F., Faurot, K. R., Suchindran, C. M., … & Hibbeln, J. R. (2013). Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis. Bmj, 346, e8707. https://www.ncbi.nlm.nih.gov/pubmed/23386268
Conclusion: Advice to substitute polyunsaturated fats for saturated fats is a key component of worldwide dietary guidelines for coronary heart disease risk reduction. However, clinical benefits of the most abundant polyunsaturated fatty acid, omega 6 linoleic acid, have not been established. In this cohort, substituting dietary linoleic acid in place of saturated fats increased the rates of death from all causes, coronary heart disease, and cardiovascular disease. An updated meta-analysis of linoleic acid intervention trials showed no evidence of cardiovascular benefit. These findings could have important implications for worldwide dietary advice to substitute omega 6 linoleic acid, or polyunsaturated fats in general, for saturated fats.
- Harcombe, Z., Baker, J. S., Cooper, S. M., Davies, B., Sculthorpe, N., DiNicolantonio, J. J., & Grace, F. (2015). Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis. Open heart, 2(1). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4316589/ (A systematic review and meta-analysis were undertaken of RCTs, published prior to 1983, which examined the relationship between dietary fat, serum cholesterol and the development of CHD)
Conclusion: Dietary recommendations were introduced for 220 million US and 56 million UK citizens by 1983, in the absence of supporting evidence from RCTs.
- Ramsden, C. E., Zamora, D., Majchrzak-Hong, S., Faurot, K. R., Broste, S. K., Frantz, R. P., … & Hibbeln, J. R. (2016). Re-evaluation of the traditional diet-heart hypothesis: analysis of recovered data from Minnesota Coronary Experiment (1968-73). bmj, 353, i1246. https://www.ncbi.nlm.nih.gov/pubmed/27071971
Conclusion: Available evidence from randomized controlled trials shows that replacement of saturated fat in the diet with linoleic acid effectively lowers serum cholesterol but does not support the hypothesis that this translates to a lower risk of death from coronary heart disease or all causes. Findings from the Minnesota Coronary Experiment add to growing evidence that incomplete publication has contributed to overestimation of the benefits of replacing saturated fat with vegetable oils rich in linoleic acid.
- Ravnskov, U., Diamond, D. M., Hama, R., Hamazaki, T., Hammarskjöld, B., Hynes, N., … & McCully, K. S. (2016). Lack of an association or an inverse association between low-density-lipoprotein cholesterol and mortality in the elderly: a systematic review. BMJ open, 6(6), e010401. https://bmjopen.bmj.com/content/6/6/e010401
Conclusion: High LDL-C is inversely associated with mortality in most people over 60 years. This finding is inconsistent with the cholesterol hypothesis (ie, that cholesterol, particularly LDL-C, is inherently atherogenic). Since elderly people with high LDL-C live as long or longer than those with low LDL-C, our analysis provides reason to question the validity of the cholesterol hypothesis. Moreover, our study provides the rationale for a re-evaluation of guidelines recommending pharmacological reduction of LDL-C in the elderly as a component of cardiovascular disease prevention strategies.
- Abdelhamid, A. S., Martin, N., Bridges, C., Brainard, J. S., Wang, X., Brown, T. J., … & Song, F. (2018). Polyunsaturated fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews, (11). https://www.ncbi.nlm.nih.gov/pubmed/30019767 (We included 49 RCTs randomising 24,272 participants, with duration of one to eight years)
Conclusion: Increasing PUFA intake probably slightly reduces risk of coronary heart disease and cardiovascular disease events, may slightly reduce risk of coronary heart disease mortality and stroke (though not ruling out harms), but has little or no effect on all-cause or cardiovascular disease mortality.
(Ref D) D M Dreon, H A Fernstrom, H Campos, P Blanche, P T Williams, R M Krauss, Change in dietary saturated fat intake is correlated with change in mass of large low-density-lipoprotein particles in men, The American Journal of Clinical Nutrition, Volume 67, Issue 5, May 1998, Pages 828–836, https://doi.org/10.1093/ajcn/67.5.828
(Ref E) Drehmer, M., Pereira, M. A., Schmidt, M. I., Alvim, S., Lotufo, P. A., Luft, V. C., & Duncan, B. B. (2016). Total and full-fat, but not low-fat, dairy product intakes are inversely associated with metabolic syndrome in adults. The Journal of nutrition, 146(1), 81-89. https://academic.oup.com/jn/article/146/1/81/4616088
Akter, S., Kurotani, K., Nanri, A., Pham, N. M., Sato, M., Hayabuchi, H., & Mizoue, T. (2013). Dairy consumption is associated with decreased insulin resistance among the Japanese. Nutrition research, 33(4), 286-292. https://www.sciencedirect.com/science/article/pii/S0271531713000286
Rautiainen, S., Wang, L., Lee, I. M., Manson, J. E., Buring, J. E., & Sesso, H. D. (2016). Dairy consumption in association with weight change and risk of becoming overweight or obese in middle-aged and older women: a prospective cohort study. The American journal of clinical nutrition, 103(4), 979-988. https://academic.oup.com/ajcn/article/103/4/979/4662886