Aren't saturated fatty acids dangerous for the heart?
Saturated fats: bad for the heart?
Saturated fats appear not to increase the risk of heart and vascular diseases, and polyunsaturated Omega 3 may not have a protective effect on heart health. Nutritional guidelines that for years have promoted the consumption of foods rich in Omega-3 fatty acids and discouraged saturated fat intake may need to be reconsidered.
This is reported by research conducted at the University of Cambridge (UK) in collaboration with Harvard University in Boston (USA), published in the journal Annals of Internal Medicine. Specifically, it is a meta-analysis, a study summarizing results from works conducted on a specific topic, that reviews the evidence on the association between fatty acids and coronary diseases.
Fatty acids and cardiac events
Fatty acids are the building blocks of animal and vegetable lipids. They are classified based on length and chemical structure into: saturated, monounsaturated, and polyunsaturated. Saturated fatty acids include palmitic acid, found in palm oil, meat, and cheese. Among monounsaturated fats, the most common is oleic acid, the main component of olive oil. Polyunsaturated fatty acids are divided into Omega-3 and Omega-6. The first group includes alpha-linolenic acid, mainly found in flax seeds, EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid), abundant in fish. The second group includes, among others, linoleic acid, mainly present in vegetable oils.
Numerous studies have shown that saturated fats cause an increase in blood cholesterol and thus heart risk. A diet high in saturated fats also seems to increase the likelihood of developing tumors. Conversely, scientific evidence shows that unsaturated fatty acids, especially Omega-3, protect against cardiovascular diseases and prevent some types of tumors and cognitive dysfunctions. In recent years, major food safety agencies have recommended limiting saturated fat intake and increasing polyunsaturated fat intake to protect the heart.
Do Omega-3 protect against cardiovascular risk?
The study in question reviewed 82 publications on the risk of coronary diseases in relation to diet, considering more than 600,000 people in Europe, North America, and Asia. From these analyses, it emerges that reducing saturated fats in the diet alone does not help predict heart disease risk. The study reported that daily Omega-3 intake has a protective effect against cardiovascular risk, but these results are not statistically significant.
According to one of the study’s authors, Dr. Dariush Mozaffarian from the Department of Epidemiology at Harvard University, current findings therefore do not agree with guidelines encouraging high polyunsaturated fat consumption and low saturated fat intake. This is because, as has emerged in recent years, it is wrong to consider a single nutrient in relation to disease prevention; instead, one must consider the overall effects of food.
Therefore, guidelines should shift to food-based recommendations rather than single nutrients. According to Richard Bazinet, Professor of Nutritional Sciences at the University of Toronto, two points need to be disproved: first, that reducing saturated fats provides cardiovascular protection; second, that not all polyunsaturated fats are effective. An example of his thinking concerns processed meats, low in fat, such as turkey or chicken, which may negatively affect heart disease risk due to their high sodium content.
Currently, the only path to follow for healthy eating seems to be based on wholesome foods, unprocessed foods, fruits, and vegetables. Despite scientific evidence confirming that high levels of EPA, DHA, and linoleic acid are associated with a lower coronary risk, Bazinet notes that in some diets, like the Canadian one, linoleic acid constitutes only 5% of consumed oils, while oils rich in Omega-3 and Omega-6, such as soybean and canola oil, represent 55% and 25% of the diet, respectively.
A study with many limitations
It must be considered that the study in question does not take into account individual diseases or issues but refers to the whole set of cardiovascular problems and does not distinguish between primary prevention (preventing a disease) and secondary prevention (including immediate diagnosis of the pathology).
Despite the data not being statistically significant, daily Omega-3 intake has demonstrated a protective effect relevant to public health recommendations. The authors reported a 25% decrease in coronary problems risk associated with circulating EPA and DHA as well as a strong trend toward reducing cardiovascular risk with 1-2 grams per day of EPA + DHA administration. It must also be considered that participants in randomized clinical trials do not always follow instructions correctly, which may skew study data.
Omega-3: important components of cardioprotective diets
This study, despite lacking statistical significance, shows that high blood levels of EPA and DHA are linked to reduced cardiovascular events and emphasizes the importance of consuming these fatty acids. EPA and DHA, taken both from food sources such as fatty fish and supplementation, are important components of a healthy diet and lifestyle. The study confirms that increasing Omega-3 intake and decreasing Omega-6 intake slows inflammatory processes.
Source: Rajiv Chowdhury, MD, PhD; Samantha Warnakula, MPhil; Setor Kunutsor, MD, MSt; Francesca Crowe, PhD; Heather A. Ward, PhD; Laura Johnson, PhD; Oscar H. Franco, MD, PhD; Adam S. Butterworth, PhD; Nita G. Forouhi, MRCP, PhD; Simon G. Thompson, FMedSci; Kay-Tee Khaw, FMedSci; Dariush Mozaffarian, MD, DrPH; John Danesh, FRCP; and Emanuele Di Angelantonio, MD, PhD. “ Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk: A Systematic Review and Meta-analysis”. Ann Intern Med. 2014;160(6):398-406-406. doi:10.7326/M13-1788
