The Good Dietary Fat
By Dr. Kate Dudek
Not all fats are bad. For a generation that has grown up obsessed with the fat content in all they eat, this concept may take some getting used to.
In order to maintain a healthy diet, we need a minimum of 10% of our daily calorie intake to come from fats. In fact, experts agree that up to 30% can come from fats, but it is essential to make sure they are the right fats. There are two essential fatty acids, omega-3 and omega-6. Omega-3 is found in fish and some nuts. Omega-6 is found in many vegetable oils such as corn and sunflower oil and in other foods such as eggs. The modern, Western diet typically contains too much omega-6 and not enough omega-3 and, unfortunately, our bodies are unable to convert excess omega-6 to omega-3. Whilst omega-3 can be cardiac-protective and reduce the risk of cancer, an imbalance between the two essential fatty acids has been linked to a higher death rate from cardiovascular disease. Our ancestors had a diet containing roughly equal levels of omega-3 and omega-6; today we consume up to 15 times more omega-6 than omega-3. Considering omega-6 has been correlated with high blood pressure and increased risk of atherosclerotic blood clots, this is definitely a change for the worst.
Preliminary work suggests that adopting a diet rich in green, leafy vegetables might counteract some of this imbalance as well as having the added benefit of boosting fertility.
One of the biggest problems with our diet today is an over-consumption of trans fatty acids. Food manufacturers chemically modify, or ‘hydrogenate’, polyunsaturated fats to give them an increased shelf life and more stability. Margarine, fried fast food and bakery products all contain high levels of trans fatty acids. Aside from providing calories, there is absolutely no nutritional benefit to a diet rich in hydrogenated fats. Quite the reverse, in fact. Trans fatty acids raise the levels of ‘bad’ LDL cholesterol, which increases the risk of heart disease, they also lower the levels of ‘good’ HDL cholesterol. In addition, their pro-inflammatory effects further increase the likelihood of cardiac problems, as well as contributing to a higher risk of diabetes and other health issues.
There are steps we can take to lower our intake of trans fats, although avoiding them altogether is difficult. In 2006 the Food and Drug Administration (FDA) ruled that all nutrition labels must clearly state the quantity of trans fatty acids, thus tracking our intake is easier.
Another way we can ensure we are getting the right fats in our diet is to look for products that contain unsaturated fats and use these rather than those that contain saturated fats or trans fats. Some of the best examples of foods rich in unsaturated fats are fish, olives, avocados, nuts and seeds. Consuming these food groups in moderation can lower cholesterol levels and reduce the risk of heart disease. It is also worth attempting to reduce the quantity of saturated fat in your diet. Saturated fats are found in animal products and certain vegetable oils, including coconut oil and palm oil. Some simple substitutions can make a big difference to your cholesterol levels and associated health risks, for example the use of olive oil or canola oil in place of vegetable oil.
- Block, R C, et al. “Omega-6 and Trans Fatty Acids in Blood Cell Membranes: a Risk Factor for Acute Coronary Syndromes?” American Heart Journal, vol. 156, no. 6, Dec. 2008, pp. 1117–1123., doi:10.1016/j.ahj.2008.07.014.
- Johnson, M, et al. “Green Leafy Vegetables in Diets with a 25:1 Omega-6/Omega-3 Fatty Acid Ratio Modify the Erythrocyte Fatty Acid Profile of Spontaneously Hypertensive Rats.” Lipids in Health and Disease, vol. 17, no. 1, 15 June 2018, p. 140., doi:10.1186/s12944-018-0723-7.
- Mozaffarian, D, et al. “Trans Fatty Acids and Cardiovascular Disease.” The New England Journal of Medicine, vol. 354, no. 15, 13 Apr. 2006, pp. 1601–1613., doi:10.1056/NEJMra054035.
- Simopoulos, A P. “The Importance of the Ratio of Omega-6/Omega-3 Essential Fatty Acids.” Biomedicine & Pharmacotherapy, vol. 56, no. 8, Oct. 2002, pp. 365–379., doi:10.1016/S0753-3322(02)00253-6.
- The Truth Abouts Fat. WebMD, https://www.webmd.com/food-recipes/features/truth-about-fats#1