We’ve been told for decades that eating too much saturated fat – the kind found in fatty meats and dairy products – can increase the risk of heart disease.
In recent years, though, controversial studies grabbed media attention by concluding that saturated fat is, in fact, not a risk factor for cardiovascular disease.
Headlines hailing the return of butter and bacon have led many consumers adrift, causing them to wonder what to eat. Is saturated fat now good for you?
Last month, the American Heart Association (AHA) released an advisory report in an effort to clear up the confusion and misconceptions surrounding the link between saturated fat and cardiovascular disease.
The report, published in the journal Circulation, answered the question that earlier studies which exonerated saturated fat failed to ask: What happens to cardiovascular disease risk when you reduce saturated fat intake and replace it with other types of fats – such as polyunsaturated and monounsaturated fats – or carbohydrates?
That’s an important question since when we cut back on something in our diet, we end up eating something else in its place. And depending on what that replacement food is, we may or may not be improving our health.
After a comprehensive analysis of the scientific evidence – including the most recent studies – the AHA’s evidence review refuted the notion that saturated fats are not tied to heart risk.
American Heart Association’s conclusions
Based on the overall weight of existing evidence, the AHA advisory concluded that reducing saturated fat and replacing it with polyunsaturated or monounsaturated fats (unsaturated fats) is beneficial to heart health.
Randomized clinical trials – the gold standard of scientific evidence – for example, have shown that replacing saturated fats from meat and dairy with polyunsaturated vegetable oils reduced the risk of cardiovascular disease by roughly 30 percent, similar to statin drugs.
Observational studies that follow large groups of people forward for many years have also found that a lower saturated fat intake, in conjunction with a higher intake of polyunsaturated and monounsaturated fats, is associated with lower rates of cardiovascular disease and all-cause mortality. (Such studies uncover associations, but they don’t prove causality.)
Replacing saturated fats with refined carbohydrates, however, has not been shown to decrease heart risk. In other words, it seems that refined starchy foods and added sugars are equally as bad as saturated fats, at least the types of saturated fats that we typically eat.
Substituting saturated fat with whole grains, on the other hand, has been linked to a lower risk of coronary heart disease.
It’s known than saturated fat increases LDL cholesterol in the bloodstream, a major risk factor for hardening and narrowing of the arteries and cardiovascular disease. Eating less saturated fat and more polyunsaturated and monounsaturated fats helps lower LDL cholesterol.
Saturated fats not created equal
Saturated fat, found in animal foods such as meats, poultry with skin, butter, cheese and whole milk as well as some plant-based oils (e.g., palm oil, coconut oil, cocoa butter), isn’t one compound. Rather, it’s a group of different fatty acids that have different effects in the body.
Palmitic and myristic acids, two saturated fatty acids found in fatty cuts of meat and high fat dairy, have been shown to raise LDL blood cholesterol, promote inflammation and contribute to atherosclerosis.
Stearic acid, which makes up about 20 per cent of the fat in beef, 30 per cent of the fat in cocoa butter (e.g., chocolate) and 10 to 15 per cent of the fat in lamb, does not raise blood cholesterol.
Lauric acid, the predominant saturated fatty acid in coconut oil, raises LDL cholesterol but to a lesser extent than butter fat. Some research also suggests that lauric acid has beneficial properties.
It’s complex, I know. Even so, we don’t eat individual saturated fatty acids, we eat foods that contain a mix of them.
And let’s be honest, the prevailing North American diet doesn’t get the majority of its saturated fats from dark chocolate and coconut oil. Think pizza, cheeseburgers, ice cream and a growing abundance of ultra-processed foods.
Sources of unsaturated fats
Cooking oils, nuts and seeds contain a mix of unsaturated fats, but contain predominantly polyunsaturated or monounsaturated fats.
Polyunsaturated fats are found in grapeseed, sunflower, safflower, sesame, canola and corn oils. Soybeans, Brazil nuts, walnuts, pine nuts, sunflower seeds, pumpkin seeds, flax seeds, chia seeds and hemp seeds are also good sources.
Oily fish such as salmon, trout, Arctic char, sardines, herring, mackerel and anchovies are plentiful in omega-3 fats, a type of polyunsaturated fat.
Good sources of monounsaturated fats include olive, peanut, avocado and canola oils, olives, avocados, almonds, cashews, peanuts, pecans and pistachios.
A word about trans fats
Trans fats, formed through a chemical process called partial hydrogenation, are used in many crackers, cookies, pastries, snack foods and fried foods to extend shelf life and add taste and texture.
A steady intake of trans fats raises LDL cholesterol, lowers HDL (good) cholesterol and is strongly linked with a greater risk of heart disease.
While many manufactures have voluntarily reduced the use of trans fats and meet recommended targets, others have not; some foods still have high levels of partially hydrogenated oils.
In April of this year, Health Canada released a “Notice of Proposal” to ban industrial-produced trans fats in foods. Once finalized, the regulation will force manufacturers to reformulate their products.
So, what should we be eating?
The AHA advises limiting saturated fat intake to five to six per cent of daily calories. But let’s not get too hung up on numbers.
Yes, it’s prudent, evidence-based advice to watch your saturated fat intake. And, of course, to avoid industrial trans fats.
But saturated fat isn’t the whole story when it comes to preventing heart disease. By focusing on single nutrients – be it saturated fat or added sugars for that matter – we risk missing the forest for the trees.
It’s the overall quality of your diet that matters the most.
Two of the best-studied dietary patterns shown to guard against heart disease, as well as a myriad of other health conditions, are the Mediterranean and the DASH diets (Dietary Approaches to Stop Hypertension).
Both emphasize fruits and vegetables, whole grains, beans and lentils, nuts, unsaturated oils, fish and poultry and both limit red meat, as well as foods and beverages high in added sugars and sodium.
Other lifestyle habits matter, too. Not smoking, getting regular exercise, maintaining a healthy weight and managing stress also play an important role in reducing the risk of cardiovascular disease.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.