Low fat or low carb? Butter or margarine? Avocado oil or coconut oil? Bombarded with contradictory media reports on the ever-changing landscape of nutrition research, it’s difficult for anyone to know which fats and other foods they should eat, and in what quantities.
We know that cardiovascular diseases (CVD) are the No. 1 cause of death globally and a leading cause of death in Canada and the United States. We also know that 80 percent of chronic disease could be alleviated by following a healthy diet, avoiding tobacco, maintaining a healthy weight, and getting regular exercise.
In an effort to follow a healthy diet, it’s tempting to focus on individual nutrients. This serves us well in preventing nutrient deficiencies (think vitamin C and scurvy). It doesn’t work so well as a strategy for avoiding chronic disease.
We eat food—ideally, three to six times per day—not individual nutrients. So, when it comes to fats, we really need to focus on dietary patterns.
Fats and Cardiovascular Disease
There have been many studies looking at diet and its impact on the heart. When the scientific community has examined the link between saturated fat (in butter, meat fat, chicken skin, and high-fat dairy products) and risk of developing CVD, conflicting findings have emerged.
One review of the evidence showed that saturated fat has no relationship with CVD. However, this research didn’t consider what nutrient replaced saturated fat. Another review of the evidence demonstrated that the risk of developing CVD varies depending on what nutrient replaces the saturated fat.
When you eat trans fats—found in partially hydrogenated oils and vegetable oil shortening, which are common in deep-fried foods, doughnuts, and other store-bought baked goods—instead of saturated fats, your risk of CVD increases. However, if you eat unsaturated fats, especially polyunsaturated fats found in olive oil, nuts, seeds, and fish, your risk of CVD decreases.
Coconut Oil or Olive Oil?
The effects of coconut oil as a replacement for other dietary fats, such as butter, olive oil, and canola oil, have not been studied in relation to CVD. The impact of coconut oil on heart disease risk remains unknown.
We do know, however, that coconut oil raises some risk factors for CVD. For example, it increases cholesterol compared to polyunsaturated fats (in vegetable oils, nuts, seeds, and fish) that lower cholesterol.
Olive oil, on the other hand, has been shown to reduce cardiovascular disease when eaten as part of the “predimed” diet. It’s important, then, to look at dietary patterns rather than individual fats.
Plant-Based Diets Are Best
Our Western diet pattern includes sugar-sweetened beverages, processed meats, refined carbohydrates (commercially baked goods like muffins and doughnuts), and combination foods (such as pepperoni pizza and bacon cheeseburgers).
There is substantial evidence that a Mediterranean diet pattern reduces cardiovascular disease. This involves eating plant foods—vegetables, fruit, whole grains, nuts, legumes, and olive oil—plus fish and a moderate amount of wine.
Men with heart disease in the Lyon Diet Heart Study following the Mediterranean diet had a 30 percent reduction in secondary heart events. Participants following the “predimed” diet had a 30 percent risk reduction of developing CVD. The diet plans are similar and are high in fat from additional nuts or olive oil.
Vegetarian diet patterns are mostly plant-based, but can include some animal foods, such as dairy products, eggs, and fish. Communities known for their longevity and low incidence of heart disease include Sardinia in Italy, Icaria in Greece, Okinawa in Japan, and Loma Linda in California.
These so-called “blue zones” all follow healthy lifestyles including vegetarian diets. Their staples are vegetables and fruit, whole grains, legumes, and nuts, and may include fish. Meat is consumed only on special occasions.
When combined with intensive exercise, another plant-based diet followed in the Lifestyle Heart Trial led to the reversal of heart disease. This was a very low-fat vegetarian diet (with fat accounting for only 10 percent of total calories) that consisted of vegetables, fruit, whole grains, and legumes, with small amounts of nonfat dairy products.
In these diet patterns, fat content ranges from 10 percent to 40 percent of total calories. This shows that both low-fat and high-fat diets lower risks of CVD—if they are plant-based.
Eat Your Fruits and Veggies
We should all be eating five to 10 servings of fruits and vegetables daily. Research shows that having five servings of vegetables and fruit per day is protective against CVD, but having 10 servings of vegetables and fruit per day lowers heart disease risk by 24 percent.
One serving is equivalent to one medium-sized fruit, a half-cup of chopped fruit or berries, a quarter-cup of dried fruit, a half-cup of cooked or raw vegetables, or one cup of salad greens. About 40 percent of Canadian and American children consume at least five servings of vegetables and fruit per day.
Cruciferous vegetables, such as broccoli, cabbage, green leafy vegetables, spinach, and kale, along with beta-carotene-rich fruits and veggies like tomatoes, carrots, and squash, demonstrate the most beneficial effects. Apples, pears, berries and citrus fruit, like oranges, are also highly beneficial.
Choose Whole Grains and Legumes
We should also eat at least three servings per day of whole grains. The research shows this lowers CVD risk by 19 percent.
What’s a serving? It can be one slice of whole grain bread, half a slice of whole grain pita bread, a half-cup of cooked whole grain pasta or corn, or a third-cup cooked grains like barley, bulgur, or brown rice.
Legumes also reduce our risk of heart disease. The research shows that eating four servings of legumes per week lowers CVD risk by 14 percent.
We should be eating three to four servings per week of black beans, garbanzo beans, kidney beans, navy beans, soybeans, lentils, or dried peas. One serving is measured as three-quarters of a cup of cooked legumes.
Finally, back to the fats: Eating fatty fish at least two to four times per week reduces CVD risk by 17 percent, according to research. One serving of fish is defined as 3 ounces of cooked salmon, mackerel, herring, sardines, tuna, halibut, or other fish.
Eating at least three servings of nuts per week is a good idea. Just one quarter-cup of nuts consumed four times weekly reduces CVD by a whopping 24 percent, according to research. One serving of nuts is defined as one quarter-cup of walnuts, almonds, hazelnuts, pecans, cashews, peanuts, or pistachios, or two tablespoons of natural almond, cashew, or peanut butter.
Seeds—such as pumpkin, flax, chia, sunflower, and sesame seeds—and butters made from sesame and sunflower seeds also lower CVD risk. Olive oil, peanut oil, and avocado oil all lower CVD risk, as do avocados, which improve your cholesterol profile.
Enjoy minimally processed plant foods from nature most of the time. They are better for us. And, as a bonus, eating them is better for the planet, too.
is a clinical instructor of land and food systems at the University of British Columbia. This article was originally published on The Conversation.