Back when the latest research supported the idea that “fats make us fat” and likely caused heart attacks, functional food manufacturers cleverly re-framed the old idea of margarine as the new heart-healthy and weight-friendly butter alternative. The Dieticians of Canada, the American Dietetic Association, and many mainstream health professionals currently recommend consuming non-hydrogenated margarine products. However, the evidence is not as clear-cut as you might expect, and it’s worth taking a second look at whether margarine is a healthier alternative to butter just because it’s lower in saturated fat.
Until rather recently, most margarine products underwent a manufacturing process called hydrogenation that changed the chemical structure of unsaturated oils to saturated fats, which are harder at room temperature. This process uses potentially toxic metal catalysts such as nickel and cadmium, and creates a by-product called trans-fats that many of us now know are associated with heart disease and cancer. Some research also links trans-fats with the development of Alzheimer’s disease, diabetes, and infertility, and is the reason for numerous health warnings from such institutions as the World Health Organization and the National Academy of Science. Consequently, health experts recommend that you avoid any product with “hydrogenation” or “partial-hydrogenation” in the ingredient list.
More recent margarines are manufactured by a different process (contributed to by research at Guelph and Dalhousie universities), and may be labeled “trans-fat free” (i.e. less than 0.2 grams of trans-fats per serving). However, margarine still contains manufactured saturated fats. Data from a well known study called the Framingham study (among others), indicates that consumption of margarine actually statistically significantly increases a man’s risk of developing heart disease. Some experts suggest that this relationship exists not because of the manufactured saturation per se, but likely because the high-heat and high-pressure manufacturing process creates oxidized (rancid) oils that cause cellular damage. (By contrast, vegetables contain “anti-oxidants” which protect against cellular damage.) Margarine also generally contains multiple chemical additives and preservatives with broad negative health impacts, and may be created with various chemical solvents and emulsifiers.
Butter from pasture-fed cows contains a natural trans-fat called vaccenic acid that is actually healthy for us. Our bodies convert it to something called conjugated linoleic acid (CLA), which research shows may actually have weight-loss, anti-cancer, and cholesterol-lowering properties. Butter also contains healthy fat-soluble vitamins, such as vitamin A and D.
How is it possible for rigorous science to demonstrate that margarine is both superior and inferior to butter? When research isolates one chemical, such as saturated fat, and evaluates it against a health risk, such as heart disease, the study result may be inappropriately extrapolated and applied against whole foods that contain the isolated ingredient. So, just because butter contains saturated fat, and because some research demonstrates a link between saturated fat and heart disease, we can not assume that butter causes heart disease. Many population studies suggest that butter consumption is in no way related, or even possibly protective, against heart disease.
That said, relative to other whole, nutrient-dense foods, butter is near the bottom of the list for heart health and weight management. For whole body health, the research comes down to this: When consuming healthy amounts of good dietary fat (20% to 30% of total daily calories), focus on plant sources, whether saturated or not. Avoid animal fats (except wild, cold-water fish), and avoid synthesized/manufactured fat sources, including margarine. This will improve overall health and reduce risk of numerous chronic diseases.
Most foods contain a combination of many fats. These fats may be categorized according to their degree of chemical “saturation” (i.e. the number of double bonds present), which determines whether the fat is solid or liquid at room temperature. Here is a quick review of the somewhat complicated fat terminology.
Saturated fat: Chemically, no double bonds exist so that carbon molecules are saturated with hydrogen atoms. The molecules fit tightly together, producing a solid at room temperature. Includes most animals fats (e.g. butter) and tropical oils (e.g. palm and coconut). Is associated with heart disease, however, much research indicates that coconut oil may protect the heart and inhibit weight-gain. Also includes some “short-chain fatty acids” which are anti-microbial, protect the immune system, and are a primary food source for healthy intestinal cells.
Unsaturated fat: Chemically, double bonds exist, so that the molecules are not able to pack tightly together, creating a liquid or semi-solid product at room temperature. Includes poly-unsaturated (e.g. vegetable oil), mono-unsaturated (e.g. olive oil), and essential fatty acid (e.g. omega-3) varieties.
Trans-fat: A chemically “flipped” fat that is a byproduct of the hydrogenation manufacturing process. Healthy trans-fats also exist naturally in some animal fats.
Hydrogenated fat: Unsaturated fats, such as liquid vegetable oils, that have undergone a manufacturing process whereby the oils are chemically infused with hydrogen molecules to become “saturated” and solid or semi-solid at room temperature. Relative to naturally-occurring animal fats, these partially-hydrogenated or hydrogenated fats are often less expensive, have a longer shelf-life, a more desirable consistency for commercially baked products, and a may include a harmful byproduct called trans-fats.