When health food experts talk about good fats and bad fats, they mean you should distinguish between saturated and unsaturated fats, with all unsaturated fats being good and all saturated fats being bad. Many health organizations, for example, continue to promote the indiscriminate use of polyunsaturated fats over other types of fats. This article challenges the premise that all unsaturated fats are good, particularly omega-6 type polyunsaturated fats.
The first thing you need to know is that there are two types of unsaturated fats: monounsaturated and polyunsaturated. Monounsaturated fats are chemically stable because they have only one double bond in the fatty acid chain. Mono means one. Stable fat is desirable because it’s hearty, and it doesn’t convert to a different substance when heat is applied. Common sources of monounsaturated fats include olive oil and olives, red meat, whole milk products, nuts and avocados. Olive oil is an essential, prominent, health-promoting ingredient in the Mediterranean diet.
Polyunsaturated fats (also referred to as PUFAs or polyunsaturated fatty acids) are chemically unstable because they have multiple double bonds in the fatty acid chain. Poly means many. Unstable polyunsaturated fats are more susceptible to going bad, and they can be innocently converted into an unhealthy trans fat by high heat. It’s safer to cook with olive oil (a monounsaturated oil), tropical oils, butter or high heat canola oil. Another problem with all polyunsaturated fats is that they oxidize quickly. Oxidation is a natural process that results in a 1% to 2% production of free radicals, and free radicals have the potential to mutate and damage cells.
This is a little complicated because there are also two types of polyunsaturated fats, omega-3 and omega-6. Both types are essential for proper cell functioning, but they compete with each other for entrance into cell membranes. Omega-6 fats dominate, and too much omega-6 fat tends to make cell membranes flabby. One of the reasons why omega-6 polyunsaturated oils lower cholesterol is that cell membranes have been compromised, and cholesterol can be absorbed into tissues more easily.
A small but important nutritional detail is keeping the ratio of omega-3 to omega-6 fats in proportion. Some experts say the ratio should be one-to-one. Others say it can be four-to-one (omega-6 to omega-3). The typical Western diet far exceeds both of these recommendations and is estimated to be in the range of 15-to-one up to 30-to-one, with omega-6 fats overwhelming omega-3 fats.
Omega-3 polyunsaturated fats are found in cold water fish, shellfish, green plants and algae. The colder the water, by the way, the higher the concentration of omega-3s in the fish. Fish need it to survive the extreme temperatures. Omega-6 polyunsaturated fats are found in corn, seeds, seed oils, grains and from the animals that eat these foods. Omega-3 fats enhance immunity and reduce inflammation. Conversely, overdosing on omega-6 fats inhibits immunity, impairs cell function, promotes inflammation and lowers vitamin E levels.
Consider these tidbits about polyunsaturated fats: – I Can’t Believe It’s Not Butter is made with a vegetable oil spread (soybean oils and canola oils) which are predominantly omega-6 type polyunsaturated oils. This is a so-called healthy food that’s supposed to be superior to butter, a saturated fat. – Most chips, cookies, baked goods and fried foods are made with omega-6 type polyunsaturated oils. – Corn oil has a ratio of 100-to-one (omega-6 to omega-3). In experimental studies, mice fed corn oil were more likely to develop and grow cancer tumors. – Polyunsaturated oils are typically extracted with chemical solvents that accelerate oxidation.
Then there’s the Israeli Paradox. Israelis consume the highest ratio of polyunsaturated fat in the world; and their national consumption is estimated at 8% higher than the U.S. and 10%-12% higher than Europe. According to the nutritional guidance we all receive, this should make Israel the healthiest country in the world. Yet Israelis have a high prevalence of cardiovascular disease, type 2 diabetes, high blood pressure, and other related conditions grouped together as syndrome X. There’s also a higher incidence of cancer, especially in women.
Bottom line: Teach yourself to recognize omega-6 type polyunsaturated fats and manage your consumption of them. There are two easy ways to do it. First, cut back on or eliminate processed foods, fast foods and butter-alternative spreads. Second, limit the use of polyunsatured oil products to salads or as a dressing for vegetables after they’ve been cooked. If your budget can afford it, look for oil products that are cold-pressed, expeller-pressed, extra virgin or unrefined.
This article was orginally published on www.blogcritics.org