Dietary fats can be tricky business, as they're not all the same. While some are necessary for optimal health, others need to be balanced and some need to be avoided altogether, and understanding which is which is quite crucial, considering how important fats are for optimal health.
Here, I will review some of the basics, including the importance of balancing your omega-3 and omega-6 intake, and why replacing saturated animal fats with omega-6-rich vegetable oils is such a bad idea.
Some of this information, which will be more thoroughly covered in my upcoming book, "Superfuel," is based on research by my coauthor, James DiNicolantonio, a doctor of pharmacy and cardiovascular researcher.
For Optimal Health, Mind Your Omega-3 to Omega-6 Ratio
For years, I've stressed the importance of balancing your omega-3 to omega-6 intake to protect your health. Eating too much damaged omega-6 fat — found in abundance in processed vegetable oils — and too little animal-based omega-3 sets the stage for diabetes, cardiovascular disease, rheumatoid arthritis, cancer, depression and Alzheimer's, just to name a few.
The ideal ratio of omega-3 to omega-6 fats ranges from 1-to-1 to 1-to-5, but the typical Western diet tends to be between 1-to-20 and 1-to-50. Most people, especially Americans, are guilty of this lopsided omega-3 to omega-6 ratio, and to correct it, you typically need to do two things:
1. Significantly decrease intake of damaged omega-6 by avoiding processed foods and foods cooked in vegetable oil at high temperatures. A number of studies1,2 have found that people who regularly eat deep-fried foods have a significantly increased risk of stroke and death.
Common sources of harmful omega-6 to avoid include corn oil, canola oil, soy oil, hydrogenated or partially hydrogenated fats, margarine and shortening.
2. Increase your intake of animal-based omega-3 fats. Ideal sources include small fatty fish such as sardines, anchovies and herring, along with wild-caught Alaskan salmon, or a supplement such as krill oil.
Replacing Saturated Fats With Vegetable Oils Harms Heart Health
Unfortunately, many health authorities have insisted omega-6-rich vegetable oils are healthier than saturated animal fats such as butter and lard, and this myth has been a tough one to dismantle, despite the evidence against it.
For example, a 2013 study3 in the British Medical Journal (BMJ) found replacing saturated fat with omega-6 oils raised the risk of death if you have heart disease. As reported in a BMJ press release:4
"Their analysis involved 458 men aged 30 to 59 years who had recently had a coronary event, such as a heart attack or an episode of angina. Participants were randomly divided into two groups.
The intervention group was instructed to reduce saturated fats (from animal fats, common margarines and shortenings) to less than 10 percent of energy intake and to increase linoleic acid (from safflower oil and safflower oil polyunsaturated margarine) to 15 percent of energy intake. Safflower oil is a concentrated source of omega-6 linoleic acid and provides no omega-3 PUFAs [polyunsaturated fats]."
The control group received no specific dietary advice on fats and was allowed to eat whatever they wanted. Both groups kept food diaries for an average of 39 months.
It's worth noting that this study did not differentiate between types of saturated fats, lumping together animal fats with margarines and shortening high in saturated fat but also toxic trans fats. (The harder the margarine, the more saturated fat it tends to contain, in some cases more than butter or lard.) Despite this discrepancy, the results showed that:
- The omega-6 linoleic acid group had a 17 percent higher risk of dying from heart disease during the study period, compared with 11 percent among the control group
- The omega-6 group also had a higher risk of all-cause mortality