For years we've been told to reduce our consumption of saturated fats as a sure-fire way to prevent heart disease. But a recent analysis of 45 studies and 27 trials involving over 600,000 participants is forcing a rethink of this long held — and apparently erroneous — assumption.
The primary takeaway of this study is not necessarily that saturated fats don't contribute to heart disease (a link that's now most certainly been cast into doubt) — but that food and the way it affects our health is an incredibly complicated and multifaceted process. One of the study's authors, Dariush Mozaffarian of the department of epidemiology at Harvard University in Boston, put it best by saying: "Guidelines that focus on the nutrients, single nutrients, as targets for preventing chronic diseases don't make a lot of sense. I think we need to move to food-based guidelines, to really talk about food, not nutrients."
Indeed, a prime example of this problem is the unwarranted focus on cholesterol and its apparent association with cardiovascular disease — the so-called LDL-heart disease hypothesis. Recently, however, physicians are coming to realize that cholesterol levels do not strongly predict our chances of developing heart disease, and there are now over a dozen studies that prove it. The notion that lowering saturated fats — which are typically consumed via butter, whole milk, red meat, poultry, coconut oil, and nuts — will lower bad cholesterol is predicated on some rather shaky ideas.
And now, as the new meta-study shows, there's insufficient data to support current guidelines restricting the consumption of saturated fats in order to prevent heart disease.
A "Careful Reappraisal" Needed
For the study, which now appears in the Internal Annals of Medicine, researchers evaluated data from 72 unique studies analyzing over 600,000 participants from 18 nations. Results showed that total saturated fatty acid, whether it was measured in the diet or in the bloodstream, could not be associated with coronary disease risk. Also, intake of total monounsaturated fatty acids, long-chain omega-3 and omega-6 polyunsaturated fatty acids could not be linked to cardiovascular risk.
Actually, what they did find was that circulating levels of eicosapentaenoic and docosahexaenoic acids (two main types of long-chain omega-3 polyunsaturated fatty acids found in oily fish), and an omega-6 fat were associated with lower coronary risk. However, after investigating the effects of of omega-3 and omega-6 fatty acid supplementations on reducing coronary disease, they did not find any significant effects.
Not surprisingly, the researchers also reaffirmed what most of us already know — trans fats are evil.
"These are interesting results that potentially stimulate new lines of scientific inquiry and encourage careful reappraisal of our current nutritional guidelines," noted lead author Dr. Rajiv Chowdhury of the University of Cambridge. Indeed, given that more than 17-million people died from a cardiovascular disease in 2008, it's critical to have guidelines that are actually backed by scientific evidence.
Critically speaking, some of the participants involved in the randomized trials didn't always follow instructions, and the researchers failed to take repeated looks at fatty acids in some of the studies. But these are slight objections.
Mind What You Eat
Now it's important to note that this doesn't mean you should run out and start eating foods laden in saturated fats with reckless abandon. As already noted, it's the overall quality of the foods that matter. If you down a fast food hamburger, you're probably taking in more sodium and wheat than what's considered healthy.
What's more, as stated by Jeremy Pearson, Associate Medical Director at the British Heart Foundation: "This analysis of existing data suggests there isn't enough evidence to say that a diet rich in polyunsaturated fats but low in saturated fats reduces the risk of cardiovascular disease. But large scale clinical studies are needed, as these researchers recommend, before making a conclusive judgement."
According to Pearson, in addition to taking necessary medication, the best way to stay heart healthy is to adopt a healthy lifestyle, including smoking cessation, staying active, and ensuring an overall healthy diet. This includes not only the fats in our diet but also our intake of salt, sugar and fruit and vegetables.
Read the entire study at Annals of Internal Medicine: "Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk: A Systematic Review and Meta-analysis." Additional source: University of Cambridge.