If you know much about diet wellness, you’ll know that different fats affect your heart wellness in different ways; saturated and trans fats are bad for your heart, while most polyunsaturated and monounsaturated fats are good for your heart. However, according to a new study, published in Annals of Internal Medicine, the “bad” fats may not be so terrible after all, and that “good” fats may not actually be all that, well, good. You’d expect to find dramatic differences in health outcomes between the two fat groups, but a large meta-analysis, led by Rajiv Chowdhury, MD, PhD, of the University of Cambridge, failed to do so.
In a review of 76 trials involving more than 600,000 participants in 18 countries, the researchers found no link between saturated fat and heart disease. Saturated and trans fats have long been considered to be major culprits in raising LDL or “bad” cholesterol levels, but while saturated fat had no negative effect in this area, the study found only a slight trend indicating trans fats had a negative affect on heart health. Moreover, “good” omega-3 fatty acids, such as those found in salmon and other fatty fish, were only indicated as helpful by a slight trend, and the researchers found no reason to recommend taking omega-3 supplements such as fish oil supplements. According to the study authors, the findings ‘did not yield clearly supportive evidence for current cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats.’
Wellness expert Amanda Gardner details, ‘The American Heart Association (AHA) recommends that daily fat intake account for no more than 35% of total calories. Saturated fats (which are mostly from animal sources, like butter and meat) should account for no more than 5% to 6% of intake and trans fats (in prepared and fast foods, but increasingly being phased out) should be limited to less than 1%. Monounsaturated and polyunsaturated fats from nuts, seeds, oily fish, and vegetable oils should make up the remainder. Guidelines from other prominent health and government organizations are similar. This Annals study is only the latest instalment of questions emerging about the validity of these guidelines. But even the authors of the new study don’t recommend ditching current recommendations, and the findings may not be as radical as they first seem.’
Karol Watson, MD, PhD, professor of medicine at UCLA and director of the UCLA Barbra Streisand Women’s Heart Health Programme, points out, ‘This evidence is suggestive of what we’ve always thought. The direction of change with omega-3 showed a little benefit. The direction of change with trans fat looked like there’s harm. Saturated fat was kind of a wash. It didn’t look like a lot of harm or benefit in either direction.’ However, she adds, ‘I don’t think there’s any clear evidence that we should abandon our limitations on saturated fat. So much good science has gone into making those recommendations—we shouldn’t abandon them so easily.’
‘This paper does not say saturated fat is good for you,’ cautions AHA spokesperson Linda Van Horn, PhD, RD, professor of preventive medicine at Northwestern University Feinberg School of Medicine in Chicago. ‘This should not affect guidelines or behaviour. This paper does not change the message that the AHA is making regarding reducing saturated fat, reducing trans fat, and emphasizing the fruits, vegetables, whole grains, and fish intake that we know are especially beneficial to heart health.’ Hence, Suzanne Steinbaum, DO, a preventive cardiologist at LenoxHillHospital in New York City, warns, ‘This meta-analysis should be interpreted with caution.’