Eating foods high in saturated fats has been shown to raise the level of lousy (LDL) cholesterol in the blood and high levels of LDL have been associated with an increased risk of coronary heart disease (CHD). However, recent studies have failed to support a connection between saturated fat and CHD, which has resulted in a blitz of eye-popping headlines extricating butter, meat and the like.
This is precisely what a recent prospective cohort study titled “Saturated Fats Compared with Unsaturated Fats and Sources of Carbohydrates in Relation to Risk of Coronary Heart Disease” and published in the Journal of the American College of Cardiology sought to investigate.
In this study, the researchers followed 84,628 women and 42,908 men, all health care providers without history of heart disease, cancer or diabetes at baseline. Participants answered questions about what and how much they ate on food frequency questionnaires roughly every 4 years and the researchers analyzed their dietary intake for different types of fats and carbohydrates and their relation to CHD.
During 24 to 30 years of follow-up, they documented 7,667 cases of CHD and noted a number of interesting associations between different types of fats, carbohydrates and their relation to CHD. Their findings are quite relevant, but they don’t make for catchy headlines so I doubt you’ll see much about them unless you seek them out.
Here are a few key takeaways:
- Participants generally replaced saturated fats with calories from refined carbohydrates (e.g. white bread, white rice, pastries) rather than from whole grains or healthy fats
- Replacing total carbohydrates with the same % of energy from polyunsaturated fats was associated with a 20% decreased risk of CHD while replacing total carbs with the same % of energy from trans fats was associated with a 20% increased risk of CHD
- Substituting a % of energy from total fat with an equivalent % of energy from whole grains was associated with a 10% lower risk of CHD while replacing fat with refined starches/added sugars was associated with a 10% increased risk of CHD
- Isocaloric substitution of saturated fats by equivalent energy from MUFAs, PUFAs or whole grains resulted in 15%, 25%, and 9% lower risk of CHD, respectively
- Isocaloric substitution of refined starches/added sugars by equivalent energy from PUFAs or whole grains resulted in 22% and 11% lower risk of CHD, respectively