Current U.S. Dietary Guidelines recommend that saturated fats make up no more than 10% of our daily intake of calories to help lower the risk of cardiovascular disease. But there is growing evidence that doing so may not translate to better heart health,
according to a review published in the Journal of the American College of Cardiology in August.
“Saturated Fats and Health: A Reassessment and Proposal for Food-Based Recommendations” calls attention to the fact that certain foods rich in saturated fatty
acids, including whole-fat dairy, unprocessed meat and dark chocolate, are not associated with a greater risk of heart disease, diabetes or death.
The review aimed to answer this question: “What is the relationship between saturated fat consumption (types and amounts) and the risk of cardiovascular risk is adults?” After a careful review of the research, the authors found no evidence
from large, randomized controlled trials that a reduction in saturated fats lowers cardiovascular risk or death. In addition, other smaller studies showed some significant, but mild benefits.
What does this all mean? Here are some key takeaways.
- There isn’t much evidence to support broad dietary restrictions on saturated fat. A recent study of 135,000 people across 18 low-to-middle income countries found that a greater intake of all types of fat was associated with
a lower likelihood of dying and had a neutral association with heart disease and stroke. By contrast, diets high in carbohydrate were associated with higher risk of death but not with cardiovascular disease, according to the authors. Those reporting
the highest intake of saturated fat intake (14% of their daily caloric intake) had a lower risk of stroke.
Another large study out of the U.K. found no evidence over 10.6 years that saturated fat intake was linked to new cases of heart
disease among nearly 200,000 people. Several other studies, including the Women’s Health Initiative, similarly found that cases of heart attack and stroke were unaffected after being on a low-fat diet in which saturated fat made up less
than 10% of daily calories.
- Saturated fats aren’t all the same. One important message is that there are many types of saturated fatty acids and not all are created equal. Food sources of saturated fats contain different proportions of various fatty acids
with different biological effects. This is especially so when you consider someone’s intake of other foods, including carbohydrates or fiber.
For example, the authors explain that the amount of saturated fatty acids seen in the
blood tracks more closely with someone’s intake of carbohydrates rather than saturated fat.
- There are important caveats about the role of saturated fats on cholesterol. Researchers explained that while saturated fats can boost low-density lipoprotein (LDL), known as the “bad” cholesterol, there is some data supporting
that the larger LDL particles and not smaller ones that tend to be more strongly related to cardiovascular disease.
- We need ways to more easily identify healthful sources of saturated fat and to begin to provide a more tailored approach to support healthy eating habits that are also culturally sensitive. While limiting the consumption of saturated
fat has been a central focus of dietary guidelines since the 1970s, the authors write that “There is no robust evidence that current population-wide arbitrary upper limits on saturated fat consumption in the United States will prevent CVD
or reduce mortality.”
All guidelines should consider the types of fatty acids and, more importantly, diverse foods sources and some containing saturated fats, in moderation. For those with heart disease or high risk of heart disease, it is important to discuss the amount of
saturated fats for your condition with your doctor.
New recommendations, therefore, should focus on healthy foods, with clearer and more specific guidance about which food sources are heart protective and which are harmful. Without these details, authors express concern that some people may avoid nutrient-dense
foods like dairy in favor of foods that may be low in saturated fat but are high in refined sugar and starch. Refined carbohydrates are associated with diabetes and cardiovascular disease.
Also, until more is known about the health effects of how foods are processed, whole foods in their natural state or “gently processed” should be an important factor in new dietary guidelines, according to the report.
Visit CardioSmart.org/Prevention to learn more about heart-healthy habits.
“Saturated Fats and Health: A Reassessment and Proposal for Food-Based Recommendations,” Journal of the American College of Cardiology, August 2020. Learn about CardioSmart's editorial process. Information provided for educational purposes only. Please talk to your health care professional about your specific needs.