For years, some Americans trying to reduce their risk of heart disease have thought it best to decrease saturated fat consumption – but new science shows that we may have reason to rethink that belief.
Recently, a small, controlled feeding study in overweight and obese adults revealed that doubling and almost tripling the consumption of saturated fat from foods, such as eggs, full-fat dairy and beef, in a lower-carbohydrate diet did not increase the levels of saturated fat in the blood. Researchers also found that traditional risk markers (i.e. plasma triglycerides, glucose, insulin and markers of insulin sensitivity) actually improved at the highest level of fat consumed.
Conversely, eating more carbohydrates, especially from sugars and starches, was shown to increase blood levels of a monounsaturated fatty acid, called palmitoleic acid when part of a lower saturated fat diet. An increase in this fatty acid may indicate that a greater amount of carbohydrates are being converted into fat instead of being burned by the body.
Palmitoleic acid is associated with an increased risk for heart disease, metabolic syndrome and diabetes (Djousse et al, 2012; Warensjo et al, 2005; Zong et al, 2013; Wang et al, 2003). Previous studies found that palmitoleic acid is the most responsive fatty acid to carbohydrate consumption (Aarsland & Wolfe, 1998) and does not adequately reflect saturated fat consumption (Forsythe et al, 2010).
While this is one study, these findings support the growing body of observational evidence suggesting that there may not be an association between saturated fat consumption and disease risk (Siri-Tarino et al, 2010;Chowdhury et al, 2014).
The Bottom Line
These results help explain why evidence from observational studies indicates that the health effects of reducing saturated fat vary depending on the replacement nutrient. Based on the evidence, replacing saturated fat with polyunsaturated fats (e.g. vegetables, vegetable oils) lowers heart disease risk, whereas replacing saturated fat with carbohydrates has no benefits. All in all, findings from this study challenge the perspective that eating saturated fat from foods is harmful, and underscore the importance of considering the amount of carbohydrates that accompany saturated fat consumption.
As health and wellness professionals, it is important to focus on the food as a whole as opposed to one single nutrient. For instance, some foods that contain fat and saturated fat also provide other essential nutrients such as that seen with full-fat dairy foods. Of course, overall caloric consumption plays a role, too – with many Americans overweight or obese, it’s important to be mindful of a nutritionally balanced meal plan to provide calories within a weight management framework.
All in all, there is still a need for more research to better understand the relationship between food consumption and blood saturated fat levels and how this relates to disease risk. As research continues to discern the health effects of saturated fat, we still need to focus on the amount and source of saturated fat being eaten.