Sponsored by American Palm Oil Council
Q Describe the effect that saturated fats have on cholesterol.
A: Dietary fat has a long-standing relationship with blood cholesterol. In the 1940s and '50s it was discovered that saturated fat, largely as butterfat, meat fat or coconut oil, raised cholesterol, whereas polyunsaturated vegetable oils reduced it. Ever since, there has been a steady assault on saturated fat because high blood cholesterol causes arteries to clog, which leads to heart disease. Subsequently, we discovered blood cholesterol is transported as LDL (bad cholesterol) and HDL (good cholesterol). Ideally, LDL should be as low as possible and HDL as high as possible. Saturated fats raise cholesterol — both LDL and HDL. By contrast, polyunsaturated fats depress LDL and HDL, if consumed in excessive quantity. Saturated fats are deemed bad fats, not because they contain saturated fatty acids (SFA), but because they lack sufficient polyunsaturated fatty acids (PUFA). Awareness of the importance of the balance needed between SFA and PUFA led to the popular margarine, Smart Balance, which essentially balances SFA and PUFA by blending natural fats to provide the maximum benefit to the blood LDL and HDL relationship. With the right combination, SFA maintains the HDL level, while PUFA decrease LDL. Thus, the “badness“ in saturated fat is its relative absence of PUFA, which can be fixed by blending.
Q Describe the association between blood cholesterol and heart disease, as understood today.
A: So why do we even care about blood cholesterol? Because LDL in a high concentration damages the arterial wall, especially coronary arteries, eventually causing a heart attack. In the brain, this process clogs or breaks small arteries to cause a stroke or impair circulation to accelerate dementia. Thus, elevated LDL without enough HDL is dangerous, because HDL protects arteries by moving cholesterol back to the liver for excretion.
Q A recent study published in the American Journal of Clinical Nutrition (AJCN), failed to demonstrate the relationship between saturated fat and heart disease. How can we interpret these observations, and what does it mean for the consumer who is trying to understand how saturated fat works and how it affects his arteries?
A: A recent article in AJCN reviewed 21 large clinical studies in which almost 350,000 men and women were examined for the effect of saturated fat on heart disease and stroke (CVD). Basically, saturated fat was not a factor in CVD in diets that provided adequate polyunsaturated fatty acids (again, balance was key). In only three studies was saturated fat linked to more CVD, because PUFA intake was too low. However, when saturated fat was balanced by polyunsaturated fat the connection between saturated fat and heart disease no longer existed. The same story exists for diabetes.
To summarize, saturated fat per se is not an issue, provided adequate intake of polyunsaturated fat occurs simultaneously. Secondly, research revealed it is dangerous to replace fat with carbohydrate, or saturated fat with trans fat, if polyunsaturated fat is removed along with saturated fat. Again, a balance between saturated and polyunsaturated fat is critical at all stages of food consumption to protect against CVD and diabetes.
Q Describe the types of functionality and benefits palm oil provides for baked products.
A: Some functional benefits of palm oil have been alluded to above. But palm oil also comes in different fractions. If palm oil is melted and then rapidly cooled, it separates into an upper liquid component and a solids fraction below. The liquid palm olein fraction differs from the solids palm stearin fraction. Recalling what was said about saturated fat and polyunsaturated fat, the upper fraction is preferred because it contains more unsaturated fatty acids, including PUFA. The lower fraction is quite solid because most of its fatty acids are saturated with many polyunsaturates removed to the upper fraction. Thus, using too much stearin in baked products is less healthy than using regular palm oil, which contains more PUFA.
Palm kernel oil is even more saturated than palm stearin. And it has only one-fifth the PUFA of palm oil, and thus has the potential for raising cholesterol substantially, both LDL and HDL, if consumed in the absence of additional polyunsaturated fat.
Q How does the composition of palm oil contribute to its functionality in baked products?
A: This question is partially addressed above, because palm oil and its different fractions have higher melting points as their SFA increase and PUFA decrease. This has functionality implications. For example, to make confectionery frostings one would want a more solid fat that contains less PUFA but raises the potential for a negative effect on the blood cholesterol profile. So the ideal composition for a baker to consider would be to use the appropriate oil, either palm oil, palm olein, palm stearin or palm kernel oil, and consider adding back a certain amount of polyunsaturates to render the final oil blend more healthful.