The Facts about Fats

National Heart Month is coming to an end. For years, we have been told that low-fat and low-cholesterol diets are key to improving heart health. Because of this belief, fat is often the first nutrient to be reduced, but dietary fats play several important roles in overall health! Your brain is approximately 60% fat, and fats are essential for every cell in your body. They are crucial for hormone production, regulating smooth muscle contraction, immune function, and blood clotting. Vitamins A, D, E, and K are all fat-soluble, meaning they require fat for absorption and utilization in the body.

However, some fats should be monitored in our diet. Saturated fats, which are typically solid at room temperature, prompt the liver to produce more LDL cholesterol. Now, wait a minute—our liver makes cholesterol? Yes! Any person or animal with a liver produces cholesterol, and the liver makes all the cholesterol the body needs. Contrary to popular belief, cholesterol plays an integral role in human health. It is a structural component of every cell membrane and aids in the production of hormones (such as estrogen and testosterone) and Vitamin D. Research has shown that when dietary cholesterol intake increases, the body compensates by decreasing its endogenous (liver-produced) cholesterol production, and vice versa.

LDL cholesterol, known as “bad” cholesterol, transports cholesterol to body tissues, where it can build up as plaque in the blood vessels, increasing the risk of heart disease. On the other hand, HDL cholesterol, or “good” cholesterol, acts in reverse by transporting cholesterol back to the liver for hormone production or excretion, preventing plaque buildup.

If dietary cholesterol does not significantly impact cholesterol levels, what does? The types of fats we consume.

• Saturated fats, found in butter, cheese, meat, and tropical oils such as coconut and palm oil, prompt the liver to produce more LDL cholesterol.
• Unsaturated fats, which are liquid at room temperature, encourage less LDL production and more HDL production.
  • Monounsaturated fatty acids (found in canola, olive, peanut, safflower, and sunflower oils, as well as avocados) help lower LDL cholesterol.
  • Polyunsaturated fatty acids (found in corn, cottonseed, flaxseed, soybean oils, and fatty fish) may lower LDL cholesterol, improve insulin sensitivity, and support visual and cognitive development in infants.
• Omega-3 and Omega-6 fatty acids are essential polyunsaturated fats that the body cannot produce, meaning they must be obtained through diet.
• Trans fats, although technically unsaturated, are processed to become semi-solid at room temperature. Partially hydrogenated vegetable oils are a prime example. Trans fats increase LDL and lower HDL cholesterol—exactly the opposite of what we want for heart health.

One commonly misunderstood food is eggs. They, along with shrimp, are high in cholesterol but low in saturated fats, making them suitable for a heart-healthy diet. The dietary guidelines recommend limiting saturated fat intake to less than 10% of daily calories to reduce heart disease risk. Additionally, increasing physical activity to at least 150 minutes per week can help raise HDL levels and lower LDL cholesterol, further reducing the risk of heart disease.

Monica Nagele MS/RD is the Purdue Extension Montgomery County Extension Director, Health and Human Science Educator