What are fats?

The body uses three types of nutrients which are fats, proteins, and carbohydrates. They help the body with its energy, structural support, hormones, production of vitamins, and other functions. However, too much fat intake can be harmful. Some types of fat can lead to increasing the bad cholesterol in the body. There are beliefs that cholesterol in food is bad, but only 20% of cholesterol in the blood comes from food while most of it is made in the liver.

Why is too much cholesterol bad for the body?

There are two types of cholesterol; the HDL is the good type, and the LDL is the bad type. The HDL cholesterol helps in removing unwanted cholesterol from the body while too much LDL cholesterol can accumulate and stick to the walls of blood vessels causing sticky deposits. Later, the blood pathways become narrower making it harder for blood to pass through. Over time, the sticky deposits may break off leading to blood clots that increase the chance of stroke or heart attack.

What are the bad types of fats?
Trans unsaturated fats: Mostly made by a chemical process that turns oil from liquid to solid at room temperature.
  • Why are trans fats considered bad fats?
    • It increases the LDL “bad” cholesterol and decreases HDL “good” cholesterol in the body leading to a higher risk of heart disease.
  • Sources: soybean, margarines, processed foods such as french fries, fast foods, donuts, pastries, dry soup powders, and cookies.
  • Types of oils that have trans fats: cottonseed oil and palm oil.
  • Facts about trans unsaturated fats:
    • The FDA recommended to remove trans fats from the American diet to fight against the risk of heart disease caused by this type of fat.
    • They are cheaper to make and usually make the food tasty and look nicer.
Saturated fats: Are usually solid at room temperatures giving them the name of “solid fats”.
  • Why are saturated fats considered bad fats?
    • It increases LDL “bad” cholesterol in the body leading to a higher risk of heart disease.
  • Sources: Animal products like cheese, butter, whole milk, eggs, meats with high fat content, and cream. Manufactured foods like pastries, ice cream, biscuits, and fast foods.
  • Types of oils that have saturated fats: coconut, palm, palm kernel oils.
  • Facts about saturated fats:
    • The American Heart Association favored limiting saturated fats intake to about 5% to 6% of total daily calorie intake.
What are the good types of fats?
Polyunsaturated fats: Chemically, they have multiple unsaturated carbons leading them to be liquid at room temperatures.
  • Why are polyunsaturated considered good fats?
    • It decreases LDL “bad” cholesterol in the body lowering the chance of heart attack.
  • Types and their sources:
    • Omega 3 fatty acids:
      • Alpha-linolic acid (ALA): Flaxseed oil, soybean oil, walnuts, and their oils.
      • Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA): Seafood including fish, shellfish, and fish oils.
    • Omega 6 fatty acids:
      • Corn oil, canola oil, sunflower oil, soybean, safflower oil, walnuts, and peanut oil.
  • Facts about polyunsaturated fats:
    • They are called essential fatty acids because the body cannot make them, and can only get them from diet.
    • They help with cell growth, inflammation, and brain function.
    • Some studies showed that too much intake of DHA and/or EPA (6.5 grams/day) can lead to bleeding problems.
Monounsaturated fats: On a chemical level, they have one unsaturated carbon leading them to be liquid at room temperatures.
  • Why are monounsaturated fatty acids considered good fats?
    • They reduce LDL “bad” cholesterol in the body lowering the risk of heart problems.
  • Sources: Olive oil, sesame oil, peanut oil, canola oil, nuts (not walnuts), avocados, red meat, and whole milk.
  • Facts about monounsaturated fats:
    • They can improve insulin sensitivity while lowering the risk of diabetes, heart disease, cancers, and other health issues.
    • They do not need to be mentioned on the Nutrition facts labels, but they exist in the types of foods mentioned above.
Conclusion:

The human body needs fats for energy, shape support, vitamin production, and more. Too much of the bad fats (such as trans and saturated fats) increase LDL “bad” cholesterol leading to risk of heart disease and stroke. Meanwhile, the healthier fats (polyunsaturated and monounsaturated fats) lower this risk by reducing the bad cholesterol and increasing the HDL “good” cholesterol in the body. It is important to be mindful of the fat in your food because it can affect your health!

Prepared by Myasar Halmi, PharmD Candidate 2024

References:

  1. Fats explained. Bhf.org.uk. Published 2021. https://www.bhf.org.uk/informationsupport/support/healthy-living/healthy-eating/fats-explained#:~:text=Monounsaturated%20fat%20and%20polyunsaturated%20fat
  2. Chong EW-T, Sinclair AJ, Guymer RH. Facts on fats. Clinical and Experimental Ophthalmology. 2006;34(5):464-471. doi:https://doi.org/10.1111/j.1442-9071.2006.01250.x
  3. Mayo Clinic. High Cholesterol. Mayo Clinic. Published January 11, 2023. https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/symptoms-causes/syc-20350800
  4. Mayo Clinic. HDL cholesterol: How to boost your “good” cholesterol. Mayo Clinic. Published 2018. https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/hdl-cholesterol/art-20046388
  5. Mayo Clinic. Trans fat: Double trouble for your heart. Mayo Clinic. Published February 13, 2020. https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/trans-fat/art-20046114
  6. American Heart Association. Saturated Fat. www.heart.org. Published November 1, 2021. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/saturated-fats
  7. American Heart Association. Polyunsaturated Fat. www.heart.org. Published 2015. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/polyunsaturated-fats
  8. Harvard Health Publishing. How it’s made: Cholesterol production in your body – Harvard Health. Harvard Health. Published July 31, 2019. https://www.health.harvard.edu/heart-health/how-its-made-cholesterol-production-in-your-body