In the past decades, it has been advised to watch your fat intake, especially saturated fat. Data from the 1970’s suggested there was a correlation between cholesterol and heart disease. In return, the amount of saturated fat in the diet was associated with cholesterol amounts in the blood.
However, recent research has challenged this concept because lowering saturated fat lowers larger molecules of LDL cholesterol, not small, dense LDL cholesterol.
The small LDL particles are more of a concern for heart health, not the larger LDL cholesterol molecules (1).
Even though the interpretation of research around saturated fat and heart health has shifted somewhat, it doesn’t mean health experts are suggesting you can eat all the saturated you want.
What is more important is what you are replacing the saturated fat with in the diet. Replacing saturated fat with simple carbohydrates, as was common place in the past, is no longer recommended.
Replacing saturated fat with unsaturated fats or high fiber complex carbohydrates are still recommended for heart health.
Chemical composition
What does the term saturated and unsaturated fat even mean? The saturation of fat has to do with the carbon bonds in the chemical makeup of fat. Fats are made from carbon and hydrogen bonds.
If all of the carbon bonds are saturated with hydrogen that means it is a saturated fat. If a carbon has a double bond instead of fully saturated with hydrogen molecules, the fat is unsaturated.
If there is only one unsaturated bond in the chemical structure, the fat is considered monosaturated.
If there is more than one double bond in the chemical structure, the fat is considered polysaturated.
The classification of fats is all about the molecular bonds between carbons and hydrogens. Just this seemingly small difference can differentiate form and function (2).
Food sources
Saturated fats tend to be solid at room temperature while unsaturated fats are liquid. Plant oils are examples of unsaturated fats, and fats on animal meats or from dairy are higher in saturated.
Most foods are generally a mix of saturated, mono and polyunsaturated fats but are predominant in one type of fat.
Nuts and avocados are other food examples high in unsaturated fats. Coconut is also a predominant source of saturated fats.
Heart health
Saturated fat has been associated with increasing LDL cholesterol which was thought to increase risk for heart disease.
However as a 2013 BMJ article (3) suggests, as saturated fat was cut from Americans diets, risk for cardiovascular disease continued to increase.
A 2010 meta analysis (4) looked at data from 21 studies and concluded there was no significant evidence saturated fat is associated with increased risk for cardiovascular disease.
So is saturated fat harmful or not harmful for heart health? More research is needed to continue to clarify this relationship.
However, health experts recommend saturated fat may be considered more neutral, not necessarily healthy.
Replacing unsaturated fats with saturated fats is still recommended for heart health.
A 2015 study (5) compared the effect saturated fat, unsaturated fat and different sources of carbohydrate had on risk for heart disease.
Researchers looked at data from over 84,000 women over 42,000 men over 24-30 years. Researchers concluded higher intakes of polyunsaturated fats and whole grain carbohydrates were significantly associated with a lowered risk for heart disease.
Replacing saturated fats with refined carbohydrates was not associated with a lowered risk for heart disease.
Dietary recommendations for saturated and unsaturated fat
What are the differences for recommended intake for saturated and unsaturated fats? Harvard Health suggests using monounsaturated fat and polyunsaturated fats as much as possible to replace saturated and especially trans fats.
Fats should make up between 20-35% of your daily calorie intake. If your fat intake is on the higher end, most should be coming from unsaturated fats.
It is still recommended to limit saturated fat intake to less than 10% of total calorie intake.
Essential fatty acids omega 3 and 6
Fats play an important role in health. They help us absorb fat soluble nutrients, provide a source of energy and are an important part of every cell structure in the body.
Another important aspect of fats is they provide essential fatty acids omega 3 and 6. We need both of these fatty acids in our diets, as they are important for health.
Omega 3 is considered to have anti-inflammatory effects in the body and can help lower blood clotting. Omega 6 is the counter balance that is considered pro-inflammatory and clots the blood.
Essential omegas are found from mainly polyunsaturated fat sources. Polyunsaturated fats that provide omega 3’s include: fatty fish, nuts, seeds, flaxseeds, chia seeds and walnuts.
Most Americans tend to get too much omega 6 and not enough omega 3 in the diet. Omega 6 sources include: soybean oil, safflower oil, sunflower seed oil and corn oil.
Besides just focusing on saturated and unsaturated fat intake, focusing on eating more omega 3 fatty acid sources can be beneficial for health.
Omega 3’s are associated with heart health benefit by increasing HDL cholesterol and lowering blood triglycerides.
Conclusion: differences and comparison for saturated and unsaturated fats
Fats play an important role in the diet and overall health. In previous decades, the health message was to lower saturated fats as much as possible even if it meant replacing them with simple carbohydrates.
Now, current research does not promote replacing saturated fats with refined carbohydrates. Saturated fats may be considered more neutral than previous thought, but they should still be eaten in moderation.
Replacing saturated fats with unsaturated fats and complex carbohydrates is still considered heart healthy.
Unsaturated fats are also a source of essential fatty acids that can influence inflammation and heart health.
Choosing foods that are a good source of omega 3’s is recommended as most Americans tend to not get recommended intake of omega 3’s in their diet.
