Different saturated fatty acids have different effects on health.
What do you think about saturated fat and what is the truth? Is saturated fat good for the human body? What does saturated fat mean?
The health effects of saturated fats are a controversial topic.
In the past, saturated fat was widely believed to be the leading cause of heart disease. Today, scientists don't quite believe it.
One thing is clear – saturated fats are not a single nutrient. It is a group of different fatty acids that have different effects on health and metabolism.
This article details the 10 most common saturated fatty acids, including their health effects and dietary sources.
What is saturated fat?
Saturated fats and unsaturated fats are two broad categories of fats.
The chemical structure and properties of these groups are slightly different. For example, saturated fats are usually solid at room temperature, while unsaturated fats are liquid.
The main dietary sources of saturated fat are fatty meat, lard, tallow, cheese, butter, cream, coconut oil, palm oil, and cocoa butter.
All fats are made up of molecules called fatty acids, which are chains of carbon atoms. Different types of saturated fatty acids can be distinguished by the length of their carbon chains.
The following are the most common saturated fatty acids in the human diet:
- Stearic acid: 18 carbon atoms long
- Palmitic acid: 16 carbon atoms long
- Myristic acid: 14 carbon atoms long
- Lauric acid: 12 carbon atoms long
- Capric acid: 10 carbon atoms long
- Caprylic acid: 8 carbon atoms long
- Caproic acid: 6 carbon atoms long
Saturated fatty acids other than these are rarely found in the diet.
Saturated fatty acids with a length of less than six carbon atoms are collectively referred to as short-chain fatty acids.
These are produced when intestinal bacteria ferment fiber. They are produced in your gut by the fiber you eat and can also be found in some fermented foods.
Summary: Saturated fatty acids are one of two broad categories of fats. Common dietary saturated fatty acids include stearic acid, palmitic acid, myristic acid, and lauric acid.
How does saturated fat affect health?
Most scientists now admit that saturated fats aren't as unhealthy as previously assumed.
There is evidence that they do not cause heart disease, although their exact role is still being debated and investigated (1, 2).
However, replacing saturated fats with unsaturated fats (e.g., omega-3) may reduce the risk of heart attack (3, 4).
This doesn't necessarily mean that saturated fats aren't healthy. It simply shows that certain unsaturated fats contribute to your health.
Therefore, consuming small amounts of unsaturated fat may not be a good idea. To reduce your risk of heart disease, make sure that unsaturated fats make up a significant portion of your total fat intake.
In contrast, replacing saturated fats with carbohydrates has no health benefits. It can even damage your blood lipid profile, which is a measure of the level of lipids in your blood, such as cholesterol and triglycerides (5).
While it's clear that some saturated fats may raise LDL (bad) cholesterol levels, the link between cholesterol levels and heart disease is more complex.
For example, saturated fat raises levels of large LDL cholesterol particles that are less associated with heart disease than smaller, denser particles. (6, 7）。
Summary: Saturated fats are not as harmful as previously thought. There is growing evidence that there is no strong link between saturated fat and heart disease.
1. Stearic acid
Stearic acid is the second most common saturated fat in the U.S. diet (8).
Stearic acid slightly lowers LDL (bad) cholesterol or has a neutral effect compared to carbohydrates or other saturated fats. As a result, it may be healthier than many other saturated fats (9, 10, 11).
Studies have shown that parts of your body convert stearic acid into oleic acid, a healthy unsaturated fat. However, according to some estimates, the conversion rate is only 14% and may not have much to do with health (12, 13).
The main dietary source of stearic acid is animal fat. Except for coconut oil, cocoa butter, and palm kernel oil, the stearic acid content in vegetable fats is generally low.
Stearic acid is considered a healthy saturated fat that doesn't seem to increase your risk of heart disease.
Even in a 40-day study, stearic acid intake accounted for 11% of total calorie intake. (9）。
Summary: Stearic acid is the second most common saturated fat in the American diet. It seems to have a neutral effect on your lipid profile.
Health line test
2. Palmitic acid
Palmitic acid is the most common saturated fat in plants and animals.
This acid may account for more than half of total saturated fat intake in the United States (8).
The richest dietary source is palm oil, but palmitic acid also accounts for about a quarter of red meat and dairy fat.
Compared to carbohydrates and unsaturated fats, palmitic acid raises levels of total cholesterol and LDL (bad) cholesterol without affecting HDL (good) cholesterol. (9, 11, 14）。
High levels of LDL cholesterol are well-known risk factors for heart disease.
Still, not all LDL cholesterol is the same. A more accurate marker of heart disease is the presence of large numbers of LDL particles and small, dense LDL particles. (15, 16, 17）。
Although palmitic acid raises total LDL cholesterol, this is mainly due to the increase in large LDL particles. Many researchers consider high levels of large LDL particles to be less important, although others disagree (6, 16, 18).
When the unsaturated fat of linoleic acid is consumed at the same time, it can counteract the effects of some palmitic acid on cholesterol. (19）。
Palmitic acid may also affect other aspects of metabolism. Studies in mice and humans have shown that a diet high in palmitic acid may adversely affect mood and reduce physical activity. (20, 21）。
Several human studies have shown that consuming more palmitic acid reduces the number of calories you burn compared to consuming more unsaturated fats, such as oleic acid. (22, 23, 24）。
These aspects of palmitic acid need to be further studied before reaching definitive conclusions.
Summary: Palmitic acid is the most common saturated fatty acid, accounting for more than half of all saturated fats consumed in the United States. It raises LDL (bad) cholesterol levels without affecting HDL (good) cholesterol.
3. Myristic acid
Myristic acid causes a significant increase in total cholesterol and LDL (bad) cholesterol compared to palmitic acid or carbohydrates. However, it does not appear to affect HDL (good) cholesterol levels (11, 25).
These effects are much stronger than palmitic acid. However, similar to palmitic acid, myristic acid appears to increase levels of large LDL particles, which many scientists consider less important (6).
Myristic acid is a relatively rare fatty acid that is not high in most foods. However, certain oils and fats contain considerable amounts.
While coconut oil and palm kernel oil are relatively high in myristic acid, they also provide other types of fats, which may counteract the effects of myristic acid on blood lipids (26).
Summary: Myristic acid is a long-chain saturated fatty acid. It raises LDL cholesterol more than other fatty acids.
4. Lauric acid
Lauric acid has 12 carbon atoms and is the longest medium-chain fatty acid.
It raises total cholesterol more than most other fatty acids. Nonetheless, this increase is mainly due to an increase in HDL (good) cholesterol.
In other words, lauric acid reduces the amount of total cholesterol relative to HDL cholesterol. These changes have been linked to a reduced risk of heart disease (27).
In fact, lauric acid appears to have a greater effect on HDL cholesterol levels than any other saturated fatty acid. (11）。
Lauric acid accounts for about 47% of palm kernel oil and 42% of coconut oil. In contrast, other oils or fats that are commonly consumed provide only trace amounts.
Summary: Lauric acid is the longest medium-chain fatty acid. Although it significantly raises total cholesterol, this is mainly due to an increase in HDL cholesterol, which is good for health.
5-7。 Caproic acid, caprylic acid and decanoic acid
Caproic acid, caprylic acid, and capric acid are medium-chain fatty acids (MCFAs).
Their name comes from the Latin word "Capra", which means "female goat". They are sometimes referred to as goat fatty acids because they are rich in goat milk.
Medium-chain fatty acids are metabolized differently from long-chain fatty acids. They are easier to absorb and transport directly to your liver, where they are quickly metabolized.
There is evidence that MCFA may have the following benefits:
- Weight loss. Multiple studies have shown that they may slightly increase the number of calories you burn and promote weight loss, especially when compared to long-chain fatty acids (28, 29, 30, 31, 32).
- Increases insulin sensitivity. Some evidence suggests that medium-chain fatty acids increase insulin sensitivity compared to long-chain fatty acids. (33）。
- Antiepileptic effect. Medium-chain fatty acids, especially capric acid, may have antiepileptic effects, especially when used in combination with a ketogenic diet (34, 35, 36).
Because of its potential health benefits, MCFA is sold as a supplement called MCT oil. These oils are usually composed mainly of capric acid and caprylic acid.
Decanoic acid is the most common of these. It accounts for about 5% of palm kernel oil and 4% of coconut oil. Small amounts are present in animal fats. Otherwise, it is rare in food.
Summary: Capric, caprylic and caproic acid are medium-chain fatty acids with unique properties. They may promote weight loss, increase insulin sensitivity, and reduce the risk of seizures.
8-10。 Short-chain fatty acids
Saturated fatty acids that contain less than six carbon atoms are called short-chain fatty acids (SCFAs).
The most important SCFAs are:
- Butyric acid: 4 carbon atoms long
- Propionic acid: 3 carbon atoms long
- Acetic acid: 2 carbon atoms long
SCFAs from when beneficial gut bacteria ferment fiber in your colon.
Their dietary intake is small compared to the amount of SCFA produced in the colon. They are not common in foods and are only present in small amounts in creams and certain fermented foods.
SCFAs are responsible for many of the health benefits associated with fiber intake. For example, butyric acid is an important source of nutrition for cells in the lining of the colon (37).
The type of fiber that promotes the formation of short-chain fatty acids is called prebiotics. They include resistant starch, pectin, inulin, and arabincans (38, 39).
Summary: The smallest saturated fatty acids are called short-chain fatty acids (SCFAs). They form when friendly bacteria in your colon ferment fibers and have many potential health benefits.
Conclusion
Different saturated fatty acids have different effects on health.
Most studies have investigated the overall health effects of saturated fats — without distinguishing between different types.
The evidence consists primarily of observational studies associated with investigations. Many of them linked high saturated fat intake to an increased risk of heart disease, but the evidence was not entirely consistent.
While certain types of long-chain saturated fats may raise your LDL (bad) cholesterol levels, there is no convincing evidence that any of them cause heart disease. More high-quality research is needed.
Still, most official health organizations recommend that people limit their intake of saturated fats and replace them with unsaturated fats.
While the harmful effects of saturated fat remain controversial, most agree that replacing saturated fat with unsaturated fat is good for heart health.