Replacing the saturated fats with monounsaturated fats (or MUFAs) can help improve your mood and protect against heart disease. Keep reading to learn more about the benefits of monounsaturated fats.
What are Monounsaturated Fats?
Monounsaturated fats (MUFAs) are found in:
- Animal fats including lard, duck, and tallow
Monounsaturated fats intake can reduce the risk of heart disease, help you lose weight, and improve immune function and diabetes symptoms [R].
Types of MUFAs
The most common MUFAs in daily nutrition are oleic and palmitoleic acids [R].
For example, olive oil is 70 – 80% oleic acid. Many studies described its health benefits, such as reducing cholesterol levels, lowering blood pressure, reducing inflammation, and protecting from breast cancer [R].
How Oleic Acid Helps Reduce Cholesterol
Oleic acid blocks cholesterol absorption in the small intestine. It activates the unfolded protein response pathway and decreases NPC1L1, which is important for cholesterol absorption [R].
How Oleic Acid Prevents Breast Cancer
- increasing a growth-promoting receptor called ErbB2
- using more calcium for cellular communication
- causing cancer cells self-destruction
How Oleic Acid Helps Lower Inflammation
How Oleic Acid Helps Lower Blood Pressure
Oleic acid reduces the stability of the cell membrane, which increases the activity of a receptor for adrenaline (α2-adrenoreceptor), lowering blood pressure [R].
In the human body, palmitoleic acid is synthesized in the liver and fat tissues. Dietary sources include macadamia oil, cod liver oil, salmon, olive oil, chocolate, eggs, dairy fats, and sea buckthorn [R].
There are two forms of palmitoleic acid: cis and trans. The cis isoform is associated with decreased fat accumulation in the liver and increased insulin sensitivity. The trans isoforms are found in dairy products and partially hydrogenated oils and associated with lower risks of heart diseases and diabetes and slightly lower body fat [R, R].
How Palmitoleic Acid Lowers Cholesterol and Inflammation, and Prevents Cancer
Palmitoleic acid supports healthy metabolism by:
AMPK is an enzyme that activates energy-producing pathways and inhibits energy-consuming ones [R]. It helps prevent cancer and diabetes. At the same time, it also lowers cholesterol and triglycerides.
Other Types of MUFAs
- Undecylnic acid
- Myristoleic acid
- Petroselinic acid
- Elaidic acid
- Vaccenic acid
- Gondoleic acid
- Gondoic acid
- Cetoleic acid
- Erucic acid
- Nervonic acid [R, R]
Health Benefits of Monounsaturated Fats
1) May Help with Weight Loss
Diets high in monounsaturated fatty acids (MUFAs), such as the Mediterranean diet, may help with weight loss [R].
In obese women, a diet high in MUFAs led to more weight and fat loss than high polyunsaturated fat diet or their habitual diet [R].
However, in overweight/obese type 2 diabetics, a high-MUFA diet was as effective as a low-fat high-carbohydrate diet in terms of weight loss (4% of body weight lost), HDL levels, blood pressure, and blood sugar improvements (RCT) [R].
2) Can Help Lower Cholesterol and Triglycerides
Palmitoleic acid can:
- reduce triglycerides and cholesterol levels in people with abnormally high levels (DB-RCT) [R].
- increase HDL cholesterol [R].
- decrease LDL cholesterol [R].
3) Protect Against Heart Disease
MUFAs coexist with saturated fatty acids in several food sources. Since saturated fat may worsen heart health, it is important to consume food that contains high MUFA levels and low saturated fat levels [R].
4) Can Prevent Diabetes
Diets high in monounsaturated fatty acids (MUFAs) may be healthier for diabetic patients than low-fat, high-carbohydrate diets. The Mediterranean diet, which is high in MUFAs, improve glucose control and insulin sensitivity [R].
Overweight/obese type 2 diabetes patients can better control their diabetes with a high-MUFA diet than a high-carbohydrate diet (RT) [R].
In healthy subjects, replacing saturated fats by MUFAs in the diet helped improve insulin sensitivity (RCT) [R].
However, this favorable effect on insulin sensitivity only occurs along with a low total fat intake. Also, the high-MUFA diet had no effect on insulin secretion [R].
Olive oil intake is associated with a decreased risk of developing type 2 diabetes (meta-analysis of 29 RCTs) [R]. However, some other substances in olive oil other than MUFAs may also be responsible for these effects.
5) Benefit the Immune System and Lower Inflammation
Like fish oil, olive oil helps to:
- Increase nitric oxide (in rats) [R].
- Decrease arachidonic acid and the production of the inflammatory mediator prostaglandin E2 [R].
- Suppress inflammatory cytokines [R].
Consumption of almond (which contains MUFAs), can help to:
- Decrease E-selectin (a marker of inflamed blood vessels) [R].
- Decrease CRP (a marker of inflammation) [R].
- Reduce oxidative damage, although this could also be due to other antioxidant compounds in nuts [R].
6) Increase Bone Strength
Monounsaturated fats can help with bone health. High monounsaturated fatty acid (MUFA) intake is associated with higher bone density and lower bone fracture risk.
In a study of 187 women, high oleic acid diets were associated with increased bone strength [R].
A higher amount of MUFA compared to polyunsaturated fat in their diets also reduced the risk of bone fractures in elderly patients [R].
In mice, a high-MUFA diet increased bone thickness and volume in comparison to a high saturated fat and a normal fat diet. In addition, the high saturated fat diet also increased calcium absorption in the intestines, although it was unclear if calcium absorption had any effect on bone mineral density [R].
7) May Improve Mood and Reduce Risks of Depression
A high monounsaturated fat (MUFA) diet can help improve mood. The Mediterranean diet is associated with lower levels of depression [R].
Thus, replacing palmitic acid (a saturated fatty acid) with oleic acid (a monounsaturated fatty acid) reduces feelings of anger and hostility. However, it wasn’t clear if this was due to increased MUFAs or decreased saturated fatty acids [R].
8) Reduce Cancer Risk
Consuming monounsaturated fats (MUFAs) instead of saturated fats can help reduce cancer risk. Diets containing oleic acid reduced breast cancer risk [R].
Breast cancer risk and MUFA intake also depend on the food source of the fats. Olive oil is associated with reduced breast cancer risk. However, margarine, a highly processed source of MUFAs, does not help reduce breast cancer risk [R].
Possibly, the anti-cancer effects of olive oil were due to antioxidant content rather than to oleic acid [R].
9) Suppress Rheumatoid Arthritis Symptoms
Compared to healthy people, rheumatoid arthritis patients ate significantly fewer MUFAs, suggesting that MUFAs may prevent the disease [R].
In addition, olive oil consumption was associated with a lower risk of rheumatoid arthritis [R].
10) Protect the Liver
MUFAs can protect against liver injury due to a drug overdose.
In rats, a high-MUFA diet protected against acetaminophen (Tylenol)-induced liver injuries. The presence of monounsaturated fats in the cell membrane of liver cells reduces the cells’ susceptibility to oxidative damage [R].
In addition, diets rich in MUFAs tend to decrease liver fat content, which may protect against nonalcoholic fatty liver disease [R].
11) Increase Good Gut Bacteria
An oleic acid-derived compound can help with weight loss by restoring gut flora. Oleic acid reduces a family of bacteria called Enterobacteriaceae, which is associated with inflammation. In addition, it increases good bacteria (Bifidobacteria) [R].
12) Stop Skin Damage
However, there was no association between MUFA intake from dairy products and meats [R].
Most of these human studies had shortfalls. They were either small-scale and short-term human studies that relied on self-reported dietary choices or large-scale surveys. In addition, some of these health benefits could be caused by antioxidants in olive oil rather than MUFAs themselves. Therefore, monounsaturated fats might not be the true cause of these health benefits.
Side Effects and Negatives of Monounsaturated Fats
Monounsaturated fats on their own do not have any toxic effects [R].
However, nuts, a good source of MUFA, can cause allergic reactions [R].
Foods high in MUFA can simultaneously be high in other fats [R].
A high-fat (total fat, saturated, and monounsaturated fat) diet is associated with increased gallstone disease risk [R].
In contrast to oleic acid, uncommon MUFAs can increase the risk of heart disease. 7-hexadecenoic acid and cis-vaccenic acid were associated with higher heart attack (sudden cardiac arrest) risk in a prospective study of 2,890 elderly people [R].
Although MUFA consumption can be the cause of the increased risk, the results of this study are also associated with higher carbohydrate, protein, and alcohol intake. Therefore, it wasn’t clear if MUFAs consumption was problematic [R].
Natural Sources of Monounsaturated Fats
Oils are a natural source of monounsaturated fats [R]. Avocado, macadamia, and olive oils are predominantly monounsaturated fats, while rapeseed, peanut, almond, sesame, sunflower, and rice bran oil contain some MUFAs but are predominantly omega-6 fats.
Nuts are a good source of monounsaturated fats [R], especially macadamia nuts.
- Macadamia nuts
- Brazil nuts (dried)
- Pine nuts (dried)
3) Other Foods
There are no known drug interactions. However, a high-MUFA diet slightly increased the absorption of dextrose in rat intestines [R].
SNPs and Genes that Interact with Monounsaturated Fats
1) ADIPOQ SNP Interactions
SNP that links high monounsaturated fat consumption with obesity
- rs17300539 (-11391G>A): At high MUFA intake, GG homozygotes had higher BMI and increased obesity risk compared to people with the A allele [R].
SNP that affects insulin sensitivity in response to dietary fats
- rs266729 (-11377C>G): Men that are CC homozygous became less insulin resistant with a high-MUFA diet than with a high-saturated fat diet [R].
2) PPARγ SNPs
PPARγ is a protein that turns on other genes (transcription factor) and is activated by dietary fats. The G allele reduces PPARγ activity [R].
In an obesity intervention study where all subjects ate a Mediterranean diet, GG or GC subjects were significantly less obese than those with CC alleles. However, low MUFA diets did not lead to any difference in obesity between CC and CG/GG [R].
Moreover, CG/GG lost less weight (in % of body weight) with a high fat intake. People with the G allele have a greater resistance to weight gain, but they are also resistant to weight loss [R].
In another study of 538 adults, researchers looked at their dietary intake and physical examination results. Obese people with the G allele that consumed less MUFA had higher insulin resistance. Therefore, MUFA consumption can help lower insulin resistance and diabetes risk in people with the G allele [R].
3) PON1 Antioxidant Activity
Increased PON1 activity protects against atherosclerosis. Some fats and antioxidants can change PON1 activity. In male subjects, PON1 activity increased after a high-MUFA meal. In comparison, the high saturated fat diet slightly decreased PON1 activity [R].
However, this was not observed in female subjects [R].
5) High MUFA Shakes Activated Inflammatory Genes
A shake with high monounsaturated fatty acid (MUFA) concentration activated inflammatory genes [R].
Other Gene Interactions in Animals/Cells
- In mice, oleic acid treatment increases BCRP levels, which is an important transporter for nutrients and drugs, increasing the intestinal absorption of these substances [R].
- PPARα activation induces fatty acid breakdown in the heart. In male rats, a high monounsaturated fat diet with sunflower oil moderately increased PPARα gene and protein levels [R].
- Additionally, in obese mice, the increase of MUFA content correlated with enhanced ELOVL5 expression [R].
- In cell-based studies (bovine cells), oleic acid treatment significantly reduced cellular production from the following genes: FSHR, LHCGR, STAR, CYP11A1, HSD3B1, CYP19A1, and CCND2, and increased CD36 and SLC27A1 [R].
cis and trans MUFAs
Monounsaturated fats have only one unsaturated carbon bond compared to other fatty acids and have two forms – cis and trans. In cis-configurations, the hydrogen atoms are on the same side of the double bond, while they are on opposite sides in trans-configurations [R].
Trans monounsaturated fatty acids are semi-solid fats present in the industrial processes that partially turn oil into saturated fats (partially hydrogenated fats), such as margarine and shortening. Generally, these are harmful monounsaturated fats that are believed to cause inflammation, heart disease, and hardening of the arteries [R]. One exception to this is trans palmitoleic acid, which is associated with lower total cholesterol, triglycerides, and C-reactive protein.
Whereas, the predominant natural form of monounsaturated fatty acids (MUFAs) is the cis form.