In biochemistry and nutrition, monounsaturated fatty acids (abbreviated MUFAs, or more plainly
monounsaturated fats) are fatty acids that have one double bond in the fatty acid chain
with all of the remainder carbon atoms being single-bonded.
By contrast, polyunsaturated fatty acids (PUFAs) have more than one double bond.
== Molecular description == Fatty acids are long-chained molecules having
an alkyl group at one end and a carboxylic acid group at the other end.
Fatty acid viscosity (thickness) and melting temperature increases with decreasing number
of double bonds; therefore, monounsaturated fatty acids have a higher melting point than
polyunsaturated fatty acids (more double bonds) and a lower melting point than saturated fatty
acids (no double bonds).
Monounsaturated fatty acids are liquids at room temperature and semisolid or solid when
refrigerated resulting in a isotopic lattice structure.
Common monounsaturated fatty acids are palmitoleic acid (16:1 n−7), cis-vaccenic acid (18:1
n−7) and oleic acid (18:1 n−9).
Palmitoleic acid has 16 carbon atoms with the first double bond occurring 7 carbon atoms
away from the methyl group (and 9 carbons from the carboxyl end).
It can be lengthened to the 18-carbon cis-vaccenic acid.
Oleic acid has 18 carbon atoms with the first double bond occurring 9 carbon atoms away
from the carboxylic acid group.
The illustrations below show a molecule of oleic acid in Lewis formula and as a space-filling
model.
=== List of monounsaturated fats ===
== Health ==
Monounsaturated fats protect against cardiovascular disease by providing more membrane fluidity
than saturated fats, but they are more vulnerable to lipid peroxidation (rancidity).
The large scale KANWU study found that increasing monounsaturated fat and decreasing saturated
fat intake could improve insulin sensitivity, but only when the overall fat intake of the
diet was low.
However, some monounsaturated fatty acids (in the same way as saturated fats) may promote
insulin resistance, whereas polyunsaturated fatty acids may be protective against insulin
resistance.
Studies have shown that substituting dietary monounsaturated fat for saturated fat is associated
with increased daily physical activity and resting energy expenditure.
More physical activity was associated with a higher-oleic acid diet than one of a palmitic
acid diet.
From the study, it is shown that more monounsaturated fats lead to less anger and irritability.Foods
containing monounsaturated fats reduce low-density lipoprotein (LDL) cholesterol, while possibly
increasing high-density lipoprotein (HDL) cholesterol.Levels of oleic acid along with
other monounsaturated fatty acids in red blood cell membranes were positively associated
with breast cancer risk.
The saturation index (SI) of the same membranes was inversely associated with breast cancer
risk.
Monounsaturated fats and low SI in erythrocyte membranes are predictors of postmenopausal
breast cancer.
Both of these variables depend on the activity of the enzyme delta-9 desaturase (Δ9-d).In
children, consumption of monounsaturated oils is associated with healthier serum lipid profiles.The
Mediterranean diet is one heavily influenced by monounsaturated fats.
People in Mediterranean countries consume more total fat than Northern European countries,
but most of the fat is in the form of monounsaturated fatty acids from olive oil and omega-3 fatty
acids from fish, vegetables, and certain meats like lamb, while consumption of saturated
fat is minimal in comparison.
A 2017 review found evidence that the practice of a Mediterranean diet could lead to a decreased
risk of cardiovascular diseases, overall cancer incidence, neurodegenerative diseases, diabetes,
and early death.
A 2018 review showed that the practice of the Mediterranean diet may improve overall
health status, such as reduced risk of non-communicable diseases, reduced total costs of living, and
reduced costs for national healthcare.
== Sources == Monounsaturated fats are found in animal flesh
such as red meat, whole milk products, nuts, and high fat fruits such as olives and avocados.
Olive oil is about 75% monounsaturated fat.
The high oleic variety sunflower oil contains as much as 85% monounsaturated fat.
Canola oil and cashews are both about 58% monounsaturated fat.
Tallow (beef fat) is about 50% monounsaturated fat. and lard is about 40% monounsaturated
fat.
Other sources include avocado oil, macadamia nut oil, grapeseed oil, groundnut oil (peanut
oil), sesame oil, corn oil, popcorn, whole grain wheat, cereal, oatmeal, almond oil,
sunflower oil, hemp oil, and tea-oil Camellia.
== See also == High density lipoprotein
Saturated fat Unsaturated fat
Polyunsaturated fat Fatty acid synthesis