For discussion how dietary fats affect cardiovascular health, see Diet and heart disease.

In biochemistry and nutrition, monounsaturated fats or MUFA (MonoUnsaturated Fatty Acid) are fatty acids that have one double bond in the fatty acid chain and all of the remainder of the carbon atoms in the chain are single-bonded. By contrast, polyunsaturated fatty acids have more than one double bond.

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.

Molecular description: oleic acid[link]

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.

Relation to health[link]

Although polyunsaturated fats protect against cardiovascular disease by providing more membrane fluidity than monounsaturated fats, they are more vulnerable to lipid peroxidation (rancidity). On the other hand, 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.^[1][2] In contrast to this, the large scale KANWU study found that neither dietary monounsaturated nor supplemented polyunsaturated fats (in the form of fish oil) affected insulin sensitivity while increased consumption of saturated fat significantly decreased insulin sensitivity.^[3]

Foods containing monounsaturated fats reduce low-density lipoprotein (LDL) cholesterol, while possibly increasing high-density lipoprotein (HDL) cholesterol.^[4] However, their true ability to raise HDL is still in debate.

Levels of oleic and 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 9-d delta 9 desaturase.^[5]

In children, consumption of monounsaturated oils is associated with healthier serum lipid profiles.^[6]

Natural sources[link]

Monounsaturated fats are found in natural foods such as red meat, whole milk products, nuts and high fat fruits such as olives and avocados. Olive oil is about 75% 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 macadamia nut oil, grapeseed oil, groundnut oil (peanut oil), sesame oil, corn oil, popcorn, whole grain wheat, cereal, oatmeal, safflower oil, almond oil, sunflower oil, tea-oil Camellia, and avocado oil.

Fat composition in different foods (click at right to hide or show)

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Food	Saturated	Monounsaturated	Polyunsaturated
	As weight percent (%) of total fat
Cooking oils
Canola oil	7	59	29
Corn oil	13	24	59
Olive oil	13	74	8
Sunflower oil	10.3[7]	19.5[7]	65.7[7]
Soybean oil	15	24	58
Peanut oil	17	46	32
Rice bran oil	25	38	37
Coconut oil	92	6	2
Dairy products
Cheese, regular	64	29	3
Cheese, light	60	30	0
Milk, whole	62	28	4
Milk, 2%	62	30	0
Ice cream, gourmet	62	29	4
Ice cream, light	62	29	4
Meats
Beef	33	38	5
Ground sirloin	38	44	4
Pork chop	35	44	8
Ham	35	49	16
Chicken breast	29	34	21
Chicken	34	23	30
Turkey breast	30	20	30
Turkey drumstick	32	22	30
Fish, orange roughy	23	15	46
Salmon	28	33	28
Hot dog, beef	42	48	5
Hot dog, turkey	28	40	22
Burger, fast food	36	44	6
Cheeseburger, fast food	43	40	7
Breaded chicken sandwich	20	39	32
Grilled chicken sandwich	26	42	20
Sausage, Polish	37	46	11
Sausage, turkey	28	40	22
Pizza, sausage	41	32	20
Pizza, cheese	60	28	5
Nuts
Almonds dry roasted	9	65	21
Cashews dry roasted	20	59	17
Macadamia dry roasted	15	79	2
Peanut dry roasted	14	50	31
Pecans dry roasted	8	62	25
Flaxseeds, ground	8	23	65
Sesame seeds	14	38	44
Soybeans	14	22	57
Sunflower seeds	11	19	66
Walnuts dry roasted	9	23	63
Sweets and baked goods
Candy, chocolate bar	59	33	3
Candy, fruit chews	14	44	38
Cookie, oatmeal raisin	22	47	27
Cookie, chocolate chip	35	42	18
Cake, yellow	60	25	10
Pastry, Danish	50	31	14
Fats added during cooking or at the table
Butter, stick	63	29	3
Butter, whipped	62	29	4
Margarine, stick	18	39	39
Margarine, tub	16	33	49
Margarine, light tub	19	46	33
Lard	39	45	11
Shortening	25	45	26
Chicken fat	30	45	21
Beef fat	41	43	3
Dressing, blue cheese	16	54	25
Dressing, light Italian	14	24	58
Other
Egg yolk fat	36[8]	44[8]	16[8]
Unless else specified in boxes, then reference is: [9]

See also[link]

• High density lipoprotein
• Saturated fat
• Unsaturated fat
  • Polyunsaturated fat
• Fatty acid synthesis

References[link]

External links[link]

• Fats (Mayo Clinic)
• Types of Fats (Cardiovascular Consultants)
• The Chemistry of Unsaturated Fats