The effects of monounsaturated fatty acids on health
Fatty acids are described after two characteristics: the length of carbon atoms chain and the hydrogen saturation degree.
Monounsaturated fatty acids have single double link, which is found in the 9th carbon atom at the methyl end (omega). Four monounsaturated acids are found in foods, the most frequently met is the oleic acid (18: 1n-9), which represents 70-72% of the olive oil and avocado fats and about 50% in the rapeseed oil. Monounsaturated fatty acids can be synthesized by animals and humans, so it needs no input from outside, in other words, are not essentials. At room temperature, the monounsaturated fatty acids have a liquid or semisolid consistency. Monounsaturated fatty acids have best protecting effects on health against chronic disease, lowering the LDL (low density lipoproteins or “bad” cholesterol), increasing the HDL (high density lipoproteins or “good” cholesterol) easy lowering the blood pressure, improving the blood flow, helping to normalize the glucose in diabetics without lowering the triglycerides, and lowering the cancer diseases risk.
Thus, recent studies have shown that replacing the linoleic polyunsaturated acid (C18: 2 n6), in the alimentation, which makes up most fats in sunflower oil, with the oleic acid from olive or avocado it’s decreases the susceptibility of LDL oxidation. Low-density lipoprotein (LDL) are particularly vulnerable to oxidation, and so are the cell membranes if polyunsaturated fatty acids form the majority of constituent lipoprotein, because the doubleo links oxidizes easily. Monounsaturated fatty acids property to oxidize much harder gives them a protective effect against atherosclerosis, because they give birth to LDL particles more resistant to oxidation. Another protective action of monounsaturated fatty acids is that they don’t lower the HDL (“good” cholesterol), as happens after the sunflower oil consumption (high content of polyunsaturated acid, linoleic).
While saturated fatty acids, which are found in animals fat, activates platelets, producing their agglutination, accession to vascular endothelium and triggering processes that lead to blood clotting and thrombosis, monounsaturated fatty acids have the opposite action. It’s good to know that polyunsaturated fatty acids, which make up the majority in sunflower, germ corn and soy oil, increase platelet aggregation, which for it favors the oxidation of low density lipoprotein (LDL).
Monounsaturated fatty acids, which also reside in cell membranes, are much less vulnerable to lipid peroxidation compared to polyunsaturated fatty acids.
It is known that oxidative damage of DNA and fats contribute in a significant way to the cancer etiology, atherosclerosis and rheumatoid arthritis.
While the polyunsaturated fatty acids that are found in sunflower, corn germ and soy oil are most susceptible substrates to reactive oxygen species attack, avocado and olive oil monounsaturated fatty acids have anti-inflammatory properties and can reduce the production of inflammatory mediators (1-8 interleukin, interferon and tumor necrosis factor).
In the etiology of cancer, many genotoxic agents act through the common mechanism of DNA acid oxidative lesions , genes substrate. Oxidative processes can be responsible for initiating carcinogenic changes by DNA oxidation, but can also operate as promotion, influencing the activity of genes that regulate growth and cell differentiation, acting synergistic on initiators factors.
Diets rich in linoleic acid, ie rich in sunflower, corn germ and soy oil favors more the tumor formation, as a result of the increased oxidative stress. The fact that monounsaturated fatty acids (e.g., oleic acid from olive and avocado) are much harder oxidized, can give them a protective role against cancer.
A further protective effect of the oleic acid (from avocado and olive) against cancer is that it does not alter the immune response. Polyunsaturated fatty acids (eg linoleic acid) are required for T-cell mediated immunity, but the large quantities that are used by oil and margarine suppress this function, increasing the risk of cancer diseases.
It was noted that in countries where olive oil consumption is particularly used, coronary heart disease mortality is lower. Monounsaturated fatty acids lower the triglycerides in the blood, not only LDL.
Finally, vegetable oils, along with cereals germ, is the most important source of alpha-tocopherol (vitamin E) in most diets, and olive oil contains 12 mg to 100 g. Alpha-tocopherol acts as a free radical septage, to protect cell membranes from oxidative damage. Among the many chronic diseases related to oxidative stress, recall atherosclerosis, cancer, cataracts, and inflammatory diseases.
Fatty acids contents of different oils:
- Olive Oil: 70-75% monounsaturated, 10% polyunsaturated;
- Rapeseed oil: 50-60% monounsaturated, 30% polyunsaturated;
- Peanut oil: 50% monounsaturated, 30% polyunsaturated;
- Corn oil: 27% monounsaturated, 60% polyunsaturated;
- Sunflower oil 24% monounsaturated, 65% polyunsaturated;
- Soy Oil: 22% monoinsaturated, 63% polyunsaturated;
- Grape seed oil: 16% monounsaturated, 72% polyunsaturated.