So, what are fatty acids
basically? Chemically, they are carboxylic acid with long hydrocarbon chains.
Literally, they are fats that are important source of fuel to the cells as they
break down into ATP providing energy to the heart and skeletal muscle.
Fatty acids can either be
saturated (SFA) or unsaturated. Omega-3 fatty acids [that includes EPA
(eicosapentaenoic acid), DHA (docosahexaenoic acid), and ALA (alpha-linolenic
acid)] and omega-6 fatty acids are considered essential polyunsaturated fatty
acids (PUFA) because they are required by our body to synthesize prostaglandins
and other physiological regulators. Health benefits of these fatty acids,
especially omega-3, include reducing inflammation as well as lowering the risk
of chronic diseases such as cardiovascular disease (CVD), coronary heart
disease (CHD), cancer, diabetes, high cholesterol, and arthritis. They are also
important for cognitive and behavioral functions. Studies have found low levels
of omega-3 may cause disorders such as attention-deficit hyperkinetic disorder
(ADHD), bipolar disorder, schizophrenia, and depression.
A recent review study published
in the journal
Advances in Nutrition,
summed up the health benefits of omega-3 as 'The omega-3 PUFA EPA and DHA are
important throughout life and are a dietary necessity found predominantly in
fish and fish-oil supplements. The omega-3 fatty acids EPA and DHA are
essential for proper fetal development, and supplementation during pregnancy
has also been linked to decreased immune responses in infants including
decreased incidence of allergies in infants. Omega-3 fatty acid consumption has
been associated with improved cardiovascular function in terms of
anti-inflammatory properties, and reduced major coronary events'.
Along with omega-3, omega-6 fatty
acids help with brain functions. They also look after the bone health, regulate
metabolism, and stimulate hair and skin growth. Linoleic acid (LA), an omega-6,
is amongst the most important essential fatty acids. LA gets converted to
gamma-linoleic acid (GLA) and then to arachidonic acid (AA) in the body. GLA is
thought to actually reduce inflammation. Omega-6 fatty acids, especially GLA,
is useful for health conditions such as ADHD, allergies, high blood pressure,
diabetic neuropathy, rheumatoid arthritis, osteoporosis, menopausal symptoms,
and premenstrual syndrome (PMS).
In short, essential fatty acids such as omega-3 and omega-6 are
indispensable for normal growth and development and they provide health
benefits throughout life. Incidentally, the body cannot make these essential
fatty acids. So, these must come from dietary sources.
Omega-3 fatty acids can be obtained from foods such as soybean oil,
canola oil, olive oil, sunflower oil, walnut, flaxseed, and fish such as trout,
herring and salmon.
Omega-6 can be obtained from vegetable oils such as soybean oil, corn
oil, safflower oil and other oils mentioned above.
Normally, omega-6 is plentiful in
an average diet. Rather, modern diets have more of omega-6 than omega-3 and
this imbalance may promote diseases such as asthma, CVD, autoimmune and
neurodegenerative diseases. According to a US study published in the journal
Biomedicine and Pharmacotherapy, 'human
beings evolved on a diet with a ratio of omega-6 to omega-3 essential fatty
acids (EFA) of approximately 1 (that is, equal proportion) whereas in Western
diets the ratio is 15/1-16.7/1'. The researchers further stated 'A ratio of
2.5/1 reduced rectal cell proliferation in patients with colorectal cancer,
whereas a ratio of 4/1 with the same amount of omega-3 PUFA had no effect. The
lower omega-6/omega-3 ratio in women with breast cancer was associated with
decreased risk. A ratio of 2-3/1 suppressed inflammation in patients with
rheumatoid arthritis, and a ratio of 5/1 had a beneficial effect on patients
with asthma, whereas a ratio of 10/1 had adverse consequences. These studies
indicate that the optimal ratio may vary with the disease under consideration'.
Thus, a lower omega-6 / omega-3 ratio is
more desirable in order to reduce the risk of chronic diseases.
There is another type of
unsaturated fatty acid that is currently a hot topic for discussion -
trans-fats. Natural sources of dietary trans-fats are fatty parts of meat and
dairy products. Artificial trans-fats are found in foods that contain
hydrogenated oil. Artificial trans-fats are found in margarines and vegetable
shortenings, frozen pizzas, baked goods such as cake, cookies, pie, and also in
coffee creamers, fast food, and other processed foods. According to the CDC,
'Consuming trans-fat increases low-density lipoprotein (LDL, or
"bad") cholesterol contributing to the leading cause of death in the
U.S. - coronary heart disease (CHD). Trans-fat may also have other adverse
health effects like decreasing high-density lipoprotein (HDL, or
"good") cholesterol'.
Considering these facts, the FDA
required mandatory trans-fat labeling on all packaged food and a few years
later some states in America have issued a trans-fat ban and a rule requiring
fast food restaurants to post calorie info on menus. More recently,
legislations have been passed banning trans-fats in schools as well.
The American Heart Association's
Nutrition Committee recommends restricting intake of total fat to less than
25-35 percent of total calories required per day, with saturated fat intake to
less than 7 percent and trans-fat intake to less than 1 percent of total daily
calories. The Committee suggests that 'remaining fat should come from sources
of monounsaturated and polyunsaturated fats such as nuts, seeds, fish and
vegetable oils'.
Significant research studies are
still being carried out to know more about the health benefits of fatty acids.
In view of this, we await the results of the advances made in fatty acid and
lipid research.
References:
1. http://www.issfal2012.com/
2. Swanson D, Block R, Mousa SA. Omega-3 fatty acids EPA and
DHA: health benefits throughout life. Adv Nutr. 2012 Jan;3(1):1-7.
http://advances.nutrition.org/content/3/1/1.full?sid=0bd774e3-f734-47a5-b0b4-a091a7df5719
3. http://www.umm.edu/altmed/articles/omega-6-000317.htm
4. http://www.ncbi.nlm.nih.gov/pubmed/12442909
Source-Medindia
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