The Main Omega-3
Fat, of course, gets a bad rap. The
harmful propensities of several types of fat are now well known.
Considerable confusion has existed, however, since the 1970's, when
essential fatty acids from fish oil were found to be beneficial.
Indeed, we can thank Greenland Eskimos for the discovery, because it
was their high fat diet from cold water fish that made their very low
rate of coronary artery disease noteworthy.
Two members of the Omega-3 family of
fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid
(EPA), are particularly noted for their cardio-protective properties
and positive impact on certain unwanted immune actions and by-products.
DHA, in particular, plays a key role in the proper formation,
development, and functioning of the brain, retina and central nervous
system.
DHA and Brain/Central Nervous System Function
DHA is selectively incorporated into
the nerves, retina and gray matter of the brain, that is, tissues
responsible for nerve transmission. In fact, DHA makes up 60% of the
lipids in the brain and nerve tissue.
The
prevalence of DHA in brain cell membranes results in the powerful
impact on the fluidity and function of the cell walls. According to Dr.
Paris Kidd, "membranes are the major 'work' surfaces of all known
cells, and nerve cells especially carry out their specialized
functions."
The
benefits of a compound such as DHA may be a result of its capacity to
regulate proteins found in cell membranes. Some researchers have
suggested that mental abnormalities which increase in prevalence as we
age could be related to a life-long deficiency of essential fatty
acids, in particular DHA.
DHA and EPA for Cardiovascular Health
Beginning in the 1970's, researchers
studying the diet of Greenland Eskimos noted two things. First, their
diet, much like that of all Americans, contains a high percentage of
fats. This observation seemed paradoxical in that their incidence of
coronary ailments is surprisingly low. Their difference was that their
diet included lots of fish, the oils of which contain DHA and EPA.
Subsequent studies have demonstrated
that DHA and EPA decrease triglycerides and increase HDL (high density
lipoprotein, the "good" cholesterol) levels. EPA, in particular,
appears to decrease blood clotting and stabilize heart rhythm. Various
other studies suggest that DHA may positively influence blood pressure.
DHA and EPA for Heart & Tissue Protection
DHA and EPA work synergistically to
reduce immune damage to tissues, yet each exerts its influence in
different ways. EPA promotes the production of beneficial eicosanoids
(hormone-like substances), which counteract the production of excessive
arachidonic acid. DHA, on the other hand, takes action during the early
physiological phase of the process in which free radicals damage
tissues. Results are significant - the FDA allows that "supportive but
not conclusive research shows that consumption of EPA and DHA omega-3
fatty acids may reduce the risk of coronary artery disease."
DHA and EPA for Pregnancy/Lactation
As a major structural component of the
brain and central nervous system, DHA is essential for proper
development of the growing fetus and infant. Consequently, sufficient
intake of DHA and EPA during pregnancy is vitally important, especially
during the last trimester when brain and eye development are at their
highest.
Some research
suggests that material stores of DHA should be maintained as early as
three months prior to conception to ensure an adequate supply for the
fetus. Conversely, maternal diets containing trans-fatty acids
negatively affect the amount of DHA available to the growing fetus.
DHA
is naturally found in mother's milk. Scientists believe this to be the
primary reason why breast-fed children tend to have higher IQ scores
and better visual acuity than formula-fed children. Research has shown
that increased maternal intake of DHA lead to higher breast milk DHA
concentrations. Source: Jarrow Formulas
View our Selection of Products
Scientific References Kristensen, S.D., Schmidt, E.B. et al. Omega-3 Fatty Acids: Prevention and Treatment in Vascular Disease (Bi and Gi Publishers) Chapter 20.
Harris, W.S. (1999). Non-pharmacologic treatment of hyper triglyceridemia focus on fish oils. Clin Cardiol 22 (6): II-40-3.
Gerster, H. (1998). Can adults adequately convert alpha-linoleic acid to eicosapentaenoic acid and docosahexaenoic acid? Int J Vitam Nutr Res 68 (3): 159-173.
Burgess, J.R. (2000). Long chain polyunsaturated fatty acids in children with attention deficit hyperactivity disorder. Am J Clin Nutr 71: 327S-330S.
Decsi T et al.
Inverse association between trans isomeric and long-chain
polyunsaturated fatty acids in cord blood lipids of full-term infants. Am J Clin Nutr. 2001 Sep;74(3):364-8.
Litman BJ, Niu SL,
Polozova A, Mitchell DC. The role of docosahexaenoic acid containing
phospholipids in modulating G protein-coupled signaling pathways:
visual transduction. J Mol Neurosci. 2001 Apr-Jun;16(2-3):237-42.
Chung BH et al.
Effects of docosahexaenoic acid and eicosapentaenoic acid on
androgen-mediated cell growth and gene expression in LNCaP prostate
cancer cells. Carcinogenesis. 2001 Aug:22(8):1201-6.
Ringborn T et al. Cox-2 inhibitory effects of naturally occurring and modified fatty acids. J Nat Prod. 2001 Jun;64(6): 745-9.
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