Advancements in Nutrition and Nutritional Therapy
The omega series (primarily omegas 3, 6, and 9) fatty acids have been intensively studied and recognized for their primary and secondary roles in many biochemical reactions and health parameters. Depending on the specific form and the animal in question, the omega series fatty acids are often considered essential as the body must obtain either their precursor or final form from the diet.
For example, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), also known as the “fish oils,” are considered truly essential to domestic cats who cannot convert these fatty acids from the plant-based precursor α-linolenic acid (ALA). As a general rule the more herbivorous the animal the better its conversion from ALA to DHA and/or EPA. The converse is true of carnivorous animals who are generally poor converters.
Omega-6 series fatty acids (linoleic acid [LA] is the principle physiologic form and comes primarily from plant-based sources and plant-eating animal tissue) often have opposing functions to omega-3 series fats. Omega 9 series fatty acids (including oleic acid and erucic acid) commonly come from plant oils and animal fat. Omega 9 fatty acids are often not considered essential because many animals can construct these fats from unsaturated fat. Studies on omega-3 and omega-6 fatty acid supplementation are extensive in mammals.
Additionally, there are numerous studies on both fatty acid types in birds, primarily in poultry species. The value and role(s) of omega 9 fatty acids in birds have yet to be clearly defined.
Omega series fatty acids are most often listed by their form (e.g., ALA, DHA, LA) and in milligram amounts. Serving size and/or dose recommendations are often included. These fatty acids may be packaged in gel capsules (preferred form for stability reasons), gel sticks, dry powder, pump and pour-on bottles, and more. DHA and EPA are highly unstable and currently best kept in gel capsules. All fatty acid supplements should be stored in dark cool locations and in tightly sealed bottles or capsules to slow oxidation.
With some exceptions, most studies on fatty acid quality pertain to contaminants. In particular, persistent organic pollutants (POPs) are of greatest concern as these toxic compounds bioaccumulate and biomagnify in animal tissues, particularly marine species. While plants can also contain POPs, these organic compounds are typically deposited on the leafy portions of the plants and are not bioaccumulative and do not magnify as is common with predator species.
POP exposure is associated with a host of problems including endocrine disruptions; cancer; and neurobehavioral, reproductive, and developmental disturbances in humans and animals. Contamination with polychlorinated biphenyls, organochlorinated pesticides, polybrominated diphenyl ethers, pristine, squalene, unresolved complex mixtures, aryl hydrocarbon receptor agonist (digoxin-like), polychlorinated dibenzo-p-dioxins/furans was noted in a number of studies of fish oils and omega 3 fatty acid supplements. In 2004 ConsumerLab, an independent reviewer of nutraceuticals, reported that 6 of 20 omega-3 fatty acid products did not contain the label-stated amount of one or more essential fatty acids.
The website stated “two of the products that failed made claims on their labels that their ‘potency’ had been ‘tested’ or ‘verified’.” In a 2014 revised review of 30 omega-3 fatty acid supplements, ConsumerLab reported that five products failed to meet basic quality testing.