Essential Fatty Acids
With the increasing refinement of oils, reliance on fast foods, and consumption of low-fat foods and saturated and hydrogenated oils over the past several decades, the Western diet is abysmally deficient in essential fatty acids (EFAs). Due either to a lack of EFAs in the diet or because of poor absorption, actual deficiency states are common, manifesting in a number of ways. Deficiencies of EFAs can result in fatigue, dry skin and hair, a decrease in fertility, dry eyes and mucus membranes, and poor childhood cognitive development, as well as adverse impacts on immune health, mental health, cardiovascular health, joint health, cognitive health, and the body's normal inflammatory response.*
What are Essential Fatty Acids?
Essential fatty acids are referred to as essential because they can't be made in the body; instead, they must be obtained from foods or dietary supplements. There are two primary essential fatty acids: linoleic acid from the omega-6 family of fatty acids and alpha-linolenic acid from the omega-3 family. Whether a fatty acid is designated as an omega-6 or an omega-3 depends on its chemical structure. Molecules of omega-6 fatty acids have a double bond at the sixth carbon atom, while omega-3 fatty acids have a double bond at the third carbon atom.
Dietary sources of the omega-6 fatty acid linoleic acid include most vegetable and seed oils; with safflower, sunflower, and corn oils being particularly good sources. Linoleic acid is then converted in the body to gamma-linolenic acid (GLA).
Dietary sources of the essential omega-3 fatty acid alpha-linolenic acid (ALA) also include the vegetable and seed oils; in particular, flax, chia, and hemp. ALA is then converted by the body into the important omega-3 fatty acids normally found in fish &ndash EPA and DHA.
The body's conversion of linoleic acid and alpha-linolenic acid is not always easy to achieve, however. Circumstances arising from diabetes, insulin resistance, and consumption of trans-fats and alcohol can impede this conversion. Vitamins B3, B6, and C and the minerals magnesium and zinc are necessary to convert these EFAs into their important downstream forms.* Therefore, consuming already-formed GLA or EPA/DHA may be the best option.* GLA can be found in high concentrations in the seed oils of borage, black currant, and evening primrose. Higher levels of EPA/DHA can be achieved from eating cold-water fish or taking EPA/DHA supplements that have been extracted from cold-water fish, krill (a small shrimp-like crustacean), or algae (DHA in particular).*
Food sources of EPA/DHA include salmon, mackerel, sardines, hoki, anchovies, tuna, pollock, flatfish, shrimp, and crab. While eating these types of fish does provide some health benefits, their consumption does not come without risk, because it is known that these fish can also contain trace amounts of PCBs and the heavy metals, mercury, cadmium, arsenic, and lead.
Because of concerns over environmental contamination in fish, many individuals choose to get their omega-3 fatty acids via fish-oil supplements. Reputable companies use only purified fish oils that have been molecularly distilled to remove PCBs and heavy metals.
Why Are Essential Fatty Acids Important?
- EFAs support good cardiovascular health*
- EFAs promote circulation*
- EFAs help maintain healthy cholesterol and triglyceride levels*
- EFAs support joint mobility*
- EFAs promote cognitive health and support memory*
- EFAs support normal cognitive development in children*
- EFAs support healthy neurological function*
- EFAs help maintain healthy kidneys*
- EFAs support the body's normal inflammatory response*
As can be seen from the above list, most systems in the body can benefit from EFAs in the diet and from supplementation.* This is particularly true for the cardiovascular system, the kidneys, the intestinal tract, the brain, the neurological system, and the skin and bones.*
Health Benefits of Fish Oil
Interest in the health benefits of cold-water fish oil has greatly increased since a landmark study twenty years ago found native Greenlanders had lower rates of heart disease despite consumption of high amounts of fatty fish. Unfortunately, the typical U.S. diet is almost devoid of omega-3 fatty acids from fish.
According to a recent ABC News report, some cardiologists believe it is now time for omega-3 fatty acids to join other nutrients for which the U.S. Government has established a recommended daily intake. A paper published in the Journal of the American College of Cardiology
suggests a daily intake of 500 mg of EPA/DHA in order to meet nutrient needs, with a recommendation of 800-1,000 mg daily for individuals with known cardiovascular health concerns.
Fish oil has been found, in both epidemiological and clinical studies, to support the heart and blood vessels by helping to maintain already normal levels of cholesterol and triglycerides and by supporting the body's normal inflammatory response.* Fish oil also helps maintain healthy nerves, skin, and kidneys, and already normal blood sugar levels.* In studies of various populations, individuals who eat more fish have a higher incidence of good mental health, and studies using fish oil show improved mood.*
DHA, found in fish and some algae, is a downstream metabolite of EPA. Because there is some interconversion between DHA and EPA, if there is a deficit of one it can be made up when the other is present. DHA is essential for normal brain and retinal function.*
DHA: For Infants and the Elderly
DHA's benefit for normal cognitive development in infants and children is well understood.* Rapid growth of the human brain occurs during the latter part of pregnancy and the first few months after birth, and infants rely on maternal intake of DHA for normal brain development.* Human trials demonstrate that DHA supplementation during pregnancy and lactation promotes the normal development of mental processing and intelligence in young children.* Infant studies suggest DHA intake is vital for brain development.*
Concurrent with normal aging, DHA levels in the brain and blood can diminish, and overly-decreased levels have been associated with a decline in brain functions such as learning and memory.* Research suggests DHA repletion in the elderly may be beneficial because it has the potential to promote nerve signaling, possibly translating to improved brain function.* DHA can cross the blood-brain barrier, protecting cell membranes from toxin-induced oxidative damage, particularly from pesticides.*
What About GLA?
GLA from borage oil, black currant oil, and evening primrose oil can help maintain the body's normal inflammatory response.* GLA also helps offset the adverse effects of another omega-6 fatty acid called arachidonic acid,* a fatty acid found in meat, poultry, and dairy products. GLA and its metabolic successor DGLA compete with arachidonic acid and help prevent its negative effects on the body.* Because both GLA in the omega-6 pathway and EPA/DHA in the omega-3 pathway are converted in the body to chemicals called prostaglandins that have several health benefits,* there is significant overlap between the effects of GLA and fish oils.