"Killer" fats are what we hear so much about recently, with large numbers of people turning to low fat diets. Little do they know, they are also decreasing their intake of the healing fats that are required for life. Improper low fat diets, useful for atherosclerosis, can kill you over the long term. Children are especially vulnerable to damage from low fat diets. To balance the one-sided view on fats, we must talk about essential fatty acids (EFAs): an adequate supply of healing fats is even more important to health than the avoidance of killer fats.
Like vitamins, EFAs
are essential to health. Older literature, in fact, refers to them as vitamin F. Vitamins and EFAs are essential for the following reasons:
- We must have them to live and to be healthy
- Our bodies cannot make them from other substances
- We must obtain an adequate supply from external sources - from food or from supplements
- Deficiency results in gradual deterioration of cells and tissues, and ultimately, in death
- Increasing the intake to adequate levels reverses the signs brought about by deficiency.
This definition of essentiality reflects the fact that essential nutrients perform key functions in our cells and tissues that the body cannot live without.Special Properties Of EFAs
While EFAs are like vitamins in their essentiality, they differ in other respects. Vitamins are required in very small amounts (a few mg per day) whereas EFAs are macronutrients, necessary in grams per day. EFAs are perishable, deteriorating rapidly when exposed to light, air, heat and metals. Unlike vitamins, EFAs cannot be dried, powdered and stored for several years. EFA
sensitivity makes careful processing and freshness extremely important.Omega-6 And Omega-3 EFAs
Many standard texts on nutrition suggest three EFAs: linoleic, linolenic, and arachidonic acids. This outdated information is wrong. Two fatty acids
are essential to human health. (Fish require only one fatty acid
and plants require neither - they make their own.) The first is the omega-6 EFA, which is called linoleic acid (LA). LA is abundant in polyunsaturated
safflower, sunflower and corn oils. The second, known as the omega-3 EFA, is called alpha-linolenic acid (LNA) and is sometimes referred to as super-unsaturated; it is found abundantly in flax
and hemp seeds.
LA and its derivatives belong to the omega-6 family of polyunsaturates. In addition to linoleic acid (LA), this family includes the down-line metabolites gamma-linoleic acid (GLA
), dihomogamma-linolenic acid (DGLA), and arachidonic acid (AA).
If LA is provided by foods, our cells make GLA, DGLA, and AA. Omega-6 conversion can be inhibited by bad fats (margarines, shortenings, trans-fatty acids, hard fats, sugar and cholesterol
), lack of minerals (magnesium
), vitamin deficiencies (B3
, C, E), viruses, obesity, diabetes
, aging, and rare genetic mutations. In such situations, oil containing omega-6 derivatives can help. GLA is present in evening primrose, borage, and black currant seed. DGLA is found in mother's milk and AA in meats, eggs and dairy products.
LNA and its derivatives belong to an omega-3 family of superunsaturates. Besides LNA, this family includes the down-line metabolites eicosapentanoic acid (EPA), and docosahexanoic acid (DHA
). If LNA is provided by foods, our cells make DHA and EPA. When the conversion of EFAs
to their derivatives is inhibited by the factors listed above, DHA from black currant seed oil, or EPA and DHA from fish oils and northern ocean algae can be given.
A study on elderly Japanese patients demonstrated that blood levels of the omega-3 fatty acids
EPA and DHA increase after prolonged consumption of ALA from a plant-based oil. The change is slow and requires about 10 months of supplementation. However, the result of the study suggests that supplementation with ALA from flax oil
may to some degree have the same beneficial role as supplementation with fish oil. This news may be particularly interesting to people following a vegetarian
diet or for those who do not eat fish products. [Journal of Nutrition Science Viturminol, December 1999
]Properties Of EFAs
The value of LA and LNA to health results from their chemical properties. EFAs react with oxygen: EFA-rich oils such as flax, hemp and safflower were traditionally used in paints because they oxidize, dry and harden quickly when exposed to air. When fresh, these oils are valuable human foods. EFAs absorb sunlight, increasing their ability to react with oxygen by about 1,000-fold and making them very active chemically.
EFA molecules carry slight negative charges that cause them to repel one another. They spread out in all directions. This property enables EFAs to carry oil-soluble toxins from deep within the body to the skin surface for eliminations. EFAs form associations with the sulfhydryl group (cysteine
) in proteins, important in reactions that make possible the one-way movement of electrons and energy on which life depends. EFAs store electric charges that produce bioelectric currents important for muscle, cell membrane and nerve functions, including the transmission of messages.
In nature's package, EFA-rich oils keep for years without spoiling. Once processed and out of that package, light, air and heat attack EFAs
. Like perishable produce, EFA-rich oils should be made with care and obtained fresh. Frying and deep-frying destroy EFAs by the combined effects of light, oxygen and heat, producing toxic substances that can lead to atherosclerosis
EFA-rich oils should be made and packaged in the absence of light, oxygen and heat. Frozen solid, oils remain unspoiled for a long time because freezing does not damage them. Manufacturers should ship them directly to retailers or consumers without stops along the way.
Function; Why it is RecommendedEFAs
play their essential roles by:
- Helping to form the membrane barrier that surrounds our cells and intracellular factories (organelles)
- Determining fluidity and chemical reactivity of membranes
- Increasing oxidation rate, metabolic rate, and energy levels
- Serving as starting material for hormone-like regulating molecules (prostaglandins) that govern cell activities on a moment-to-moment basis
As structural components of membranes, EFAs
help form a barrier that keeps foreign molecules, viruses, yeasts, fungi and bacteria
outside of cells, and keeps the cells' proteins, enzymes, genetic material and organelles (small organs) inside. They also help regulate the traffic of substances in and out of our cells via protein channels, pumps and other mechanisms.
They perform similar functions in membranes that surround organelles within our cells. EFAs
fulfill many functions:
- Regulate oxygen use, electron transport, and energy production - our cells' most important moment-to-moment processes
- Help form red blood pigment (hemoglobin) from simpler substances
- Keep juice-producing (exocrine) and hormone-producing (endocrine) glands active
- Help make joint lubricants
- Are precursors of prostaglandins (PGs), three families of short-lived, hormone-like substances that regulate blood pressure, platelet stickiness and kidney function. A delicate balance between PGs with opposing functions, in part determined by omega-6 and omega-3 intake, determines the health of our cardiovascular system.
- Help transport cholesterol
- Help generate the electrical currents that make our heart beat in an orderly sequence
- Are precursors of derivatives such as DHA, which are needed by the most active tissues - brain, retina, adrenal glands and testes
- Help our immune system fight infections by enhancing peroxide production
- Help prevent the development of allergies.
EFAs play a role in every life process in our body and life without them is impossible. When consuming an EFA-poor diet, expect a diversity of health problems.
Of approximately fifty known essential nutrients, LA has the highest daily requirement. The amount needed varies with season, latitude, levels of activity and stress, nutritional state, and individual differences. Just 1-2% of calories (1 teaspoon per day) prevent signs of deficiency in most healthy adults. LA optimums are around 3-6% of calories (1 tablespoon
per day), requiring about 30 IU of vitamin E
to help prevent rancidity. Obese people and those eating hard fats, sugar and trans-fatty acids require more.
Nutrients essential for LA functions include magnesium
, and vitamins A, carotene
, C and E.
An adult carries about 10 kilograms of body fat, of which approximately 1 kilogram is LA. Vegetarians' bodies carry up to 25% of their body fat as LA. People with degenerative disease average only about 8% of their body fat as LA.
Alpha-linolenic acid (LNA) optimums range between 1-2 tsp per day, averaging 2% of daily calories. Body content in healthy people is around 2% of fat, or half a pound of LNA. LNA requires the same antioxidants
, minerals and vitamins necessary for LA functions.Omega-6 To Omega-3 Ratio
Omega-6 to omega-3 ratios in healthy populations range from 1:2.5 (Inuit diets) to 6:1 (other traditional diets). Since 1850, omega-3 consumption has decreased to one-sixth its traditional level, resulting in an omega-6 to omega-3 ratio of 20:1 (contemporary polyunsaturated oil diets), which is associated with degenerative conditions.
Long-term exclusion of omega-6 oils and excessive use of flax oil
can result in a reverse imbalance of the one commonly seen, i.e. too much omega-3. They should remain in balance. If a person has cancer, inflammatory
conditions, or needs to lose weight, omega-3 should be favored. Otherwise, an omega-6 to omega-3 ratio of between 2:1 and 3:1 is suitable.RequirementsFlax
, our richest source of omega-3, quickly replenishes a long-standing omega-3 deficiency. 1-2 tbsp
per day of good quality flax oil for a few months should suffice. Cold-water fish (salmon, sardines, mackerel, herring) are a good source of the metabolites EPA and DHA
. There is now an algae-derived oil (click here
for details) that has both DHA and EPA, suitable for vegans
. Fish obtain their DHA and EPA ultimately from the consumption of algae.Hemp seed oil
has a remarkable fatty acid
profile, being high in the desirable omega-3s and also delivering some GLA
, which is absent from the fats we normally eat. Hemp oil contains 57% linoleic and 19% linolenic acids, in the 3:1 ratio that matches our nutritional needs. Once difficult to find, many health food stores now routinely make hemp seed oil available as the demand for it has increased.
Mary Enig, PhD is a respected researcher in the field of fats and oils, especially the hydrogenated, partially-hydrogenated and trans fats. The latest findings appear to implicate all seed oils in the promotion of cancer, heart disease, diabetes
, obesity, allergies, adrenal
failure and stroke
. The list of implicated oils includes canola, soy, corn, safflower, sunflower and all hydrogenated and partially-hydrogenated fats and oils. If this turns out to be true, then limiting the intake of the omega-6 EFAs
becomes increasingly important.
of flax seed
has about 7.5gm of the short chain omega-3 which would be converted by the body to about 750mg of the long chained EPA and DHA
. A tablespoon of hemp oil has about 2.5gm ALA (or 250mg of EPA and DHA). A tablespoon of fish oil, on the other hand, has about 12,000mg of EPA and DHA. Since the informal NIH recommendations are for 660mg of the long chained omega-3s, the recommended daily intake would be the equivalent of about:
1 tablespoon of flax
== 3 tablespoons
of flax seed
== 3 tablespoons of hemp oil == 4 tablespoons of canola oil == 1/4 teaspoon of fish oil.