The essential fatty acids (EFAs)

Fatty acids are simply components of fats.  There are TWO essential fatty acids.  Essential means you NEED to get them from the diet because the body cannot manufacture them.

• The first is alpha-linolenic acid (LNA or ALA), and it belongs to the omega-3 family of fatty acids.  You can find ALA in flax (abundantly), and in small quantities in walnuts, cold pressed canola oil, wheat germ (the part taken out when making white flour), and dark green leafy vegetables (in tiny amounts).  By by far the best food source of ALA is flax seed and flax oil.

  These foods are not especially popular in the typical American diet, so it is no wonder that about 95-99% of the US population is deficient in the essential fat ALA.  This deficiency plays a role in practically all degenerative diseases like heart disease and cancer, arthritis, skin conditions, diabetic neuropathy, immune function, and premenstrual syndrome.
   

• Linoleic acid (LA) is the other essential fatty acid, belonging to the omega-6 family of fatty acids.  It is found abundantly in soy oil, sunflower seeds, safflower seeds, pumpkin seeds, sesame seeds, tahini, corn oil, and in most nuts.  The typical American diet contains too much LA in comparison to ALA because people consume so much refined vegetable oils made of the abovementioned foods.  They not only cook with these oils, but also eat margarine, crackers, cookies, and other processed foods which contain those oils.

  The right ratio of linoleic acid versus alpha-linolenic acid in the diet is important.  It should be around 3:1 or 2:1, meaning two-three times as much LA as ALA.  Typically in the American diet this ratio is more like 20:1.  Some researchers believe an imbalance may lead to a variety of mental disorders, including hyperactivity, depression, brain allergies, and schizophrenia.
   

• DHA and EPA (see below), while technically non-essential, are essential fatty acids for many of us, because while our bodies should be able to make these from ALA, it has been proven that in many people this conversion process does not happen efficiently. So it apperas that for most people, DHA and EPA become essential fats that we need to get from diet.

Non-essential omega-3 and omega-6 fats

There exist also other (non-essential) omega-3 and omega-6 fatty acids, which your body can (in perfect conditions) manufacture from the two essential ones.

• Non-essential omega-3 fatty acids include DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid). The body can convert ALA to EPA, and then EPA to DHA; however this conversion does not always seem to happen efficiently and then these oils would need to be obtained from diet. Infants and children need DHA for proper brain growth from their diet (and breast milk can have a lot of it!).
   
• Non-essential omega-6 fatty acids include AA (arachidonic acid) and GLA (gamma-linolenic acid) which your body makes from LA (the omega-6 essential fatty acid).

Converting ALA to EPA and DHA

Based on recent research, the conversion from ALA to EPA and then to DHA is often found insufficient in humans. That can happen (obviously) if you don't get enough of the raw material ALA, or if you don't get enough of vitamins C, B6, B3, or enough zinc and magnesium, which all are needed in the conversion from ALA to DHA and EPA.  Also, if the diet contains too much omega-6 fats in comparison to ALA (as is usually the case in western diets), then the conversion is slowed down. Another factor is too elevated insulin levels.

There are probably other factors, as well, that impede this conversion process. However, in general us mammals are equipped to convert ALA to EPA and DHA, because DHA is needed in our eyes and brains, and vegetarian animals such as horses and cows ARE able to fare quite well with their diets.

But given the western diet, stressful lifestyle, and pollutants in the environment, for most of us it is prudent to eat not only flax or flax oil, but also sources of DHA and EPA as well - which means oily cold-water FISH, like salmon, trout, sardines, herring (and mackerel if it didn't have too much mercury in it).

Does a woman need more EFA's during pregnancy/breastfeeding?

Yes.  The brain is over 60% fat and very rich in both omega-3 and omega-6 EFA derivatives so the baby needs essential fatty acids (EFAs) for brain development and brain function.  These are drawn from the mother's body during pregnancy and breastfeeding.

So during pregnancy and breastfeeding the mother gets depleted of essential fatty acids, especially the omega-3 fatty acids.  Each child gets less EFAs than the previous child, depleting the mother even further, UNLESS the mother augments her diet with EFAs, like flax oil and oily fish.

This depletion of the mother's EFA stores for baby's brain building can explain why younger children have more developmental and behavioral problems than older children, especially if the chilren are born close together.  It also can explain why women experience far more depression, fibromyalgia, and chronic fatigue, and more inflammatory, autoimmune, and collagen diseases than men.

Sources

Dr. David William's Alternatives Newsletter September 1999 issue

Udo Erasmus: Fats That Heal, Fats That Kill

FAQ of Essential fats, oil processing, good fats, trans fats, etc. from Udoerasmus.com

Humans Turn ALA to EPA/DHA (Fish Oil) - by Udo Erasmus

The Human Brain - Essential fatty acids

Fats for Health.com - Your source for Essential Fatty Acid Information and News.