In this section we discuss the Essential Fatty Acids (EFAs) including: What are the EFAs? They’re fats, of course -- but they’re different from other fats. Why does your body need EFAs even while dieting?
Many fat people are probably quite deficient in the EFAs. What are the known deficiency symptoms? How could you tell? For example, skin problems and nerve problems are likely to occur in people who are deficient in one or the other of the EFAs.
Most importantly, in this section,we discuss how dieters make sure they get enough of the EFAs in their diets without also getting a lot of Calories In other words, what foods can provide the EFAs, but won't also provide lots of Calories from other fats.
A lack of the essential fatty acids (EFAs) in your diet can make weight gain easy and weight loss nearly impossible.
The body's need for EFAs (essential fatty acids) is well-known to scientists but nearly unknown to most ordinary people. (And even scientists weren't sure about one of the EFAs until about 10 years ago.)
There are two EFAs. Chemically, they are fats -- and they are both vital nutrients. Just like vitamins, your body must have them to maintain its health, but cannot make them for itself. Therefore, you must get them from the food you eat. (Note: People who chronically suffer from dry, flaking, or thin skin, or need to use skin lotions of various sorts most of the time, should suspect an EFA deficiency.)
When your body begins to run low on one of the EFAs it often triggers hunger, cravings, aches, pains, low energy levels, or some other unpleasant symptom to try to stimulate you to eat, because eating is the only possible way you can get it more of the EFAs it needs. Of course, hunger makes you eat too much food with too many Calories when you're not dieting -- and it makes weight-loss nearly impossible when you are dieting.
EFAs are found in fats. But they are found only in some fats.
This means that "fat" is really a "dual-use" nutrient. Most fats provide nothing but those concentrated Calories that you definitely don't need. Other fats provide the EFAs that are vital to being able to stay on your diet.
In the modern world, you can eat fat all day long
and still never get near an essential fatty acid..
As I’m sure you know by now, the main premise of The diet is that if your body doesn’t get the nutritional things it needs to keep you healthy—including the essential fatty acids (EFAs)—it has various ways to “stimulate” you to eat to try to get them. This destroys your diet. (“So-o-o, you don’t vant to eat, ehhh…? Ve haf vays of ma-a-aking you!”)
However, as dieters, we’re not really very interested in the details of how our body makes us eat and destroys our diets. We prefer to simply make sure it gets all the things it needs, including EFAs, so that it won't have any reason to pull any of its tricks. This is what understanding the diet’s Essential Oil and other Vital Factors let us do.
The fatty acids in fats and oils have two physiological functions:
All fatty acids can be burned for energy. But only a few can function as building blocks. Of those that do function this way, your body can manufacture all but two—ALA (alpha linolenic acid) and LA (linoleic acid). These two must come from food—which is why they are called “essential” fatty acids (EFAs). (It is fortunate that there are only two EFAs since this means that while dieting we only have to manage these two—rather than twenty or so.)
You already know you have plenty of the “burnable” kind of fatty acid—because you can go look at all of them in the mirror any time you want. But despite this plentiful sufficiency, it is quite possible that you are still almost starving for the other kind—the EFAs. If you are, you can be sure that hunger is wide-awake using all of its sneakiest tricks to make you eat too much and (it hopes) get it some EFAs in the process.
In this chapter we first focus on the structural function of fatty acids and then (more importantly) on how to make sure we get the right fatty acids in the right amounts to keep hunger happy. (For a discussion of the energy-related functions of fat please see More On… Energy Metabolism & Storage.)
As I’ve mentioned, there are two known EFAs—alpha linolenic acid (ALA) and linoleic acid (LA). In theory, if you have enough of these two, your body can make all the other fatty acids it needs for structural purposes. Both ALA and LA are poly-unsaturated fatty acids (PUFAs).
ALA is a member of the “Omega-3” class of fatty acids and your body can make other needed members of this class from ALA (if it has enough ALA from your diet to work with). LA is a member of the “Omega-6” class of fatty acids and your body makes the other Omega-6 fatty acids it needs from LA (if it has enough LA to work with). Various fatty acids of each of these two classes are essential to life and health and the members of the two classes cannot be converted into one another by human metabolism.
Various substances derived from fatty acids in each of these two classes constitute a significant part of practically all cell membranes. The functioning of the cell itself is strongly influenced by how much of each of them is in the cell membrane. These effects include changes in the sensitivity to insulin—which itself strongly affects both energy and fat metabolism. (For more information on this relationship and its connection to dieting see More On… Energy Metabolism & Storage and More On… Carbohydrate.)
To a very great degree, the amount of each fatty acid in the cell membrane depends on how much ALA or LA you eat in your food. This means that if you eat a great deal more LA than ALA (as usually happens in “ordinary life”), most cell membranes will contain much more of the Omega-6 class of substances than the Omega-3 class—and this in turn will influence how the cell functions.
Therefore, maintaining an appropriate balance in the diet between these two families of poly-unsaturated fatty acids is important. The standard recommendation to simply eat poly-unsaturated oils and stay away from saturated fat is not exactly wrong, but it is much too simplistic to be useful to dieters trying to control hunger.
In “normal life” you are therefore likely to be more deficient in the Omega-3 family of fatty acids than in the Omega-6 family because they are less widely distributed in food. This is the reason nutrition scientists often recommend eating fish regularly. Many types of fish contain a lot of the two main Omega-3 fatty acids that your body normally makes from ALA. These are EPA and DHA.
When your body gets these directly from food, it does not need as much ALA as it would otherwise. In the same way, some foods have large amounts of ARA, the main Omega-6 fatty acid, normally made from LA. Your body can also absorb this fatty acid directly from food and therefore require less LA than it would otherwise.
Most of the body’s known needs for Omega-3 and Omega-6 fatty acids are really for these derivative forms (EPA, DHA, and ARA) rather than directly for ALA or LA. And of course each of these derivatives in turn is used to make many other things.
In 1989, at the last revision of the U.S. official scientific RDIs (the RDAs), the Food and Nutrition Board of the National Research Council declined to set RDAs for LA or ALA. However, in 1990, the Canadian Ministry of National Health and Welfare, perhaps reflecting an additional year’s worth of data and thought, released the report of its Scientific Review Committee which did state the Recommended Nutrient Intakes (RNIs) of EFAs for Canadians. The report stated that the RNI for LA was between 7 and 11 grams per day and the RNI for ALA was between 1.1 and 1.8 grams per day for adults. (You can round this up to two grams for convenience). Therefore, we dieters now have some official EFA recommendations to use.
The EFA amounts we find in the Canadian RNIs agree with the normal practice of at least one group of medical nutrition specialists. Enteral nutrition specialists point out that 2-5 teaspoons of safflower oil taken orally will prevent EFA deficiency. This amount of safflower oil will provide about the same range of LA intake as the Canadian RNI recommendation.
|
Table 18: EFA RDIs RDIs for EFAs |
||||
|---|---|---|---|---|
| Fatty Acid | Source | Amount | Calories | RDI |
| Linoleic Acid (LA) | 1 Tblsp (14 g) Safflower Oil |
10 grams |
120 | 7-11 grams |
| Alpha Linolenic Acid (ALA) | 1 Tsp (4.6 g) Flaxseed Oil |
2.3 grams |
40 | 1.1-1.8 grams |
|
RDIs are Canadian Recommended Nutrient Intakes (RNI) |
||||
|
Table 19: EFA Sources (Oils) |
||||
|---|---|---|---|---|
|
Type of Oil |
Fatty Acid Type - Grams per TABLESPOON (14g) |
|||
| LA (C18:2w6) |
ALA (C22:3w3) |
ARA (C20:4w6) |
DHA (C22:6w3 |
|
| Safflower Oil | 10.0 | 0.1 | 0.0 | 0.0 |
| Flaxseed Oil | 2.2 | 7.1 | 0.0 | 0.0 |
| Canola Oil | 2.8 | 1.3 | 0.0 | 0.0 |
| Soybean Oil | 6.9 | 0.9 | 0.0 | 0.0 |
| Walnut Oil | 7.2 | 1.4 | 0.0 | 0.0 |
| Sunflower Oil | 8.9 | 0.0 | 0.0 | 0.0 |
| Corn Oil | 7.9 | 0.1 | 0.0 | 0.0 |
| Cottonseed Oil | 7.1 | 0.0 | 0.0 | 0.0 |
| Sesame Oil | 5.6 | 0.0 | 0.0 | 0.0 |
| Peanut Oil | 4.3 | 0.0 | 0.0 | 0.0 |
| Almond Oil | 2.4 | 0.0 | 0.0 | 0.0 |
| Olive Oil | 1.1 | 0.1 | 0.0 | 0.0 |
| Cod-liver Oil | 3.1 | 0.127 | 0.127 | 1.5 |
| Salmon Oil | 0.2 | 0.1 | 0.1 | 2.5 |
| Herring Oil | 0.2 | 0.1 | 0.0 | 0.6 |
|
Note that oils contain other fatty acids besides those
listed here. |
||||
As I pointed out in my rant in Part One, there is a serious tendency for people to try to eliminate fat altogether when they diet. But this is also a serious mistake! You need your EFAs to remain healthy and hunger will make your diet a miserable and possibly dangerous experience without them.
So if you are one of those people who wish to ignore my wondrous words of wisdom and do entirely without “demon-fat”, first please go and re-read my rant about this.
Then if you are still determined to do this unwise thing, read the sections below concerning the known EFA clinical deficiency symptoms so that you’ll at least have a chance to recognize the deficiency when it happens to you. (But keep in mind that these clinical deficiency symptoms are only the most obvious signs of poor health.)
The most noticeable symptoms of a deficiency of either LA or ALA are various skin problems. (These may not show up for weeks if you happen to have large reserves of the EFAs.) There may also be other symptoms. Perhaps you may already have some of them.
Alpha linolenic acid (ALA) deficiency symptoms are very subtle and easier to miss than those of LA (even professionals miss them). This is most likely the reason why they were not scientifically recognized in humans until fairly recently. However, ALA deficiency can be confirmed by blood tests that measure the amount of Omega-3 fatty acids in circulation.
Clinically recognizable ALA deficiency symptoms usually take the form of "scaly skin (much like dandruff) together with skin atrophy" (very thin skin). Other symptoms can be scaly dermatitis and/or small rips or abrasions (excoriations) in the skin. In one case, a "thickened, crusty, and scaly skin" was reported.
These symptoms can probably occur anywhere on the body, but have been reported particularly on hands, forearms, shoulders, and face. (In my own case, the skin on the backs of my hands becomes dry and rough. This clears up in less than two days when I take the recommended amounts of the EFAs.)
Because linoleic acid (LA) is necessary for so many biochemical functions, the list of possible deficiency symptoms is quite long. In humans, drying and flaking of the skin are the most obvious short-term symptoms.
Classic symptoms are skin problems; reduced growth rate; increased loss of water due to a change in skin permeability; male and female infertility; kidney damage; and eventual death. Other symptoms are usually sub-clinical and must be determined by laboratory tests.
Until recently, the development of human EFA deficiency was considered extremely rare. However, more recently, with the development of sensitive lab tests for such indices as the triene/tetraene ratio, EFA deficiency has been documented in many groups, particularly the elderly, hospitalized, and/or physically stressed individuals. It may well (now) also be more common in the general population. As scientists say, “more investigation is required”.
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