First of all I'd like to say that I'm not a science student or any kind. But lately I came accross this Prostaglandin F2 alpha (PGF2a) thing.
I read it somewhere it said that elevated level of PGF2a causes Dysmenorrhea ?
Is it true AA [Arachidonic Acid (an omega-6 PUFA)] can be found in linoleic acid (LA)? But isn't AA can be found mainly in animal only (errmm..said wikipedia) and LA is abundant in vege oil like olive, sasame, etc?. So which is which? My home usually cook with red palm oil.
What sort of herbs stimulate or has PGF2a or has AA then (since AA is the precursor of PGF2a, yes/no?)?
Well, for someone who “isn’t a science student”, you are asking a pretty sophisticated and important question.
You can get my book from a library or you might enjoy irritating Barnes and Noble by leisurely reading it in their lounge with a nice latte without committing to buy it. Then just look up the flax seed, evening primrose, and borage seed chapters, and you will see more than you probably ever wanted to know about how these fatty acids like linoleic acid and arachidonic acid get converted to different prostaglandins. But to save you from this, I took some excerpts from my book below, and added more to address your specific question:
I don’t like to tell people what they should and shouldn’t take (there are enough people out there doing that already!) but instead I like to look at the cause and effect molecular mechanisms by which a substance works. Some mechanisms are better for some people than for others.
Also, we can’t judge a substance based on where it is from—any more than we can judge a person based on where they are from—that isn’t helpful or informative. You judge them based on what they do, and how they do it! So regardless of whether it is from “nature” or a lab bench (I argue that people are animals and part of nature anyway so this distinction doesn’t mean much to me) I just look at the mechanism and ask, is this an appropriate mechanism for your individual body? It does seem, however, that I keep finding that it is better for us to get more of our food from plants than from animals. You at least seem to be trying to do this with your red palm oil--that's good!--but you could make some better choices for oils.
But let’s get some terms defined, first.
You wonder if a certain prostaglandin causes menstrual problems, and the short answer is, that particular prostaglandin you mention (PG F2-alpha) might. It is used as a medication to induce labor and causes uterine contractions, or what you might call “cramps” when you make it all by yourself to your dismay. And yes, the sources of that particular prostaglandin are omega-6 fatty acids such as linoleic acid. The most abundant omega-6 fatty acid in our diets is linoleic acid (LA), which our body can convert to arachidonic acid (AA) (another omega-6), and then that under certain circumstances can get converted to this particular prostaglandin (F2-alpha).
So, it isn’t true that “arachidonic acid is found in linoleic acid”—it is true that linoleic acid is readily converted to arachidonic acid in our bodies after our enzymes tack a couple of carbons onto the chain, lengthening it from 18 carbons to 20 carbons. So linoleic acid is a precursor to arachidonic acid. (Both are found in meats to some extent, when the livestock eats plant sources of them.)
Your red palm oil doesn’t have the glut of linoleic acid that other vegetable oils like corn oil, safflower, and sunflower oil have, but it does have about 10% from what I can see. It also has a lot of saturated oils, which are not essential, and these won’t oppose the conversion of linoleic acid into arachidonic acid, which is what you appear to be rightly concerned about.
If you want to oppose the action of linoleic acid metabolically speaking, you would be better off getting more omega-3 fatty acids from your oils. Flax oil, walnut oil, and fish oil (from fish or fish oil capsules) are excellent sources of these.
Although I’m not in the business of telling people what they should and shouldn’t take, there are times when I am compelled to shout out about what might obviously help a lot of people! Lots of nutritionists and health care professionals are concerned that we eat too much linoleic acid, which is an omega-6 fatty acid, and not enough of the omega-3 fatty acids. I used to be skeptical about this, when the topic was raised 20 years ago! But after reading lots of boring scientific research articles on fatty acid metabolism, I’ve been thoroughly won over by this argument, too.
I admit it; it’s really an oversimplification for me to classify all omega-6’s as “bad” and all omega-3’s as “good.” The problem is their ratio in our diets. If you look the assortment of fatty acids in the modern diet, the “rare” essential fatty acids are the omega-3’s, and this has some health experts worried. They argue that our diets once possessed a 1:1 ratio of omega-6 to omega-3 fatty acids that is now skewed in favor of omega-6’s as high as either 10:1 or 20:1, depending on which expert you talk to. Modern society has recently become so adept at harvesting and using certain vegetable oils—corn oil, safflower oil, soybean oil, and sunflower oil—and these are all loaded with the omega-6 fatty acid linoleic acid. This we to feed to our livestock in the form of corn, a source of omega-6 oil, rather than their preferred grass, enabling even our commercial meat supply to be unbalanced with omega-6’s. Grass-fed livestock has more omega-3’s. Omega-3’s are abundant in fish oils and flax seed oil, and present to a lesser extent in other vegetable oils and nut oils.
So what’s wrong with eating linoleic acid? You do need some linoleic acid because you can’t make it. This puts it in the class of “essential” fatty acids. Obviously it’s better to have essential fatty acids than the non-essential ones that we already make, like saturated fatty acids. These are the infamous artery-clogging agents found in animal fats. Possibly even more menacing are the relatively unnatural “trans” fats created by partially hydrogenating oils, that many fast and processed foods are now dripping with, and like saturated fats, these are also tied to health problems. On the one hand, people who have more essential fatty acids than non-essential ones generally fare better, health-wise.
On the other hand, some essential fatty acids are healthier than others. The proportion of linoleic acid in our diet is disproportionate compared to other essential fatty acids. A glut of one type of essential fatty acid drowns out the beneficial actions of the others.
This is where people start talking about those omega-3 fatty acids and omega-6 fatty acids, which we have to get in our diet, because we can’t make them, and so they are called “essential”. These have some obvious fates after we eat them. Either they get “burned” into carbon dioxide for energy, or we will merrily stash them away as fat, regardless of our opinion about that, and they also get readily incorporated into the material making up our cell membranes—the outer boundary of our cells. Indeed, you can see what sort of fatty acids someone has been eating by looking at whether their cell membranes contain omega-3 derived fatty acids or omega-6 fatty acids—you really are what you eat.
The reason the terms 3 and 6 are used is because it matters whether an prostaglandin is made from one or the other. The “3” or the “6” indicates the position of something called a double bond in the fatty acid. The reason we care about that is that that position tends to stay in place as the fatty acid gets chemically changed in our bodies. So, an omega-3 will remain an omega-3 as it is transformed into other fatty acids, and an omega-6 will remain an omega-6 as it is transformed into other fatty acids. Thus the ratio of the kinds that your are eating will be preserved even after they are chemically altered into other fatty acids by your body.
The prostaglandins are part of a larger group of similar molecules collectively called eicosanoids. The “eicos” means 20, as they are all formed from fatty acids that are 20-carbons long.
Keep in mind that both omega-3s and omega-6s compete for the same enzymes to convert them to other more physiologically active molecules. So by eating more omega-3's, you can slow down and reduce the conversion of omega-6's into things like that prostaglandin you are worried about.
Eicosanoids, classified as prostaglandins, thromboxanes, and leukotrienes, work only briefly in tissues nearby where they are generated, and are thus called “local” hormones. Nonetheless they have powerful and often opposing actions on blood pressure, blood clotting, pain and inflammation, allergic and immune responses, uterine and gastrointestinal cramps, digestion, brain development and mood, even tumor development and growth...in other words, just about everything you can think of!
Both classes of essential fatty acids, the omega-3’s and the omega-6’s, are used to make 20 carbon fatty acids, which are transformed to hormone-like eicosanoids. The types of essential fatty acids you have stored influence what types of eicosanoids you tend to make. At the risk of oversimplification, I’ll come to the punch line: the omega-6 fatty acids generally make more pro-inflammatory, damaging eicosanoids. Eicosanoids derived from the omega-3 fatty acids are more anti-inflammatory and protective. Inflammation is just our protective systems gone overboard, so to speak, so the omega-6 system of eicosanoids isn't bad, it just seems that we are overdoing it with with the supply of omega-6 in the modern diet.
Alpha-linolenic acid, or ALA, is the main omega-3 fatty acid in flax seed oil, and you can readitly turn it into at least one valuable fatty acid found in fish oil. ALA gets incorporated into your cell membranes and fat after you eat it, so you store it. Ignoring minor pathways, it has two general fates: it can either be “burned” for energy, or turned into another omega-3 fatty acid. This is typical: omega-3 fatty acids, when metabolized by your enzymes, can only be turned into other fatty acids of the omega-3 class, and omega-6’s can only get turned into other fatty acids of the omega-6 class.
The 18-carbon ALA is lengthened by 2 carbons and 2 more double bonds are added, to make eicosapentaenoic acid, or EPA. This is one of the essential fatty acids in fish oil that everyone is now raving about for its health benefits. If you haven’t heard lately that nutritionist want you to eat more fish oil because of its omega-3 fatty acids, you’ve been living on another planet. If you don’t eat fish, you can make at least one fish fatty acid, EPA, by taking flaxseed oil. Why is EPA so exciting?
Medical professionals are rewriting the textbooks, literally. We are only now becoming aware of how important EPA derived eicosanoids are. In fact, if you look at even relatively recent medical textbooks, they only discuss ones derived from the omega-6 fatty acid, arachidonic acid, and barely mention the ones derived from EPA. Most texts are now being revised to include discussions of their activities, fortunately.
EPA derived eicosanoids perform the following healthy tasks. EPA is used to make the following menu of eicosanoids: prostaglandin E3 (PGE3), prostacyclin I3 (PGI3), thromboxane A3 (TXA3), and leukotriene B5 (LTB5).
Now here is what the omega-3 derived eicosanoids do. Hold on, this is a lot of data:
PGE3 has an anti-inflammatory mode of action similar to that of steroids like hydrocortisone: it prevents the omega-6 eicosanoid precursor arachidonic acid from being liberated from cell membranes, thus halting its conversion into inflammatory omega-6 derived eicosanoids. In addition, PGE3 reduces intraocular pressure, so scientists are now looking at it as a possible glaucoma treatment.
PGI3 is anti-inflammatory by the same mechanism: it prevents arachidonic acid release, plus it potently inhibits blood clot formation.
While the omega-6 arachidonic acid derived thromboxane, TXA2, makes platelets sticky, potently forming blood clots and narrowing blood vessels, the EPA-derived TXA3 is relatively inactive and competes with it.
Similarly, the leukotrienes derived from omega-6 arachidonic acid are countered by the leukotrienes made by EPA. The leukotrienes made from arachidonic acid (such as LTB4) mediate the distressing bronchoconstriction in asthma, as well as chronic asthmatic hypersensitivity and acute asthma attacks. They are also involved in the inflammatory processes seen in disorders like cystic fibrosis, inflammatory bowel disease, and psoriasis. Although the leukotriene B5 derived from EPA also signals the immune system, it does so more weakly by an order of magnitude, and competes with formation of the more inflammatory leukotrienes. Thus it tames the immune system’s response, without shutting it down.
You can’t easily turn flax seed oil’s ALA into the second valuable fatty acid in fish oil, at least not very well. I write this to correct a common misconception still bandied about the nutritional literature. Fish oil’s other valuable omega-3 fatty acid is the 22-carbon long docosahexaenoic acid, or DHA. Although humans have enzymes capable of turning ALA into DHA, human studies repeatedly show that we just don’t do it very well, though some sources (often associated with flax oil sellers) glibly say that you can. This is frustrating, if you realize how important DHA is, and if you don’t eat fish oil!
Recent data suggest maybe this is because excess linoleic acid (the omega-6) opposes this conversion, so maybe you can convert ALA to DHA if you lower your linoleic acid intake enough. So that's potentially good news for the non-fish eaters out there, (and good news for fish) but I am waiting for more data to see that hypothesis can be better supported.
DHA is not used to make eicosanoids (it doesn’t have the prerequisite 20 carbon length chain for that) but it is of startling importance in the brain’s growth, development, and signaling, as well as retinal function. Because of the growing awareness of our requirement for DHA and our limitations in making it, some are now suggesting this fatty acid is essential on its own, because ALA isn’t a very good precursor to it. There are even interesting theories about how pre-hominids required moving from the trees to an environment next to water, to obtain a source of fish. This supposedly helped them to evolve better brains, but I am not an an anthropologist.
I am not sure what to recommend to strict vegetarians because of this, and I do sympathize (I’m a vegetarian, but I joke that I am now a bad one because of these studies I have read—I’m not a strict one, and I take fish oil. And OK, I like to eat fish!) It’s possible you can make some DHA from flax seed oil, but don’t expect to make a lot. The fish oil has omega-3s simply because certain fish eat certain cold water algae, which supply the fatty acids themselves. So maybe we can just grind up some vat grown algae in a blender and mold it into the shape of a fish and not hurt the ocean's ecology. I'll eat it, I'm easy.
I may have gone a bit off topic there, but there is so much to say about these interesting essential fatty acids! Somebody shut me up! So try getting more omega-3 oils from one source or another, and limiting your linoleic acid intake. I hope that helps!