I do not recall the details now but I do recall that many alternative health practitioners, and some biochemists, were saying that while borage oil has a high omega-6 GLA content than alternatives, there were other chemicals that caused problems in mamy patients and so they prefered evening primrose oil.
I was aware of this theory about omega-6s in CFS back in 1989 when I first tried them. in 1993 I found a CFS doctor who was an expert on this - the world leader on this in his day - whose practice was only five minutes walk from my flat. (Dr. Andriya Martinovic; his paper with Grey is on PubMed, the other papers, published or unpublished are not found using PubMed.) Some of the original research on the desaturase enzymes, which brought much of this to light, was Australian from 1984.
How our bodies respond to omega-6 fats could be a subject for a decades long study by a very large institute with a lot of funding, but they probably still wouldn't fully understand it. It is very complicated. The response is non linear. One day on 100mg of GLA you might respond really well, the next day crash with major flu-like symptoms. In my own case I took evening primrose oil for years - during those years my health kept getting worse. This is most likely to be caused by the interaction of critical enzymes and CFS symptoms. If your CFS is getting worse, so are these pathways.
Here is why it is good. GLA bypasses the first step in essential fatty acid megabolite synthesis (delta-6-desaturase or D6D) providing absolutely essential substrate for the synthesis of both series 1 and 2 prostaglandings, as well as a lot of other hormones. D6D is highly affected by oxidative stress, and has an absolute requirement for reduced glutathione, both of which are problems in CFS. For this reason many of us have a deficiency in long chain omega-6 fats. GLA supplementation bypasses the rate limiting step. Hormones produced from these fats are also absolutely essential to the repair of the gastrointestinal tract, which is relevant to leaky gut etc.
Now for the bad. Enzymes responsible for turning GLA into proinflammatory hormones are dynamically regulated. NOBODY has been able to reliably get good results from omega-6 fats without some problems for anything but the stricly short term. Dr. Barry Sears invented the Zone diet to control the enzymes because he couldn't get a consistent hormonal response out of high GLA oils. Now in CFS at least one of the enzymes required to convert GLA to series 2 prostaglandins etc, and hence proinflammatory hormones, is very active. So while we are often deficient in these substance, if we supply GLA we will also overuse it to make these inflammatory hormones, and risk inducing flu-like symptoms - or making existing symptoms worse. I currently believe we make too little of the long chain fat arachidonic acid, but use too much of it to create nasty hormones. Arachidonic acid release is also how alcohol poisoning kills people, which is why I think so many of us can't handle alcohol. Aside from all the nasty hormones the body makes with it if uncontrolled, it can trigger massive
oxidative stress to the mitochondria.
So how would you determine who can and can't take GLA? Probably by knowing if you can or can't drink alcohol. Even then I would keep the dose low.
These arguements do not apply to omega-3 but that is another topic.
As far as fasting is concerned, you are right that most CFSers do not do well on fasts. A small minority of patients do seem to do well on very short fasts (24 hours) according to Dr Martinovic. Mostly we just risk a major hypoglycaemic episode.
Mike--- BTW...ME/CFS patients should never fast and make sure to eat plenty of fats especially omega 6 such as Borage oil, with enzymes.