For years I suffered the fate of hayfever whenever winter abated and the sun reared its head. For me, summer was filled with dread as I awaited the sniffly eyes, the runny nose and the sore throat.

I tried everything the doctor could throw at me, nasal sprays that felt like they were freezing my brain, antihistamines that felt useless, and even steroids (you never saw Arnie sneezing did you).

In my early twenties I became focused on studying health and began working in the "industry", eventually becoming a nutrition guru (I apologise). I flirted with many ideas around solving my allergies, and truly believed that by being "healthy", I deserved some sort of reward in the form of less itchy eyes or a throat that didn't feel like I'd swallowed a thousand razor blades.

Over the years rapeseed (canola) became more and more abundant in the surrounding countryside, which became a real problem for me every year. This was my first real problem with the crop which I now consider one of the dirtiest of the lot. Yet it took me several more years before I linked it (in fact all polyunsaturated oils) to allergies.

"a high ratio of n-6/n-3 PUFA increased the serum HDL-C level"
http://www.ncbi.nlm.nih.gov/m/pubmed/19729862/

On the face of it that seems good, the so called heart healthy oils raise the "good" HDL cholesterol. However....

"...positive linear associations were found between HDL cholesterol levels and allergic rhinoconjunctivitis (AR), atopic eczema (AE) and, furthermore, between the intake of PUFA and allergic sensitization in men (P<0.01). After adjustment, an increasing risk for atopic diseases with increasing levels of HDL cholesterol and an increasing risk for allergic sensitization with increasing intakes of PUFA remained statistically significant."
http://www.ncbi.nlm.nih.gov/m/pubmed/14519141/

I wasn't a major consumer of polyunsaturated fats but my HDL (the so called good cholesterol) was high, which at the time I was proud of, taking it as evidence of my healthy heart. Thanks to the work of some renegade scientists (Ray and co.), we now know (at least those of us separated from media and industry propaganda) that HDL isn't as good as we were told. 
http://science.sciencemag.org/content/351/6278/1126

HDL raises in response to toxins. So the mechanism by which flora spread probably works, is that it causes stress/damage/inflammation which causes a rise in the so called good HDL which then ferries the toxins to your liver in order to excrete them.

According to the advert, "reducing your consumption of saturated fat contributes to the maintenance of normal blood cholesterol levels", that would be the "normal" levels that firstly show no benefit in reducing cardiovascular events, and secondly the ones mentioned above that are simply a response to a toxin.

​My own high HDL level was most likely a result of the low carbohydrate diet I followed for many years and the subsequent high cortisol levels.

"...HDL (the so called good cholesterol) concentrations were higher (P<.05) in the carbohydrate restriction (CR) groups compared to the control groups. In contrast, high dietary cholesterol (CR-H and control-H) resulted in higher concentrations of total and LDL (the one thats actually good) cholesterol compared to those guinea pigs fed the low-cholesterol diets (P<.01). Dietary cholesterol significantly increased the total number of LDL particles (P<.001) and the number of small LDL (P<.001), as determined by nuclear magnetic resonance. In contrast, carbohydrate restriction (CR-L and CR-H) resulted in lower concentrations of medium very-low-density lipoprotein and small LDL particles compared to the high-carbohydrate groups"
http://www.ncbi.nlm.nih.gov/pubmed/18495466​

"Cortisol...showed a positive correlation (r = .21) with high density lipoprotein cholesterol. The relationship between cortisol and high density lipoprotein cholesterol persisted after adjustment for gender, body mass index, waist-hip ratio, cigarette and alcohol use, triglyceride level, and diabetes."
http://www.ncbi.nlm.nih.gov/pubmed/7490384

"...cortisol concentrations were consistently lower during the high carbohydrate diet than during the high protein diet (7.74 ± 0.71 μg/d1 vs. 10.6 ± 0.4 μg/d1 respectively, p<0.05), and there were parallel changes in corticosteroid binding globulin concentrations (635 ± 60 nmol/1 vs. 754 ± 31 nmol/1 respectively p<0.05). The diets were equal in total calories and fat. These consistent and reciprocal changes suggest that the ratio of protein to carbohydrate in the human diet is an important regulatory factor for steroid hormone plasma levels and for liver-derived hormone binding proteins."
http://www.sciencedirect.com/science/article/pii/0024320587900865

As a good paleolitic eater I avoided sugar as I knew it was a poisonous toxin way back before Jamie Oliver was still sipping Coca Cola totally unaware of the propaganda train he was to push many years later. Despite my avoidance, my cortisol levels continued to be raised, an issue which I ignored for some time due to it not making much paleo sense.

"Sucrose, but not aspartame, consumption associated with reduced (P = .024) stress-induced cortisol. The sucrose group also had a lower reactivity to naltrexone, significantly (P = .041) lower nausea, and a trend (P = .080) toward lower cortisol." 
http://press.endocrine.org/doi/10.1210/jc.2014-4353

So after many years in the low carb wilderness things just weren't making sense and I made a decision to open my books and become a little more scientific which lead me back to my pre-paleo diet and a variety of super scientists that inspired me to dig further.

As it turned out, a high-carbohydrate diet increases TG levels and decreases HDL-C (HDL cholesterol) as well as HDL apoA-I.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2682989/

And the severity of anaphyLACTIC shock in both rats and mice is altered by the concentration of glucose in the blood. Hypoglycaemia (as is common in the low carb world) increases the effect whereas shock severity is decreased or halted by a hyperglycaemia induced state in which 'excess' glucose is administered.
 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1557370/pdf/bripharmchem00014-0149.pdf

Some year ago I wrote about the absurdity of attempting to treat hayfever (a histamine issue) with local honey, as though it was a virus and immunity could be built up somehow via consuming the honey. That some people claim it works was attributed to the placebo effect. Yet I am now more drawn to the theory that it is the sugar that simply reduces catecholamines (stress hormones) and with it the inflammation and HDL leading to a reduction is symptoms.

As final note, this may be a factor in the relief claimed by some who receive homeopathic hayfever treatment. Less a placebo and more an actual benefit from the sugar pill.