The protective effects of PEA can be traced back in literature to 1943. The first scientific findings already pointed out PEA was a enhancer of our natural resistance.
The American bacteriologists Coburn and Moore demonstrated in 1943 that supplying food with dried egg yolk to underprivileged children living in poor parts of New York city prevented the recurrence of rheumatic fever in spite of repeated attacks of haemolytic streptococcal infection.
“PEA in the first half of last century was identified as an enhancer of our natural immunity.”
The first studies
In a subsequent study for two years 30 children at a convalescent rheumatic home received four egg yolks daily. No other change in diet was made and no antibacterial drugs were given. 22 of these children contracted 24 proved group-A streptococcal infections (based on serology), but none showed clinical evidence of rheumatic recurrences. This was in sharp contrast to previous experience in the convalescent home where rheumatic recurrences had been seen each year.
Subsequently, Coburn and colleagues were also the first to report in 1954 a phospholipid fraction prepared from egg yolk that showed antiallergic activity in an assay in the guinea pig.
The antiallergic factor of egg yolk was subsequently purified by Long and Martin in 1956 such a way that it was clear that this factor showed a biological and chemical similarity to a preparation obtained earlier in 1950 from peanut and what appeared to be a closely related substance from “vegetable lecithin.”
The birth of PEA
1957 was the birth year of PEA as a chemical structure. Kuehl and other employees of MSD reported to have succeeded in isolating a crystalline anti-inflammatory factor from soybean lecithine and they identified it as the chemical structure S-(2-hydroxyethyl)-palmitamide, the official chemical name of palmitpylethanolamide.
They isolated the compound also from a phospholipid fraction of egg yolk and from hexane-extracted peanut meal. The products obtained was subsequently tested by in a local passive joint anaphylaxis assay in the guinea pig.
When applying their isolation procedure to soybean lecithin, they obtained a partially purified fraction from which the homogeneous factor was obtained by crystallization from cyclohexane. The crystalline material, had a melting point of 98-99′, and was described as neutral, optically inactive, and possessed the formula C18H3702N.
Hydrolysis of the factor resulted in palmitic acid and ethanolamine and thus the compound was identified as N-(2-hydroythyl)-palmitamide. In order to close the circle of isolation and identification they were able to synthesize the compound by reflux in ethanolamine with palmitic acid according to a well known procedure described in the chemical literature of that time.
Anti-inflammatory effects of PEA
They further analyzed the anti-inflammatory activity of a series of derivatives of PEA and could prove that the basic moiety of the molecule was responsible for its anti-inflammatory activity. The nature of the acid group appeared to them to be of no importance, because in addition to ethanolamine itself, N-(2-hydroxyethyl)-lauramide, S- (2-hydroxyethyl) -salicylamide and N- (2-hydroxy- ethyl)-acetamide were all potent anti-inflammatory properties. These pharmacological properties of the ethanolamine-derivates appeared to be quite specific, since other homologs did not show a biological response in the assay.
The protective effects of PEA avant la lettre in Streptococci infections were discovered by Coburn, who presented a review of his work and his hypothesis that eggs contained an important protective factor against infection, especially in rheumatic fever, in 1960 in the Lancet, and he argued that:
- inadequate nutrition is part of a poor environment;
- rheumatic-fever children usually lack sufficient eggs in their diets;
- the escape from poverty is followed by an increase in the consumption of eggs and a decrease in the incidence of rheumatic fever;
- supplementation of children’s diets with egg yolk or certain fractions thereof is followed by decreased rheumatic susceptibility ;
- and there is a fraction of egg yolk which in extremely small amounts has been found to have high antiallergic activity in laboratory animals.
Coburn described a number of field studies to support his hypothesis. The first of these field studies was conducted in 89 rheumatic boys and girls living in New York City slums. They received the egg yolk enriched supplements, and no prophylactic drugs were given. The clinical results clearly showed that children whose normal diet was reinforced with powdered egg yolk (equivalent to six eggs daily), were much more protected against infections in comparison to other children.