Royal jelly is secreted by the hypopharyngeal gland (sometimes called the brood food gland) of young worker (nurse) bees, to feed young larvae and the adult queen bee. Royal jelly is always fed directly to the queen or the larvae as it is secreted; it is not stored. This is why it has not been a traditional beekeeping product. The only situation in which harvesting becomes feasible is during queen rearing, when the larvae destined to become queen bees are supplied with an over-abundance of royal jelly. The queen larvae cannot consume the food as fast as it is provided and royal jelly accumulates in the queen cells (see Figure 6.1). The exact definition of commercially available royal jelly is therefore related to the method of production: it is the food intended for queen bee larvae that are four to five days old.
The differentiation between queen and worker bees is related to feeding during the larval stages. Indeed, all female eggs can produce a queen bee, but this occurs only when, during the whole development of the larvae and particularly the first four days, they are cared for and fed "like a queen". Queen rearing, regulated by complex mechanisms within the hive, induces in a young larva a series of hormonal and biochemical actions and reactions that make it develop into a queen bee. A queen bee differs from a worker bee in various ways:
in its morphology:the queen develops reproductive organs while the worker bee develops organs related to its work such as pollen baskets, stronger mandibles, brood food glands and wax glands.
in its development period:on average the queen develops in 15.5 days while worker bees require 21 days.
in its life span:the queen lives for several years as compared to a few months for the worker bee,
and its behaviour:the queen lays up to several thousand eggs a day while workers lay eggs only occasionally. Unlike workers, the queen never participates in any common hive activities.
It is mainly the spectacular fertility and long life-span of the queen, exclusively fed on royal jelly, which have suggestively led people to believe that royal jelly produces similar effects in humans. In the early 1950's, articles began to appear, particularly in the French beekeeping press, in praise of the virtues of royal jelly, referring to research conducted in several hospitals. Chauvin (1968) however, was unable to find the source of such information and therefore considered it unfounded.
The myth of royal jelly started with an amazing biological phenomenon on the one hand and commercial speculation on the other, which, on the basis of initial results obtained by entomologists and physiologists, exploited the suggestibility and imagination of consumers willing to be seduced by the fascination of this rare and unknown product was exploited. In fact, royal jelly was so rare and so little known that it was impossible to verify its actual presence in many products claiming its content.
In the years immediately following its first marketing, royal jelly quickly became widely known and consumed and the increasing demand motivated experts to refine production techniques and led more and more beekeepers to specialize in this activity. At the same time, research on quality control of the commercial product and identification of its biological and clinical properties found growing support.
Consumption of royal jelly has been growing ever since, even without its benefit to human health having ever been scientifically confirmed. The Western medical establishment has always been wary of the effects claimed for this product and in most cases refuses to consider it, largely because of the way royal jelly was initially promoted. In spite of a vast number of publications praising its virtues and the apparently abundant bibliography, there is still a serious lack of scientific data on the clinical effects of royal jelly.
Physical characteristics of royal jelly
Royal jelly is a homogeneous substance with the consistency of a fairly fluid paste. It is whitish in colour with yellow or beige tinges, has a pungent phenolic odour and a characteristic sour flavour. It has a density of approximately 1.1 g/cm3 (Lercker et al., 1992) and is partially soluble in water. Aqueous solutions clarify during basification with soda.
Viscosity varies according to water content and age - it slowly becomes more viscous when stored at room temperature or in a refrigerator at 50C. The increased viscosity appears to be related to an increase in water insoluble nitrogenous compounds, together with a reduction in soluble nitrogen and free amino acids (Takenaka et al., 1986). These changes are apparently due to continued enzymatic activities and interaction between the lipid and protein fractions. If sucrose is added, royal jelly becomes more fluid (Sasaki et al., 1987). Such changes in viscosity have also been related to the phenomena which regulate caste differentiation in a bee colony (see also 6.4.1).
Certain debris in royal jelly, is a sign of purity as, for example, the ever present fragments of laarval skin (see also 6.8). Wax fragments too, are encountered more or less regularly, but their presence is largely dependent on the collection method. Stored royal jelly often develops small granules due to precipitation of components.
The composition of royal jelly
Numerous chemical analyses of royal jelly have been published over the years. Only recently though, have highly refined technologies given detailed analyses of the unusual composition and complexity of this somewhat acidic substance (pH 3.6 to 4.2).
The principal constituents of royal jelly are water, protein, sugars, lipids and mineral salts. Although they occur with notable variations (Table 6.1) the composition of royal jelly remains relatively constant when comparing different colonies, bee races and time.
Water makes up about two thirds of fresh royal jelly, but by dry weight, proteins and sugars are by far the largest fractions. Of the nitrogenous substances, proteins average 73.9% and of the six major proteins (Otani et al., 1985) four are glycoproteins (Takenaka, 1987). Free amino acids average 2.3% and peptides 0.16% (Takenaka, 1984) of the nitrogenous substances. All amino acids essential for humans are present and a total of 29 amino acids and derivatives have been identified, the most important being aspartic acid and glutamic acid (Howe et al., 1985). The free amino acids are proline and lysine (Takenaka, 1984 and 1987). A number of enzymes are also present including glucose oxidase (Nye et al., 1973) phosphatase and cholinesterase (Ammon and Zoch, 1957).An insulin-like substance has been identified by Kramer et al. (1977 and 1982).
Composition of royal jelly (form Lercker et al., 1984 and 1992)
|Proteins (N x 6.25)||17% of dry weight||45% of dry weight|
|Sugars||18% of dry weight||52% of dry weight|
|Lipids||3.5% of dry weight||19% of dry weight|
|Minerals||2% of dry weight||3% of dry weight|
The sugars consist mostly of fructose and glucose in relatively constant proportions similar to those in honey. Fructose is prevalent. In many cases fructose and glucose together account for 90% of the total sugars. The sucrose content varies considerably from one sample to another. Other sugars present in much lower quantities are maltose, trehalose, melibiose, ribose and erlose (Lercker et al., 1984, 1986 and 1992).
The lipid content is a unique and from many points of view, a very interesting feature of royal jelly. The lipid fraction consists to 80-90% (by dry weight) of free fatty acids with unusual and uncommon structures. They are mostly short chain (8 to 10 carbon atoms) hydroxy fatty acids or dicarboxylic acids, in contrast to the fatty acids with 14 to 20 carbon atoms which are commonly found in animal and plant material. These fatty acids are responsible for most of the recorded biological properties of royal jelly (Schmidt and Buchmann, 1992). The principal acid is 10-hydroxy-2-decanoic acid, followed by its saturated equivalent, lO-hydroxydecanoic acid. In addition to the free fatty acids, the lipid fraction contains some neutral lipids, sterols (including cholesterol) and an unsaponifiable fraction of hydrocarbons similar to beeswax extracts (Lercker et al., 1981, 1982, 1984 and 1992).
The total ash content of royal jelly is about 1 % of fresh weight or 2 to 3 % of dry weight. The major mineral salts are, in descending order: K, Ca, Na, Zn, Fe, Cu and Mn, with a strong prevalence of potassium (Benfenati et al., 1986).
The vitamin content has been the object of numerous studies, from the moment when the first research (Aeppler, 1922) showed that royal jelly is extremely rich in vitamins. Table 6.2 indicates the results obtained by Vecchi et al., (1988) with regard to water-soluble vitamins. Other authors report averages close to the minimum values of Table 6.2 (Schmidt and Buchmann, 1992). Only traces of vitamin C can be found.
As far as the fat-soluble vitamins are concerned, it was initially thought that, given the enormous fertility of the queen bee, royal jelly would contain vitamin E. But tests have shown that it does not. Vitamins A, D and K are also absent (Melampy and Jones, 1939).
During the first studies, much emphasis was placed on the search for sex hormones in royal jelly. The first positive tests were later proven wrong. Melampy and Stanley (1940) showed no gonadotropic effects on female rats and Johansson and Johansson (1958) clearly demonstrated the absence of any human sex hormones. Recently though, with much more sensitive radio-immunological methods, testosterone has been identified in extremely small quantities: 0.012 ~g/g fresh weight (Vittek and Slomiany, 1984). In comparison, a human male produces daily 250,000 to 1 million times the amount present in one gram of fresh royal jelly (Schmidt and Buchmann, 1992). No biological effect has been demonstrated for such small amounts.
Table 6.2 Vitamin content of royal jelly in mg per gram of
fesch weight (Vecchi et al., 1988)
|Thiamine||Riboflavin||Pantothenic Acid||Pyridoxine||Niacin||Folic acid||Inositol||Biotin|
Numerous minor compounds, belonging to diverse chemical categories, have been identified in royal jelly. Among these are two heterocyclic substances, biopterine and neopterine at 25 and 5 ijg/g of fresh weight respectively. These compounds are found in the food of worker bee larvae too, but at about one tenth of these concentration (Rembold, 1965). Other substances identified include several nucleotides as free bases (adenosine, uridine, guanosine, iridin and cytidine) the phosphates AMP, ADP, and ATP (Marko et al., 1964), acetylcholine (1 mglg dry weight, Henschler, 1954) and gluconic acid (0.6% of fresh weight, Nye et al., 1973).
In all popular and scientific literature, there is a fraction of royal jelly described as "other, as yet unknown". This phrase not only emphasizes the incomplete state of analytical knowledge about the product, but also the lack of understanding of the biological activities (proven or presumed) of royal jelly. Up to now, despite many efforts, most of these activities have not been proven definitely, nor have they been attributed to any of the known components.
The physiological effects of royal jelly On honeybees
The effect of royal jelly on honeybee larvae, for which it was originally intended as food, is briefly described since in addition to being a fascinating biological phenomenon, it is also the basis of the royal jelly "myth".
In the 1950's, in the wake of new discoveries in the medical field of such wonder drugs as penicillin, hormones and vitamins became "popular" and were seen by many as the simple answers to many biological questions. The elusive "hormonal" effect of royal jelly on honeybee larvae led to the belief that its almost miraculous action on bee larvae could be similar on humans.
By deduction these "hormonal" effects were not only responsible for the caste differentiation between worker and queen bee, but also for the enormous fertility of a queen genetically equal to a worker bee, distinguished apparently only by the food it ate. The same applies to the queen's longevity, unique for an adult insect. Though it is known that royal jelly is a necessary food for the queen's survival and productivity, it is not known which royal jelly fractions are essential, which ones can be replaced and what constitutes minimum or optimum requirements for a queen. Almost all the attention has been focused on the immature stages of development.
Numerous studies were carried out to discover hormones or other substances powerful enough to induce all the necessary changes and give the queen such "superior" qualities. Indeed, the initial studies led to the belief that a "queen determinator" did exist and was an extremely unstable substance (as elusive as eternal life). It appeared to be so unstable that one day after secretion, it was already ineffective. However, the results of other studies did not confirm this hypothesis.
In an attempt to identify the queen determinator, all the components of royal jelly, particularly the more unusual ones or those with known biological activity or present in greater quantity have been tested. In the late 1980's the mystery had still not been solved and a number of contrasting hypotheses had produced equally convincing explanations. Rembold et al. (1974) ware thought to have been close to identifying a specific substance with queen determinator activity which they had isolated; other researchers proposed a differentiation mechanism based on the different proportions of nutrients in the food of worker and queen bee larvae. Weiss (1975) and Asencot and Lensky (1975) believed it was the sugar content of larval food (higher for the young queen bee larvae) that was supposed to cause the differentiation into queens.
More recently, Sasaki et al. (1987) proposed yet another hypothesis incorporating the many contrasting results from other researchers and suggested the "correct" viscosity of royal jelly was a key factor together with higher consumption, but even this theory still has to be substantiated with proof. In other words, it is still not known how royal jelly works nor what is responsible for its amazing effects.
However, if parallels are still being drawn between honeybees and royal jelly, and humans and royal jelly, then they should serve to emphasize the complexity and interdependence of different therapies and factors such as who is taking what, when and how much. Eating royal jelly, or rubbing it into the skin will not make anyone younger or live for a thousand years. On the other hand, using it to supplement and support other diets, activities or medicines may have synergistic effects which cannot be explained by a list of compounds and their individual effects. Tests of such a hypothesis in clinical and scientific trials are needed. There is plenty of circumstantial evidence, reviewed in the following section, that leads us to believe that royal jelly might be highly beneficial to mankind.
Unconfirmed circumstantial evidence
Royal jelly was initially advertised for its rejuvenating effects (De Belfever, 1958). The activities most frequently reported in advertisements and constantly confirmed in the declarations of those who have taken royal jelly are indicated in Table 6.3, citing the contents of one of Europe's most widespread and popular publication on the subject (Donadieu, 1978). Royal jelly, taken orally for 1-2 months by swallowing or letting it melt under the tongue in doses of 200-500 mg a day, is said to act as a tonic and stimulant, with a euphoric effect on healthy humans.
In addition to these indications, users declared that royal jelly had solved most of their health problems. In many cases these were chronic or recurring disorders, for which other treatments did not lead to the desired results, so that the effects obtained by taking royal jelly have been considered "miraculous".
It must be emphasised that these claims are unconfirmed by any scientific studies or documentation. There is no proof that the effects are exclusively or even mostly attributable to royal jelly.
People who have taken royal jelly said that they soon experienced a feeling of general well-being, i.e. an effect on their physical output (resistance to fatigue), intellectual performance (greater learning capacity and better memory) and on their mental condition (greater self-confidence, feeling of well-being and euphoria). In other words, royal jelly appears to act as a general stimulant, improving immune response and general body functions.
A list of properties, benefits and improvements attributed to royal jelly quoted from personal case histories and non-scientific literature.
|Internal Use||External Use|
|Stimulant - physical performance, better memory, learning capacity and self-confidence||Epithelial stimulation and regrowth|
|General health improvement||Anti-wrinkle|
|Anorexia||Sebaceous secretion (fat secretions of skin glands) normalized|
|Sexual desire and performance|
|Increased resistance to viral infections|
|High blood pressure|
|Low blood pressure|
|Chronic and incurable disorders|
Royal jelly is neither toxic when injected into mice and rats at high dosages of up to 3 g per kg body weight per day (Hashimoto et al., 1977) nor mutagenic, as tested on DNA of Salmonella typimurium (Tamura et al., 1985).
Takahashi et al., (1983) reported cases of allergic contact dermatitis in 2 out of 10 patients subjected to patch tests. In the context of allergic reactions it needs to be mentioned that intramuscular or intraperitoneal injections, the most common form of royal jelly administration in early years, have been completely abandoned (even under strict medical supervision) because of the risk of serious allergic reactions (Dillon and Louveaux, 1987) Today, royal jelly is most often administered orally and externally (in cosmetics).
In vitro studies have confirmed that lO-hydroxydecanoic acid in royal jelly has antibiotic activity. The antibiotic effectiveness is thermostable, i.e. is not destroyed by moderate heating, but it decreases with improper or long-term storage. Antibiotic action has been proven against the following microorganisms: Escherichia coli, Salmonella, Proteus, Bacillus subtilis and Staphylococcus aureus (Lavie, 1968; Yatsunami and Echigo, 1985). It shows one quarter of the activity of penicillin against Micrococcus pyrogens and is also fungicidal (Blum et al., 1959). In vitro, antiviral effects have been described (Derivici and Petrescu, 1965) and better resistance to viral infections has been observed in mice.
This same antibiotic action of fatty acids is neutralized by raising the pH above 5.6. Since injection into blood, muscle or the peritoneal cavity will raise the pH to 7.4, and the pH is above 5.6 in the intestines, the therapeutic value of the anti-bacterial activity of fatty acids is likely to be negligible for any internal applications, but will remain effective for topical use.
In studies on the internal effects of royal jelly with live animals or humans the jelly is usually administered either by mouth or by injection. The latter allows better assessment of hormonal activities ascribed to royal jelly but carries a substantial risk of allergic reactions.
Positive effects on reproductivity, though not necessarily due to hormone-like action, have been reported at least for chickens, quails and rabbits. Rabbits reacted to a normal diet supplemented with 100-200 mg of royal jelly per kilogramme of body weight with increased fertility and embryonic development (Khattab et al., 1989). Japanese quail reached sexual maturity sooner and laid more eggs after supplementation of diets with high doses (0.2 g) of lyophilized (freeze-dried) royal jelly (Csuka et al., 1978). Bonomi (1983) increased egg production, fertility and hatching in laying hens by using 5 mg royal jelly per kg of feed, but Giordani (1961) found no histological changes in male or female reproductive organs or weight gain with higher doses of 10 to 40 mg per day.
Growth rates of mice slightly increased with a dosage of 1 g of royal jelly per kg of feed, but decreased with higher dosages (Chauvin, 1968). Bonomi (1983) reported weight increases in chicken, partridges and pheasants with a supplement of S mg royal jelly per kg of feed and Salama et al. (1977) reported weight increases in rats when 10, 20 or 40 mg were injected directly into their stomachs. The administration of 0.02 g of royal jelly to calves less than 7 days old gave a weight gain of 11 - 13 % during the following 6 months in comparison with untreated controls (Radu-Todurache et al., 1978). They also mentioned that the treated calves showed lower mortality and higher resistance to infection.
Intravenous injections cause slight vasodilation (temporary enlarging of blood vessels) and have a hypotensive effect (lowering blood pressure); both due to acetylcholine in royal jelly (Jacoli, 1956; Shinoda et al., 1978).
Injections of royal jelly solutions induced higher blood sugar levels than oral applications (Chauvin, 1968). No hypoglycemic (insulin-like) reaction could be shown in rats (Fujii et al., 1990). Afifi et al. (1989) reported weight increases in guinea pigs after injection of 100-300 ing royal jelly per kilogramme of body weight. Small doses injected into cats raised haemoglobin and erythrocyte counts and repeated doses of up to 10 mg/kg of body weight stimulated motor activity and weight gains in mice. Repeated higher doses of 100 mg/kg in mice, however, caused weight loss and impaired cerebrocortical (brain cortex) cellular metabolism (Lupachev, 1963).
In other studies human diseases were simulated in animals in order to identify the mechanisms of royal jelly action. Thus it is known that royal jelly can reduce blood plasma levels of cholesterol and triglycerides (Cho, 1977) and cholesterol and arterial cholesterol deposits in rabbits when these disorders were induced experimentally (Carli et al. 1975). Nakajin et al., (1982) stated that although royal jelly has no effect on lipid levels in blood plasma in normal rabbits, it can reduce the cholesterol content in the blood of animals fed on a diet which induced high levels of blood cholesterol.
Vittek and Halmos (1968) found that royal jelly promoted bone healing in rabbits. The healing of skin lesions was accelerated and anti-inflammatory action was shown for rats by Fujii et al. (1990).
Other researchers tested royal jelly and some of its compounds on tumour cell cultures, showing the inhibitory action of lO-hydroxydecanoic acid (Townsend et al., 1960) and certain dicarboxylic acids. However, they also showed that the same acids could induce tumours in mice when royal jelly is mixed with the culture medium (several mg/ml at less than pH 5) prior to injection into the test animals (Morgan et al., 1960). Wagner et al., (1970) found no significant effects of prolonged survival in mice irradiated against experimentally induced tumours and treated with royal jelly (20 mg/kg of body weight) as compared to control mice which did not receive any royal jelly. More recently, Tamura et al., (1987) have shown tumour growth inhibition in mice with prophylactic and therapeutic oral administration of royal jelly. Inhibition of rapid-growth cancers (leukaemia) was insignificant but it was noticeable on slow-growing, solid tumours (Ehrlich and Sarcoma strains).
Studies of the effects of royal jelly on humans are extremely numerous, particularly in Eastern Europe. A few early studies were presented in Russian by Braines (1959, 1960 and 1962). Most studies however, arc difficult to evaluate for the scientific value of the reported information. Although many are presented as scientific publications, they often lack details on test methods, use parameters difficult to quantify (well-being, euphoria and rejuvenation) do not entirely exclude effects from other concurrent treatments, or use subject numbers too small to exclude accidental effects or natural variation. Of all the works consulted and selected for this chapter, of which a few are summarized in Table 6.4, not one is totally without criticism. The information presented therefore must be considered only as an indication of possible effects requiring further clinical testing.
The mechanisms of royal jelly's activity is not known and none of the numerous hypotheses have been confirmed. An early explanation (Johansson and Johansson, 1958) claiming high vitamin content as a contributory factor can be refuted on the grounds that the same effects should then be achievable with vitamin supplements or a glass of milk, which contains amounts of vitamins similar to the usual dose of royal jelly. Beneficial effects on intestinal flora through selected anti-microbial action can mostly be excluded due to pH. The action of some compounds on endocrine glands, or becoming part of enzyme systems or directly affecting intermediate metabolism has been suggested by Bonomi (1983).
A list of some effects of royal jelly on humans.
|Premature bebies and those with nutritional deficiencies of various origins||8-100 mg orally, improvement of general condition; increase in weight, appetite, red blood cells and haemoglobin||
Malossi & Grandi, 1956
Prosperi and Ragazzini, 1956
Prosperi et al., 1956
|Elderly (70-75 years), anorexic, depressed and low blood pressure patients||
20 mg injected every second day, improvements on all accounts
20 mg taken orally every second day, improvements as above
|Psychiatry||Improvements of asthenia, nervous breakdown, emotional problems and counteraction of side effects of psychoactive drugs||Telatin, 1956|
|Chronic metabolism||Mixture or royal jelly, honey and ginseng, improvements in weight gain and psychological conditions, but changes of blood characterisics||Borgia et al., 1984|
|Stimulating metabolism||Stimulating effects comparable to that by proteins, effect assumed to be due to activity of enzymatic complexes||Martinetti and Caracristi, 1956|
|Wound healing||5-30 mg/ml injected into burn blisters, improved regrowth of skin||Gimbel et al., 1962|
No toxic effects have been observed in royal jelly for external use, as food or for injection. Allergic reactions however, as a result of contact or injection, may occur. As with all other potential allergenic substances, small quantities should be tried for a few days before using full doses. In case of allergic reactions, its use should be suspended immediately.