Honey is the most used of the products derived from beekeeping but because it is a normal food it is not discussed in this book. Three by-products of beekeeping – royal jelly, bee pollen and bee propolis – are used as dietary supplements. Detailed information about all products produced from beekeeping can be found in Krell (1996).
Royal jelly is a substance secreted by young worker bees and used to feed the young larvae and the queen bee throughout her life. Royal jelly is not normally stored in the hive because it is fed directly to the larvae or queen as it is secreted. However, some accumulates around the larval queen in the ‘queen cell’ in the early stages of development. Krell (1996) explains that in order to produce royal jelly commercially the hive must be stimulated to produce queens at inappropriate times and that one hive has the potential to produce about 500 g of royal jelly during the course of a summer.
The observation that the royal jelly diet of the queen bee is associated with great fecundity and a much longer life than other female bees has probably led to suggestions that it may have similar beneficial effects in humans and that it is ‘the queen of foods’ for human beings.
Fresh royal jelly varies in composition but a typical composition might be:
• 70% water
• 12% carbohydrate (mainly as glucose and fructose)
• 12% protein
• 5% lipids.
Given that a typical daily dose in supplements is 250-500 mg, these amounts of macronutrients are nutritionally insignificant. Royal jelly is practically devoid of fat-soluble vitamins and vitamin C. It contains B vitamins and several minerals but the amounts present in a typical supplement dose are nutritionally insignificant and would probably not reach 1% of the Reference Nutrient Intake (RNI) for any vitamin or mineral. Royal jelly also contains an assortment of other chemically diverse substances, which from a human perspective are present in minute amounts (free nucleotide bases, acetylcholine and two heterocyclic compounds, biopterine and neopterine).
There are huge numbers of claims for the beneficial effects of taking royal jelly supplements and some for its topical use; according to Krell (1996) there is almost no scientific substantiation for these claims. Prominent amongst these claims for royal jelly is that it acts as a general tonic, reducing fatigue, improving mental and physical performance and leading to a general health improvement. There are reports that in vitro it has antibacterial activity and that it has anti-tumour activity in animal studies but their significance for human consumption is impossible to say.
There is one review of the effect of royal jelly on serum lipids in animals and humans which suggests that previous studies have shown it to be effective in reducing blood cholesterol levels in animals and people. No other studies or reviews on the effects of royal jelly on blood lipids were found in the English language literature either before or after 1995 during an electronic literature search. There are numerous case reports of people developing allergic reactions after consuming royal jelly. These allergic reactions can occasionally be severe and life-threatening. People with asthma should avoid royal jelly because it may precipitate severe asthma attacks. Leung et al. (1997) suggested that in Hong Kong, where use of royal jelly supplements is common, risk of allergy to royal jelly was high and positively associated with other allergic conditions, including asthma.
Bee pollen is a mixture of pollens collected by bees from flowers mixed with nectar and regurgitated honey and thus containing digestive enzymes of the bees. It is collected from bees, as they enter the hive, by a wire mesh that brushes the pollen off into a collecting vessel. The exact composition of bee pollen will depend upon the types of flower that it has been collected from. Typically bee pollen contains about 20% protein and 30-40% carbohydrate mainly in the form of simple sugars. It contains smaller amounts of lipids including essential fatty acids. It does not contain fat-soluble vitamins, except carotenoids, but does contain water-soluble vitamins and essential minerals. As typical doses in supplements are in the range 0.5-1.5 g, this will make little contribution to the human requirements for either macro – or micronutrients.
Bee pollen contains flavonoids, carotenoids, free amino acids, nucleic acids and many enzymes (although these will be inactivated and digested in the human gut). Several of these constituents are known to have antioxidant activity and so bee pollen probably has some antioxidant activity; it is also claimed to have anti-inflammatory activity.
As with royal jelly, there are numerous claimed beneficial effects of bee pollen supplements, including a general increase in vitality, improved athletic performance, reduced atherosclerosis and lowered blood pressure. It is also claimed to be beneficial in the treatment of benign hypertrophy of the prostate gland in men but no clinical trials were found in the English language literature to support this. Some trials of its effects upon athletic performance were carried out in the 1970s and 1980s (e.g. Maughan and Evans 1982 in swimmers) but none of these found it to be effective.
There are several reports of allergic reactions to bee pollen, some of which have resulted in life-threatening anaphylaxis. Anyone with a known allergy to pollen should avoid bee pollen and it should probably be avoided by anyone with a history of atopic disease (eczema, asthma or allergic rhinitis). Claims that it may be helpful in curing allergies are based upon false logic. Pure pollens collected directly from the plant to which a person is allergic can be used to desensitise people to particular pollens when injected in controlled doses. Eating bee pollen with its unpredictable content is likely to provoke allergic reactions rather than to desensitise. Given the risk of allergic reactions and the lack of any substantial evidence for benefit, bee pollen is not recommended as a dietary supplement.
Bee propolis is a complex mixture of plant resin collected from plants, beeswax and bee secretions. The bees use it for various construction purposes in their hives, including sealing up brood cells. It has antibacterial, antifungal and perhaps even antiviral properties, which help reduce microbial spoilage within the hive and presumably also infections in the bees. The caffeic acid esters found in bee propolis have been shown to have anti-tumour activity using in vitro human cancer cell lines and with animal models of cancer. Propolis itself has also been shown to have anti-cancer activity in vitro.
The exact composition of propolis will vary according to a number of factors, not least of these being the plant sources of the resin component; almost two hundred individual components have been identified. Krell (1996) suggests that a typical composition might be:
• 50% plant resin rich in flavonoids and phenols including caffeic acid and other hydroxycinnamic acids
• 30% lipids, mainly beeswax but also some plant lipids
• 10% essential oils
• 5% pollen
• 5% other organic material and minerals.
Much of the suggested benefit of bee propolis is based upon extrapolation of its in vitro antimicrobial activity and its anti-tumour activity in human cancer cell lines and experimental animal models. No clinical trials of propolis were found in the English language in an electronic search of the literature.
Bee propolis or its extracts (usually ethanolic extracts) are sold for use as supplements in the form of tablets, capsules or liquids. The dose is not established but manufacturers recommend the equivalent of 0.5-1 g of propolis. There are numerous case reports of contact dermatitis resulting from exposure to bee propolis as well as other reports of allergic reactions. There seems to be little basis for recommending bee propolis as a general dietary supplement.