Royal jelly

Royal jelly is the secretion of the hypopharyngeal, or brood food, glands of young nurse bees, which feed it to young larvae and to the queen. It is fed at once and never stored, so it can be harvested only during queen rearing: commercial royal jelly is the food intended for queen larvae four to five days old. ¹

Queen or worker. Every female egg can become a queen, but only if the larva is fed like a queen throughout its development, especially in the first four days. A queen develops in 15.5 days instead of 21, lives several years instead of a few months and can lay several thousand eggs a day. ¹

What makes a queen. In 2011 a study in Nature reported that a royal jelly protein named royalactin induces queen development. ³ In 2016 another team, also in Nature, could not confirm that effect in honeybees, so the question remains open. ⁴ FAO had already noted that it is still unknown which fractions of the jelly are essential. ¹

Appearance. Royal jelly is a fairly fluid, homogeneous paste, whitish with yellow or beige tinges, with a pungent phenolic odour and a sour taste. Its density is about 1.1 g/cm³ and its pH 3.6–4.2. In storage, even in a refrigerator, it slowly becomes more viscous, and small granules may form. ¹

Composition. Fresh royal jelly contains 57–70 % water; in dry matter there are 17–45 % proteins, 18–52 % sugars, mostly fructose and glucose, 3.5–19 % lipids and 2–3 % minerals, above all potassium. Free fatty acids make up 80–90 % of the lipids, chiefly 10-hydroxy-2-decenoic acid. It contains B vitamins, only traces of vitamin C and no vitamins A, D, E or K; testosterone is present only at 0.012 µg per gram. ¹

How it is harvested. Colonies are made to rear queens outside the natural swarming season, which requires movable-comb hives and experienced staff. The jelly is removed from each queen cell with a spatula or suction device, filtered through fine nylon, put into dark glass or food-grade plastic and refrigerated immediately. A well-managed hive gives about 500 g in a season of five to six months, while cells from natural swarms yield only a gram or two. ¹

Storage and forms. Royal jelly is sold fresh, frozen, freeze-dried or mixed with other products; industry prefers the freeze-dried form. Refrigeration at 0–5 °C is the minimum, and freezing below −17 °C is better; in Europe about 18 months in the fridge or 24 months frozen are recommended, and no more than 12 months in the fridge after thawing. ¹ Honey is sometimes enriched with royal jelly, but in the EU nothing may be added to a product sold as honey. ²⁶

Health and safety. FAO stresses that the benefit of royal jelly to human health has never been scientifically confirmed. Injections were abandoned because of serious allergic reactions, and patch tests caused allergic contact dermatitis in 2 of 10 patients. ¹ In Australia and New Zealand every food containing royal jelly must warn that it has caused severe allergic reactions and, rarely, deaths, especially in people with asthma or allergies. ⁵

Why it matters to you. If you have asthma or allergies, treat royal jelly with caution: food law in Australia and New Zealand requires a warning about severe allergic reactions. ⁵ Keep it cold and do not expect hormonal or rejuvenating effects: the testosterone content is negligible and no health benefit has been proven. ¹