Complex sentence: The incidence of allergic side effect in people that consume royal jelly is unknown, however it has been suggested that the risk of having an allergy to royal jelly is higher in people who already have known allergies.
Split into simpler sentences: The incidence of allergic side effect in people that consume royal jelly is unknown. However, it has been suggested that the risk of having an allergy to royal jelly is higher in people who already have known allergies.