ABSTRACT
The genus Betula belongs to the Betulaceae family of trees, which includes the hazels, alders and hornbeams, all of which flourish in cooler areas of the world. The plant sterol β-sitosterol is extracted from the wood pulp of the European white birch, B. pendula, and used as a food supplement to reduce blood cholesterol and symptoms in benign prostatic enlargement. Betula pendula, and other birches, have two particular uses in Scandinavia today, as a source of lumber and the other, very large-scale use, is as a source of wood pulp from which paper and similar materials are made. Birch pollen is the predominant tree pollen in northern Europe that causes asthma and allergic rhinitis and is also associated with certain types of food allergy. Use of β-sitosterol for mild benign prostatic enlargement in older men improves urinary flow but has no effect on the size of the prostate.
