The lingonberry is a wild fruit of the far north, a staple of the diets of people in Alaska, Canada, Russia, and Scandinavia, a prominent ingredient in Swedish cooking. Lingonberry grows on dry forest soil, most commonly in pine forests and in lichen heaths. Its purplish-red berries grow in clusters close to ground level. A botanical relative of the cranberry, the lingonberry has a distinct flavor that offsets the sweetness of puddings and pancakes, complements the flavors of duck, and makes an interesting mixed drink. Most Americans can most easily find lingonberries in IKEA.

While most healthy foods are evaluated in terms of their enzyme content, lingonberries are best known for their antizyme content. Lingonberries contain a chemical that deactivates the enzyme ornithine decarboxylase (ODC). A "critical mass" of ODC is necessary for pre-cancerous cells in epithelial tissues, that is, cells in the linings of the ducts of the breast, the cervix, the esophagus, the uterus, and the ovaries, to assemble the proteins they need to multiply and spread. Epidemiologists have long recognized that rates of breast cancer are lower in countries where lingonberries are eaten regularly. Using lingonberries, or lingonberry extracts, in cancer treatment is on the horizon, and their eventual in mainstream medical treatment will probably be combined with other dietary modifications that deprive cancer cells of the amino acids on which OCD works.

Lingonberries are also among the most highly concentrated sources of quercetin and myristicin. This plant chemical is an antihistamine, blocking the release of histamine in the linings of the nose and throat, without inducing the drowsiness common with most allergy medications.

It is best to use lingonberries fresh or frozen. The traditional way of storing lingonberries in their own juice without any preservatives (the fruit containing a natural preservative) prevents spoilage, but destroys up to 60 percent of the quercetin. Boiling the berries to extract the juice destroys up to 85 percent of the quercetin, and even lingonberry jams and conserves lose their phytochemical content after 9 months storage at room temperature.

Nutritionally, lingonberries are so potent that not everyone should eat them. Generally speaking, if your doctor tells you should not drink grapefruit juice while taking a certain medication, you should not eat lingonberries, either. Lingonberries interfere with the absorption of antibiotics in the same class as Cipro (for a complete list, see Allergies in Part 1). And if you get hives when you eat shellfish, you probably should not eat lingonberries. These berries contain natural benzoates, which also occur in high concentrations in shellfish, especially shrimp.