There is a tendency, among barmier alternative therapists, to see metaphysical significance in everything. If you have a sprained shoulder from lugging shopping back from Tesco, a rolfing masseur or crystal healer might say you are bearing too much responsibility - that there is, metaphorically, a "weight on your shoulders". By similar divination, heartburn might imply a failing relationship, a pain in the neck that you are a pain in the neck, or a twisted knee that you are carrying an emotional burden that is somehow compressing your joints.
Herbal medicine is much the same. The shape, colour and texture of a plant are said to convey its intended use - and devil's claw (otherwise known as grapple plant or wood spider) is one such herbal talisman. The dried seed pods of Harpagophytum procumbens look like a beige, desiccated starfish that has shrivelled into a claw with dozens of hooked protuberances. A perennial shrub that grows in the parched savannah of the Kalahari and parts of Madagascar, the plant looks like this even when alive. Then, when the rains come, it explodes with lush foliage and red, trumpet-like flowers. This is a metaphor for what is meant to happen to an arthritic hand or elbow after taking devil's claw: it springs back to life.
Traditionally, the herb is used in southern Africa and in Europe to treat arthritis, but research has shown it to have little effect on the condition. However, clinical trials have shown that standardised extracts of devil's claw can be useful for alleviating lower back pain. The most conclusive study was in 1996 (published in the journal Phytomedicine), when nine patients out of 51 taking devil's claw were pain-free after four weeks, compared with one out of 54 taking a placebo. The herb is also known to ease muscular pain and the discomfort caused by poor circulation.
Devil's claw extract is made from the shrub's dried, secondary tubers and contains chemical compounds from the iridoid glycoside family. It is also a source of "bitter principles" - substances that stimulate the stomach to boost production of gastric acid, improving digestion. Analysis shows devil's claw to be a source of aluminium, calcium, cobalt, iron, magnesium, phosphorous, sodium and tin. It also contains flavonoids and sterols (sugars with anti-inflammatory qualities) and compounds that act as a diuretic, stimulate the heart, lower blood pressure and raise blood-glucose levels.
However, because it increases stomach acidity levels, devil's claw can have dangerous side-effects for people with gastric or duodenal ulcers and those with gallstone problems. And, because of its effect on the heart, it should not be taken by people with cardiac arrhythmia (irregular heartbeat) or other heart problems - and there is evidence that it may stimulate the muscles of the womb in the same way. It is therefore unsuitable during pregnancy and - until its effects are better known - while breastfeeding.
In people outside these categories, devil's claw is well-tolerated in normal prescribed dosages - such as two 480mg tablets daily of standardised extract, equivalent to eating 4g of the powdered root. In trials involving patients with lower back pain, muscular tension and myalgia, this standard dose proved not only effective, but had none of the nasty side-effects associated with many conventional anti-inflammatory drugs. However, like many herbal remedies, it is known to have adverse effects when taken with some medicines. In particular, you should not self-treat with devil's claw if you are taking anti-diabetic drugs, tablets for cardiac arrhythmia or high blood pressure, or muscle relaxants.
Although devil's claw was not directly implicated, researchers at the University of Chicago reported in July that some herbs containing similar compounds can increase the effects of anaesthesia during surgery. As with all herbal remedies, consult a GP before taking this one.
Next time: valerian
