Used wisely, herbal remedies have much to offer
Good cooks love herbs for the variety of flavours they impart to food. An increasing number of Canadians, however, are discovering herbs may also enhance their well-being. As the use of complementary or alternative medicine grows, healthcare practitioners and consumers alike are demanding better and more objective information about the herbal preparations currently sold in Canada.
Here’s a look at four commonly used herbs and the kind of information about them that should be available to all consumers.
Evening primrose (Oenothera biennis) oil contains gamma linolenic acid (GLA), an omega 6 fatty acid the body uses in a variety of biochemical reactions. It appears the body-s ability to make GLA decreases with age. Individuals with specific medical conditions such as asthma, diabetes and eczema may have an increased risk for GLA deficiency.
It’s thus argued evening primrose oil may alleviate the symptoms of people with these conditions. Unfortunately, many of the claims made are not currently supported by scientific evidence – even the use of evening primrose oil by people with eczema or other skin conditions remains controversial. It’s also wide advertised as a treatment for the symptoms associated with menopause – despite the fact that research indicates it’s not very good at treating hot flushing or sweating. On a positive note, essential fatty acids such as those found in evening primrose oil may be good for promoting cardiovascular health.
Overall, evening primrose oil appears very safe, but it’s recommended patients diagnosed with mania or epilepsy use it with caution. Although there are no reports of drug interactions with the herb, people taking beta-blockers, lithium carbonate or anticoagulants should talk to their doctor or pharmacist before taking it.
Garlic (Allium sativum) has been used medicinally for centuries. Today, it’s best known for its cardiovascular effects. There’s scientific evidence garlic may help lower cholesterol levels, but claims that it can lower blood pressure are not supported by research to date. Studies of the diets of several large groups of people suggest increased ingestion of garlic may be associated with a decreased incidence of some types of cancer (especially stomach and colon cancer).
But it’s not all good news. Stomach upset and heartburn have been described following high doses of garlic (the equivalent of five or more cloves daily). Garlic may also be associated with bleeding problems in rare cases. It’s recommended that all garlic supplements be discontinued at least one week before any elective surgical procedures and that you inform your physician if you’re taking garlic. There is a wide variety of garlic products on the Canadian market. A dose equivalent to one to eight cloves (400-1200 mg of garlic powder) taken daily in divided doses appears to be effective. Questions about different dosage forms of garlic should be directed to your pharmacist.
The ginkgo (Ginkgo biloba) tree is the oldest known tree species on earth, which has led some to conclude that taking ginkgo products will increase one’s life span. Unfortunately there’s no scientific evidence to support these claims. Ginkgo has been extensively studied and found to cause a slight, but noticeable, improvement in the memory of patients with AlzheimerÕs disease and other types of dementia. Currently there’s no evidence that ginkgo will improve the memory of people who do not have any memory problems to start with. A typical dose is 40 mg of ginkgo extract (standardized to 24 per cent ginkgo-flavone glycosides) taken three times daily. Ginkgo may also help to improve the symptoms of people with a variety of circulatory disorders such as intermittent claudication (partial obstruction of blood flow to the legs). Research is continuing in this area. The most common side effect of ginkgo is a headache, which can occur if you take too large a dose too quickly. There’s also some evidence that in rare cases, ginkgo can cause bleeding problems. Anyone taking anticoagulant drugs should check with their physician or pharmacist before taking ginkgo.
There are several important things to remember about herbal medicines:
- They are medicines and you should let your pharmacist and physicians know if you are taking any herbs;
- There are a lot of claims made about herbs which are not supported by scientific evidence;
- Some herbs can be very helpful if used appropriately.
Heather Boon is an assistant professor in the Faculty of Pharmacy, University of Toronto, and author of The Botanical Pharmacy.