With winter upon us, what are the best herbal remedies to deal with colds and flu? Echinacea is one that is well known, with good-quality products available (see PROOF! vol 6 no 7), but a close second in the popularity stakes is the herb goldenseal.
Goldenseal (Hydrastis canadensis) has a long history of use. Originating in North America, it was a popular Native American remedy for sore throat, fever, digestive disorders, diarrhoea and urinary tract problems. It was also applied externally to heal snakebite, mouth sores, and inflamed eyes and skin.
European settlers took it up so enthusiastically that the plant was almost driven to extinction. Today, it is still an officially endangered plant, and all the goldenseal we buy should be from cultivated plants.
With the advent of modern laboratory analysis, at least some of goldenseal's traditional properties appear to be confirmed. It is a broad-spectrum antibiotic, effective against disease-causing bacteria such as Chlamydia, Escherichia coli and Salmonella (Antibiotics, 1976; 3: 577-88). Goldenseal has also proved ''''very active'''' in the test-tube against all 15 strains of Helicobacter pylori, the bacterium that causes stomach ulcers (Phytother Res, 2003; 17: 217-21). It can also slightly boost immunoglobulins, key players in the immune system (Immunol Lett, 1999; 68: 391-5).
The medicinal properties of goldenseal are concentrated in its roots as two active ingredients, berberine and hydrastine. Berberine is an antibiotic whereas hydrastine is an astringent.
Berberine is also 'anticholinergic' in that it is a muscle relaxant in, for example, the bladder, intestines and airways (Pharmacol Toxicol, 2000; 87: 218-22). In the lab, it has shown activity against streptococci, one of the major causes of sore throat (Planta Med, 2003; 69: 623-7).
Yet, despite goldenseal's promising chemistry, there have been few clinical trials of the herb itself. Most evidence has been collected in developing countries on berberine alone. Studies have shown that 200-400 mg of berberine is effective in both cholera and dysentery, and is often superior to tetracycline (Dan Med Bull, 1996; 43: 173-85). In malaria, too, berberine has been demonstrated to be almost the treatment of choice, as it can kill the parasites causing the disease even when they have become resistant to conventional drugs (East Afr Med J, 1997; 74: 283-4).
Berberine is also popular in modern Chinese medicine, where it is used for heart problems - often alongside conventional drugs. One study of more than 150 patients with congestive heart failure showed that 1.2-2 g/day of berberine not only relieved many of their symptoms, but also extended their lives. This is thought to be because berberine dilates blood vessels (Am J Cardiol, 2003; 92: 173-6).
However, there appear to have been no clinical trials carried out in the West - which is odd, given that goldenseal has been popular since the 18th century, and was even listed in the US National Formulary until 1955. In particular, there is no research evidence to support its use for colds and flu - one of the main reasons for its current popularity, and why it is one of the top five best-selling herbs.
In the 1990s, goldenseal received an extra boost to its celebrity when it was rumoured to mask the presence of illegal drugs in urine. However, officially this is said to be untrue, although there is no evidence to support this denial.
Helping or hindering?
Today, goldenseal's prime reputation is as a 'herbal antibiotic', with herbalists citing some of the studies quoted above. The problem is that these are mainly test-tube findings that are not necessarily applicable to the real world.
The fact is, goldenseal cannot be used as a herbal alternative to conventional antibiotics. Although berberine is an antibiotic, it is poorly absorbed by the body - 400 mg taken by mouth ends up as only 100 mcg in the bloodstream, or 0.5 per cent of the amount needed to kill bacteria (Bensky D, Gamble H, Chinese Herbal Medicine: Materia Medica, Seattle, WA: Eastland Press, 1986). Goldenseal itself contains relatively little berberine.
However, goldenseal may plausibly have an antibiotic effect when used externally - for example, as a mouthwash for sore throat or on wounds. It may also act directly on urinary bacteria since berberine is heavily excreted in the urine.
As for goldenseal's use for colds/flu, not only is there no scientific evidence of benefit, but it may cause genuine harm. ''''Taking goldenseal too early in a cold can have negative effects'''', says American herbalist Paul Bergner. ''''It may overstimulate the mucous glands, ultimately causing dry membranes.'''' In other words, goldenseal may act just like conventional cold remedies, drying the mucus and making the cold appear to get better, while actually only inhibiting the healthy inflammatory reaction, weakening the immune response and prolonging the illness.
The problem is that goldenseal has paradoxical effects. Its active ingredients both stimulate and inhibit the mucous membranes. Thus, goldenseal is known as a mucous membrane 'alterative' in that it can increase a deficient mucus flow, but decrease an excessive flow.
''''I believe goldenseal acts as an 'antibiotic' to the mucous membranes,'''' says Bergner, ''''not by killing germs directly, but by increasing the flow of healthy mucus, which contains its own innate IgA antibodies. This effect is unnecessary in the early stages of a cold or flu, when mucus is already flowing freely.''''
In short, for winter colds, you may be better off without goldenseal altogether although, if you do decide to take it, you should at least know what you 're buying.
For this lab test, we asked a specialist lab to analyse each of nine leading brands of goldenseal for its active ingredients.
Natural variations in the quantity of active ingredients in the raw plant material can range from 2-10 per cent. Although not mandatory, a generally agreed-upon 'standardised' amount of active ingredients for goldenseal is at least 8 per cent. However, only one of our test products managed to meet this 8-per-cent level.
Also, given the high cost of the raw plant material ($60 or lb36/lb), manufacturers may be tempted to adulterate their products with lower-priced substitutes - a practice the herbal trade calls 'spiking'. Goldenseal provides an ideal opportunity for spiking as there is a cheaper alternative called Oregon grape root (Berberis aquifolium), which is chemically similar to goldenseal, yet costs a mere $2.20 or lb1.32/ lb - one-twenty-fifth the cost of goldenseal. The main difference is the active ingredients: compared with goldenseal, Berberis contains a higher ratio of berberine to hydrastine.
According to the American Botanical Council, any goldenseal product with a berberine-to-hydrastine ratio of more than 2:1 should be considered 'suspect' (HerbalGram, 2001; 53: 56-9). When US pharmacologists tested 17 American goldenseal products in an analysis similar to our own, they found several with an atypical ratio of active ingredients, suggestive of spiking (J Am Pharm Assoc [Wash DC], 2003; 43: 419-23).
What did PROOF! find in our UK survey? In our product ratings, we've ranked them primarily by value for money - expressed as total active ingredients (TAIs) per lb. Other criteria were: helpful and accurate labelling; sensible dose formulation; and organic cultivation. Because goldenseal is particularly useful in liquid form (see box on the right), we have counted that as an extra plus.
Distributor: Organic Nutrition
Price: lb10.95 for 60 350-mg capsules
Organic Nutrition is a young company based in West Sussex, producing a range of exclusively organic products claimed to be ''''manufactured using gentle processes to ensure maximum strength''''. This pack of powdered goldenseal capsules is high strength, delivering 18 mg of berberine and 13 mg of hydrastine per capsule - the highest in our lab test - making it the best value for money at 268 mg of TAIs/ lb. At 9 per cent, its TAIs are well up to international standards. This is let down only by the relatively uninformative label.
Price: lb10.99 for 45 425-mg capsules
A modest offering from a UK company based in Kent, this product appears to be made with genuine powdered goldenseal and is good value for money at 134 mg of TAIs/ lb. The pack sensibly cautions against use by pregnant or nursing mothers, but each individual capsule may be somewhat on the high side for daily dosing.
Distributor: Organic Nutrition
Price: lb10.95 for 50 mL
Organic Nutrition again scores well for their liquid version. Although fourth in terms of price (delivering 65 mg of TAIs/ lb) and of only moderate potency (13 mg of TAIs/mL), being both a liquid and organic propels it into third place.
High-potency Golden Seal
Price: lb13.99 for 50 mL
Despite what it says on the label and given that wild goldenseal is an officially protected plant, we deduce that this product comes from organically cultivated plants. One mL is claimed to contain ''''the equivalent of 200 mg of herb''''. Because of the herb 's natural variability, this statement is difficult to confirm. However, the product is high in both berberine (10 mg/mL) and hydrastine (7 mg/mL), so the high-potency claim is justified. However, it 's pricey - you get only 61 mg of TAIs for your lb.
Price: lb13.95 for 50 520-mg vegicaps
Solgar offers an even heavier capsule than Nutriscene, but the strength is more apparent than real. The label claims that the powdered capsules come from goldenseal root (the richest part of the plant for TAIs), but our lab detected 18 mg of berberine and 5 mg of hydrastine per capsule - an unusual ratio of nearly 4:1. Nevertheless, you get a reasonably generous 84 mg of TAIs for your lb.
Price: lb7.95 for 60 125-mg capsules
Unusually, this product has a 'quality guaranteed' certificate of analysis from a US lab, stating that the capsule is 10-per-cent TAIs. However, our lab found only 7 per cent. (The certificate also appears to refer to a 250-mg capsule.) This confusing claim mars an otherwise good product, with a sensible capsule size that allows a flexible dose, and offers 63 mg of TAIs/ lb.
Golden Seal Root
Distributor: Herba Naturelle
Price: lb18.95 for 100 mL
This relatively large bottle of liquid goldenseal is let down by the contents - just 7 mg of TAIs per mL. The labelling is also minimal, merely suggesting a recommended daily dose. This product is ultimately poor value, offering only 44 mg of TAIs for your lb.
Distributor: Nature's Answer
Price: lb13.95 for 30 mL
A low-volume product, but with a seemingly high level of TAIs - over 16 mg/mL. However, our lab analysed the berberine-to-hydrastine ratio as 3:1. The pricetag is also high - you get only 34 mg of TAIs/ lb. The label says the product ''''Promotes A Healthy Immune System'''', but human evidence of such an effect appears to be lacking..
Distributor: Nature's Plus
Price: lb11.19 for 30 250-mg capsules
Although Nature's Plus promises that each capsule is ''''standardized to a minimum of 10% (25 mg) hydrastine and berberine'''', our lab found something very different inside each capsule - just 7 mg of berberine and a miserable 0.5 mg of hydrastine. These figures strongly suggest that at least some of the contents are not derived from goldenseal plants. It also means that you get only 23 mg of TAIs/ lb.
Distributor: Natural Nutrition Centre
Price: lb17.95 for 60 500-mg capsules
We've given this product the lowest possible rating as it isn't goldenseal. Our lab found no hydrastine, so it's not Oregon grape root either. It does contain 9 mg of berberine/capsule, or 30 mg of TAIs/ lb.