Herbal Supplements: Are they safe?
Last October a study done at the University of Guelph received a lot of publicity because it indicated that herbal supplements may be contaminated and could be dangerous.
The study was published in the journal BMC Medicine and indicated that 44 herbal preparations supplied by 12 different manufacturers were tested using a new method called DNA barcoding.
Although this may sound very scientific, the truth of the matter is that when you analyse products scientifically there are two basic methods; qualitative and quantitative. These words may sound alike but qualitative analysis is looking for the presence of specific compounds in the preparation and quantitative analysis tells you how much of that compound is actually there.
I am sure many of you have watched crime shows on television or in the movies that show how minute traces of DNA can solve a murder or a rape that occurred twenty years ago. That old 20 year carpet may still have traces of the victim’s DNA. That is why this new method of DNA barcoding does not work when testing herbal supplements.
The majority of herbs are grown in the wild. There are no farms for gingko biloba, milk thistle, stinging nettle or even Echinacea. Many of these herbs are found in your garden and are grown in soil that contains many other compounds such as pollen, walnuts that fall off trees, chemicals from acid rain and host of other plant species whose seeds are blown by the winds in spring and fall.
If we test an Echinacea plant to determine if it contains Echinacea, we will of course find this substance. We can then measure how much was in the plant. However, if we use DNA barcoding we will find the DNA of almost everything else that plant came in contact with. We may find the DNA of a few species of worms. We may find some nut species DNA from a few nuts buried by a squirrel nearby. In fact there is almost no limit to the hundreds of varieties of DNA we will find because of the newer modern methods of detecting even the slightest traces of DNA species.
These trace amounts are so minute that they could only be seen, not with a regular microscope but with an electron microscope that can also see viruses. There is not enough of any of these compounds to produce any ill effects but their presence is enough to scare people away from ingesting herbal products.
The University of Guelph study, headed by Steven Newmaster, a professor of botanical science and botanical director of the Bio Diversity lab in Guelph, showed that 2 of the 44 products were pure and unadulterated. Sixty per cent of the herbal supplements had other plants that were not on the label; 32 per cent had other extraneous ingredients and 20 per cent had rice and soya fillers that were not on the label.
Unfortunately, if you read the entire study from top to bottom, none of the manufacturers were listed in the report so we do not know who produced the so-called bad contaminated products. In Canada our supplement and pharmaceutical manufacturers adhere to a policy known as GMP, good manufacturing practices, in which there is actually more product in the bottle than is on the label. For example when you purchase a bottle of Vitamin C that is labelled to contain 1000mg per capsule, each capsule actually contains anywhere between 1030 and 1050 milligrams so that by the time the product reaches its expiry date it has no less than 1000mg of Vitamin C per dose.
In the first place, those people who had fillers in their product that were not on the label should be identified. Secondly, in spite of the DNA barcode testing, each bottle should have been tested not only to find the presence of the actual herb, but to find the amount of that herb and if it conformed to the stated amount on the label.
The result of this study is something that is very flawed and incomplete so why was it done in the first place and why use such an unusual method?
The answer to that question is money. Since Dr.Steven Newmaster is the head of the Bio Diversity division at the University of Guelph, DNA barcoding is his research project and he would like to sell this technology to all manufacturers of plants, vitamins and pharmaceuticals. After all, DNA is the newest and latest technology and if his new methods were adapted by industry, he may become a rich man and the University of Guelph would earn royalties forever.
The problem that I stated earlier is the fact that plants are grown in the wild and contain trace amounts of DNA of many other plants and even creatures that crawl in the earth. DNA barcoding would probably be an excellent tool for the pharmaceutical companies that make all their drugs from synthetic compounds and not natural ones. This would insure no contamination in the finished pharmaceutical. However, when it comes to herbs that grow naturally in our environment, this methodology cannot be used and the test results only create a lot of panic and fear.
Since our government passed the National Health Act in 2004, Health Canada tests all products sold in Health Food Stores and insures that what is on the label is in the bottle. By the end of this year all natural products will have an NPN number and be registered with Health Canada. Many of you may not like Health Canada but their job is to ensure the safety of the food, supplements and drugs that we take and overall they do a very good job.