In a world where everyone seems to be obsessed with their health, it's no wonder alternative and complementary therapies are big business.
Globally they are estimated to be worth around $52 billion a year.
And in New Zealand, where about half the population takes dietary and health supplements, the natural products industry contributes an estimated $1.4 billion a year to the economy.
In fact the industry here has grown by 40 per cent in the last five years.
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New Zealanders are now confronted with a bewildering array of potions, pills and powders, which are supposed to cure or alleviate almost every ailment known to humankind.
They can also call on the services of a multitude of alternative health practitioners such as homeopaths, naturopaths, osteopaths, chiropractors, acupuncturists, iridologists, reflexologists, aromatherapists, massage therapists and goodness knows who else.
ACC payments to osteopaths, chiropractors and acupuncturists alone have more than doubled in the past decade and are now around $40 million a year.
It's a crowded marketplace where consumers are spoilt for choice, a situation that alarms many members of the medical establishment who use words such as "quackery" and "witchcraft" to describe the treatment and medicines offered by some members of the natural health brigade.
Sour grapes and patch protection you might think, but the doctors won't have a bar of that, maintaining that most alternative therapies are, at best, of little benefit, and, at worst, positively lethal.
'Quackery' or not?
Tauranga-based Shaun Holt, who has degrees in medicine and pharmacy, has a foot in both camps.
The natural remedies researcher has written books on remedies that really work and complementary therapies for cancer, and is in no doubt that some alternative and complementary therapies are effective.
But he warns consumers to do their homework before embarking on a course of treatment that could have adverse consequences.
"There are some useful complementary and alternative medicines and therapies which we should be using more," he told the Bay of Plenty Times Weekend.
"But there are also a lot that are a waste of time and money or even harmful. It is estimated that only around 5 per cent are supported by good scientific evidence (but) there are hundreds of therapies, and so 5 per cent of hundreds means that there are lots of useful ones."
Holt advises New Zealanders to check out research institutions such as the Mayo Clinic in the US (www.mayoclinic.org) before committing to a therapy or medicine. He also counsels them to be sceptical of glowing endorsements from high-profile personalities and public figures, including doctors and scientists.
Should that give consumers any reassurance about the efficacy and safety of the therapy in question?
"Absolutely not ... The only reassurance comes from good research."
But for many of us, it's hard to resist the allure of natural remedies when some of the smartest people on the planet choose to use them.
Apple co-founder Steve Jobs deliberately delayed his recommended treatment for pancreatic cancer in order to take alternative medicines.
But by the time he opted to undergo conventional treatment the cancer could not be contained and he died in 2011, provoking American cancer specialist Ramzi Amri to say that "it seems sound to assume that Mr Job's choice for alternative medicine has eventually led to an unnecessarily early death".
Closer to home renowned New Zealand scientist Sir Paul Callaghan, who was diagnosed with aggressive bowel cancer, took a break from chemotherapy to trial high-dose vitamin C infusions.
In his blog at the time he said: "Let me be clear. I do not deviate one step from my trust in evidence-based medicine."
However, if there was a potentially effective but unproven drug, "why would I not try it," he said. "Am I mad? Probably."
But in 2012, after analysing data from six months of blood test results, he was forced to concede that "there is absolutely no evidence of any beneficial effect of high-dose intravenous vitamin C in my case."
He said he wanted to make the results of his experiment public because of the risk that his use of vitamin C would be used to falsely promote the therapy.
The way people promoted products without evidence was "quite repellent".
He said people with cancer had the right to try unproven therapies themselves, but should do so in consultation with their specialist or GP.
Sir Paul died a few months later at the age of 64.
At the time Holt said he was not surprised the treatment had not worked, "though I really wish it had".
So just what alternative therapies and medicines does Holt find beneficial?
"In general, good therapies with proof they can help and which I recommend include: massage therapy, aromatherapy, music therapy, hypnosis, yoga, tai chi, Omega-3 fish oils for many conditions, multi-vitamins, ginger, medical honey for wounds and skin diseases, zinc for colds, honey for cough, TENS machines and St John's wort." Also on his list of positive products is marijuana, which he believes has excellent medicinal properties.
The cannabis debate
"In my view, it is a scandal that it is not legal for medical use. "There is no doubt that marijuana is very effective for a lot of difficult medical problems, including pain, nausea and stimulation of appetite.
"Politicians have made it illegal for personal use, wrongly in my view, but even so it makes no sense that it should not be used for medical reasons."
Holt believes alternative and complementary therapies can be helpful in the treatment and management of two common illnesses in New Zealand - cancer and depression.
"Around one in 10 adults take antidepressants and they are very hard to stop taking. Natural products are better than antidepressant tablets. A study comparing Omega-3 fish oil to fluoxetine (Prozac) for severe depression found that the fish oil was better.
"Others that work include B vitamins and S-adenosyl methionine. Exercise and light therapy are also very good and proven to be effective."
... not only is there no good evidence that they work, there is no possible way they can work
And he says cancer patients' symptoms, which can include stress, anxiety, pain, nausea, fatigue and depression, can be alleviated with complementary medicines that are used in conjunction with conventional medical treatment. Effective complementary therapies for cancer included ginger, medical honey, valerian and zinc as well as massage/music therapy, hypnosis and meditation, he says.
About 80 per cent of all the companies involved in New Zealand's natural products industry, including all the major brands and manufacturers, belong to Natural Products NZ which describes itself as the voice of the industry.
It says New Zealand has a track record of identifying and exploiting the medicinal uses of natural products, from harnessing the antibacterial properties of manuka honey to identifying a non-calorific natural sweetener.
Demand for natural health
Executive director Alison Quesnel says the increasing global demand for natural health products is being driven by people who want to take control of their own health and take steps to prevent major disease where possible.
She says there is consistent year-round demand for arthritis and anti-inflammatory preparations such as Omegas 3 and 6 in the form of fish and flaxseed oils, and a rising demand for women's health products and brain health products.
"Probiotics, particularly for gut health, are another rising star.
"The growing popularity of natural products reflects growing need for affordable healthcare options that complement or replace pharmaceutical products."
Ms Quesnel says New Zealand's leading manufacturers base their products on comprehensive research and, where possible, clinical trials.
"Natural products are safe if taken as either prescribed or recommended on the label.
"We encourage people to read labels thoroughly and consult with a qualified health professional beforehand, particularly if they are already taking other forms of dietary supplements and/or pharmaceutical medications."
Beware of cowboys
Asked whether there are many cowboys in the industry making money from shonky products she says: "Although there are some cowboys out there, just as is the case with any type of product or service, they are in the minority.
"Our members adhere to a strict code of ethics and we actively enforce this so as to maintain high product quality, safety and efficacy standards."
One of those members is Health House, which last year opened a state-of-the-art manufacturing/distribution facility and retail shop in the Tauriko Business Estate in Tauranga.
The business was started by David Coory whose lifelong passion for natural health products was triggered when he had a heart attack.
Keen to understand what provoked the coronary he ended up writing a book entitled Stay Healthy By Supplying What's Lacking In Your Diet.
The book focused on the health benefits of minerals and vitamins, and led Coory to develop a complete mineral/vitamin supplement tailored for the needs of New Zealanders.
From this, Health House was born in 2003, the company now being run by Coory's son, Mike, and employing 20 staff.
Mike Coory told the Bay of Plenty Times Weekend that the business is thriving, sending out more than 600 orders a week. "Health House customers are very passionate about the products and, while a lot of them are older, they share the Health House philosophy of quality natural health products that work.
There's strong, compelling, clinical evidence that chiropratic is as good as anything else out there. It doesn't mean it's superior but it's as good as anything else.
"Younger family members and the majority of new customers are referred by existing customers."
Coory says the business originally sourced its products from contract manufacturers but in 2008 an opportunity arose to acquire a facility in Tauranga, allowing it to have full control over manufacturing and quality.
"We introduce new products based on customer demand and have recently made available a potent Turmeric (Circumin) capsule and a new vitamin C complex chewable tablet."
Groundbreaking health products
Companies such as Health House are providing a valuable service to consumers, according to Holt, who trusts it to make groundbreaking medical honey products on his behalf.
What riles him are those who sell products or provide services which, in his opinion, are completely ineffective or downright dangerous.
The reason he spoke out against things like homeopathy and chiropractors was that "not only is there no good evidence that they work, there is no possible way they can work".
He says people taking homeopathic products, which are "diluted to such a degree that not a single molecule remains", are deceived by the placebo effect, and do not attribute improvements in their health to other treatments or lifestyle changes.
"The lunacy of homeopathy can be summed up by a real product that is available from a main UK supplier. "It's called Berlin Wall and consists of dust from the Berlin Wall, diluted until none remains, and sold to people to help them stop feeling repressed.
"Although homeopathic products themselves do no harm as they contain no active ingredients, there can be serious problems when people use them instead of real medicines."
Gwyneth Evans, of the New Zealand Council of Homeopaths said: "Ask anyone who has experience in homeopathy whether it has worked or not, you will get a positive answer."
Research director of the New Zealand College of Chiropratic Heidi Haarik responded: "There's strong, compelling, clinical evidence that chiropratic is as good as anything else out there. It doesn't mean it's superior but it's as good as anything else."
Given the plethora of natural products in the marketplace, consumers face a daunting task sorting the wheat from the chaff. But help is on the way.
Due to become law this year is the Natural Health and Supplementary Products Bill, which will regulate the manufacturing and selling of natural health products and strengthen rules around which ingredients and health benefit claims can be made.
Claims made about the benefits of such things as vitamins will need to be backed by evidence under the new system, a move that has been welcomed by Natural Products NZ, which says it will help the banning of such products as a "miracle" Ebola cure sold by a "health and healing" church last year.
The potentially fatal concoction contained chlorine dioxide, a potent bleach used for industrial water treatment and stripping textiles.
Holt, a member of the expert advisory committee for the bill, says the current laws governing the manufacturing and selling of natural products are "a mess" and if the Bill "gets it right, it will be a big step in the right direction and great for consumers".