The vitamin boom: Do supplements really work?

New Zealanders increasingly turn to supplements for protection against everything from colds to Covid. But do our laws deny us access to products that may actually help us? Donna Chisholm reports.

Nowhere are New Zealanders’ conflicted attitudes to vitamin supplements better illustrated than in the Dunedin home of Dr Lisa Houghton, a professor of nutrition at the University of Otago, and her accountant husband Brett Dailey.

Ask Houghton whether it’s a good idea to take multivitamins and she’ll tell you the people who need them least are those who take them most; that we get the critical nutrients we need from our food. Apart from taking iron when she was younger, she doesn’t use them. Then she laughs and adds, “But my husband loves them.” Dailey, she says, has given each of their three daughters, now in their teens and early twenties, a multivitamin tablet each day since they were preschoolers.

All five have been vegetarians for several years and oldest daughter Erin is trying veganism, but Houghton, who does most of the cooking, ensures they get healthy, balanced meals. But Dailey says even before they moved to a plant-based diet, he offered multivitamins as a kind of dietary insurance policy. “From a young age, they had the chewable tablets and we just kept up with it the whole time. I always felt diet can’t be perfect every day, that’s for sure.” He says Houghton “doesn’t tell me not to do it, but sometimes she rolls her eyes at the supermarket when I’m buying them. I’m just trying to fill a gap.” He says although healthy meals are always available, the girls “don’t always eat everything they should”.

Dailey accepts that his attitudes are based more on his heart than his head, but he’s not alone. In New Zealand, research by market analysts IRI shows the vitamin and supplements market is worth $473 million a year – up 65 per cent on 2015 – with multivitamins the largest sector at about $40 million. Research in the US suggests supplement users are typically older, healthier, wealthier and Caucasian – a demographic that’s unlikely to be very different here. “It still stands that the people who take them the most need them the least,” says Houghton.

Categorised as medicines

Sales increased further during Covid. In the six months to August last year, sales of vitamins in the “cold and flu” category rose 8.9 per cent, when compared with the same period the year before, and sales of cold and flu products suggesting they could boost immunity were up nearly 6 per cent. And that’s with zero evidence that over-the-counter medicines make any difference.

Despite that, and the staggering cumulative cost, we rationalise that if they won’t hurt us, only our pocket, what’s wrong with a top-up just in case we go off the dietary rails from time to time. In December 2018, New Scientist magazine identified three groups for whom some supplements may be useful: women who are pregnant or trying to conceive should consider taking folic acid , which has been estimated to more than halve the risk of neural tube defects such as spina bifida; infants who are exclusively or partially breastfed may benefit from supplemental vitamin D, which is present at very low levels in breast milk; and adults over the age of 50 who may absorb less of certain nutrients, including vitamin D, because they produce less stomach acid.

Vitamin D and calcium supplements can increase bone strength and calcium supplements can reduce the risk of fractures. It’s also common practice for vegans to require supplementation with vitamin B12, which is not found in plants, although nut milks are often fortified.

Houghton says although physiological changes as we age can increase the need for some supplements, “Mother Nature does a lovely job of making sure we don’t need as much as we used to of some things, including iron”.

But at the University of Canterbury’s School of Psychology, Speech and Hearing, researcher Professor Julia Rucklidge is frustrated our laws mean that even when there is evidence that some supplements – such as a micronutrient combination she uses in her clinical trials – have a therapeutic effect, they can’t be sold in sufficient strength because they would then be categorised as medicines, which would require them to be regulated under the Medicines Act. It’s the reason dietary-supplement manufacturers are deliberately vague when they promote their products and avoid therapeutic claims, mostly resorting to the nebulous suggestion of “supporting” or “promoting” a bodily function such as sleep, joint, brain or digestive health. At present, dietary supplements are regulated as “foods”, so are not tested for efficacy or toxicity.

Rucklidge wants micronutrients for which there is evidence of benefit to be allowed to be sold in therapeutic doses without having to be categorised as medicines, because they have a strong track record of safety. She says they should be regulated under their own act, not one written for pharmaceuticals. “I want people to be able to make informed choices about improving their own mental health through supplements, for which there is a lot of evidence. They don’t need to be legislated at the same level of a medicine because the risk is so much smaller. It’s much harder to harm yourself with a nutrient than a drug.”
She says consumers shouldn’t simply take very high doses of existing supplements to try to reach a therapeutic dose because the nutrients work synergistically. “You might push one of the nutrients into an area where you start to be concerned about toxicity.”

She says an Annals of Internal Medicine article “shows outdated thinking. If you supplement with one nutrient and don’t balance it with others, you will run into problems, as they showed.” But she says this has little relevance to the approach she is taking in her research.

Rucklidge has been studying the effects of high doses of micronutrients on people with a psychological problem such as attention deficit hyperactivity disorder (ADHD), stress and pre-menstrual syndrome, and in small clinical trials has found that those who took them improved their well-being and symptoms more than those taking a placebo or an active treatment.

She uses the same set of micronutrients in all her studies. It contains vitamins A, C, D, E and all the Bs, magnesium, calcium, iron, phosphorus, iodine, zinc, selenium, copper, manganese, chromium, molybdenum, potassium and some amino acids. The nutrients are based on a formula developed in Canada, where she gained her PhD before coming to New Zealand in 2000. They assist in the manufacture of neurotransmitters as well as in other biochemical reactions and perhaps also alter the diversity of the gut microbiome. Most reports about the effects of supplements focus on physical, not mental, health, she says.

Rucklidge believes the evidence for the effects of nutrition on mental health is collectively overwhelming and wants nutrient interventions – diet manipulation and/or extra nutrients – to be mainstream in public mental health services. Of course, good nutrition is different from added nutrients – experts advise we should improve our diet before taking pills to plug the gaps. Supplements don’t contain all the nutrients and antioxidants in fruit and vegetables, and the nutrients in food often function in combination with each other. “Manipulate your diet and take out all the ultra-processed food. You’re not going to harm yourself by doing that,” says Rucklidge.

Science-based approach

Clinical nutritionist Ben Warren, who founded “scientific holistic” health business BePure nine years ago, was three years into a doctorate in mental health and nutrients with Rucklidge when Covid hit, disrupting his research. He’s since abandoned his PhD, but still tries to bring a science-based approach to his business. As well as offering a range of tests including genetics, measures of organic acids, urine metabolites, blood markers and inflammatory levels, BePure sells a range of supplements including multivitamins, fish oil, zinc, probiotics and energy and wellness “packs”. They are pricy: his multivitamins cost $119 for a two-month supply or $69 for one month, and two months of his gut-health product nearly $150.

But Warren says his contain much higher doses of most nutrients than rival products and the price is therefore relatively cheaper. Even then, customers are advised to take five of the multivitamins a day. A therapeutic dose for mental-health benefits, according to Rucklidge’s studies, is much higher still.

Warren says he’s “way down the rabbit hole” of supplementation, and takes 36 pills a day – 18 in the morning and 18 in the afternoon. He swallows two handfuls during the interview, after explaining why: “That’s for the liver, that’s high-dose zinc, that’s curcumin, that’s co-enzyme Q10 … there’s fish oil, a herbal product for the kidneys, more zinc with B6, the BePure multivitamin and a special form of B12, because I have a genetic mutation that means my body poorly uses it.”

To those who say a half-hour jog every day might be better for him, Warren argues he struggles to fit in the time to go for a run or to the gym, even though he has no trouble completing strenuous workouts when he does. He believes it’s very difficult “if not impossible” to get all the nutrients we need from the modern diet.

Rucklidge says one of the biggest problems is that rules around labelling and therapeutic claims mean consumers are simply left in the dark about what would help them and how much to take.

Aggressive selling

Mark Honeychurch, former chairman of NZ Skeptics and secretary of the Society for Science Based Healthcare, says most people just don’t get the nuance of the wording of supplement ads. “I don’t think the average person on the street, when they see the word ‘supports’, knows that it’s about the Advertising Standards Authority considering that this isn’t a therapeutic claim.” He says although the major companies, which sell the supplements commonly available in supermarkets, for example, toe the legislative line, many other sellers of fringe products have no such scruples. “They’re so ubiquitous that it’s something of a whack-a-mole to stop them.”

Equally concerning is the sale of unproven supplements – and, worse, homeopathic products – in pharmacies. “I get that they want to make money and I get it’s a cut-throat business and the amount of money they can make from prescriptions is getting less and less. But it appears that they have been using the reputation they have to sell people basically ineffective supplements and sometimes they do it really aggressively. It’s rare that you walk into a pharmacy and they don’t have walls full of vitamins and supplements. But on top of this, pharmacy staff and pharmacists are quite often actively pushing these things. Having gone in asking when I’m legitimately ill, they’ll say, ‘You should buy this high-dose vitamin C or think about aged garlic leaf.'”

Despite dietary supplements having a generally strong track record of safety, there have been high-profile exceptions. In 2018, the Director-General of Health issued a public warning about the risk of liver damage from the natural product Arthrem, sold to “support joint health and mobility”. The makers have since agreed to stop selling it.

In January 2019, three Healtheries detox teas were withdrawn from sale after a Consumer NZ investigation showed they contained the Medsafe-regulated laxative senna without approval.

The Pharmacy Council’s code of ethics, which until March 2018 required any product sold to have credible evidence of efficacy, now says pharmacy staff should tell consumers if products don’t have scientific evidence that they work. Honeychurch and others believe that’s simply not happening and that even homeopathic products are actively promoted.
Professor Clare Wall, who heads the University of Auckland’s master of health sciences in nutrition and dietetics programme, says pharmacists and their staff need to be “upskilled” about the advice they’re offering, because most of their information would come from the supplement companies themselves.

“I’m not saying pharmacists don’t abide by those policies [the council’s code of ethics], but I’m not sure whether they even have that opportunity to discuss that with people who are coming into the pharmacy and buying the supplements. I know for pharmacists there is a tension because it is a business.”

She says her local pharmacy sold powdered broccoli that could be sprinkled on food as a “concentrated antioxidant”. “It sounds reasonable, doesn’t it? It’s probably harmless, but totally unnecessary.” So, isn’t it simply a case of caveat emptor? “No, it’s still misleading because there is no research to say that making broccoli into a powder and concentrating it is going to be better for you, and that’s what it implies.”

She believes supplement companies target pharmacies because of the apparent legitimacy they provide. The value of dietary supplements sold in pharmacies rose from $105 million in 2015 to $176.8 million in 2019, and pharmacies have around 37 per cent of the total market share.

Pharmacy Council chair Jeff Harrison says there would be important “unintended consequences” if complementary and alternative medicines were removed from pharmacies, because consumers would then entirely self-select, without a pharmacist to either suggest a product for which there was better evidence or advise them to see a doctor or other health professional. “At the same time, I accept there is credence given to products by their being available in pharmacies. This is a dilemma, but I think it illustrates the situation is not quite as binary as people might like to believe.”

Attempts to regulate supplements under the Natural Health and Supplementary Products Bill stalled in 2017 when the proposed legislation was shelved. The Government is now developing the Therapeutic Products Bill to update the Medicines Act. The Health Ministry says natural supplements are “inadvertently captured” by the Therapeutic Products Bill, but they are expected to be excluded by the time it returns to Parliament. It says this will allow work to continue on a separate regulatory regime for supplements. Said a ministry spokesperson: “The Government recognises the need for comprehensive and fit-for-purpose regulation of natural health products and dietary supplements, and is exploring how best to achieve this.”

Right nutrients

Brett Dailey says he doesn’t notice that the supplements make him feel any better, but he’s happy to persevere. Daughter Erin is taking iron and vitamin C rather than multivitamins now that she’s eating more vegan food since leaving home. “If you’re on a restricted diet, it’s your responsibility to make sure you’re getting the right nutrients.”
Youngest sibling Ryan was the first in the family to become a vegetarian. She and sister Kennedy say they’re so used to the daily regime that they don’t even question it, and they admit their diet can fall short given their taste for sweet snacks and chips.

Houghton, however, says the evidence for vitamin supplements being useful as a nutritional-insurance policy is usually based on theory because it’s practically impossible to do the clinical studies necessary to prove it.

“In the case of supplements, we can’t take away a nutrient entirely to create a placebo – people consume nutrients every day in the food they eat.” She says the evidence for benefits usually comes when people are deficient in some nutrients, which most New Zealanders aren’t. However, the country’s last nutrition survey was more than 10 years ago and Houghton says we don’t have a clear picture of what we’re eating and whether we are at risk of lower intakes of some nutrients.

In past surveys, most Kiwis had low intakes of calcium, selenium and vitamin D, and one in four had inadequate intakes of zinc. “A better understanding of the gaps in the diet of the population would allow better recommendations for the type and dose of supplements to take.”

Until then, Dailey – and many others – will keep heading to the supermarket supplement aisle. Houghton and her colleagues, meanwhile, will linger in the fruit and vege section.

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