Message in a bottle

Does your doctor know about all the pills you take? We spend a billion dollars on multivitamins and other dietary supplements every year, but are we taking them safely—and do we really need to take them at all? Sally Blundell investigates.

We spend a billion dollars on dietary supplements every year, but do we really need to? Should we believe recent headlines claiming they do more harm than good? Sally Blundell finds out how to stay safe when taking supplements—and when eating the right food is even better

Photo: Oppenheim Bernhard / Digital Vision / Getty Images

Thirty-year-old Nelson physiotherapist Louise Sawers has her health sorted. She has a good diet, she exercises, she radiates good health. Every day she takes Hydraplenish supplements—a source of hyaluronic acid—for skin and joints, lysine supplements for cold sores and a general multivitamin containing zinc, folate, selenium and B vitamins. She keeps her GP informed of what she is taking and has regular blood tests.

“I’m quite fussy about what I take,” she says. “I don’t take anything because it’s a fad. The GP said I should take an iron supplement but it didn’t agree with me, so I adjusted my diet. Now I eat a diet rich in iron and vitamin C.”

Louise is not alone. New Zealanders spend a small fortune—approaching one billion dollars a year—on minerals, vitamins, amino acids and essential fatty acid supplements. The 1997 National Nutrition Survey (more up-to-date results from the 2009 survey aren’t yet available) found that 40 percent of men and 43 percent of women took supplements regularly, the most common being multivitamins and minerals.

The same survey found that the people most likely to take supplements are those who, like Louise, already pay careful attention to their health. So why are healthy people taking so many pills? Is it just uninformed guesswork, a faddish response by the worried well—or is it well-considered health-consciousness?

Some say it’s a habit that started in the 1970s, when the popular belief that taking vitamin C could ward off the common cold spread as quickly as the virus itself. Others say supplements are just a modern-day delivery system for the traditional soups, brews, poultices and herbs we’ve treated ourselves with for generations: St John’s Wort for depression, kava for nerves, evening primrose oil for PMS and B vitamins for stress.

But the days of supplements being seen as ‘chicken soup in a pill’ are over. The so-called ‘bioactives sector’ is big business, clocking up $760 million in revenue in 2007. According to Natural Products New Zealand, the sector is on track to achieve its target of $1 billion by 2013. Pioneering research into the field of epigenetics is gaining new insights into individual genetic responses to certain foods and nutrients, offering the potential for further research and development— and new extremes in dietary treatments.

As more supplements flood onto the market, headline-grabbing reports are questioning not only whether natural health supplements work, but whether they’re safe.

In 2008 the respected Cochrane Collaboration, an independent healthcare network, published findings claiming there was no evidence that antioxidant supplements prevent many diseases and, worse, that taking vitamins A and E may actually increase your risk of mortality. The study quickly came under fire for not including causes of death (which may have had nothing to do with supplement use), for not using all the available studies (only 67 of the 814 available), and for focusing on the wrong form of Vitamin E (alpha-tocopherol, which actually depletes the gamma-tocopherol that protects people from cancer).

Earlier this year an NZ Herald headline shouted: “Major research finds link between multi-vitamin pills and breast cancer”, reporting that a Swedish study found women who take daily multivitamin pills are nearly 20 percent more likely to develop breast cancer. But dig deeper, and it turns out that the 20 percent increase was the relative risk; the study found a 0.32 percent risk of breast cancer for women taking multivitamins regularly, compared with a 0.26 percent risk for non-vitamin-takers—a difference in absolute risk of less than 0.1 percent.

The very same week, BusinessWeek cited new research claiming that women who take multivitamins and calcium supplements had a reduced risk of developing breast cancer. Days earlier, a Korean study concluded that women with the human papilloma virus who used multivitamins had a 79 percent lower risk of developing cervical cancer.

It’s almost impossible for a nonchemist to figure out which reports to believe, but it seems that the sensible response to last year’s sensationally titled Inside NZ documentary ‘Are Vitamins Killing You?’ is ‘No’.

A 2006 coroner’s report found three deaths related to supplements: in 2003 a child choked on a large vitamin pill; in 2006 a woman who had taken folic acid supplements terminated her pregnancy after discovering the foetus had spina bifida (although the Government recommends pregnant women take 600–800 mcg of folic acid a day to prevent such neural tube defects, over-the-counter supplements are limited to 500 mcg); and a man died after taking an Indian herbal product bought by direct mail. He had pre-existing prostate cancer and had taken a wide variety of substances.

And in the US, where over half the population takes daily nutritional supplements, poison statistics from 2008 show that not a single one of them died as a result of taking vitamins, minerals, amino acids or herbs.

Can you buy nutrition in a pill?

Although they may not be killing us, the growing popularity of supplements is a concern for many health professionals. Problems arise when people take a pill instead of eating well, says Winsome Parnell, associate professor in the Department of Human Nutrition at the University of Otago. “That’s not a good approach—if you don’t eat well you’ll probably have insufficient amounts of a wide range of nutrients. How do you know the supplements you choose will top up those particular nutrients and in an appropriate amount?” She believes supplements should be available only by prescription, following a medical diagnosis.

The official line comes from the Ministry of Health, which recommends supplement pills only in specific circumstances: folic acid for pregnant women; vitamin B12 for vegans; calcium for children with a diagnosed milk allergy; Vitamin D for the institutionalised; and iron to treat iron-deficiency anaemia. Other than that, it says we should get all our required nutrients from a balanced diet of fruit, vegetables, nuts, seeds, wholegrain cereal foods, reduced-fat dairy foods, lean meats, fish, poultry, and small amounts of poly- or monounsaturated fats and oils.

Diet is definitely the best source of nutrients, says nutrition scientist Dr Karen Silvers—but we need to change our approach in order to get the most from our food. “When you’re using fertilisers and pesticides you’re not looking after the earth, and it is the earth that provides the nutrients and the minerals.” The key to good health, she says, is eating fresh, locally sourced fruit and vegetables, letting go of anger and stress, and sleeping well.

Her advice is hard to argue with— but to Mapua GP Tim Ewer, meeting everyone’s nutritional needs with diet alone seems a little idealistic. “For someone who has no health issues and is not stressed, who has a really balanced diet of food grown in very good soil that is not treated with too many agrichemicals, then it’s true,” he says. “But that’s a lot of ifs.”

Poor soil, too many chemicals and exposure to light and heat can all diminish the nutrient content of our food. Vegetables boiled for just a few minutes can lose 25 percent of their vitamin C.

Christchurch naturopath Michael Woods points to increases in rheumatoid arthritis, inflammatory bowel disease, hypothyroidism, and infertility in young males as examples of where diminished nutrient levels can lead. “If we can get everything we need from our food then why are we so unwell? We really don’t know what a balanced diet should contain, because we don’t know what’s in our food and we don’t have control over our food chain.”

The 2002 National Children’s Nutrition Survey found that most New Zealand five- and six-year-olds are getting a satisfactory intake of vital nutrients, but some older girls need to boost their zinc (16 percent of girls aged 11–14 had an inadequate intake) and calcium (18 percent of girls had an inadequate intake), while 37 percent of Pacific girls were low in vitamin A. Many adult women are low in iron, and iodine deficiencies are reappearing among all adults.

So which supplements are worth taking?

A daily multivitamin from a reputable brand, containing a mixture of B vitamins and the essential trace elements selenium, zinc, boron and iron is, says Michael, “good insurance”. Even supplement sceptic Winsome Parnell says that taking a multivitamin and mineral is safe, if taken in the recommended dose— although she doubts it’s necessary.

The much-touted omega-3 oils have been found to be beneficial in maintaining heart health, promoting brain development (although the jury is still out on their effect on depression) and as antiinflammatory agents.

David Musgrave, agronomist and founder of Waihi Bush Organic Farm, knows just how effective high-quality omega fats can be. When his son Oliver developed an extreme case of eczema at the age of two, he sought every form of medical assistance. “We were desperate.” Steroid creams just moved the problem around, and while an incredibly restricted diet made some difference, “he still ended up most nights scratching”.

Then a friend gave David a bottle of Canadian flax seed oil. “Within a week Oliver was in his own bedroom for the first time in his life.” Being a scientist, David started reading the medical literature, and in 1994 he began pressing his own flax seed oil at his farm in Canterbury. Last year Waihi Bush flax seed oil capsules and a range of related products recorded a $2 million turnover.

It seems that, despite the scare stories, we’re still buying supplements— but you get what you pay for. A bottle of 800 fish oil capsules for $20 sounds good, but the fish stock can be contaminated with mercury or chromium, the oil may have been extracted using solvents, and exposure to air can leave the contents dangerously oxidised. Pharmaceutical grade, molecularly distilled varieties are pricier, but safer. Others say it’s better to get your omega-3s from cold-pressed flax seed and walnut oils, or by eating oily fish like sardines, mackerel and salmon.

But there is more cause for concern than just the impact of supplements on our wallet. Like our Nelson physiotherapist Louise Sawers, many of us take a variety of supplements—and it’s important to let your doctor know what you’re taking.

While excess water-soluble vitamins pass through the body fairly easily, fat-soluble minerals can lurk around, impeding the absorption of other minerals. Taking zinc from several different sources, for example, can inhibit the proper functioning of iron in the body. Increasing calcium intake may upset the important calcium-magnesium ratio.

While most of the products in health food shops fall within good manufacturing processes, it’s important to read the label. Avoid colouring agents, artificial sweeteners (see page 70) and preservatives (such as sodium benzoate), and follow the recommended doses. If you do want a fish oil supplement, seek out capsules in a light-impermeable container with a distant use-by date (or a recent packed-on date) and store in a cool place.

Most importantly, avoid doubling up on nutrients when taking a variety of supplements. Excessive doses of vitamin A, vitamin D, iron and selenium are all likely to have a negative effect. Megadoses of vitamin C can cause diarrhoea and stomach cramps.

But that, says Michael, can be said for any form of medication. “A normal dose of over-the-counter medicine such as paracetamol can have more toxic effects than any vitamin.”

Sally Blundell