April 1st 2026
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WellBeing Magazine
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Explore how the issues of safe dosages and therapeutic benefits of vitamins like vitamin C and other supplements can be approached from a holistic perspective.
Around the turn of the 20th century, humanity was aware of the types of foods needed to maintain health but lacked knowledge about the specific nutrients in food that achieved this. These were later, in 1912, named “vitamins” by a Polish biochemist named Casimir Funk. The first half of that century saw the discovery of all of the 13 essential vitamins that are known today.
It is advisable to preference obtaining vitamins and minerals (micronutrients) from food before considering supplement products, the main reason being the synergistic benefits of taking these micronutrients with macronutrients (protein, fat and carbohydrates) and phytonutrients (chemicals such as carotenoids, flavonoids and phytoestrogens) that food typically contains. Similarly, when taking supplements, it is usually recommended to take them with meals.
Another consideration when taking both supplements and pharmaceuticals is the possibility of negative interactions between the two. This is worth investigating, perhaps with a health professional.
Yet another issue to be aware of is the use of questionable inactive ingredients in cheaper supplements. These can include artificial colours, hydrogenated oils, talc (magnesium silicate) and titanium dioxide. In New Zealand they must be listed on the label, but in Australia this is not required. However, the information can be obtained by finding the “Aust L” number on the front label, entering it into the Australian Register of Therapeutic Goods page and opening the PDF summary.
Despite media coverage that tends towards the negative, supplements are popular, with 2023 Australian Bureau of Statistics figures showing that about 30 per cent of the population took a vitamin and/or mineral product during that year, more commonly women than men. For New Zealand, the figure appears to be similar.
Shaping perceptions
Much traditional media in Australia and New Zealand maintains a pro-mainstream-medicine, antinaturopathy bias that has more recently tied in with negative connotations applied to the wellness sector. For supplements, the twin messages from such media outlets are that for most people, these products fail to offer health benefits and may in fact be harmful. This distorts perceptions so that readers and listeners are liable to believe that the health consequences from taking supplements are more likely to be negative than beneficial.
One of the most frequently repeated messages is that anyone who eats a healthy balanced diet should not need supplements. However, the nutritional properties of food have been dropping since the early 20th century, largely as a result of diminishing soil quality tied to unsustainable intensive farming practices. Eating a carrot today is not the same as eating a carrot a century ago. With further nutrition losses expected due to climate change, a nutritionally adequate diet today might not be an adequate diet at some point in the future.
In the US, figures from the 2000s showed more than 98 per cent of the population having at least one nutritional defi ciency. Faced with this type of health challenge, it is best to regard a combined multivitamin and mineral product as a type of insurance policy to maximise the probability of receiving adequate nutrient intake. Such a viewpoint is echoed by the American Medical Association, which, in 2002, stated, “The Journal of the American Medical Association today is advising all adults to take at least one multivitamin pill each day.”
While public perception tends to gravitate towards achieving the recommended daily intake (RDI), bear in mind there are health advantages from exceeding it by some margin, so the game-plan should be to aim higher. Vitamin supplements are the subject of media warnings about their ineffectiveness and potential danger. How can the issues of safe dosages and purported therapeutic benefits be approached from a holistic perspective?
A naturopath whom I spoke to raised the issue of self-dosing with a range of supplements that might not be tailored to the individual’s specific needs, and emphasised the benefits of receiving naturopathic advice.
The recommended daily intake and above
The RDI (also known in some countries as the recommended daily amount) of a micronutrient is usually defi ned as what is needed to meet the nutritional needs of nearly all healthy people, and avoid a defi ciency state. An extra margin is then added to take into account variations in absorption and metabolism.
A deficiency condition exists where the body lacks the nutrients it requires to support physiological processes. Well-known defi ciency diseases prevented, and mostly reversible, by vitamin intake include scurvy (vitamin C), rickets (vitamin D) and pellagra (vitamin B3/niacin.) This disease-prevention thinking is rooted in the early-20th-century scientific research that led to vitamins being discovered.
Australia and New Zealand share the same food regulation system, and for some vitamins and minerals a suggested dietary target (SDT) has been set, substantially higher than the RDI, with the aim of preventing or reducing the risk of chronic disease. These are vitamin A, vitamin B9 (folate), vitamin C, vitamin E, sodium and potassium. To give an example, while the RDI for vitamin C is 45mg for men and women, the SDT is several times higher, at 220mg (men) and 190mg (women). In addition to the personal health benefits of meeting the SDT, this stands to reduce downstream resources and costs in the medical system.
Another, more ambitious, perspective is to use nutrient intake as a means of optimising health rather than avoiding states of disease, pursuing an optimal daily intake well above the RDI. It’s possible, however, to have too much of a good thing. For most nutrients, there is an adult upper intake level, which is the highest level that is not expected to lead to any adverse health effects.
Avoiding excessive doses
Some vitamins and minerals are harmful in large amounts. Intake can add up when you total what is derived from food (including fortified foods) with all supplements (including as co-factors in products). It is worth taking the time to read the small print. Keep an eye on:
- Vitamin A. Chronic excess intake can result in a condition called hypervitaminosis A, which is linked to liver damage and other symptoms. A toxic longterm adult dosage is considered to be in excess of 10,000 international units (IU) or 3000 micrograms (mcg) daily. It is generally recommended to avoid Vitamin A supplements during pregnancy. Unexpected sources include prescription drugs with vitamin A and retinol skin cream.
- Vitamin B6. This has been subject to negative media attention during 2025, due to excessive doses causing peripheral neuropathy (nerve damage) and muscle weakness in some people, symptoms that are usually reversible. The daily upper intake level varies widely around the world, from 12mg in the EU and 50mg in Australia/New Zealand to 100mg in the US. In Australia, the Therapeutic Goods Administration (TGA) takes a precautionary approach to B6 and requires warnings on products with more than 10mg.
- Selenium. The toxicity of this antioxidant mineral in excess quantities is well known. Brazil nuts are particularly selenium-rich, with one nut containing around 68-91mcg, more than the RDI, and about a fifth of the Australian/New Zealand daily upper intake level of 400mcg. It’s worth noting that New Zealand’s soils have naturally low selenium levels.
- Zinc. If adults exceed the daily 40mg upper intake level on an ongoing basis, this can cause a physiological imbalance by interfering with copper absorption. Even higher levels can lead to symptoms such as nausea, dizziness and headaches. Unexpected dietary sources include some denture adhesive creams.
The orthomolecular perspective and megadosing
The word “orthomolecular” was coined in 1968 by Nobel Prize-winning scientist Linus Pauling. Orthomolecular researchers and practitioners generally endorse high micronutrient intakes, up to what they consider a safe limit, for therapeutic purposes. This movement’s areas of focus include nutrition, detoxification and metabolic balance. It aspires to reverse chronic conditions through therapeutic nutrition.
One of its principles is that, compared to healthy people, sick people need far more nutrients. The ideal is to find an optimum amount, tailored to the individual. For this reason, the movement recommends consulting with an orthomolecular practitioner.
Unsurprisingly, vitamin megadosing (also sometimes known as megavitamin therapy) is a controversial and sometimes polarising topic. In contrast to the orthomolecular view, the mainstream perspective is that high doses are generally ineffective and possibly dangerous. However, orthomolecular figures such as Dr Thomas Levy are adamant that higher doses can succeed therapeutically when trials with deliberately chosen low doses fail.
When pursuing this approach, it is not advisable to regularly exceed the upper intake level (with the exception of vitamin C, which is notably safe), while ensuring that the amounts taken are therapeutically effective for the condition. Taking large quantities of one micronutrient in isolation over the long term can create nutritional imbalances and interfere with absorption of some other nutrients. It is good to maintain a balance.
New Zealand dairy farmer Alan Smith narrowly avoided dying from swine flu in 2010 when members of his family lobbied, against resistance from hospital doctors, for the use of intravenous (IV) vitamin C. When he fully recovered, the medical community rejected the idea that the vitamin C was responsible for his survival.
In the field of cancer, IV vitamin C is widely used as a complementary therapy, either in conjunction with chemotherapy, in order to enhance the chemosensitivity of cancer cells, or as a stand-alone. There is an increasing body of evidence to support its use, and its safety is not in dispute. Some clinics offer IV vitamin infusions as a general health boost.
Where a vitamin A deficiency exists, receiving a high dose is a way to reduce the risk of measles complications. This intervention is recommended by the World Health Organization for infants and children with acute measles cases, in such areas where population-level defi ciencies are prevalent. Depending on age, the dosage used is 50,000-200,000 IU per day over two days. These huge amounts are safe because they are received over a very short time by children who are deficient.
Studies indicate that vitamin B2, magnesium and CoQ10 are effective in preventing migraines. Their use has been endorsed by multiple peak bodies in the headache field.
Sepsis is a serious condition that kills millions of people annually and represents about 20 per cent of all global deaths. Paul Marik was running the ICU at a hospital in Norfolk, Virginia, USA, when in 2016 he saved the life of a woman who was dying from sepsis, by trying an injection of vitamin C, corticosteroids and vitamin B1 (thiamine.) He reported that his department had been losing about one to two patients per week to sepsis, but over the following year it did not lose any to the condition.
Helping to tackle COVID-19
At the start of the COVID-19 pandemic, an anonymous and scientifically knowledgeable collective launched the website C19early.org. Its mission was to aggregate all scientific studies relating to the effectiveness against COVID of a range of drugs, supplements and other diverse interventions. The slant of the website is towards early treatment, which offers greater scope than delayed treatment for minimising the risk of contracting a severe case of COVID.
Among higher-dose vitamins and minerals, most effective for early treatment were found to be:
- Vitamin A, with a 62 per cent average improvement. However, the number of studies was limited.
- Vitamin D, with a 60 per cent average improvement (used in 18 countries).
- Zinc, with a 41 per cent average improvement (used in 23 countries).
- Vitamin C, with a 39 per cent improvement (used in 22 countries).
The use of vitamins for COVID was largely dismissed by the media in a similar, but less aggressive, fashion to its dismissal of effective unpatented drugs such as ivermectin and hydroxychloroquine.
Where do the risks lie?
The medical mainstream remains largely focused on the risk of harm from over-dosing rather than the serious health implications of chronic under-dosing and the “elephant in the room” issue of diminishing nutrition in food.
Meanwhile, the world needs to get on board with the message that to optimise health, it is necessary to look beyond the RDI and, to achieve this, supplements can play an important role.
Resources
Australian Register of Therapeutic Goods
Australia/New Zealand Suggested Dietary Targets
Orthomolecular Medicine News Service
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