Choosing Wisely: What Clinicians Should Look For In Nutritional Supplements

Nutritional inadequacies are commonplace in Australia.[1] It is therefore not surprising that approximately 47%[2] of adults take nutritional supplements, reflecting a growing awareness of the importance of adequate nutrition to support health. However, according to 2019 data[3], almost half of vitamin and mineral supplementation is self-prescribed. This highlights an opportunity for clinicians to fill a crucial gap in education to ensure the safety and efficacy of supplement choice for their patients.

The risks of self-selection

While convenient, the self-select approach has its shortfalls. Poor quality supplements can hinder health outcomes as patients may choose inappropriate forms, dosages, or combinations of nutrients that fail to address their individual needs. Furthermore, certain vitamins and minerals can interfere with medications. According to 2018 data[4], 1 in 3 Australians[5] are taking a prescription medication, making drug-nutrient interactions a growing cause of concern. Women are more likely than men to take almost all types of medications, including VMS, making this patient demographic an important focus for education and guidance. [6]  

Education gaps cause confusion

In today’s fast-paced healthcare environment, practitioners are not only tasked with symptom management but also supporting patients toward achieving optimal health. However, many clinicians feel inadequately trained in nutrition and/or overwhelmed by product choice, resulting in prescribing hesitancy.[7]^,[8]  Supplement education is therefore crucial to break through the confusion, with the goal of minimising risk and improving health outcomes for patients.[9]

What to look for in a vitamin and mineral supplement 

When guiding patients on nutritional supplements, clinicians should assess several key factors to determine product appropriateness. This can include:

·         Reviewing ingredient composition and dosing in alignment with current clinical guidelines

·         Evaluating the quality and relevance of evidence cited by the manufacturer

·         Confirming product safety through certification of third-party testing and regulatory compliance.

Supplement manufacturers that provide transparent and accessible access to this information can significantly support informed clinical decision-making.

Factors to consider when assessing supplement appropriateness

Safe and compliant dosing

Clinicians must remain vigilant in identifying both excessive and insufficient nutrient dosing in vitamin and mineral supplements (VMS), as deviations from the Recommended Daily Intake (RDI) may negatively impact health outcomes. [10]  Although micronutrients are often perceived as inherently safe, excessive intake - such as vitamin B6 - has been associated with adverse effects. In Australia, increasing reports of vitamin B6–associated peripheral neuropathy have led the Therapeutic Goods Administration (TGA) to implement stricter regulatory controls, with products exceeding 10mg now requiring a warning label and doses above 50mg per day will require pharmacist oversight by 2027. [11] These changes will help to reduce risk, but do not negate the need for clinician guidance, due to potential accumulative exposure to high vitamin B6 from supplement combining. Brands that factor in safe supplement combining when formulating their products can assist clinicians with navigating safer supplement combinations.

Conversely, underdosing also presents risks, particularly when supplements fail to meaningfully contribute to dietary shortfalls. Notably, many leading pregnancy supplement brands in Australia do not meet the TGA requirement to provide at least 25% of the RDI[12] for calcium, despite evidence that many Australian women do not achieve adequate calcium intake through diet alone.[13]

In this context, clinicians play a critical role in evaluating supplement composition, identifying clinically relevant gaps or excesses relative to RDI, and guiding patients toward safe, effective, and compliant supplementation strategies.

Bioavailability

Bioavailability is central to the effectiveness of supplements because only the fraction of a nutrient that is absorbed and utilised by the body can deliver a physiological benefit. Simply increasing the dose does not guarantee improved outcomes, as many nutrients are absorbed via mechanisms that limit uptake and increase competition at higher intakes.

Bioavailability can be affected by factors such as dosing, nutrient competition and format. For example, larger single doses of calcium can compete with iron for intestinal transport, whereas calcium doses below approximately 800 mg do not appear to significantly inhibit iron absorption.[14] Additionally, lower, split doses of iron have shown superior absorption and gastrointestinal tolerability compared with large doses.[15]

Different formats can also affect bioavailability. For instance, calcium citrate has shown superior bioavailability in those with low stomach acid[16], and powder forms of calcium carbonate have shown superior bioavailability to tablet forms of citrate.[17]

Clinicians can optimise bioavailability through appropriate dosing, nutrient formats, and synergy between complementary nutrients, supporting supplement efficacy and patient outcomes.

Palatability and tolerability

Palatability and tolerability are important considerations when recommending nutritional supplements, as they directly influence patient adherence and sustained use.[18] Unpleasant taste or gastrointestinal side effects - such as nausea or constipation - can significantly reduce compliance, particularly among women with increased sensitivity, such as during pregnancy.[19] Formulation plays a key role; for example, micronised iron preparations have been shown to improve gastrointestinal tolerability and compliance compared to conventional iron salts, while also offering a neutral taste profile.¹⁹ Selecting products that are optimised for palatability and tolerability can help support patient outcomes through improved adherence. 

TGA listing

In Australia, TGA-listed medicines - identified by an AUST L number on the label - apply to therapeutic products containing pre-approved, low-risk ingredients and making limited health claims.[20]  Although these products are not individually assessed for efficacy prior to market entry, sponsors are legally required to hold supporting evidence and comply with established quality and safety standards. Brands that transparently provide access to this documentation enable clinicians to more easily evaluate product credibility, regulatory compliance, and suitability for patient care.¹⁸

Independent testing

Independent testing provides an objective check that a supplement contains what it claims on the label, in the stated dose, and without harmful contaminants. Unlike in-house testing, independent third-party analysis reduces conflicts of interest and increases confidence in product quality, purity, and consistency between batches. For clinicians and consumers, independent testing helps identify issues such as under- or overdosing, heavy metals, undeclared ingredients, or degradation over time, all of which can directly affect safety and efficacy. In a crowded supplement market, independent verification is a key marker of transparency, accountability, and trust.

Cost and Accessibility

Cost should be considered alongside quality and safety when recommending nutritional supplements, as it can also influence adherence and clinical effectiveness. Accessibility is equally important in this context, with both retail and online availability offering distinct benefits. While retail offers immediacy, online access supports convenience, continuity of supply, and improved reach for patients in remote or rural settings, while enabling access to detailed product information to support informed choices. Clinicians can help guide patients toward options that balance affordability, formulation quality, and accessible purchasing pathways to support sustained, effective supplementation.

In summary:

By identifying high-quality, evidence-backed brands and products, clinicians can help patients effectively address nutritional gaps, support overall health and wellbeing, and minimise the risk of adverse effects from supplementation. Consideration of dosing, formulation quality, palatability, tolerability, accessibility, and cost is essential to personalised care, sustained adherence, and the maintenance of patient trust.