Using Supplements Responsibly: Quality, Evidence and Interactions

Supplements occupy a large place in functional and integrative practice, and in the lives of patients. Many patients arrive with bags of products; many practitioners recommend at least some. Earlier articles in this library examined the evidence for nutritional medicine and the risks of interactions. This article is about the practical discipline of recommending and managing supplements responsibly: choosing products, reading labels, dosing, reviewing and stopping.

Start with the indication

Every supplement recommendation should answer a specific question: what is this for, and what is the evidence? Appropriate indications include confirmed deficiency, established needs such as folic acid before conception, specific conditions with trial evidence, and situations where diet cannot meet needs. General wellness, boosting and detox are not indications.

Quality and regulation

In many countries, supplements are regulated more lightly than medicines, and quality varies. Analyses of products have found contents that differ from labels, contamination with heavy metals or microbes, and undeclared pharmaceutical ingredients, particularly in products marketed for weight loss, sexual enhancement and muscle building. Regulators maintain public lists of products found to contain hidden drugs.

Independent certification schemes test products for identity, potency and contaminants. Examples include certification by pharmacopoeial bodies and sports testing programmes that check for banned substances. Certification does not prove effectiveness, but it reduces the risk that a product contains something other than what the label claims.

Reading the label

Dose and upper limits

Tolerable upper intake levels, set by expert bodies, estimate the highest daily intake unlikely to cause harm in most people. Supplements can exceed them easily, especially when products overlap. Nutrients with notable risks at high intakes include vitamin A, vitamin D, vitamin B6, niacin, iron, zinc, selenium and iodine. Doses above upper limits may be appropriate for short term treatment of confirmed deficiency under supervision, but not as a general habit.

Hidden duplication

Patients taking several products often duplicate nutrients without realising it. A multivitamin, a B complex, an energy drink and a hair supplement may each contain B6 or biotin; a thyroid support formula, a multivitamin and kelp may each contain iodine. Adding up total daily intake of each nutrient across all products is one of the most useful parts of a supplement review.

Interactions and safety

Check each product against the patient’s medicines, conditions and life stage, using reliable resources. Pay particular attention to anticoagulants, immunosuppressants, antiepileptics, diabetes medicines, antidepressants, thyroid hormone and hormonal contraception, and to pregnancy, kidney and liver disease and upcoming surgery.

Review and stopping rules

Every supplement should have a planned review. Useful questions include:

• Has the indication been met? A corrected deficiency may need a lower maintenance dose or none.
• Is there evidence of benefit in this patient?
• Is the patient still taking it consistently?
• Has anything changed, such as new medicines, pregnancy or kidney function?
• Can food now meet the need?

Deprescribing supplements that are no longer needed reduces cost, pill burden and risk.

Documentation

Record the product name, manufacturer, dose, indication, start date, planned review date and any interactions considered. Share significant information with the patient’s doctor, particularly where supplements may affect medicines or test results.

Conflicts of interest

Practitioners who sell supplements, or receive income from companies that make them, have a financial interest that can influence recommendations. Professional ethics codes in several health professions address this. Responsible practice includes disclosing any financial interest, offering patients the option of buying equivalent products elsewhere, basing recommendations on evidence rather than product lines, and avoiding recommending products solely because they are available to sell.

A supplement audit

A structured audit of every product a patient takes can be done in a single consultation, often with a brown bag review.

1. List every product, with ingredients and doses.
2. Note the reason for each and who recommended it.
3. Total the daily intake of key nutrients across all products.
4. Compare with needs, deficiencies and upper limits.
5. Check interactions and quality.
6. Decide for each product: continue, adjust, replace with food, or stop.
7. Set review dates.

A worked audit

An illustrative patient, a 58 year old woman, takes 12 products. The audit finds:

She leaves with 4 products instead of 12, a lower cost, a clearer plan and a follow up to review her tingling and sleep.

Integrity in practice

Supplements can be valuable clinical tools when they are used for clear indications, chosen for quality, dosed carefully, reviewed regularly and recommended without conflict of interest. That discipline protects patients and strengthens the credibility of the practitioners who use them.