By Steven Paul, registered dietitian, The Whole You Dietitian
Having money at stake is a reason to look closely at any claim. That applies to the pharmaceutical industry. It applies just as much to the wellness industry, and to anyone who points to a problem and then sells the solution.
“Don’t trust pharma, it has vested interests”
This is the claim as many people hear it. A pharmaceutical company profits when its medicine is used, so the argument goes that its science cannot be trusted. In my experience, the same reasoning is rarely applied on the wellness side. A supplement brand, a programme or an influencer makes a claim about what is wrong with your health and then sells the product that answers it. The financial interest is the same kind of interest, and it deserves the same scrutiny.
Why people doubt industry-funded research, and what the evidence shows
The doubt has a real basis: funding can tilt results. A Cochrane review of 75 papers compared studies paid for by drug and device companies with studies paid for by other funders. Across the 25 papers that assessed efficacy results, which covered 2,923 studies, industry-sponsored studies more often reported results that favoured the drug or device being tested. Almost all of those studies tested drugs rather than devices. The review rated this finding as moderate quality evidence. It covered drugs and devices only, so it says nothing about food, supplements or wellness products either way.
Food research raises the same concern, with a less consistent answer. A 2007 analysis of 206 articles on soft drinks, juice and milk found that interventional studies funded entirely by industry were more likely to favour the sponsor than those with no industry funding, though the estimate was imprecise. A 2016 systematic review and meta-analysis of 12 reports found a similar tendency in the eight reports (340 studies) that assessed authors’ conclusions, but it was not statistically significant, meaning it could have arisen by chance. Its authors described the findings as suggesting a link without establishing one.
Put together, the evidence supports checking who paid for a study. It does not support writing off an entire industry, and it does not show that wellness-funded claims are safe from the same problem.
“Doctors and dietitians are part of the system, so ignore them”
A second version of the argument targets people instead of studies. It says that doctors, nurses, dietitians and other trained professionals learn inside a system shaped by pharmaceutical money, so they repeat that industry’s evidence. Those outside the system are cast as the ones willing to say what insiders will not.
Part of it is true. A 2021 systematic review of 36 studies of payments to physicians in the United States found that payments were associated with higher prescribing in 89 of 101 analyses, including more prescribing of the paying company’s drug. The studies were observational and 21 of the 36 had serious risks of bias. The authors say that findings on timing and dose-response suggest a causal relationship, but observational studies cannot prove cause. In the UK, the industry’s own disclosure database listed £813.3 million of payments and other transfers of value in 2024, of which £554.0 million was for research and development collaborations.
Professionals are expected to declare their interests. The GMC asks doctors to be open and honest about all of them, the HCPC standards require registrants to “declare issues that might create conflicts of interest”, and NICE publishes a register of its committee members’ interests. These are professional duties backed by regulators. In the US, the Sunshine Act places the legal duty to report payments to doctors on the manufacturers, and the reports are published. Influencers are not exempt from disclosure either. UK advertising rules require paid content to be labelled. The Advertising Standards Authority analysed more than 50,000 pieces of Instagram and TikTok content from 509 UK accounts in 2024. It found that 57% of the influencer ads met the rules, 9% used an unclear label and 34% had no disclosure.
The argument goes further than the evidence, though. The payments research measures prescribing: what doctors prescribe after receiving money. It does not measure the nutrition or lifestyle advice they give. Dietetic advice rests mostly on nutrition and food research, and the industry ties studied among nutrition professionals are mostly with the food industry, which featured in 91 of the 115 documents in a 2023 scoping review. UK nutrition organisations have also called for better nutrition teaching in medical school, which suggests a gap in training more than a shared position.
A claim is not wrong because the person presenting it trained in medicine, and it is not right because the person stands outside it. Each claim is tested on its evidence, whoever presents it.
How big is the money on each side?
These are estimated figures from industry research organisations:
- Wellness industry, all sectors (including spas, tourism and beauty): about US$6.8 trillion in 2024, estimated by the Global Wellness Institute.
- Of which diet, nutrition and weight loss: about US$1.1 trillion.
- Of which vitamins, supplements and weight loss products and services: about US$280 billion (calculated: US$167.0 billion plus US$112.9 billion is US$279.9 billion).
- Pharmaceutical industry: about US$1.7 trillion in 2025, estimated by Grand View Research.
A like-for-like comparison is difficult because the two sources define their industries differently. The wellness total includes spas, tourism and beauty and excludes prescription drugs, which fall under the pharmaceutical industry. The Global Wellness Institute is supported by sponsors and Grand View Research is a commercial report publisher, so I regard both figures as estimates and draw no ranking from them. They do show that both industries are large and that both have a financial interest in what people believe about health.
The seller of the solution
A company selling a medicine profits when people believe they need it. A person who says a problem is widespread, hidden or dangerous, and then sells a supplement, a test, a programme or a course as the answer, profits in the same way. Neither has to be dishonest for the interest to exist. If a financial interest is grounds for doubt in one case, it is grounds for doubt in the other.
How to judge the claim in front of you
Check the claim being made as well as who is making it. Four questions help:
- What exactly is being claimed?
- What does the evidence in people support?
- Is the person making the claim also selling the solution?
- Who pays, and is it declared?
A claim can be right when a seller makes it, and wrong when no one is selling anything.
My conclusion
I found no study that compares bias between these two industries, or that shows professional training makes clinicians repeat pharmaceutical evidence, so this is my reasoning from the evidence above and not a study finding. Vested interests are a reason to look closer at everyone: industry, clinicians and influencers. Dismissing one side on that ground alone, while trusting the other, does not hold up.
References
Advertising Standards Authority (2025) Influencer ad disclosure on social media: Instagram and TikTok report (2024). London: ASA. Published 9 May 2025.
Advertising Standards Authority and Committee of Advertising Practice (2026) Recognising ads: social media and influencer marketing. London: ASA.
Aggarwal, A. and Fell, A. (2025) ‘Disclosure UK 2024: new record for transparency, with nine in ten healthcare professionals named in database’, ABPI blog, 27 June. London: Association of the British Pharmaceutical Industry.
Chartres, N., Fabbri, A. and Bero, L.A. (2016) ‘Association of industry sponsorship with outcomes of nutrition studies: a systematic review and meta-analysis’, JAMA Internal Medicine, 176(12), pp. 1769-1777. doi:10.1001/jamainternmed.2016.6721.
General Medical Council (2024) Identifying and managing conflicts of interest. London: GMC.
Global Wellness Institute (2025) 2025 Global Wellness Economy Monitor. Miami: Global Wellness Institute.
Grand View Research (2026) Pharmaceutical market report. San Francisco: Grand View Research.
Hamel, V., Hennessy, M., Mialon, M. and Moubarac, J.-C. (2023) ‘Interactions between nutrition professionals and industry: a scoping review’, International Journal of Health Policy and Management, 12, article 7626. doi:10.34172/ijhpm.2023.7626.
Health and Care Professions Council (2024) Standards of conduct, performance and ethics. London: HCPC.
Jones, G., Macaninch, E., Mellor, D., Spiro, A., Martyn, K., Butler, T., Johnson, A. and Moore, J.B. (2022) ‘Putting nutrition education on the table: development of a curriculum to meet future doctors’ needs’, BMJ Nutrition, Prevention & Health, 5(2), pp. 208-216. doi:10.1136/bmjnph-2022-000510.
Lesser, L.I., Ebbeling, C.B., Goozner, M., Wypij, D. and Ludwig, D.S. (2007) ‘Relationship between funding source and conclusion among nutrition-related scientific articles’, PLoS Medicine, 4(1), e5. doi:10.1371/journal.pmed.0040005.
Lundh, A., Lexchin, J., Mintzes, B., Schroll, J.B. and Bero, L. (2017) ‘Industry sponsorship and research outcome’, Cochrane Database of Systematic Reviews, 2, MR000033. doi:10.1002/14651858.MR000033.pub3.
Mitchell, A.P., Trivedi, N.U., Gennarelli, R.L., Chimonas, S., Tabatabai, S.M., Goldberg, J., Diaz, L.A. and Korenstein, D. (2021) ‘Are financial payments from the pharmaceutical industry associated with physician prescribing? A systematic review’, Annals of Internal Medicine, 174(3), pp. 353-361. doi:10.7326/M20-5665.
National Institute for Health and Care Excellence (2023) Policy on declaring and managing interests for advisory committees: frequently asked questions. London: NICE.
United States (2010) Patient Protection and Affordable Care Act, Pub. L. 111-148, s. 6002.
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This content is for educational and informational purposes only and does not substitute for professional medical advice, diagnosis, or treatment.