Randomized trial shows multivitamins reduce hypertension risk in older adults with poor diets — Evidence Review

A new study finds that daily multivitamin use does not lower blood pressure or hypertension risk for most older adults, but small benefits appear for those with poorer diets or normal baseline blood pressure. Related research generally supports the idea that multivitamin benefits are most apparent in populations with lower dietary quality or specific deficiencies, rather than as a universal preventive measure (1, 5, 6).

• Large trials in populations with micronutrient-poor diets, such as rural China, have shown reduced hypertension and cerebrovascular disease with multivitamin supplementation, supporting the new study’s finding that diet quality modifies the benefit (1).
• Reviews and consensus statements highlight that multivitamin/mineral supplements primarily help individuals with inadequate micronutrient intake, while evidence for broad cardiovascular benefits in well-nourished populations remains inconsistent (5, 6).
• Long-term trials in generally healthy, well-nourished adults have not found significant reductions in cardiovascular events or hypertension risk from daily multivitamin use, aligning with the current study’s overall null findings for the general population (4).

Study Overview and Key Findings

Controlling blood pressure is a cornerstone of preventive health in older adults, yet questions remain about the role of daily multivitamin use in managing hypertension risk. The new study, conducted within the COSMOS trial, addresses whether a widely available multivitamin (Centrum Silver) can reduce hypertension risk or lower blood pressure in older adults over several years. It stands out by specifically examining subgroups defined by baseline diet quality and blood pressure, providing nuanced insights into who may benefit from supplementation.

Property	Value
Study Year	2025
Organization	Mass General Brigham
Journal Name	American Journal of Hypertension
Authors	Rikuta Hamaya, Sidong Li, Jessica Lau, Susanne Rautiainen, Bernhard Haring, Simin Liu, Aladdin H Shadyab, Lisa Warsinger Martin, Sylvia Wassertheil-Smoller, Pamela M Rist, JoAnn E Manson, Howard D Sesso, COSMOS Research Group
Population	Older adults without hypertension
Sample Size	n=8905
Methods	Randomized Controlled Trial (RCT)
Outcome	Hypertension risk, blood pressure changes
Results	Multivitamins lowered hypertension risk in those with poorer diets.

Literature Review: Related Studies

To place these findings in context, we searched the Consensus paper database, which contains over 200 million research papers, using targeted queries to identify relevant studies. The following queries were used:

1. multivitamins hypertension risk poor diet
2. daily multivitamins health benefits
3. diet quality multivitamin efficacy

Topic	Key Findings
Does multivitamin supplementation reduce hypertension or cardiovascular risk?	- Supplementation may reduce hypertension and cerebrovascular disease risk in populations with poor baseline nutrition (1). - Large trials in well-nourished populations show no significant reduction in cardiovascular events (4).
How does baseline diet quality influence multivitamin efficacy?	- Benefits of multivitamin supplementation are most pronounced in those with micronutrient deficiencies or poor dietary intake (1, 5, 6). - Diet quality modifies the effect of supplementation on blood pressure and health (5).
Are multivitamins effective for the general population?	- Evidence for broad preventive benefits in well-nourished adults is inconsistent or lacking (4, 5, 6). - Some improvements in micronutrient intake and possible small benefits in subpopulations with specific needs (6, 8).
What is the potential mechanism and safety of long-term multivitamin use?	- Multivitamins can improve micronutrient intake and fill nutritional gaps, with a good safety profile within recommended limits (6, 8). - No evidence for harm in healthy adults; possible benefits for cognition and specific outcomes (8, 9).

Does multivitamin supplementation reduce hypertension or cardiovascular risk?

Several studies have explored whether multivitamin supplementation can lower hypertension risk or prevent cardiovascular disease. The current study’s nuanced findings—no overall benefit, but modest effects in those with poorer diets—echo results from earlier research. For example, the Linxian Nutrition Intervention Trial found reduced hypertension and cerebrovascular disease in rural Chinese adults with low baseline micronutrient intake (1). Conversely, the Physicians' Health Study II observed no significant reduction in cardiovascular events from daily multivitamin use in a large cohort of well-nourished US male physicians (4).

• Populations with poor baseline nutrition show the clearest cardiovascular and hypertension benefits from multivitamin supplementation (1).
• In well-nourished populations, supplementation has not consistently reduced hypertension risk or cardiovascular events (4).
• The new study’s subgroup findings are consistent with the idea that population context matters for supplementation efficacy (1, 4).
• Broad public health recommendations for multivitamin use in cardiovascular prevention remain unsupported in general populations (4).

How does baseline diet quality influence multivitamin efficacy?

The effectiveness of multivitamin use is not uniform and appears to depend strongly on the initial nutritional status of individuals. Both observational and interventional studies suggest that supplementation is most beneficial for those with micronutrient-poor diets or existing deficiencies (1, 5, 6). The new study’s finding that benefits were limited to participants with lower diet quality aligns with this body of evidence.

• Individuals with inadequate micronutrient intake or lower diet quality experience greater health improvements from supplementation (1, 5, 6).
• Diet quality scores (such as AHEI, aMED) can help identify who may benefit most from supplements (5).
• Supplementation effects tend to diminish as diet quality improves, supporting targeted rather than universal use (5, 6).
• The new study reinforces the importance of considering baseline nutritional status when evaluating multivitamin efficacy (1, 5, 6).

Are multivitamins effective for the general population?

Research consistently shows that the benefits of multivitamins for chronic disease prevention in the general, well-nourished population are limited. Large randomized controlled trials and reviews have found no substantial reduction in cardiovascular disease or mortality with daily multivitamin use (4, 5, 6). However, supplementation can help fill micronutrient gaps and may provide modest benefits for specific subpopulations, such as older adults or those with identified deficiencies (6, 8).

• No significant reduction in major cardiovascular events, hypertension, or total mortality in healthy adult populations (4, 5).
• Multivitamins can help individuals meet recommended micronutrient intakes, especially when dietary gaps exist (6, 8).
• Some evidence suggests benefits for cognitive function and prevention of other conditions in targeted groups (8, 9).
• Broad recommendations for multivitamin use in disease prevention are not supported for the general, well-nourished public (4, 5, 6).

What is the potential mechanism and safety of long-term multivitamin use?

Multivitamin/mineral supplements are widely used to improve micronutrient intake. Evidence shows they are generally safe when taken within recommended limits and can help address nutrient deficiencies (6, 8). Some studies note possible benefits for cognition and specific health outcomes, but broad preventive claims lack robust support (8, 9).

• Multivitamins can safely fill nutritional gaps, particularly in older adults and other at-risk groups (6, 8).
• No significant risk of harm or increase in mortality with standard multivitamin use in healthy adults (8).
• Possible improvements in cognitive performance among adults with suboptimal micronutrient intake (9).
• The safety and utility of long-term supplementation support its use in targeted, rather than universal, contexts (6, 8).

Future Research Questions

Although recent findings clarify that multivitamin supplementation primarily benefits individuals with poor dietary intake or specific deficiencies, several important questions remain. Future research should address these gaps to guide personalized supplementation strategies and public health recommendations.

Research Question	Relevance
Does multivitamin supplementation reduce hypertension risk in younger or middle-aged adults?	There is limited evidence regarding the effects of multivitamins on blood pressure in populations younger than older adults; studying younger age groups could clarify whether benefits are age-dependent (1, 2).
What nutritional biomarkers predict response to multivitamin supplementation?	Identifying specific biomarkers could help target supplementation to those most likely to benefit, moving beyond general dietary assessments (5, 6).
Are there long-term adverse effects of daily multivitamin use in different populations?	Although safety data are reassuring, more long-term studies in diverse populations are needed to confirm the absence of harm, especially for high-dose or specific formulations (6, 8).
How do specific micronutrient deficiencies modulate the effects of multivitamin supplementation on blood pressure?	Understanding which deficiencies (e.g., potassium, magnesium) most influence blood pressure response could lead to more precise interventions (2, 5).
Can personalized nutrition advice improve the effectiveness of multivitamin supplementation?	Integrating individualized dietary counseling with supplementation may enhance health outcomes compared to supplement use alone, particularly in at-risk groups (5, 6).