Supplements Boost Postmenopausal Serum Biomarkers

Medscape

a day ago

Postmenopausal women who took vitamin B 12 , fish oil, or flaxseed oil as dietary supplements had significantly higher levels of accompanying serum biomarkers than those who did not use these supplements, based on new data presented at American Society for Nutrition (ASN) 2025 Annual Meeting.
Dietary supplement use in the US is common among older adults, but data on the health effects of dietary supplements remain relatively mixed, said presenting author Hannah T. Baillie, MS, RD, in an interview.
Hannah T. Baillie, MS, RD
'One way to measure whether or not supplements could be getting to the intended targets in the body is to measure the amount of the supplement's nutrients in the blood. This could inform whether the supplements have their intended health effects in an objective manner,' said Baillie, a PhD student at the University of Washington, Seattle.
To examine the associations between dietary supplements and higher serum concentrations of corresponding biomarkers, Baillie and colleagues enrolled 153 participants in the Women's Health Initiative in a 2-week controlled feeding study.
The participants consumed an individualized menu, including a habitual diet, and continued use of their usual dietary supplements. After 2 weeks, the researchers measured serum vitamin B 12 , lutein plus zeaxanthin, and phospholipid fatty acids.
In a multiple linear regression analysis, the geometric mean serum concentration of vitamin B 12 was 58% higher among women who used any type of vitamin B 12 dietary supplement than among nonusers ( P < .001). In addition, the geometric mean serum concentrations of phospholipid docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) ranged from 38% to 46% higher among users of fish oil or flaxseed oil supplements than among nonusers ( P < .0001).
Use of dietary supplements containing lutein plus zeaxanthin had no significant impact on serum concentrations ( P = .72).
However, individuals who used two sources of a dietary supplement containing vitamin B 12 as well as two different sources of supplementation with lutein plus zeaxanthin had significantly higher serum biomarker levels than either individuals who took a single multivitamin containing B 12 and lutein plus zeaxanthin or individuals who took neither ( P < .0001 for both).
'I was surprised by how many different supplements participants were taking; I expected it to be high, but one participant was taking 18 supplements per day,' Baillie told Medscape Medical News . 'I was also surprised by the lack of association between use of lutein + zeaxanthin-containing supplements and serum lutein + zeaxanthin concentrations,' she said. The negligible increases in serum concentrations with supplement use point to potential issues with absorbing or utilizing these nutrients from supplemental sources, she noted.
The study findings highlight the need for clinicians to ask patients not only about the use of dietary supplements but also about the dose of those supplements, said Baillie.
The researchers also looked at serum concentrations in response to different doses of vitamin B 12 . 'We looked to see if those taking individual vitamin B 12 , just a multivitamin containing B 12 , both those supplements, or neither had different serum concentrations of vitamin B 12 ,' Baillie said.
The researchers found that individuals taking > 1000 mcg in a supplement (an average amount in single B 12 supplements) did not have significantly higher serum concentrations than those taking both supplements (which would represent a larger dose).
The unreliable and inadequate labeling of nutrient content on dietary supplement packaging was a main study limitation, Baillie told Medscape Medical News . 'Although the contents from labels of each dietary supplement were recorded into our database, prior research has shown there may be discrepancies in what is reported on labels and what each supplement contains,' she said. 'Additionally, labels are not consistent in how nutrient information is reported; for example, for fish oil supplements, omega-3 fatty acids are sometimes displayed as total omega-3 fatty acids, sometimes as EPA and DHA, and on other labels as total EPA + DHA,' Baillie said. This discrepancy makes consistent assessment of total nutrient intake a challenge and limits what conclusions that can be drawn from the data, she noted.
Raising Awareness, Examining Intake
'Additional research investigating best practices for assessing nutrient intake from dietary supplements is needed, and this may require changes in the requirements around dietary supplement labeling,' Baillie told Medscape Medical News . Future research also should address assessing serum response among a more heterogeneous population, she added.
Older women often take supplements without knowing their full effect, and the current study is important to help alert clinicians to ask patients about type, timing, and dose, said Christine M. Sager, MD, an assistant professor in the Department of Obstetrics and Gynecology at East Tennessee State University, Johnson City, Tennessee, in an interview.
The findings were not unexpected, said Sager, who was not involved in the study. 'In clinical practice, we see similar elevations in B 12 when patients are taking B vitamins,' she said.
The current study is too short and too small to make global recommendations on supplement intake, but the results suggest that the type, dose, and time of day matter for many supplements, just as with medications, although research on this topic is limited, Sager said. 'Also, serum levels do not always correlate with goals of therapy,' she noted. Looking ahead, the safety and efficacy of intravenous vitamins and supplements is an important question for additional research, Sager added.