Only 35% of people actually stick with their calcium and vitamin D supplements as prescribed, according to a Gram Research analysis of 360 patients in Madrid. The study found that how much people like their supplement’s taste and texture is one of the strongest predictors of whether they’ll keep taking it. Chewable tablets showed better adherence rates than powders or fizzy formulations, and people who rated their supplement 5 out of 5 were six times more likely to be adherent.
A new study of 360 people in Madrid found that only about one-third of patients actually stick with their calcium and vitamin D supplements as prescribed. Researchers discovered that how a supplement tastes and feels matters just as much as remembering to take it. The study revealed that people often claim they’re taking their pills regularly, but pharmacy records show they’re actually taking far fewer doses. The good news: choosing the right formulation, especially chewable tablets with pleasant flavors, can significantly boost how many people actually stick with their supplements long-term.
Key Statistics
A cross-sectional study of 360 participants in Madrid found that only 34.7% of people truly adhered to calcium and vitamin D supplements when using strict criteria combining self-reporting, questionnaires, and pharmacy records.
In the same study, 70.8% of participants claimed they were taking their calcium and vitamin D supplements regularly, but pharmacy records showed only 40.3% had actually picked up at least 90% of their expected doses.
People who gave their calcium and vitamin D supplement a perfect 5 out of 5 rating for overall acceptability were 6.17 times more likely to be adherent compared to those with lower ratings.
Forgetfulness was the primary reason for non-adherence in 63.8% of participants who weren’t sticking with their calcium and vitamin D supplements, followed by taste and texture problems.
The Quick Take
- What they studied: Why people do or don’t stick with taking calcium and vitamin D supplements, focusing on how the pill tastes, feels, and looks
- Who participated: 360 adults from a hospital area in Madrid, Spain, who had been prescribed calcium and vitamin D supplements for at least 6 months
- Key finding: Only 35% of people truly stick with their calcium and vitamin D supplements as directed, but 71% claim they do. People who like how their pill tastes and feels are much more likely to keep taking it.
- What it means for you: If you’re struggling to remember your calcium and vitamin D supplements, switching to a different formulation that tastes better might help you stick with it. Talk to your doctor or pharmacist about options like chewable tablets instead of powders or fizzy drinks.
The Research Details
Researchers called 360 people randomly who lived in a hospital’s service area in Madrid and had been taking calcium and vitamin D supplements for over 6 months. They asked detailed questions about whether people were taking their pills and how much they liked them. They also checked pharmacy records to see how many refills people actually picked up over the previous 6 months. This combination of methods helped them get a more accurate picture than just asking people if they were taking their pills.
The researchers classified 22 different supplement formulations into groups based on their taste and sweetness. They asked people to rate how much they liked the taste, texture, and overall experience of their supplement on a scale of 1 to 5. They then used statistical analysis to figure out which factors predicted whether someone would stick with their supplements.
Most studies about supplement adherence rely only on asking people if they take their pills, which tends to overestimate how much people actually take. This study is important because it compared what people said with actual pharmacy records, revealing a big gap between perception and reality. By focusing on how supplements taste and feel, the research identifies something doctors and pharmacists can actually change to help people stick with their treatment.
This study followed established research guidelines for cross-sectional studies. The researchers used multiple methods to measure adherence, which strengthens their findings. The fact that pharmacy records showed much lower adherence than self-reporting suggests the study captured a real problem that other research might have missed. The statistical model they used to identify factors associated with adherence showed good accuracy, meaning their conclusions are likely reliable.
What the Results Show
The study found that only 34.7% of participants were truly adherent to their calcium and vitamin D supplements when using strict criteria that combined self-reporting, a standard adherence questionnaire, and pharmacy refill records. This is dramatically lower than the 70.8% of people who claimed they were taking their supplements regularly. When researchers looked only at pharmacy records, they found that 40.3% of people had picked up at least 90% of their expected doses in the previous 6 months.
Chewable tablets showed significantly better adherence rates compared to powders that dissolve on your tongue or fizzy effervescent formulations. Among the factors that predicted whether someone would stick with their supplements, the most powerful was how much they liked their supplement overall. People who gave their supplement a perfect 5 out of 5 rating were about 6 times more likely to be adherent than those who rated it lower.
Women were nearly 3 times more likely to stick with their supplements than men. Interestingly, people taking more than 10 different medications were actually more likely to be adherent to their calcium and vitamin D, possibly because they had developed better pill-taking habits. Supplements with polyol-based sweeteners, a type of sugar substitute, showed better adherence rates than other formulations.
About 15% of participants reported experiencing side effects from their supplements, and these adverse reactions significantly reduced the likelihood of adherence. Forgetfulness was the main reason people didn’t stick with their supplements, reported by nearly 64% of those who weren’t adherent. The second most common reason was problems with how the supplement tasted or felt, followed by intolerance or side effects. The agreement between different methods of measuring adherence was only moderate, meaning that asking people if they take their pills doesn’t always match what pharmacy records show.
This research confirms what other studies have suggested: people often overestimate how regularly they take their supplements. However, this study goes further by identifying that formulation characteristics, not just patient factors, play an independent role in adherence. Previous research has focused mainly on patient demographics and health conditions, but this study shows that how a supplement tastes and feels is just as important. The finding that chewable tablets work better than other forms provides practical guidance that hasn’t been emphasized in previous research.
The study only included people from one hospital area in Madrid, Spain, so the results may not apply to other regions or countries where different supplements are available. The study was cross-sectional, meaning it captured a snapshot in time rather than following people over months or years, so researchers couldn’t determine whether formulation preferences cause better adherence or whether people who are naturally more adherent simply choose better-tasting supplements. The study relied on pharmacy records from one source, which may not capture supplements purchased elsewhere. Additionally, the study didn’t measure actual blood levels of calcium and vitamin D, so it’s unclear whether better adherence actually translates to better health outcomes.
The Bottom Line
If you’re taking calcium and vitamin D supplements, try different formulations to find one that tastes good and feels pleasant to take. Chewable tablets appear to be a better choice than powders or fizzy forms. If you experience any side effects, talk to your pharmacist about switching to a different brand or formulation. Setting reminders on your phone or using a pill organizer can help with forgetfulness, which is the most common reason people stop taking their supplements. Strong evidence supports that finding a supplement you actually like taking makes you much more likely to stick with it.
Anyone prescribed calcium and vitamin D supplements should pay attention to these findings, especially if they’ve struggled to remember to take them. Healthcare providers and pharmacists should consider asking patients about their supplement preferences and be ready to suggest alternatives if someone isn’t sticking with their current formulation. This is particularly important for older adults and women, who are more likely to be prescribed these supplements.
You might notice improved adherence within 1 to 2 weeks of switching to a supplement formulation you prefer. However, the real benefit comes from consistent long-term use over months and years, which is when calcium and vitamin D build stronger bones and provide other health benefits.
Frequently Asked Questions
Why do so many people stop taking calcium and vitamin D supplements?
Forgetfulness is the main reason, but how the supplement tastes and feels matters significantly. Research shows that 35% of people truly stick with their supplements, often because they dislike the taste or experience side effects. Switching to a more pleasant formulation, like chewable tablets, can help.
Do chewable calcium and vitamin D supplements work better than other types?
Chewable tablets show higher adherence rates than powders or fizzy formulations in real-world use. While all forms deliver the same nutrients, people are more likely to keep taking supplements they actually enjoy, making chewables a practical choice for many.
How accurate are people when they say they’re taking their supplements?
Very inaccurate. Research found that 71% of people claimed they were taking their calcium and vitamin D regularly, but pharmacy records showed only 40% actually picked up their refills consistently. Self-reporting overestimates adherence by nearly 30 percentage points.
What should I do if my calcium and vitamin D supplement causes side effects?
Talk to your pharmacist about switching to a different formulation or brand. The study found that side effects reduced adherence likelihood by 76%, so finding a better-tolerated option is crucial for long-term success with supplementation.
Can my pharmacist help me find a calcium and vitamin D supplement I’ll actually take?
Yes. Research shows that overall satisfaction with how a supplement tastes and feels is one of the strongest predictors of adherence. Your pharmacist can suggest alternatives based on your preferences and help you find a formulation you’ll stick with long-term.
Want to Apply This Research?
- Track your supplement adherence by logging each dose in the app and rate how much you like your current formulation on a 1-5 scale weekly. If your rating drops below 4, set a reminder to discuss alternative formulations with your pharmacist.
- Use the app to set daily reminders for your calcium and vitamin D supplement at the same time each day. If you find yourself skipping doses, use the app’s formulation tracker to note which types (chewable, powder, fizzy) you prefer, then discuss switching with your pharmacist.
- Monitor your monthly refill patterns through the app by connecting to your pharmacy records. Track any side effects or taste preferences you notice, and review this data quarterly with your healthcare provider to identify whether a formulation change might improve your adherence.
This research describes patterns in supplement adherence but does not provide medical advice. The findings apply to a specific population in Madrid and may not generalize to other regions. Before starting, stopping, or changing any calcium or vitamin D supplement, consult with your healthcare provider or pharmacist, especially if you have kidney disease, heart conditions, or take medications that interact with calcium or vitamin D. This study measured adherence patterns but did not assess health outcomes or blood nutrient levels. Individual responses to supplements vary based on age, health status, and other medications.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.