Research shows that people with Hansen’s disease (leprosy) have significantly lower levels of protective nutrients and less muscle mass than healthy people. A case-control study of 118 people in Brazil found that leprosy patients had vitamin D levels nearly 46% lower, zinc levels 31% lower, and muscle mass 18% less than controls. According to Gram Research analysis, these nutritional deficiencies may weaken immune response and suggest that nutritional screening should become routine in leprosy patient care.
A new study from Brazil compared 59 people with Hansen’s disease (leprosy) to 59 healthy people and found major differences in their nutrition and body composition. People with leprosy had significantly less muscle mass, weaker immune nutrients like vitamin D and zinc, and were much less physically active. According to Gram Research analysis, these nutritional deficiencies may make it harder for the body to fight the infection and recover. The findings suggest that doctors should routinely check the nutritional status of leprosy patients as part of their treatment plan.
Key Statistics
A 2025 case-control study of 118 people in Brazil found that patients with Hansen’s disease had vitamin D levels of 21.4 nanograms per milliliter compared to 39.7 in healthy controls, representing a 46% reduction in this immune-supporting nutrient.
Among 59 leprosy patients studied in Brazil, 81.4% were physically inactive compared to only 42.4% of 59 healthy controls, suggesting a strong association between inactivity and Hansen’s disease susceptibility.
A Brazilian case-control study found that leprosy patients had median skeletal muscle mass of 25.7 kilograms versus 31.4 kilograms in controls, representing an 18% reduction in muscle tissue that may impair immune function.
Research on 59 Hansen’s disease patients revealed zinc levels of 60.6 micrograms per deciliter compared to 88.2 in healthy controls, a 31% deficiency in this critical immune nutrient.
The Quick Take
- What they studied: Whether people with Hansen’s disease (leprosy) have different nutrition levels and body composition compared to people without the disease
- Who participated: 118 people total: 59 with leprosy (mostly the more severe form) and 59 healthy controls, all living in Espírito Santo, Brazil between February and December 2025
- Key finding: People with leprosy had significantly less muscle mass (25.7 kg versus 31.4 kg), lower levels of protective nutrients like vitamin D and zinc, and were much more likely to be physically inactive (81.4% versus 42.4%)
- What it means for you: If you or someone you know has leprosy, nutritional screening and support should be part of medical care. Better nutrition may help the body fight the infection more effectively. However, this is one study in one region, so more research is needed before making major changes to treatment protocols.
The Research Details
This was a case-control study, which means researchers compared two groups: people who had leprosy and people who didn’t. They measured three types of information: what people ate (dietary intake), their body measurements like weight and muscle mass (anthropometry), and blood tests showing nutrient levels (biochemical markers). The study took place over 11 months in Brazil, a country where leprosy is still relatively common. Researchers carefully matched the two groups so they would be similar in other ways, making it easier to see if leprosy itself caused the differences they found.
The leprosy patients in the study mostly had the more severe form of the disease (95% had multibacillary leprosy, meaning they had more bacteria in their bodies). About 81% had the borderline type, which is a specific classification doctors use. This matters because it means the findings apply most directly to people with more advanced leprosy, not mild cases.
The researchers measured muscle mass, body fat, hip and other body circumferences, and tested blood levels of important nutrients including vitamin D, zinc, selenium, and vitamin B12. They also asked people about their physical activity levels and eating habits.
Case-control studies are useful for identifying patterns and differences between sick and healthy people, which can point researchers toward causes or contributing factors. By measuring actual blood nutrient levels rather than just asking people what they eat, this study provides objective evidence. The combination of body measurements and blood tests gives a complete picture of nutritional status. This approach helps doctors understand whether leprosy patients need special nutritional support as part of their treatment.
This study has several strengths: it measured actual nutrient levels in blood rather than relying only on memory of what people ate, it included both body measurements and blood tests for a complete picture, and it was conducted in a real-world setting where leprosy is common. However, the sample size was relatively small (59 people per group), so findings may not apply to all leprosy patients everywhere. The study was conducted in one region of Brazil, so results might differ in other countries or climates. The researchers did not report how they selected participants or whether there were any dropouts, which could affect reliability. This is a single study, so results need confirmation from other research before changing medical practice.
What the Results Show
People with leprosy had significantly less muscle mass than healthy controls: a median of 25.7 kilograms compared to 31.4 kilograms. This difference was statistically significant, meaning it’s unlikely to be due to chance. They also had smaller hip circumferences (103.5 centimeters versus 112.0 centimeters), indicating overall smaller body frame and less muscle.
Physical inactivity was dramatically more common in the leprosy group: 81.4% of people with leprosy were physically inactive compared to only 42.4% of healthy controls. This large difference suggests that leprosy either causes people to move less or that inactive people are more susceptible to leprosy.
Blood tests revealed striking nutrient deficiencies in the leprosy group. Vitamin D levels were nearly half as high (21.4 versus 39.7 nanograms per milliliter). Zinc was significantly lower (60.6 versus 88.2 micrograms per deciliter). Selenium was also substantially reduced (62.4 versus 89.0 micrograms per liter). Vitamin B12 levels were lower in the leprosy group (235 versus 420 picograms per milliliter). All of these nutrients are important for immune function, meaning leprosy patients may have weaker immune defenses due to these deficiencies.
Body mass index (BMI, a measure of weight relative to height) was similar between groups, suggesting that leprosy patients weren’t necessarily overweight or underweight overall. However, the composition of their bodies was different: they had less muscle and likely more fat. This is important because it means simple weight measurements might miss the real nutritional problems in leprosy patients. The study also noted that cases were characterized mostly by the multibacillary form of leprosy, which is the more contagious and severe type, suggesting these findings apply to people with more advanced disease.
Previous research has suggested that nutrition plays a role in leprosy susceptibility and severity, but this study provides concrete evidence of specific nutrient deficiencies. The findings align with what we know about how vitamin D, zinc, and selenium support immune function. The low muscle mass finding is consistent with other research showing that chronic infections can cause muscle wasting. However, this is one of the first studies to comprehensively measure multiple nutrients in leprosy patients in an endemic setting, so it adds important new evidence to the field.
The study included only 59 people with leprosy in one region of Brazil, so results may not apply to leprosy patients in other countries or climates. The researchers did not report detailed information about how participants were selected or whether some people refused to participate, which could introduce bias. The study measured nutrients at one point in time, so we don’t know if these deficiencies existed before leprosy developed or if they resulted from the disease. The study did not measure dietary intake in detail enough to determine if low nutrient levels were due to poor diet or poor absorption of nutrients. Cause and effect cannot be determined from this type of study: we know leprosy patients have lower nutrients, but we don’t know if poor nutrition increases leprosy risk or if leprosy causes nutrient deficiencies.
The Bottom Line
Healthcare providers treating leprosy patients should consider routine nutritional screening, including blood tests for vitamin D, zinc, selenium, and B12 levels. Moderate confidence: this is one study, but the findings are consistent with what we know about immune function. Patients with leprosy should be encouraged to maintain physical activity as much as their condition allows, since inactivity was very common in this group. Low to moderate confidence: the study shows inactivity is associated with leprosy, but doesn’t prove it causes leprosy. Nutritional supplementation may be beneficial for leprosy patients with documented deficiencies, but this should be determined by a healthcare provider based on individual blood test results. Moderate confidence: the study shows deficiencies exist, but doesn’t test whether supplementation improves outcomes.
People with leprosy or their healthcare providers should pay attention to these findings. People living in areas where leprosy is common may want to ensure adequate nutrition and vitamin D levels as a preventive measure, though this study doesn’t prove prevention. Public health officials in leprosy-endemic regions should consider whether nutritional screening should be part of standard leprosy care. People with other chronic infections may find these findings relevant, though this study specifically examined leprosy. People who are generally interested in how nutrition affects immune function and disease susceptibility will find this research interesting.
If a leprosy patient has nutrient deficiencies and begins supplementation, it typically takes 4 to 12 weeks to see improvements in blood nutrient levels, depending on the nutrient and severity of deficiency. Improvements in muscle mass and physical function may take several months of consistent supplementation combined with physical activity. The study was conducted over 11 months, so longer-term effects are unknown. This study does not provide information about how quickly nutritional support might improve leprosy outcomes or recovery time.
Frequently Asked Questions
What nutrients are most deficient in people with leprosy?
A 2025 Brazilian study found that leprosy patients had significantly lower vitamin D (21.4 versus 39.7 ng/mL), zinc (60.6 versus 88.2 mcg/dL), selenium (62.4 versus 89.0 mcg/L), and vitamin B12 (235 versus 420 pg/mL) compared to healthy controls. These nutrients are essential for immune function.
Does leprosy cause muscle loss or does muscle loss increase leprosy risk?
This study found that leprosy patients had significantly less muscle mass (25.7 versus 31.4 kg), but cannot determine cause and effect. Leprosy may cause muscle wasting, or weak muscles may increase susceptibility. More research is needed to understand the relationship.
Should leprosy patients take vitamin supplements?
The study shows leprosy patients have documented nutrient deficiencies, but does not test whether supplementation improves outcomes. Healthcare providers should order blood tests to identify specific deficiencies and recommend personalized supplementation based on individual results.
How common is physical inactivity in leprosy patients?
A 2025 case-control study found that 81.4% of leprosy patients were physically inactive compared to 42.4% of healthy controls. This suggests either that leprosy causes inactivity or that inactive people are more susceptible to infection.
Can better nutrition prevent leprosy?
This study shows leprosy patients have lower nutrient levels but does not test whether better nutrition prevents infection. While adequate nutrition supports immune function generally, this research cannot confirm whether it prevents leprosy specifically.
Want to Apply This Research?
- Track weekly physical activity minutes and monthly vitamin D, zinc, and selenium intake through food or supplements. Set a goal of at least 150 minutes of moderate activity per week and log actual nutrient intake to identify gaps.
- Users with leprosy or at risk should use the app to log daily physical activity (even light movement like walking), track nutrient-rich foods (fatty fish for vitamin D, nuts and seeds for zinc, whole grains for selenium), and set reminders for supplement doses if prescribed. Create a simple checklist: ‘Did I move today?’ and ‘Did I eat a nutrient-rich food?’
- Establish a baseline by logging current activity levels and typical nutrient intake for one week. Then set incremental goals: add 10 minutes of activity weekly and add one nutrient-rich food daily. Review progress monthly and share data with healthcare provider at appointments. Track any changes in energy levels or physical function as secondary indicators of improvement.
This research describes nutritional differences in leprosy patients but does not establish that nutritional deficiencies cause leprosy or that supplementation treats it. If you have leprosy or suspect you may have it, consult a healthcare provider for proper diagnosis and treatment. Do not use this information to self-diagnose or self-treat. Nutritional supplementation should only be undertaken under medical supervision based on blood tests and individual health status. This article summarizes one case-control study and should not be considered definitive medical guidance. Always discuss nutritional changes with your healthcare provider, especially if you take medications or have other health conditions.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.