We explored the connection between vitamin D levels and upper respiratory tract infections (URTIs) among military recruits during their training. This observation spanned across different seasons and included over 1,600 recruits. Our aim was to understand how achieving sufficient vitamin D levels could potentially impact the frequency and severity of colds among physically active individuals.
In an additional phase of the research, we conducted a randomized controlled trial with 250 male recruits. They received either a placebo, simulated sunlight exposure, or oral vitamin D3 supplements during winter. This comparison allowed us to see if these methods effectively increased vitamin D levels to a sufficient status of 25(OH)D at 50 nmol/L or higher.
Notably, our findings showed that only 21% of recruits had adequate vitamin D during winter, yet those who did were 40% less likely to suffer from URTIs. Furthermore, both vitamin D supplementation strategies similarly helped nearly all participants achieve sufficient levels. Vitamin D supplementation notably reduced the severity of URTI symptoms by 15% and the number of days with URTIs by 36% compared to placebo.
While the supplementation strategies did not significantly alter other immune factors, such as salivary secretory immunoglobulin A, the overall reduction in respiratory infections indicates a beneficial effect of maintaining vitamin D sufficiency during military training.
Read More
8
Vitamin D3 aids cold recovery
Intake of 25-Hydroxyvitamin D3 Reduces Duration and Severity of Upper Respiratory Tract Infection: A Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study.
We explored how 25-hydroxyvitamin D3 (25OHD), a form of vitamin D, influences upper respiratory tract infections (URTIs), commonly known as colds. In a carefully designed clinical study, we followed 428 participants aged 45 to 74 over a 16-week period. They were randomly assigned to receive either 10 μg of 25OHD daily or a placebo, all while maintaining a double-blind setup to ensure accurate results.
Our findings revealed that those who took 25OHD had reduced duration and severity of their cold symptoms. Participants reported improvements in their overall quality of life during the bouts of URTI. By tracking the health of the participants through surveys designed to measure cold symptoms, we gathered valuable data that indicates vitamin D3 could play a helpful role in managing colds.
This suggests that incorporating vitamin D3 into our diets may be beneficial when we catch a cold, potentially leading to a quicker recovery. It’s a promising avenue for anyone looking to ease the discomfort and duration of these frustrating infections.
Read More
7
Vitamin D's limited cold impact
High-dose oral vitamin D supplementation for prevention of infections in children aged 0 to 59 months: a systematic review and meta-analysis.
We evaluated the impact of high-dose vitamin D supplementation, specifically doses exceeding the standard 400 IU, on preventing colds and other infections in children under five years of age. Our analysis included seven studies, involving a total of 5,748 children, which looked into how effective vitamin D might be in reducing the incidence of upper respiratory tract infections.
Interestingly, while our findings showed no significant benefit of high-dose vitamin D on the prevention of upper respiratory tract infections as a whole, we did observe a noteworthy reduction in specific illness occurrences. We noted a 57% reduction in colds, a 56% reduction in coughs, and a 59% decrease in fever rates with daily doses exceeding 1,000 IU.
However, we must approach these findings with caution, as the evidence supporting the reduction in cough and fever was of lower certainty. No significant effects were observed regarding other conditions such as bronchitis or otitis media. Overall, while high-dose vitamin D may help with colds specifically, further research is needed to solidify these conclusions.
Read More
Most Useful Reviews
10
Effective for colds
I take it in large doses for 4-5 days when treating colds and SARS, and it always works!
Read More
9
Excellent quality
Life Extension is a premium dietary supplement brand. Their Vitamin D3 stands out because of its olive oil extract. The good quality cold-extracted olive oil is the primary ingredient. Following its use, I noticed fewer infections and colds, and my health improved substantially. Highly recommended.
Read More
9
Quick cold relief
I am really deficient in vitamin D, and after my nutritionist recommended this product, I’ve had no side effects. Recently, I fell ill but took 10,000 IU, and the cold receded promptly! I highly recommend it.
We explored the connection between vitamin D levels and upper respiratory tract infections (URTIs) among military recruits during their training. This observation spanned across different seasons and included over 1,600 recruits. Our aim was to understand how achieving sufficient vitamin D levels could potentially impact the frequency and severity of colds among physically active individuals.
In an additional phase of the research, we conducted a randomized controlled trial with 250 male recruits. They received either a placebo, simulated sunlight exposure, or oral vitamin D3 supplements during winter. This comparison allowed us to see if these methods effectively increased vitamin D levels to a sufficient status of 25(OH)D at 50 nmol/L or higher.
Notably, our findings showed that only 21% of recruits had adequate vitamin D during winter, yet those who did were 40% less likely to suffer from URTIs. Furthermore, both vitamin D supplementation strategies similarly helped nearly all participants achieve sufficient levels. Vitamin D supplementation notably reduced the severity of URTI symptoms by 15% and the number of days with URTIs by 36% compared to placebo.
While the supplementation strategies did not significantly alter other immune factors, such as salivary secretory immunoglobulin A, the overall reduction in respiratory infections indicates a beneficial effect of maintaining vitamin D sufficiency during military training.
Read More
8
Vitamin D3 aids cold recovery
Intake of 25-Hydroxyvitamin D3 Reduces Duration and Severity of Upper Respiratory Tract Infection: A Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study.
We explored how 25-hydroxyvitamin D3 (25OHD), a form of vitamin D, influences upper respiratory tract infections (URTIs), commonly known as colds. In a carefully designed clinical study, we followed 428 participants aged 45 to 74 over a 16-week period. They were randomly assigned to receive either 10 μg of 25OHD daily or a placebo, all while maintaining a double-blind setup to ensure accurate results.
Our findings revealed that those who took 25OHD had reduced duration and severity of their cold symptoms. Participants reported improvements in their overall quality of life during the bouts of URTI. By tracking the health of the participants through surveys designed to measure cold symptoms, we gathered valuable data that indicates vitamin D3 could play a helpful role in managing colds.
This suggests that incorporating vitamin D3 into our diets may be beneficial when we catch a cold, potentially leading to a quicker recovery. It’s a promising avenue for anyone looking to ease the discomfort and duration of these frustrating infections.
Read More
7
Vitamin D's limited cold impact
High-dose oral vitamin D supplementation for prevention of infections in children aged 0 to 59 months: a systematic review and meta-analysis.
We evaluated the impact of high-dose vitamin D supplementation, specifically doses exceeding the standard 400 IU, on preventing colds and other infections in children under five years of age. Our analysis included seven studies, involving a total of 5,748 children, which looked into how effective vitamin D might be in reducing the incidence of upper respiratory tract infections.
Interestingly, while our findings showed no significant benefit of high-dose vitamin D on the prevention of upper respiratory tract infections as a whole, we did observe a noteworthy reduction in specific illness occurrences. We noted a 57% reduction in colds, a 56% reduction in coughs, and a 59% decrease in fever rates with daily doses exceeding 1,000 IU.
However, we must approach these findings with caution, as the evidence supporting the reduction in cough and fever was of lower certainty. No significant effects were observed regarding other conditions such as bronchitis or otitis media. Overall, while high-dose vitamin D may help with colds specifically, further research is needed to solidify these conclusions.
Read More
7
Vitamin D's role in Raynaud management
Serum vitamin B12 and D levels in children with Primary Raynaud Phenomenon: a retrospective cohort study.
We explored the impact of vitamin D and B12 deficiencies in children experiencing primary Raynaud phenomenon (RP), which causes temporary blood flow changes often triggered by cold or stress. Our study aimed to identify how common these vitamin deficiencies are in pediatric patients and whether they influenced the severity of Raynaud symptoms.
Out of 40 young participants, a significant portion—41.5% for vitamin B12 and 39% for vitamin D—showed low serum levels of these vitamins. After providing supplementation, we observed improved symptoms in many cases, particularly through warming techniques. However, it's important to note that while vasodilator treatment needs were generally unchanged regardless of vitamin B12 levels, those who had vitamin D deficiencies and subsequently received vitamin D treatment required significantly less vasodilator therapy.
Overall, while some positive effects of vitamin D were noted, further research is necessary to conclusively determine its role in managing primary RP symptoms and its effectiveness in combating cold-induced episodes.
Read More
7
Vitamin D reduces cold symptoms
Intake of 25-Hydroxyvitamin D May Reduce the Severity of Upper Respiratory Tract Infection: Post hoc Analysis of a Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study.
We explored the effects of 25-hydroxyvitamin D (25OHD) on individuals experiencing upper respiratory tract infections (URTIs), commonly known as colds. In a well-structured study, participants with low vitamin D levels received either a daily dose of 10 micrograms of 25OHD or a placebo for a span of 16 weeks. The participants' symptoms were assessed using the Wisconsin Upper Respiratory Symptom Survey-21, focusing on how the vitamin impacted their cold symptoms.
Our findings showed that those taking 25OHD reported significant reductions in physical symptoms such as runny noses, sneezing, and head congestion compared to those on the placebo. Additionally, the quality of life scores improved for most symptoms, except for ease of breathing. However, it’s important to note that there was no significant difference in the total number of cold events or how often participants used medications like antibiotics or pain relievers.
Collectively, these results suggest that adequate intake of vitamin D can help ease cold symptoms, particularly those affecting the nose, and might enhance overall well-being when a cold strikes. This indicates that vitamin D may play a positive role in managing the discomfort associated with upper respiratory infections.
I take it in large doses for 4-5 days when treating colds and SARS, and it always works!
Read More
9
Excellent quality
Life Extension is a premium dietary supplement brand. Their Vitamin D3 stands out because of its olive oil extract. The good quality cold-extracted olive oil is the primary ingredient. Following its use, I noticed fewer infections and colds, and my health improved substantially. Highly recommended.
Read More
9
Quick cold relief
I am really deficient in vitamin D, and after my nutritionist recommended this product, I’ve had no side effects. Recently, I fell ill but took 10,000 IU, and the cold receded promptly! I highly recommend it.
Read More
9
Rapid relief
I drink high doses at the first symptoms of a cold along with vitamin C, and by morning, everything is better.
Read More
9
Strong immunity
Vitamin D3 was a real discovery for me! After a few months of taking it, I noticed a significant improvement in energy levels, endurance, and even mood. It effectively supports immunity; I used to suffer from colds frequently, but now I hardly get them. The condition of my hair and skin has improved too. This product is well absorbed and has no side effects. I recommend it for anyone lacking "sunny" vitamin, especially in winter—it's vital for health!
Cold is a term that refers to a state of low temperature, often associated with a perceptibly chilly environment or the sensation of being cool to the touch. Scientifically, cold is relative to the presence and movement of heat, which is a measure of energy within matter. In everyday terms, we experience cold through weather changes, such as during winter months, and it can also be described in the context of specific temperature ranges – for example, temperatures below 32 degrees Fahrenheit (0 degrees Celsius) generally signify freezing conditions, which can impact outdoor activities, personal comfort, and various ecological systems.
Moreover, the sensation of cold is not solely dependent on temperature; factors like humidity and wind chill can enhance the feeling of coldness. When discussing cold in terms of human health, prolonged exposure to cold conditions can lead to hypothermia or frostbite if body heat is not effectively maintained. Hence, it's crucial to dress appropriately and take necessary precautions during colder months to prevent adverse effects. Understanding the concept of cold can help individuals better prepare for seasonal changes and ensure their comfort and safety.
Vitamin D is a fat-soluble vitamin that's essential for maintaining healthy bones and teeth, supporting immune system function, and facilitating normal cell growth and development. It plays a crucial role in calcium absorption in the gut, which is vital for bone health. Unlike most vitamins, our bodies can produce Vitamin D when exposed to sunlight, specifically UVB rays, which is why it’s often referred to as the "sunshine vitamin." However, depending on your geographical location, lifestyle, and skin type, getting sufficient Vitamin D from the sun alone can be challenging, particularly during the winter months.
In addition to sunlight, Vitamin D can be obtained from certain foods such as fatty fish (like salmon and mackerel), fish liver oils, and fortified foods like milk and cereals. Some individuals may also consider supplements, especially if they're at risk for deficiency. Insufficient vitamin D levels are linked to various health issues, including rickets in children, osteomalacia in adults, and even an increased risk of chronic diseases. Regularly checking your vitamin D levels and consulting with a healthcare professional can help ensure you're meeting your needs for optimal health.
Vitamin D is often discussed in relation to immune health, and some studies suggest that it may play a role in reducing the risk of upper respiratory infections, including the common cold. Adequate levels of vitamin D might help enhance your immune response, potentially making your body more effective at fighting off infections. However, the evidence is not entirely conclusive, and while some individuals with low vitamin D levels may experience more frequent colds, it's important to consider that other factors also contribute to overall immunity, such as lifestyle and diet.
If you’re considering using vitamin D supplements to prevent or mitigate the effects of a cold, it’s always best to consult with a healthcare professional. They can provide tailored advice based on your specific health needs and possible deficiencies. While maintaining sufficient vitamin D levels can be beneficial for your immune system, it should not be seen as a guaranteed solution to avoid catching colds, especially during peak cold and flu seasons.
Based on user reviews, the time it takes to see results from taking this vitamin D supplement for cold symptoms can vary significantly. Many users report experiencing noticeable improvements within just a few days. For instance, one user states that taking high doses at the first signs of a cold resulted in feeling better by the next morning Read Review. Another user mentions that after taking a higher dose of 15,000 IU, they felt absolutely healthy by morning Read Review.
Conversely, some users have noted longer timelines for noticing the full benefits, with one review citing improvements in well-being occurring over a span of 2-3 weeks Read Review. Others mentioned using the supplement consistently during colder months to maintain immunity, suggesting that ongoing use may be necessary for greater effectiveness against frequent colds Read Review. In summary, while many users enjoy quick relief, maintaining a regular regimen can contribute to overall immune health.
Emerging evidence suggests that vitamin D may have a potential role in alleviating cold symptoms, though the research is still somewhat mixed. One significant study showed that individuals with low vitamin D levels who received oral supplementation reported a notable reduction in cold symptoms such as runny noses and head congestion compared to those on a placebo [5]. Another study indicated that high doses of vitamin D might lower the incidence of colds and upper respiratory infections in young children, reporting a 57% reduction in colds among those receiving daily doses exceeding 1,000 IU [2].
However, it's important to highlight that while some studies point toward benefits, others find minimal impact on the overall incidence or severity of colds with vitamin D supplementation [1]. Overall, while vitamin D supplementation may help ease certain cold symptoms and improve recovery speed, more extensive and consistent research is needed to fully understand its efficacy in preventing and treating colds across various populations.
Users report a variety of improvements in their symptoms after taking this vitamin D supplement, particularly for colds and overall immune health. Many users have noted that they experience a rapid recovery when they take high doses at the first signs of a cold, with one user claiming to feel significantly better by the next morning after taking 15,000 IU Read Review. Others have mentioned that this supplement not only helps in acute situations but also leads to a reduced frequency of colds over time; one user indicated having "almost no colds" after consistent daily intake for several years Read Review.
In addition to diminishing cold symptoms, many users have noted improvements in energy levels and overall health. For instance, one user mentioned that taking vitamin D3 resulted in an increase in endurance and a better mood, as well as less susceptibility to infections Read Review. Another reported that taking the vitamin regularly transformed their experience during cold winters, alleviating chronic fatigue and sleepiness Read Review. While individual results can vary, the overall consensus suggests that this vitamin is a beneficial addition for those seeking to enhance their immunity and manage cold symptoms effectively.
Users report positive experiences when combining this vitamin D supplement with other supplements to manage cold symptoms. Specifically, many have successfully paired it with vitamin C, noting synergy in bolstering their immune response. One user highlighted that combining high doses of vitamin D with vitamin C at the first signs of a cold led to significant improvements by the following morning Read Review. Another review mentions taking vitamin D alongside omega-3s, suggesting a multi-faceted approach that enhances effectiveness against colds Read Review.
Moreover, users reportedly find that increasing the dosage during illness further strengthens immune defenses. For example, one user stated they typically consume one capsule for maintenance but double it during cold episodes Read Review. This approach of upping the intake during illness appears to be common, with users emphasizing its effectiveness in recovery times and overall health improvements. Overall, the consensus is that combining vitamin D with other supplements, particularly vitamin C, can enhance its benefits for cold management.
Research suggests that high-dose vitamin D supplementation may provide benefits for treating cold symptoms, particularly in children. A study found that children taking daily doses exceeding 1,000 IU of vitamin D experienced a significant reduction in colds, coughs, and fever rates, with reductions of 57%, 56%, and 59%, respectively [2]. While these findings are promising, they should be approached with caution due to varying levels of evidence supporting these observations. For children, a specific effective dose noted was 800 IU daily, which also correlated with quicker recovery from mild respiratory symptoms [1].
Additionally, general studies have indicated that vitamin D helps reduce the severity of cold symptoms, improve quality of life during illness, and may decrease the number of days one suffers from upper respiratory infections (URTIs). For example, participants receiving daily doses of 10 μg (approximately 400 IU) of vitamin D3 showed reduced symptoms like runny nose and sneezing [5]. While these doses may not directly prevent the onset of colds, maintaining adequate vitamin D levels could help many manage their symptoms more effectively, ultimately supporting a quicker recovery [6].
9
Rapid relief
I drink high doses at the first symptoms of a cold along with vitamin C, and by morning, everything is better.
9
Fast recovery
I purchase this for the fourth time and truly like it! If I have a cold, I take 15,000 IU, drink plenty of water, and by morning I feel absolutely healthy.
7.5
Visible effectiveness
Great vitamins! A good supplement with quality ingredients for immune health. I take it as a course during the cold season. I noticed effectiveness within 2-3 weeks, and my well-being has improved.
9
Increased energy
Effectively! I take vitamin D regularly, as the cold season in my region lasts nine months. Daytime sleepiness has vanished, energy has increased, efficiency has improved, and I no longer suffer from colds. I do not notice any side effects when taking it.
9
No colds experienced
This D3 is of very high quality. Since I’ve been taking it daily for the past few years, I have had almost no colds throughout the year. It has proven effective.
9
Strong immunity
Vitamin D3 was a real discovery for me! After a few months of taking it, I noticed a significant improvement in energy levels, endurance, and even mood. It effectively supports immunity; I used to suffer from colds frequently, but now I hardly get them. The condition of my hair and skin has improved too. This product is well absorbed and has no side effects. I recommend it for anyone lacking "sunny" vitamin, especially in winter—it's vital for health!
9
Eliminates fatigue
This vitamin is crucial for those in cold climates. My drowsiness and chronic fatigue have vanished, and it's more cost-effective than the American equivalent. It’s easy to take and has improved my vitamin D levels significantly.
9
Long-term use
I have been taking D3 5000 for colds for about three years; it is very effective, especially when paired with vitamin C and omega-3s.
9
Prevention method
Effective Vitamin D3 for prevention. I take 1 capsule regularly, but for colds, I increase it to 2 capsules a day for 3-4 days. It helps significantly. Supplementing vitamins benefits my immunity.
7
Vitamin D reduces cold symptoms
Intake of 25-Hydroxyvitamin D May Reduce the Severity of Upper Respiratory Tract Infection: Post hoc Analysis of a Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study.
We explored the effects of 25-hydroxyvitamin D (25OHD) on individuals experiencing upper respiratory tract infections (URTIs), commonly known as colds. In a well-structured study, participants with low vitamin D levels received either a daily dose of 10 micrograms of 25OHD or a placebo for a span of 16 weeks. The participants' symptoms were assessed using the Wisconsin Upper Respiratory Symptom Survey-21, focusing on how the vitamin impacted their cold symptoms.
Our findings showed that those taking 25OHD reported significant reductions in physical symptoms such as runny noses, sneezing, and head congestion compared to those on the placebo. Additionally, the quality of life scores improved for most symptoms, except for ease of breathing. However, it’s important to note that there was no significant difference in the total number of cold events or how often participants used medications like antibiotics or pain relievers.
Collectively, these results suggest that adequate intake of vitamin D can help ease cold symptoms, particularly those affecting the nose, and might enhance overall well-being when a cold strikes. This indicates that vitamin D may play a positive role in managing the discomfort associated with upper respiratory infections.
7
Vitamin D's limited cold impact
High-dose oral vitamin D supplementation for prevention of infections in children aged 0 to 59 months: a systematic review and meta-analysis.
We evaluated the impact of high-dose vitamin D supplementation, specifically doses exceeding the standard 400 IU, on preventing colds and other infections in children under five years of age. Our analysis included seven studies, involving a total of 5,748 children, which looked into how effective vitamin D might be in reducing the incidence of upper respiratory tract infections.
Interestingly, while our findings showed no significant benefit of high-dose vitamin D on the prevention of upper respiratory tract infections as a whole, we did observe a noteworthy reduction in specific illness occurrences. We noted a 57% reduction in colds, a 56% reduction in coughs, and a 59% decrease in fever rates with daily doses exceeding 1,000 IU.
However, we must approach these findings with caution, as the evidence supporting the reduction in cough and fever was of lower certainty. No significant effects were observed regarding other conditions such as bronchitis or otitis media. Overall, while high-dose vitamin D may help with colds specifically, further research is needed to solidify these conclusions.
5
Vitamin D and cold symptoms
The Effects of Vitamin D Supplementation on Respiratory Infections in Children under 6 Years Old: A Systematic Review.
We explored the effects of vitamin D supplementation on respiratory infections, particularly colds, in children under six years old. By examining various studies published until February 2023, we observed diverse findings, with some studies reporting benefits while others found no significant advantage. Overall, eight studies were included, with a total of 2,189 children assessed.
While a few studies indicated that low vitamin D levels might be linked to an increased risk of respiratory infections, only one study specifically noted that children who took 800 IU of vitamin D daily for three months experienced fewer mild respiratory symptoms and recovered more quickly. However, a significant number of studies showed no notable differences in the rates or severity of colds when vitamin D supplementation was used.
In essence, the evidence regarding vitamin D's role in preventing or effectively treating colds in young children is still unclear. We did find some indications that certain doses, like 80 IU/kg/day, may help reduce acute respiratory infection risks, but most research highlighted only minor benefits, such as quicker recovery rather than preventing infections. Variability in study design and supplementation protocols contributed to these inconclusive results, highlighting the need for further research.
8
Vitamin D3 aids cold recovery
Intake of 25-Hydroxyvitamin D3 Reduces Duration and Severity of Upper Respiratory Tract Infection: A Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study.
We explored how 25-hydroxyvitamin D3 (25OHD), a form of vitamin D, influences upper respiratory tract infections (URTIs), commonly known as colds. In a carefully designed clinical study, we followed 428 participants aged 45 to 74 over a 16-week period. They were randomly assigned to receive either 10 μg of 25OHD daily or a placebo, all while maintaining a double-blind setup to ensure accurate results.
Our findings revealed that those who took 25OHD had reduced duration and severity of their cold symptoms. Participants reported improvements in their overall quality of life during the bouts of URTI. By tracking the health of the participants through surveys designed to measure cold symptoms, we gathered valuable data that indicates vitamin D3 could play a helpful role in managing colds.
This suggests that incorporating vitamin D3 into our diets may be beneficial when we catch a cold, potentially leading to a quicker recovery. It’s a promising avenue for anyone looking to ease the discomfort and duration of these frustrating infections.
References
Marusca LM, Reddy G, Blaj M, Prathipati R, Rosca O, et al. The Effects of Vitamin D Supplementation on Respiratory Infections in Children under 6 Years Old: A Systematic Review. Diseases. 2023;11. 10.3390/diseases11030104
Carboo JA, Dolman-Macleod RC, Malan L, Lombard MJ. High-dose oral vitamin D supplementation for prevention of infections in children aged 0 to 59 months: a systematic review and meta-analysis. Nutr Rev. 2024;82:579. 10.1093/nutrit/nuad082
Kisla Ekinci RM, Taskin Karacay IE, Celik U. Serum vitamin B12 and D levels in children with Primary Raynaud Phenomenon: a retrospective cohort study. Eur J Clin Nutr. 2022;76:1615. 10.1038/s41430-022-01151-0
Harrison SE, Oliver SJ, Kashi DS, Carswell AT, Edwards JP, et al. Influence of Vitamin D Supplementation by Simulated Sunlight or Oral D3 on Respiratory Infection during Military Training. Med Sci Sports Exerc. 2021;53:1505. 10.1249/MSS.0000000000002604
Shimizu Y, Ito Y, Uotsu N, Yui K. Intake of 25-Hydroxyvitamin D May Reduce the Severity of Upper Respiratory Tract Infection: Post hoc Analysis of a Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study. Nutrients. 2020;12. 10.3390/nu12123769
Shimizu Y, Ito Y, Yui K, Egawa K, Orimo H. Intake of 25-Hydroxyvitamin D3 Reduces Duration and Severity of Upper Respiratory Tract Infection: A Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study. J Nutr Health Aging. 2018;22:491. 10.1007/s12603-017-0952-x