5/5/2025
Last update
5/5/2025
Reviewed By
Overview
SCIENTIFIC SCORE
Possibly Effective
Based on 12 Researches
7.3
USERS' SCORE
Good
Based on 1 Review
8.5
Top Medical Research Studies
8
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.
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
We investigated how dihydroporphyrin iron (DH-Fe) acts as a plant growth regulator, particularly in enhancing cold tolerance. Our research focused on plants that are usually sensitive to low temperatures, finding that DH-Fe plays a vital role in helping these plants cope with cold stress by using different concentrations of this treatment.
Through our study, we applied varying levels of DH-Fe to see how it impacts carbon and nitrogen metabolism, as well as oxidative stress responses, when plants were exposed to low temperatures. Notably, we observed that DH-Fe significantly reduces oxidative stress and other harmful effects associated with cold exposure. For instance, it reduced certain sugars while simultaneously boosting the activity of enzymes crucial for sugar breakdown and nitrogen assimilation.
Among the various findings, we noted that a concentration of 20 μg·L of DH-Fe was particularly effective, improving the overall health and resilience of the plants against low temperatures. This suggests that by applying the right amount of iron, we can potentially mitigate the negative effects of cold weather on sensitive plant species, providing a fresh perspective on how to enhance cold tolerance through nutrient management.
Overall, our findings shine a light on how incorporating iron into agricultural practices might be a practical strategy for improving plant resilience to cold stress.
Through our study, we applied varying levels of DH-Fe to see how it impacts carbon and nitrogen metabolism, as well as oxidative stress responses, when plants were exposed to low temperatures. Notably, we observed that DH-Fe significantly reduces oxidative stress and other harmful effects associated with cold exposure. For instance, it reduced certain sugars while simultaneously boosting the activity of enzymes crucial for sugar breakdown and nitrogen assimilation.
Among the various findings, we noted that a concentration of 20 μg·L of DH-Fe was particularly effective, improving the overall health and resilience of the plants against low temperatures. This suggests that by applying the right amount of iron, we can potentially mitigate the negative effects of cold weather on sensitive plant species, providing a fresh perspective on how to enhance cold tolerance through nutrient management.
Overall, our findings shine a light on how incorporating iron into agricultural practices might be a practical strategy for improving plant resilience to cold stress.
Read More
7
Effectiveness of Vitamin C on Colds
We explored the effects of vitamin C on the common cold and pneumonia by examining a range of studies. Interestingly, research on animals suggests that vitamin C may have protective effects against infections. However, when it comes to preventing colds in the general population, taking more than 1 gram of vitamin C per day didn’t show significant benefits.
But there's a twist! Participants engaged in heavy physical activities saw their cold incidence reduced by half with vitamin C supplementation. Additionally, regular intake of 1 gram or more daily was linked to a 15% decrease in cold severity. While some therapeutic trials showed inconsistent results when vitamin C was taken after cold symptoms appeared, two studies did indicate that larger doses (6-8 grams per day) could effectively shorten the duration of colds compared to lower doses.
Our investigation also looked into pneumonia, but the studies were conducted in unique settings, such as a boarding school and military recruits. This makes it hard to generalize the findings to the wider population. Yet, some trials suggested benefits for pneumonia patients. Finally, the role of vitamin C in treating COVID-19 and sepsis remains unclear, with mixed results.
Given that vitamin C seems to alleviate symptoms and shorten the duration of colds, while being safe and affordable, it might be worth considering a dose of 6-8 grams per day to see if it helps at an individual level.
But there's a twist! Participants engaged in heavy physical activities saw their cold incidence reduced by half with vitamin C supplementation. Additionally, regular intake of 1 gram or more daily was linked to a 15% decrease in cold severity. While some therapeutic trials showed inconsistent results when vitamin C was taken after cold symptoms appeared, two studies did indicate that larger doses (6-8 grams per day) could effectively shorten the duration of colds compared to lower doses.
Our investigation also looked into pneumonia, but the studies were conducted in unique settings, such as a boarding school and military recruits. This makes it hard to generalize the findings to the wider population. Yet, some trials suggested benefits for pneumonia patients. Finally, the role of vitamin C in treating COVID-19 and sepsis remains unclear, with mixed results.
Given that vitamin C seems to alleviate symptoms and shorten the duration of colds, while being safe and affordable, it might be worth considering a dose of 6-8 grams per day to see if it helps at an individual level.
Read More
Most Useful Reviews
8
Reduces cold sensitivity
1 people found this helpful
Worked great! I bought these because I am naturally cold and spend a lot of time outdoors. Being anaemic with low iron my entire life, my diet never helped much. Since I started taking these, I no longer feel as if I'm freezing while everyone else is comfortable.
Read More
Medical Researches
SCIENTIFIC SCORE
Possibly Effective
Based on 12 Researches
7.3
- All Researches
9
We explored the effects of ascorbic acid, commonly known as vitamin C, on cold tolerance in tomato seedlings. In our study, we discovered that applying vitamin C significantly boosts the seedlings' ability to handle cold stress.
By enhancing the antioxidant defense system, vitamin C treatment increased the enzyme activity in the seedlings' leaves. Additionally, it raised levels of important compounds such as proline, sugar, and abscisic acid, all of which play crucial roles in plant stress responses.
Our observations showed that vitamin C also protects the photosynthesis system of tomato seedlings. This implies that it helps maintain chlorophyll function, which is critical for the plant's overall health, especially under cold conditions.
Moreover, we found that vitamin C treatments led to increased expression of genes linked to antioxidant enzymes and cold response mechanisms. Overall, our findings suggest that exogenous vitamin C is a beneficial approach to improve cold tolerance in tomatoes and may provide helpful insights for farmers looking to cultivate hardier varieties during colder months.
By enhancing the antioxidant defense system, vitamin C treatment increased the enzyme activity in the seedlings' leaves. Additionally, it raised levels of important compounds such as proline, sugar, and abscisic acid, all of which play crucial roles in plant stress responses.
Our observations showed that vitamin C also protects the photosynthesis system of tomato seedlings. This implies that it helps maintain chlorophyll function, which is critical for the plant's overall health, especially under cold conditions.
Moreover, we found that vitamin C treatments led to increased expression of genes linked to antioxidant enzymes and cold response mechanisms. Overall, our findings suggest that exogenous vitamin C is a beneficial approach to improve cold tolerance in tomatoes and may provide helpful insights for farmers looking to cultivate hardier varieties during colder months.
Read More
9
We explored the effects of adding nano-scale zero-valent iron modified biochar (nZVI@BC) to two different anaerobic ammonia oxidation (anammox) systems. Our goal was to determine whether this iron-enhanced biochar could improve the cold resistance of low-nitrogen anammox processes during cold conditions.
The results were striking. At lower temperatures, the system with nZVI@BC maintained a robust nitrogen removal efficiency of around 80%. In comparison, the system with regular biochar saw its efficiency drop to about 69.49%, showing that iron truly makes a difference in cold performance.
We also noted that the biomass enriched with nZVI@BC contained significantly more heme-c, a vital component that contributes to the biological processes in these systems. Plus, the addition of nZVI@BC led to more extracellular polymeric substances and better granulation of the biomass, as well as an increased number of anammox bacteria, all of which play crucial roles in maintaining effective nitrogen removal.
Importantly, specific anammox genes proved essential in keeping nitrogen removal performance high, even at chilly temperatures of 15°C. Overall, our findings suggest that incorporating iron-modified biochar may be a game-changer for treating low-nitrogen wastewater in cold environments.
The results were striking. At lower temperatures, the system with nZVI@BC maintained a robust nitrogen removal efficiency of around 80%. In comparison, the system with regular biochar saw its efficiency drop to about 69.49%, showing that iron truly makes a difference in cold performance.
We also noted that the biomass enriched with nZVI@BC contained significantly more heme-c, a vital component that contributes to the biological processes in these systems. Plus, the addition of nZVI@BC led to more extracellular polymeric substances and better granulation of the biomass, as well as an increased number of anammox bacteria, all of which play crucial roles in maintaining effective nitrogen removal.
Importantly, specific anammox genes proved essential in keeping nitrogen removal performance high, even at chilly temperatures of 15°C. Overall, our findings suggest that incorporating iron-modified biochar may be a game-changer for treating low-nitrogen wastewater in cold environments.
Read More
8
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.
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
We investigated how dihydroporphyrin iron (DH-Fe) acts as a plant growth regulator, particularly in enhancing cold tolerance. Our research focused on plants that are usually sensitive to low temperatures, finding that DH-Fe plays a vital role in helping these plants cope with cold stress by using different concentrations of this treatment.
Through our study, we applied varying levels of DH-Fe to see how it impacts carbon and nitrogen metabolism, as well as oxidative stress responses, when plants were exposed to low temperatures. Notably, we observed that DH-Fe significantly reduces oxidative stress and other harmful effects associated with cold exposure. For instance, it reduced certain sugars while simultaneously boosting the activity of enzymes crucial for sugar breakdown and nitrogen assimilation.
Among the various findings, we noted that a concentration of 20 μg·L of DH-Fe was particularly effective, improving the overall health and resilience of the plants against low temperatures. This suggests that by applying the right amount of iron, we can potentially mitigate the negative effects of cold weather on sensitive plant species, providing a fresh perspective on how to enhance cold tolerance through nutrient management.
Overall, our findings shine a light on how incorporating iron into agricultural practices might be a practical strategy for improving plant resilience to cold stress.
Through our study, we applied varying levels of DH-Fe to see how it impacts carbon and nitrogen metabolism, as well as oxidative stress responses, when plants were exposed to low temperatures. Notably, we observed that DH-Fe significantly reduces oxidative stress and other harmful effects associated with cold exposure. For instance, it reduced certain sugars while simultaneously boosting the activity of enzymes crucial for sugar breakdown and nitrogen assimilation.
Among the various findings, we noted that a concentration of 20 μg·L of DH-Fe was particularly effective, improving the overall health and resilience of the plants against low temperatures. This suggests that by applying the right amount of iron, we can potentially mitigate the negative effects of cold weather on sensitive plant species, providing a fresh perspective on how to enhance cold tolerance through nutrient management.
Overall, our findings shine a light on how incorporating iron into agricultural practices might be a practical strategy for improving plant resilience to cold stress.
Read More
8
We investigated how selenium supports cucumber seedlings in coping with cold stress, with a surprising focus on iron. As we delved into this, we found that the levels of abscisic acid, a crucial plant hormone, changed significantly when selenite was applied during cold conditions. This suggested a noteworthy interaction between selenium and iron in improving the resilience of cucumber plants.
Our study revealed that iron uptake and distribution played a vital role in how effectively selenium mitigated cold injury. By conducting a thorough examination of gene expression in the leaves and roots of the cucumber seedlings, we highlighted the importance of these processes.
To better understand the relationship between abscisic acid and melatonin in response to selenium application, we used specific inhibitors to dig deeper. Our findings indicated that melatonin, acting as a signal before abscisic acid, is integral to how selenium boosts cold tolerance in cucumbers. We also discovered that the transcription factor CsGATA3 influences the expression of the gene CsCOMT1, which affects melatonin levels, further linking these elements to iron uptake.
Overall, we provided crucial insights that can aid in cucumber cultivation and breeding efforts, especially regarding enhancing cold tolerance through careful management of selenium and iron.
Our study revealed that iron uptake and distribution played a vital role in how effectively selenium mitigated cold injury. By conducting a thorough examination of gene expression in the leaves and roots of the cucumber seedlings, we highlighted the importance of these processes.
To better understand the relationship between abscisic acid and melatonin in response to selenium application, we used specific inhibitors to dig deeper. Our findings indicated that melatonin, acting as a signal before abscisic acid, is integral to how selenium boosts cold tolerance in cucumbers. We also discovered that the transcription factor CsGATA3 influences the expression of the gene CsCOMT1, which affects melatonin levels, further linking these elements to iron uptake.
Overall, we provided crucial insights that can aid in cucumber cultivation and breeding efforts, especially regarding enhancing cold tolerance through careful management of selenium and iron.
Read More
User Reviews
USERS' SCORE
Good
Based on 1 Review
8.5
- All Reviews
- Positive Reviews
- Negative Reviews
8
Reduces cold sensitivity
1 people found this helpful
Worked great! I bought these because I am naturally cold and spend a lot of time outdoors. Being anaemic with low iron my entire life, my diet never helped much. Since I started taking these, I no longer feel as if I'm freezing while everyone else is comfortable.
Read More
Frequently Asked Questions
No FAQs are available for this product and symptom.
References
- Hemilä H, Chalker E. Vitamin C for the common cold and pneumonia. Pol Arch Intern Med. 2025;135. 10.20452/pamw.16926
- Wang X, Ran C, Fu Y, Han L, Yang X, et al. Application of Exogenous Ascorbic Acid Enhances Cold Tolerance in Tomato Seedlings through Molecular and Physiological Responses. Int J Mol Sci. 2024;25. 10.3390/ijms251810093
- 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
- Jian SF, Huang YF, Chen DL, Zhong C. Dihydroporphyrin iron (III) enhances low temperature tolerance by increasing carbon and nitrogen metabolism in . Front Plant Sci. 2024;15:1522481. 10.3389/fpls.2024.1522481
- Wen D, Yang N, Zhang W, Wang X, Zhang J, et al. GATA3-COMT1-Melatonin as Upstream Signaling of ABA Participated in Se-Enhanced Cold Tolerance by Regulate Iron Uptake and Distribution in Cucumis sativus L. J Pineal Res. 2025;77:e70028. 10.1111/jpi.70028
- Zhang Y, Zhang Z, Sun Z, Zhao Y, Cui Y, et al. Effects of Cold Deformation and Heat Treatments on the Microstructure and Properties of Fe-15Cr-25Ni Superalloy Cold-Drawn Bars. Nanomaterials (Basel). 2024;14. 10.3390/nano14231949
- Chen W, Zhang L, Liu Z, Liu W, Lu B, et al. Mechanism of nano-scale zero-valent iron modified biochar for enhancing low-nitrogen anammox process resistance to low temperatures. J Environ Sci (China). 2025;152:442. 10.1016/j.jes.2024.05.049
- Suo W, Li L, Zheng Y, Pan S, Niu Y, et al. Effect of seed priming with zinc, iron and selenium on the low temperature tolerance of Nicotiana tabacum L. during seed germination. Biochem Biophys Res Commun. 2024;735:150806. 10.1016/j.bbrc.2024.150806
