Our Mission Statement
GrassrootsHealth is a nonprofit public health organization dedicated to promoting optimal health worldwide through research, education, and advocacy, with a primary focus on the role of vitamin D. Through evidence-based education, resources, and our citizen-science approach to research, we empower individuals to make informed decisions about their health and healthcare providers to move research into practice.
With a panel of 48 senior vitamin D researchers from around the world contributing to its operations, GrassrootsHealth has been running the world’s largest public health intervention study since 2007 – the D*action field trial – to solve the vitamin D deficiency epidemic worldwide.
New to vitamin D? Start with the most important thing you should know to improve your health today.
Managing your vitamin D level is one of the easiest steps you can take towards improving your health.
In 2007, GrassrootsHealth was founded by Carole Baggerly† with the mission of moving vitamin D research findings into the hands of the public and into practice. Over the past 15+ years, our global campaign has grown significantly, spreading important vitamin D research findings from the world’s top vitamin D scientists, reaching many more individuals, health care practitioners, and public health officials.
Awards
2018 – NBJ Award for Excellence in Education
2018 – Mercola Achievement Award
2016 – Humanitarian Award Recipient from the American College of Nutrition for Moving Research into Practice
Meet Carole Baggerly, Founder of GrassrootsHealth, and Jen Aliano, Director of GrassrootsHealth, dedicated to improving public health through vitamin D research, education, and advocacy.
Carole Baggerly† founded GrassrootsHealth in 2007 after discovering vitamin D’s role in reducing breast cancer risk. Following her own experience with breast cancer, she met with vitamin D researchers around the world to formulate the Scientists’ Call to Vitamin D*action, a consensus statement on what was needed to solve the vitamin D deficiency epidemic, most importantly by achieving a 25(OH)D serum level of 40-60 ng/ml (100-150 nmol/L). She initiated the Vitamin D*action study as a way to provide public access to home vitamin D blood spot testing while gathering important research data and creating educational resources for all to use.
Jennifer Aliano, MS, LAc, CCN, has been working in the field of nutrition since 2004, with over 10 years of experience in the area of vitamin D research and education specifically. She joined GrassrootsHealth in 2012; her roles have included operations and project management, study design and coordination, communications, content writing, research reviews, and educational program development. Jen co-authored several papers and played a key role in the “Protect Our Children NOW!” project at the Medical University of South Carolina.
Our Vitamin D Scientists & Experts
What Our Followers and Participants Have to Say About GRASSROOSTHEALTH
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Learn the Following Key Information with Our Free Guide and Email Lessons:
What is Vitamin D? Basics about vitamin D and its role in health- Why Do We Need Vitamin D? Explanation of the health benefits and importance
- Vitamin D Deficiency: How it affects our health and why it matters
- How to Get Vitamin D: Natural sources, supplement options, and sun exposure
- Managing Your Vitamin D Levels: Tips for integrating vitamin D practices into daily life
- Testing for Vitamin D: Importance of testing and understanding your results
- Clearing Up Confusion and Concerns: Vitamin D safety, cautions, and when to consider supplementing with vitamin D co-factors
- Supplementation Strategies: How to use supplements effectively to maintain optimal levels
- Additional Nutrients: Brief overview of other important nutrients, such as omega-3s and magnesium
What is Vitamin D?Some individuals have a higher risk of vitamin D deficiency than others. Take the quiz to discover your risk of having low vitamin D levels.Your Information is 100% Secure.
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Get your vitamin D level tested with our easy home blood spot test. Plus, explore additional nutrient testing for Omega-3s, Magnesium, and other important health measurements. Join the D*action Project to optimize your health and contribute to valuable research!
Enroll in D*action and Build Your Custom Test Kit – Choose from the Following Additional Tests
Additional Finger-prick Blood Spot Tests Available as Options to Include with Your Vitamin D
Omega-3 Index – Choose to test alone or with additional fatty acid ratios
Omega-3 Index – Choose to test alone or with additional fatty acid ratiosThe Omega-3 Index can be an indication of risk for heart disease, loss of cognitive function, cellular aging, depression, dry eye disease, and death from all causes. The AA:EPA ratio and Omega-6:3 ratio are measures of pro/anti-inflammatory fatty acids; knowing these ratios can help you take more specific steps towards improving fatty acid status and achieving lower levels of inflammation through diet and supplements.
Click to learn more about these tests and when they are important to consider.
Magnesium (Mg) – Choose to test alone or with other essential & toxic elements
Magnesium (Mg) – Choose to test alone or with other essential & toxic elementsCheck your magnesium level with or without levels of essential elements copper, selenium and zinc, and toxic elements lead, cadmium and mercury.
Click to learn more about these tests and when they are important to consider.
High Sensitivity C-Reactive Protein (hs-CRP)
High Sensitivity C-Reactive Protein (hs-CRP)Measure the level of inflammation in your body with this test. An increase in CRP levels can indicate a hidden disease that has not yet been diagnosed; in fact, some research suggests that the level of CRP can predict heart disease even ten years before diagnosis. High CRP levels are often seen in acute inflammation and have been correlated with high cardiovascular disease risk, while smaller elevations are often indicative of chronic inflammation and chronic diseases, such as metabolic syndrome and diabetes.
Click to learn more about this test and when is is important to consider.
Hemoglobin A1c (HbA1c)
Hemoglobin A1c (HbA1c)HbA1c is a measure of how healthy average blood sugar levels have been in the recent few months, and is a better representation of blood sugar health than a single glucose measurement. Higher levels are associated with a higher risk of metabolic syndrome, diabetes, cardiovascular disease, cognitive diseases, and more.
Click to learn more about this test and when is is important to consider.
Thyroid Stimulating Hormone (TSH)
Check your TSH level as an indicator of thyroid health.
Click to learn more about this test and when is is important to consider.
Add the above measurements to your vitamin D test kit!
FAQs
Why do we need vitamin D?
Every tissue in our bodies needs vitamin D and will not work correctly if we do not get enough. In its most extreme forms, vitamin D deficiency produces rickets in children and osteomalacia (bone softening) in adults. Milder degrees of deficiency are now understood to be one of the causes of a vast array of chronic diseases, including osteoporosis, impaired immune competence, various autoimmune diseases (such as diabetes and multiple sclerosis), several cancers (breast, colon, lung, lymphoma and prostate, among others) high blood pressure, pregnancy complications and cardiovascular disease. All may develop because of, or be exacerbated by, vitamin D deficiency. Asking the body to deal with these disorders without adequate vitamin D is like asking a fighter to enter battle with one hand tied behind his/her back.
What is vitamin D?
Vitamin D is one of the chemicals that the tissues of our body use to unlock the DNA blueprints which each tissue contains and which are needed for our cells to produce the many biochemical products required for their day-to-day functioning.
Where do I get vitamin D?
The principal source of vitamin D is your own skin. A chemical compound naturally present in the superficial layers of skin is converted, on exposure to UVB radiation, to cholecalciferol (vitamin D3). However, we manufacture this vitamin D only if we expose our skin to UVB radiation. If we spend all day indoors or go out only in the early morning or late afternoon, we don’t produce any vitamin D. You can also get vitamin D from food (limited), supplements and other UVB sources.
How long should I be outdoors?
There is no single right answer. A light skinned person, wearing a bathing suit, will make about 15,000 IU of vitamin D in 15-20 minutes in July at midday. Darker-skinned individuals can do the same, but it will take twice as long.
How much vitamin D do I need?
The body needs at least 4000 IU/day in order to maintain a healthy concentration of 25(OH)D in the blood. Because most of us don’t get enough sun exposure, the little vitamin D we get that way, plus food and fortified food sources, totals no more than about 2000 IU/day. Thus in order to meet the body’s need for about 4000 IU/day, most adults should take supplements providing 1000-3000 IU daily. Check grassrootshealth.net to download a table showing the relationship between intake and resulting serum levels.
Does the body have to process vitamin D before it becomes active?
The body converts vitamin D, whether by mouth or made in the skin, to a compound called 25-hydroxyvitamin D [25(OH)D]. This compound circulates in the blood and is the measure physicians or scientists use to assess vitamin D status. High levels of serum 25(OH)D show that you are getting enough vitamin D, while low levels indicate deficiency.
How long does it take to receive my blood spot test?
After you complete your questionnaire and pay for your test, your order is fulfilled within 2 business days. We ship first class mail from San Diego, CA.
How long does it take to receive my results?
It is currently taking from 10-15 days from the time you record doing the blood spot test (and mailing to GrassrootsHealth) until we post your results (US addresses.) You will receive an email (to the email address you provided as login to D*action) when we have the results.
What is the Omega-3 Index?
The Omega-3 Index is a blood test that measures the amount of omega-3 fatty acids (EPA and DHA) in red blood cell (RBC) membranes. It is expressed as a percent of total RBC fatty acids. It is a long-term and stable marker of omega-3 status, and it reflects tissue levels of EPA+DHA. An Omega-3 Index over 8% is associated with the lowest risk of death from heart disease and below 4% with the highest.
What is the cost of the Omega-3 Index test?
The Omega-3 Index test can be added to any of the vitamin D testing kit combinations; the combined cost for just vitamin D and the Omega-3 Index is $119 plus shipping for a single kit, or you can choose to subscribe to receive a slightly discounted offer. With subscriptions we will automatically bill your credit card and ship you a test at the testing interval chosen. The cost includes the collection kit, the envelope to send in your blood spot, and a detailed report of your results, which will include your Omega-3 Index and your 25(OH) vitamin D serum level.
GrassrootsHealth Achievements
- GrassrootsHealth is Founded!
- Enrollment into the D*action study begins
- The Scientists’ Call to D*action is first issued and signed by 40 international vitamin D scientists
- The first “Diagnosis and Treatment of Vitamin D Deficiency Seminar” is presented by GrassrootsHealth at the University of California, San Diego
- The Disease Incidence Prevention Chart was first released, with the need to educate practitioners of the importance of achieved serum level for specific conditions – the reminder is still needed today!
- The second “Diagnosis and Treatment of Vitamin D Deficiency Seminar” is presented by GrassrootsHealth at the University of California, San Diego
- Breast Cancer Prevention Month initiated by GrassrootsHealth
- Launch of a series of free webinars on vitamin D, “Scientists Answer YOUR Questions
- Hosted the “Vitamin D for Public Health” Seminar at the University of California, San Diego
- The Protect Our Children NOW! project is launched with all prenatal patients at the Medical University of South Carolina”
- The first Vitamin D*calculator is released
- GrassrootsHealth declares May as “National Sunshine Month
- Launch of the Omega-3 Project with the Omega-3 Index test included with Vitamin D
- Launch of the Type 1 Diabetes Prevention project with new tests added for hsCRP, HbA1c
- The Omega-3 Index calculator is released
- The Vitamin D*calculator is updated, including calculations for a loading dose
- The IRB approved Vitamin D Deficiency Risk Assessment Quiz (Beta) is released; scoring is intended to determine if an individual has a low, moderate, or high risk of having a vitamin D level below 40 ng/ml (100 nmol/L)
- The IRB approved KNOW “D” NUMBER Patient and Provider Guide to Understanding Vitamin D, Testing & Results Booklet is released to help guide providers through implementing vitamin D standards into practice
- The eBook, Vitamin D & COVID-19, A Summary of Published Research, is released for purchase; it is a condensed and concise compilation of much of this research in an easy-to-read and print PDF
- Phase 2 of the Type 1 Diabetes Prevention Project is launched to include the measurement of T1D Autoantibodies with a home blood spot test
- The North Dakota Project launches, with our first billboard exposure spreading the word to enormous audiences! This opportunity to share with the masses was made possible thanks to our very own participants.
- An online educational course (CEU approved) titled Moving Vitamin D Research into Practice: Addressing Vitamin D Deficiency to Improve Patient Outcomes, Population Health & Reduce Costs is released, along with a Vitamin D Best Practices Toolkit
- The International Virtual Vitamin D Forum & Expert Panel Discussion is Hosted with a Live Virtual Event and Ongoing Presentation
GrassrootsHealth Publications – The Big 12
GrassrootsHealth analysis associated vitamin D with 67% lower cancer risk. GrassrootsHealth found an inverse association between vitamin D serum levels and all non-skin cancer incidence. The analysis included pooled data from two study cohorts of women aged 55 years and older. Those with vitamin D serum levels ≥ 40 ng/ml, had a 67% lower risk of cancer when compared with those <20 ng/ml.
The Paper Serum 25-Hydroxyvitamin D Concentrations ≥40 ng/ml are Associated with >65% Lower Cancer Risk: Pooled Analysis of Randomized Trial and Prospective Cohort Study
Sharon L. McDonnell, MPH et al. PLOS One, April 2016
Having a vitamin D level of at least 40 ng/ml may decrease pregnancy comorbidities. This analysis found that women with vitamin D levels of 40-60 ng/ml have a 46% lower preterm birth rate than the general population (the findings were more robust in Hispanic and Black women). The analysis also showed a 59% lower risk for premature birth by pregnant women who had blood levels of vitamin D (25(OH)D) at or over 40 ng/ml by their third trimester than women who had levels below 20 ng/ml.
The Paper
Post-hoc analysis of vitamin D status and reduced risk of preterm birth in two vitamin D pregnancy cohorts compared with South Carolina March of Dimes 2009-2011 rates
Carol Wagner, et al. , Medical University of South Carolina, October 2015
You may lower your risk of type 2 diabetes by 60% with a vitamin D level over 40 ng/ml. For this study on diabetes, the GrassrootsHealth data was compared to data from the National Health and Nutrition Examination Survey (NHANES). The GrassrootsHealth cohort has a median 25(OH)D level of 41 ng/ml vs. NHANES with a median of 22 ng/ml. When comparing the number of cases seen in each population group in the study period, the GrassrootsHealth cohort has a full 60% lower incidence rate of diabetes.
The Paper
Incidence rate of type 2 diabetes is >50% lower in GrassrootsHealth cohort with median serum 25-hydroxyvitamin D of 41 ng/ml than in NHANES cohort with median of 22 ng/ml
Sharon L. McDonnell, MPH et al., The Journal of Steroid Biochemistry and Molecular Biology,July 2015
9600 IU of vitamin D a day, from all sources, is necessary to get 97.5% of the world up to 40 ng/ml. The recommended intake of vitamin D specified by the IOM is 600 IU/day through age 70 years, and 800 IU/day for older ages. Calculations by GrassrootsHealth scientists and other researchers have shown that these doses are only about one-tenth those needed to cut incidence of diseases related to vitamin D deficiency. The authors propose a new RDA with a value of approximately 7,000 IU/day from all sources.
The Paper
Letter to Veugelers, P.J. and Ekwaru, J.P., A Statistical Error in the Estimation of the Recommended Dietary Allowance for Vitamin D
Robert Heaney, MD et al., Nutrients, March 2015
A vitamin D level of 40-60 ng/ml may provide a significant reduction in risk for breast cancer. In a prospective study of 844 female participants aged 60+ years, GrassrootsHealth examined the relationship between serum 25(OH)D and the incidence of breast cancer. Those with concentrations ≥50 ng/ml had an 80% lower risk of breast cancer than those with concentrations <50 ng/ml, adjusting for age and BMI. These findings suggest that 25(OH)D concentrations above 50 ng/ml may provide additional benefit in the prevention of breast cancer.
The Paper
25(OH)D Serum Levels May Provide Additional Reduction in Breast Cancer Risk
Sharon L. McDonnell, MPH et al. American Society for Nutrition, Scientific Sessions and Annual Meeting, April 2014
Eating the right foods can help increase your vitamin D level. From 780 non-supplement taking, adult, D*action participants who completed a limited questionnaire on dietary intake along with a lifestyle questionnaire, some food sources were found to be associated with vitamin D serum levels: eggs, whole milk cottage cheese, red meat and total protein. 25(OH) D3 rose by about 1 ng/ml for each weekly serving of whole milk cottage cheese (3 oz) and each daily serving of one of the following: eggs (1 egg), red meat (3 oz) and total protein (3 oz).
The Paper
Quantifying the food sources of basal vitamin D input
Sharon L. McDonnell, MPH et al. Journal of Steroid Biochemistry and Molecular Biology, November 2013
Other than food, there are many additional ways to get your vitamin D. Based on this analysis of data provided by D*action participants, non-food factors associated with vitamin D serum levels were indoor tanning use, sun exposure, body mass index (BMI), and percent of work performed outdoors.
The Paper
Quantifyi on-food sources of basal vitamin D input
Sharon L. McDonnell, MPH et al. Journal of Steroid Biochemistry and Molecular Biology, November 2013
Vitamin D serum levels of 20-100 ng/ml have no association with kidney stones. The research team used data collected from 2,012 participants enrolled in GRH’s D*action study. Thirteen individuals reported having kidney stones during the study time; occurrences were confirmed by medical records or interview. The study found no statistically significant association between 25(OH)D serum levels and kidney stone risk. In fact, the researchers found a non-significant trend towards lower incidence of kidney stones for those with higher 25(OH)D serum levels.
The Paper
25-Hydroxyvitamin D in the Range of 20 to 100 ng/ml and Incidence of Kidney Stones
Stacie Nguyen, MPH et al. American Journal of Public Health, October 2013
Study finds the average amount of vitamin D we get per day is 2,000 IU vs. the 300 IU previously taught in medical school. In this re-analysis, the total basal input (food plus sun) was calculated to range from a low of 778 IU/d in patients with end-stage renal disease to a high of 2667 IU/d in healthy Caucasian adults. The authors conclude that:
1) all-source, basal vitamin D inputs are approximately an order of magnitude higher than can be explained by traditional food sources;
2) cutaneous input accounts for only 10–25% of un-supplemented input at the summer peak; and
3) the remainder must come from undocumented food sources, possibly in part as preformed 25(OH)D.
The Paper All-Source Basal Vitamin D Inputs are Greater Than Previously Thought and Cutaneous Inputs are Smaller
Robert P. Heaney, MD et al. The Journal of Nutrition, March 2013
Vitamin D dosing is not the same for everyone. It all starts with knowing your level. In an analysis of vitamin D serum levels and daily supplemental vitamin D intake amounts for 7,324 D*action participants, we found that while average serum level rises with increased intake, there is a wide range of individual serum levels at any given intake amount. For example, with a supplemental intake of 4000 IU/day, serum levels were observed from 20 ng/ml (50 nmol/L) to 120 ng/ml (300 nmol/L).
The Paper Vitamin D Supplement Doses and Serum 25-Hydroxyvitamin D in the Range Associated with Cancer Prevention
Cedric F. Garland, Dr PH FACE, et al. Anticancer Research, 2011
Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths In an analysis of vitamin D serum levels and daily supplemental vitamin D intake for 7,324 D*action participants, the study found that, while the average serum level generally increased with higher vitamin D intake, individual responses varied significantly. For instance, at a supplemental intake of 4000 IU/day, serum levels ranged widely, from as low as 20 ng/ml (50 nmol/L) to as high as 120 ng/ml (300 nmol/L).
The Paper The role of vitamin D in potentially reducing the risk and severity of COVID-19
Anticancer Research William Grant, Ph.D., et al., April 2020
25-Hydroxyvitamin D variability within person due to diurnal rhythm and illness: a case report This case report details the effects of high-dose vitamin D therapy in a multiple sclerosis (MS) patient, showing improvements in symptoms that suggest vitamin D’s potential immunomodulatory benefits for MS. The report underscores the importance of personalized dosing due to individual response variability and the need for monitoring to achieve safe and effective levels.
The Paper High-Dose Vitamin D Therapy in Multiple Sclerosis
Christine B. French et al., Journal of Medical Case Reports, 2019
Ready to take evidence-based steps towards maintaining a healthy vitamin D level?
Downloads and Additional Resources
GrassrootsHealth found an inverse association between vitamin D serum levels and all non-skin cancer incidence. The analysis included pooled data from two study cohorts of women aged 55 years and older. Those with vitamin D serum levels ≥ 40 ng/ml, had a 67% lower risk of cancer when compared with those <20 ng/ml.
Serum 25-Hydroxyvitamin D Concentrations ≥40 ng/ml are Associated with >65% Lower Cancer Risk: Pooled Analysis of Randomized Trial and Prospective Cohort Study
Sharon L. McDonnell, MPH et al. PLOS One, April 2016
This analysis found that women with vitamin D levels of 40-60 ng/ml have a 46% lower preterm birth rate than the general population (the findings were more robust in Hispanic and Black women). The analysis also showed a 59% lower risk for premature birth by pregnant women who had blood levels of vitamin D (25(OH)D) at or over 40 ng/ml by their third trimester than women who had levels below 20 ng/ml.
The Paper
Post-hoc analysis of vitamin D status and reduced risk of preterm birth in two vitamin D pregnancy cohorts compared with South Carolina March of Dimes 2009-2011 rates
Carol Wagner, et al. , Medical University of South Carolina, October 2015
For this study on diabetes, the GrassrootsHealth data was compared to data from the National Health and Nutrition Examination Survey (NHANES). The GrassrootsHealth cohort has a median 25(OH)D level of 41 ng/ml vs. NHANES with a median of 22 ng/ml. When comparing the number of cases seen in each population group in the study period, the GrassrootsHealth cohort has a full 60% lower incidence rate of diabetes.
The Paper
Incidence rate of type 2 diabetes is >50% lower in GrassrootsHealth cohort with median serum 25-hydroxyvitamin D of 41 ng/ml than in NHANES cohort with median of 22 ng/ml
Sharon L. McDonnell, MPH et al., The Journal of Steroid Biochemistry and Molecular Biology,July 2015
The recommended intake of vitamin D specified by the IOM is 600 IU/day through age 70 years, and 800 IU/day for older ages. Calculations by GrassrootsHealth scientists and other researchers have shown that these doses are only about one-tenth those needed to cut incidence of diseases related to vitamin D deficiency. The authors propose a new RDA with a value of approximately 7,000 IU/day from all sources.
The Paper
Letter to Veugelers, P.J. and Ekwaru, J.P., A Statistical Error in the Estimation of the Recommended Dietary Allowance for Vitamin D
Robert Heaney, MD et al., Nutrients, March 2015
In a prospective study of 844 female participants aged 60+ years, GrassrootsHealth examined the relationship between serum 25(OH)D and the incidence of breast cancer. Those with concentrations ≥50 ng/ml had an 80% lower risk of breast cancer than those with concentrations <50 ng/ml, adjusting for age and BMI. These findings suggest that 25(OH)D concentrations above 50 ng/ml may provide additional benefit in the prevention of breast cancer.
The Paper
25(OH)D Serum Levels May Provide Additional Reduction in Breast Cancer Risk
Sharon L. McDonnell, MPH et al. American Society for Nutrition, Scientific Sessions and Annual Meeting, April 2014
From 780 non-supplement taking, adult, D*action participants who completed a limited questionnaire on dietary intake along with a lifestyle questionnaire, some food sources were found to be associated with vitamin D serum levels: eggs, whole milk cottage cheese, red meat and total protein. 25(OH) D3 rose by about 1 ng/ml for each weekly serving of whole milk cottage cheese (3 oz) and each daily serving of one of the following: eggs (1 egg), red meat (3 oz) and total protein (3 oz).
The Paper
Quantifying the food sources of basal vitamin D input
Sharon L. McDonnell, MPH et al. Journal of Steroid Biochemistry and Molecular Biology, November 2013
Based on this analysis of data provided by D*action participants, non-food factors associated with vitamin D serum levels were indoor tanning use, sun exposure, body mass index (BMI), and percent of work performed outdoors.
The Paper
Quantifyi on-food sources of basal vitamin D input
Sharon L. McDonnell, MPH et al. Journal of Steroid Biochemistry and Molecular Biology, November 2013
The research team used data collected from 2,012 participants enrolled in GRH’s D*action study. Thirteen individuals reported having kidney stones during the study time; occurrences were confirmed by medical records or interview. The study found no statistically significant association between 25(OH)D serum levels and kidney stone risk. In fact, the researchers found a non-significant trend towards lower incidence of kidney stones for those with higher 25(OH)D serum levels.
The Paper
25-Hydroxyvitamin D in the Range of 20 to 100 ng/ml and Incidence of Kidney Stones
Stacie Nguyen, MPH et al. American Journal of Public Health, October 2013
In this re-analysis, the total basal input (food plus sun) was calculated to range from a low of 778 IU/d in patients with end-stage renal disease to a high of 2667 IU/d in healthy Caucasian adults. The authors conclude that:
1) all-source, basal vitamin D inputs are approximately an order of magnitude higher than can be explained by traditional food sources;
2) cutaneous input accounts for only 10–25% of un-supplemented input at the summer peak; and
3) the remainder must come from undocumented food sources, possibly in part as preformed 25(OH)D.
All-Source Basal Vitamin D Inputs are Greater Than Previously Thought and Cutaneous Inputs are Smaller
Robert P. Heaney, MD et al. The Journal of Nutrition, March 2013
In an analysis of vitamin D serum levels and daily supplemental vitamin D intake amounts for 7,324 D*action participants, we found that while average serum level rises with increased intake, there is a wide range of individual serum levels at any given intake amount. For example, with a supplemental intake of 4000 IU/day, serum levels were observed from 20 ng/ml (50 nmol/L) to 120 ng/ml (300 nmol/L).
Vitamin D Supplement Doses and Serum 25-Hydroxyvitamin D in the Range Associated with Cancer Prevention
Cedric F. Garland, Dr PH FACE, et al. Anticancer Research, 2011
In an analysis of vitamin D serum levels and daily supplemental vitamin D intake for 7,324 D*action participants, the study found that, while the average serum level generally increased with higher vitamin D intake, individual responses varied significantly. For instance, at a supplemental intake of 4000 IU/day, serum levels ranged widely, from as low as 20 ng/ml (50 nmol/L) to as high as 120 ng/ml (300 nmol/L).
The role of vitamin D in potentially reducing the risk and severity of COVID-19
Anticancer Research William Grant, Ph.D., et al., April 2020
This case report details the effects of high-dose vitamin D therapy in a multiple sclerosis (MS) patient, showing improvements in symptoms that suggest vitamin D’s potential immunomodulatory benefits for MS. The report underscores the importance of personalized dosing due to individual response variability and the need for monitoring to achieve safe and effective levels.
High-Dose Vitamin D Therapy in Multiple Sclerosis
Christine B. French et al., Journal of Medical Case Reports, 2019
- Explore the favorite vitamin D resources selected by the GrassrootsHealth community. These resources cover essential topics from dosage recommendations to the latest research findings.
Vitamin D Resource List Handout
- Access our comprehensive list of vitamin D resources, including key information, research findings, and practical tips to help you optimize your vitamin D levels.
Does the Same Vitamin D Dose Work for Everyone?
- Explore why vitamin D dosage may vary between individuals and how personal factors influence the optimal amount required for health.
GrassrootsHealth Participant Resources
- Access comprehensive resources for GrassrootsHealth participants, including guides, tools, and educational materials on vitamin D and related nutrients.
Vitamin D Therapy and Autoimmune Disorders
- Learn how vitamin D supplementation can play a role in managing autoimmune disorders, supported by current research and case studies.
GrassrootsHealth’s Breast Cancer Publication Achieves Top 10
- Read about our impactful research on the relationship between vitamin D and breast cancer, recognized as one of the top 10 publications in the field.
Nutrients and Factors That Influence Vitamin D Levels and Dose-Response
- Discover the additional nutrients and factors that can affect how the body processes vitamin D and the importance of a tailored approach to supplementation.
Seasonal Changes in Vitamin D Levels
- Understand how the changing seasons can impact your vitamin D levels and why it’s essential to monitor and adjust your intake throughout the year.
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