- The Health Quest Newsletter
- Posts
- Could Vitamin D Be Even More Vital Than We Thought?
Could Vitamin D Be Even More Vital Than We Thought?
Emerging Research Says Yes
Hector Caraballo, MD
December 23, 2023
Vitamin D: New Blueprint for Dosage Based on Age, Weight, and Health Factors
Greetings Fellow Humans 😊,
We have an essential and thorough vitamin D update for you in this week's newsletter. New research continues to show widespread vitamin D deficiency across the globe, with potentially far-reaching impacts on health.
Observational studies are finding notable links between insufficient blood vitamin D levels and increased risks for an array of chronic illnesses - including heart disease, stroke, cancer, autoimmune disorders, infections, diabetes, and even dementia. Optimizing vitamin D status is correlated with lower risks of death as well.
The paradigm is shifting on what constitutes "optimal" vitamin D levels. Where 20 ng/mL was previously the cutoff for sufficiency, experts recommend maintaining levels >30 ng/mL year-round to maximize health benefits. This likely requires supplementation beyond just sun exposure and diet for most people.
Current vitamin D intake guidelines vary based on age, weight, ethnicity, and underlying health conditions. Recommended dosages range widely - from 400 IU up to 2000 IU daily. The key is finding the "Goldilocks zone" for each individual to raise low levels without overdoing it.
Controversy still exists about whether low vitamin D directly causes illness or is associated with it. However, the accumulating evidence makes a compelling case for actively correcting deficiencies. Maintaining adequate vitamin D levels offers a simple way to support well-being with minimal risks.
Discuss your vitamin D status and supplementation practices with your physician. We'll keep you posted on emerging research about how this pivotal nutrient benefits our health!
Be Well. Be Free. Be Fair. Be Inspired-
Hector Caraballo, MD
Article link: https://doi.org/10.1016/j.jsbmb.2017.01.021
Pawel Pludowski, Michael F. Holick, William B. Grant, Jerzy Konstantynowicz, Mario R. Mascarenhas, Afrozul Haq, Vladyslav Povoroznyuk, Nataliya Balatska, Ana Paula Barbosa, Tatiana Karonova, Ema Rudenka, Waldemar Misiorowski, Irina Zakharova, Alena Rudenka, Jacek Łukaszkiewicz, Ewa Marcinowska-Suchowierska, Natalia Łaszcz, Pawel Abramowicz, Harjit P. Bhattoa, Sunil J. Wimalawansa,
Vitamin D supplementation guidelines, The Journal of Steroid Biochemistry and Molecular Biology, Volume 175, 2018, Pages 125-135
Here is a summary of the key points from the article:
- There is evidence that vitamin D provides health benefits beyond bone/calcium metabolism, but some studies contest this evidence. Overall, the evidence supports vitamin D's positive effects.
- Optimal vitamin D levels are likely 30-50 ng/mL based on evidence, higher than the 20 ng/mL recommendation by IOM guidelines focusing narrowly on bone health.
- Various organizations have set higher vitamin D intake recommendations than IOM, targeting 30-50 ng/mL levels - Endocrine Society guidelines are 600-2000 IU/day depending on age.
- Disease-specific guidelines often recommend 30-50 ng/mL levels and higher doses of 800-4000 IU/day, especially for high-risk groups.
- For treatment of deficiency (<20 ng/mL), high doses are used short-term, followed by lower maintenance doses.
- Vitamin D toxicity risk is low - toxicity generally requires levels over 150 ng/mL. Studies show high doses can safely achieve 40-60 ng/mL levels.
- Practical solutions involve sensible sun exposure, food fortification with vitamin D, and supplements when sun exposure is inadequate to maintain 30-50 ng/mL levels.
Before You Go, It’s Good to Know
Acute Respiratory Infections:
- Adults with 25(OH)D ≥38 ng/mL had 2.7 times lower incidence of acute viral respiratory tract infections compared to lower levels (p = 0.015)
Cancer:
- Women with 25(OH)D ≥40 ng/mL had a 67% lower incidence of invasive cancer compared to women with <20 ng/mL
Mortality:
- Participants with 25(OH)D <10 ng/mL had 1.5 times higher relative risk of mortality compared to those with ≥30 ng/mL
Vitamin D level correlates with considerable differences in incidence and risks of several significant diseases and mortality. Optimal levels around 30-50 ng/mL are associated with lowest risks.
The recommendations aim to provide intake levels likely to achieve optimum blood vitamin D levels for health based on age. Infants need a minimum of 400 IU. Children and teens are advised 600 IU. Adults under 50 may need 600-800 IU. Older adults require higher doses, between 800-2000 IU per day.
Among average-weight healthy adults, 1000-2000 IU vitamin D per day is typically advised. Higher doses in the range of 2000-4000 IU may be warranted for overweight or obese individuals. Those under 110 pounds can meet their needs with 600-1000 IU.
The treatment doses are significantly higher than the daily required doses to normalize vitamin D levels in deficient patients rapidly. Follow-up testing verifies treatment efficacy and avoids toxicity.
* Doses depend on body weight - obese individuals may need higher doses
* Treatment duration is typically 1-3 months
* Follow-up testing should occur after 8-12 weeks of treatment
* Activated vitamin D metabolites may be used instead for those with liver/kidney dysfunction
* Intestinal malabsorption may require higher or parenteral doses
* Phototherapy can be used as an alternative treatment approach
Q&A Section
Why do obese people require higher doses of vitamin D?
Obese individuals often require higher doses of vitamin D due to a few key factors:
Dilution effect - Vitamin D is fat-soluble, so when it enters the body, it is stored in fat tissues. Obese people have more body fat, so vitamin D gets diluted in more adipose tissue instead of the bloodstream.
Sequestration - Once stored in fat cells, less vitamin D is bioavailable and circulating for bodily needs. More gets trapped or "sequestered" in adipose tissue.
Inflammation - Obesity induces systemic inflammation, which can inhibit vitamin D activation and binding to receptors. Inflammation impairs utilization.
Less sunlight exposure - Obese people tend to spend less time outdoors being active, resulting in less vitamin D production from sunlight on the skin.
What does maximal bioactivation mean?
Vitamin D starts as an inactive form. The body converts it through steps into an active, usable form. One critical step is done by an enzyme primarily made in the kidneys. "Maximal bioactivation" means optimizing all the steps so inactive vitamin D is entirely changed into enough active form the body needs.
Vitamin D/Calciferol [25(OH)D]
⇩
⇩(conversion by enzyme)
⇩
25-hydroxyvitamin D-1α-hydroxylase (CYP27B1) found primarily in the kidneys
⇩
⇩ (converts to active form)
⇩
Active, usable form/Calcitriol [1,25(OH)2D]
The term "maximal bioactivation" refers to the complete conversion depicted in this flow chart.
Some key points about maximal Vitamin D /25(OH)D/ Calciferol bioactivation:
- This enzyme is present in both the kidneys and most extra-renal tissues
- It converts 25(OH)D to 1,25(OH)2D, which then binds to vitamin D receptors to exert biological effects
- The activity of this enzyme does not increase linearly with 25(OH)D levels
- Maximal bioactivation means the level of 25(OH)D where the enzyme reaches its peak activity. Additional substrate (25(OH)D) does not increase activation rates further.
- Studies on the kinetics of this enzyme show maximal activity is reached around 40 ng/mL of 25(OH)D.
So, having 25(OH)D levels around 40 ng/mL ensures optimal peak conversion to the active hormone. This allows maximal biological activity without needlessly increasing levels higher.
In summary, maximal bioactivation refers to the peak enzymatic conversion of 25(OH)D to 1,25(OH)2D, the level that provides maximum biological impact.
What are the optimal serum levels for Vitamin D?
Based on the evidence presented in the text, the optimal or target serum 25(OH)D levels are:
- 30-50 ng/mL (75-125 nmol/L)
Specific guidelines recommend levels in this range:
- The Endocrine Society: 40-60 ng/mL (100-150 nmol/L)
- Central European recommendations: 30-50 ng/mL (75-125 nmol/L)
- Disease prevention guidelines: 30-50 ng/mL (75-125 nmol/L)
- Kidney Disease Improving Global Outcomes: ≥30 ng/mL (≥75 nmol/L)
The evidence suggests these levels are associated with:
- Maximal 25(OH)D bioactivation (around 40 ng/mL)
What is the prevalence of low vitamin D in the USA?
The prevalence of vitamin D deficiency (VDD) and insufficiency (VDI) in the United States is significant. Between 2001 and 2010, the prevalence of VDD was approximately 28.9%, and VDI was around 41.4%. The overall prevalence rate of vitamin D deficiency was 41.6%, with exceptionally high rates in specific demographic groups. For instance, the prevalence of vitamin D deficiency was highest in Black Americans (82.1%), followed by Hispanics (69.2%). Notably, vitamin D deficiency is still prevalent in the United States.