Since this is Sunday, let's take a break from the news stream and have a short walk on the health side.
I have always been fascinated by vitamins. These are complex molecules with even more complex effects on the body. In our health conscious times, they have become important to us. This is especially the case of vitamin D.
Bottom line if you do not have time to read everything: Sunshine is probably enough vitamin D for your health. So go hiking, cycling or whatever outdoor activity you enjoy most. It will improve your mood, your health, physical and mental and reconnect you with nature.
Authored by Sheramy Tsai via The Epoch Times,
One in five Americans regularly reach for vitamin D supplements, yet most are unaware that they’re taking not just a vitamin - but a hormone.
While
renowned for bolstering bone strength and immune health, vitamin D’s
story is not straightforward. A blend of myth and established science
invites a closer look into its true nature and impact.
Vitamin D: Understanding Its Dual Role
Vitamin
D stands apart in the world of nutrients. It’s a sun-sourced substance
acting as both a nutrient and a hormone. This dual role is significant,
as hormones, which orchestrate many bodily functions, aren’t typically
taken as supplements like vitamins.
Endocrinologist Dr. Michael Holick, a leading vitamin D expert, tells The Epoch Times,
“The body more effectively utilizes vitamin D when it’s naturally
synthesized from sunlight, compared to standard supplement doses.”
This difference is key to understanding vitamin D’s health role and the complexities of supplementing a hormone.
Unlike
most nutrients, the hormonal nature of vitamin D means it has a broader
systemic impact, influencing not just bone health but also immune
function, cell growth, and inflammation control. This
understanding is crucial in guiding medical approaches to its use,
including the potential risks and benefits of supplementation.
Beyond Bone Health
Vitamin
D is more than just a bone health and immune system booster. Its
multifaceted role in the body impacts everything from mood regulation to
cardiovascular health.
At its core, vitamin D is vital for
calcium absorption in the gut, and essential for bone strength and
health. “Without enough Vitamin D, the body can only absorb 10–15
percent of calcium,” Dr. Alex Foxman,
a leading internist and preventive care specialist, told The Epoch
Times. Insufficient calcium can result in weaker bones and heightened
fracture risks.
Moreover, vitamin D is pivotal for immune health. Dr. Holick observes, “Vitamin D receptors are in almost every cell, including immune cells.” Proper levels are vital for a balanced immune response and preventing autoimmune disorders.
Dr. Nathan Goodyear, an
integrative cancer physician and director of Brio Medical, an
integrative cancer treatment center in Scottsdale, Arizona, stresses
vitamin D’s essential role in immune functionality and its influence on
chronic diseases, like cancer. He explains, “The immune system does not
work well if vitamin D is not optimal,” emphasizing its role in cancer, where immune strength is crucial.
Recent research, including melanoma studies,
indicates that vitamin D supplementation can enhance treatment
responses and prolong survival in cancer patients, even with currently
insufficient daily dosage recommendations.
Vitamin D also plays a significant role in heart health.
Studies
have linked low vitamin D levels to an elevated risk of heart disease.
Those deficient in vitamin D are more likely to experience hypertension,
heart failure, and strokes.
Mental health is another arena where vitamin D plays a significant role.
Kimberly
Parker, a licensed psychotherapist, told The Epoch Times, “There’s a
clear link between low levels of vitamin D and higher incidences of
depression and mood disorders.”
It also affects seasonal affective disorder, a depression variant tied to seasonal changes.
“I have seen my patients have a reduction of symptoms once they started
to become consistent with their vitamin D intake,” she reports.
Vitamin D’s Journey From Sunlight to Cellular Powerhouse
Vitamin
D is vital for health, existing in different forms, each taking a
unique path within our body. Grasping these forms is key to
understanding how vitamin D functions in our system.
Once vitamin D enters our body through sun, diet, or supplements, it transforms to become active.
First,
it changes into calcidiol in the liver, then into calcitriol, its
active form, in the kidneys. Dr. Holick clarifies, “Calcitriol is the
form that our body can use to perform various functions.”
Interestingly,
each form of vitamin D undergoes a similar conversion process in the
body. The source of vitamin D might differ, but the pathway it takes in
our bodies converges.
The conversion efficiency of
vitamin D can differ. The skin’s capacity to produce vitamin D3
diminishes with age and is influenced by skin pigmentation, geographical
location, and lifestyle.
Controversies in Vitamin D Testing
The
routine way to measure vitamin D levels in the body is through a blood
test called 25-hydroxyvitamin D. This measurement reflects vitamin D
levels from sunlight, food, and supplements. The less recommended 1,25-dihydroxyvitamin D test fails to gauge vitamin D reserves, rendering it ineffective for patient monitoring.
Vitamin D blood testing has surged, ranking as Medicare’s eighth most common lab test. Market reports pegged the 2023 testing market at $677.5 million, with projections reaching $1.06 billion by 2031.
Once
led by giants like Abbott, Siemens, and Quest Diagnostics, the vitamin D
testing market is now seeing a surge in home testing kits from smaller
companies. Dr. Holick recalls, “Years ago, I told Quest that this would
be their number one seller.”
“More than 10 million
vitamin D blood tests are done annually in the United States, even
though these tests are not recommended by major medical organizations,”
Dr. Morton Tavel, a cardiologist and specialist in internal medicine
and cardiovascular disease, told The Epoch Times. He references a 2020 Virginia health system study, where 10 percent of patients underwent vitamin D tests, often without medical indication.
Beyond adults, vitamin D testing in children skyrocketed 30-fold in 15 years, as per a BMJ study, though it didn’t significantly alter low vitamin D diagnosis rates.
This increase in vitamin D testing contrasts with medical associations’ guidelines, which generally discourage routine testing in asymptomatic, low-risk individuals.
For instance, the Endocrine Society recommends screening only high-risk groups. The U.S. Preventive Services Task Force sees insufficient evidence for universal screening. Choosing Wisely also advises against testing in low-risk groups, including the general population.
Dr. Joel Finkelstein from Massachusetts General Hospital’s Bone Density Center, as reported in a Harvard Health blog, voices skepticism about the rampant vitamin D deficiency screening, deeming many checks on healthy individuals unnecessary.
“Vitamin
D has been hyped massively,” he states. “We do not need to be checking
the vitamin D levels of most healthy individuals.” He challenges the
evolutionary need for high vitamin D, noting its limited presence in
natural foods and reduced synthesis in darker skin, common in sun-rich
areas.
However, many functional medicine and naturopathic doctors recommend regular vitamin D testing.
The College of Naturopathic Medicine advises those in sun-poor climates to test routinely for better health maintenance.
Aligning
with this view, Dr. Goodyear emphasizes the tests’ relevance,
particularly regarding inflammation and chronic diseases like cancer. He
told The Epoch Times, “Vitamin D will always be low in the place of
significant inflammation, both acute and chronic,” advocating for
regular monitoring for proper supplementation.
Dr. Goodyear draws
an analogy to salmon swimming upstream against a current of
inflammation, illustrating the challenges in increasing plasma vitamin D
levels in such conditions. He likens this process to standard medical
practices like monitoring blood pressure, emphasizing the need for a
similar approach in natural therapies, “The process is to evaluate, dose, re-evaluate, and then re-dose,” he adds.
Reflecting
the views of Linus Pauling, considered to be the “father of vitamin C,”
Dr. Goodyear criticizes the medical oversight of pharmacokinetics and
dynamics in natural therapies. He explains that physicians learn drug
dosage precision but often forget that this also applies to vitamins. He
advocates for a tailored approach in vitamin D therapy, moving away
from a one-size-fits-all methodology.
Defining Optimal Vitamin D Levels
According to
the U.S. Preventative Services Task Force, “No consensus exists on the
definition of vitamin D deficiency or the optimal level of total serum
25-hydroxyvitamin.”
Some experts view 25(OH)D levels under 30 ng/mL as deficient. Common standards suggest 30-60 ng/mL as sufficient. Yet, many functional health practitioners advocate for an optimal range of 50–80 ng/mL.
Recommendations according to the National Institutes for Health (NIH):
The NIH
clarifies that optimal vitamin D levels are unestablished, as they
“vary by stage of life, by race and ethnicity, and with each
physiological measure used.”
Contrasting these guidelines, voices
like Dr. Goodyear’s claim current vitamin D dose recommendations are too
low. He labels the current U.S. recommended daily allowances as
“woefully inadequate.”
Dr. Goodyear notes that the conventional
focus on preventing rickets overlooks the broader health benefits of
higher vitamin D levels. This stance argues for higher optimal ranges,
implying current standards don’t fully exploit the vitamin’s health
potential.
Too Much of a Good Thing?
Vitamin D is vital, however, there’s concern about its overconsumption, particularly via supplements. Unlike
water-soluble vitamins, which our bodies can quickly expel when in
excess, vitamin D is fat-soluble and can accumulate in the liver and fat
tissues to harmful levels, termed “vitamin D intoxication.”
Dr.
Holick cautions that vitamin D intoxication, though extremely rare, is
severe. Sun exposure can’t cause Vitamin D toxicity, but excessive
supplementation can. “Any excess vitamin D made by the sun is destroyed
by the sun. You can never become vitamin D intoxicated from sun
exposure, but you can from supplements if you take too much,” he warns.
Vitamin
D toxicity triggers excessive calcium in the blood, leading to nausea,
vomiting, and weakness. If untreated, it can escalate to kidney damage,
bone pain, and, rarely, death.
Some practitioners,
including Pam Schoenfeld, a registered dietitian, assert that excessive
vitamin D intake can lead to the depletion of retinol, the active form
of vitamin A. Ms. Schoenfeld told The Epoch Times, “The current
landscape of vitamin D supplementation often neglects the intricate
balance with other crucial fat-soluble vitamins.”
In an article for the Weston Price Foundation, Ms. Schoenfeld cautions, “More
astute practitioners know that supplementing with vitamin D, especially
at levels of 5,000 IU per day ... is not advisable unless attention is
paid to ensuring vitamin A intake is optimal.” This
perspective emphasizes the delicate balance between these essential
nutrients, suggesting that maintaining optimal levels of both is crucial
for health, particularly during pregnancy.
Critics, like Dr.
Holick, challenge this view, arguing that no substantial evidence
supports the claim that Vitamin D adversely affects vitamin A levels.
“It’s simply not true,” he notes.
The Vitamin D Supplementation Dilemma
Modern indoor lifestyles and diets low in vitamin D contribute to widespread deficiencies. Despite well-balanced diets, about 1 in 4 American adults and 70 percent of children fall short of necessary vitamin D levels.
Given these challenges, supplementation is an important consideration. Current recommendations
call for 400 international units (IU) for children up to age 12 months,
600 IU for people ages 1 to 70, and 800 IU for people over 70.
Dr. Holick endorses supplements as a straightforward solution, especially for the sun-deprived, suggesting a total daily intake of 2000–3000 IU from diet, sun, and supplements.
However,
not all practitioners agree that supplementation is necessary for
everyone. “Although many studies had linked low levels of vitamin D to
an assortment of medical conditions, when scientists tried administering
it as a means to prevent or treat those problems, this ‘wonder’
supplement failed miserably,” Dr. Tavel told The Epoch Times.
Sunshine,
a prime vitamin D source, can fulfill needs with minimal exposure. Dr.
Tavel notes, “Your vitamin D storage generally lasts for about 10 to 12
weeks,” questioning the need for constant supplementation.
The
vitamin D deficiency debate is complex. Dr. Tavel points out that “the
widespread notion that much of America is walking around deficient in
vitamin D came from a likely misinterpretation of the normal levels for
vitamin D set by the Institute of Medicine more than a decade ago.” This
has led to overestimation of deficiency rates and potentially
unnecessary supplementation.
Yet, he explains, there are specific
scenarios where supplementation is beneficial. The American Academy of
Pediatrics advises 400 IU of vitamin D daily for breastfed infants.
Those with medical conditions or limited sun exposure might also
benefit.
Dr. Tavel warns that excessive supplementation, linked to increased fall risk and other hazards, underscores the need for balance in vitamin D intake.
Supporting Dr. Tavel, New England Journal of Medicine research found no fracture risk reduction in healthy adults supplementing with 2000 IU of vitamin D compared to non-supplementers.
Vitamin
D’s necessity varies. Dr. Tavel reminds us, “For much of human history,
people got their vitamin D mostly from the sun,” highlighting our
body’s innate ability to regulate this nutrient.
Determining
vitamin D supplementation requires personal assessment, medical
consultation, and an eye on guidelines. Generally, a mix of diet, sun,
and occasional supplements suffices for most, claims Dr. Tavel.
Expanding Vitamin D Supplement Industry
The vitamin D supplement market
is rapidly growing, valued at $1,560 million in 2023 and expected to
reach $2,780 million by 2033, growing at 5.9 percent annually. Drivers
include an aging population, heightened health awareness, and a surge in
demand for vitamin-enriched products.
In response to
consumer demand, the industry is innovating with new delivery methods
and formulations, like gummies, sprays, patches, creams, and potent
capsules. This variety meets diverse preferences and needs, including
ease of use and better absorption.
The industry’s growth is also propelled by robust marketing and advertising.
Pharma and wellness firms heavily promote vitamin D supplements as key
to health, shaping consumer views and fueling market expansion.
While
this market growth mirrors a shift in health consciousness, it prompts
concerns about self-prescribed supplementation and underscores the
importance of a balanced approach to vitamin D consumption.
Best Sources of Vitamin D
Sun
exposure is key in vitamin D production. UVB (ultraviolet B) rays
convert skin cholesterol into vitamin D3, later transformed into
calcitriol, its usable form. Interestingly, skin-produced vitamin D
remains in the bloodstream for about twice as long as when ingested by food or vitamins.
Sunlight’s
vitamin D productivity varies by time, season, and location. The best
synthesis is between 10 a.m. and 3 p.m. in warmer months. However, above
37 degrees latitude, there’s negligible vitamin D production from November to March.
A 2022 study
concluded, “Sun exposure can significantly make up for deficiencies in
subjects who consume insufficient dietary Vit D. Compared with the extra
cost and time for building habits of Vit D supplementation, moderate
sun exposure appears to be a simple and costless means for the public to
start in daily practice.”
The dminder app helps users identify optimal sun exposure times for vitamin D, offering real-time data based on location, time, and weather.
Dietary sources, though fewer, contribute to vitamin D intake. Fatty fish and UV-exposed mushrooms are key sources. Incorporating these foods can help maintain vitamin D, especially in less sunny periods.
Supplementation, particularly beneficial for those in higher latitudes, is another method. A study
showed that while both sun and oral D3 supplements raise vitamin D
levels, supplements were more effective due to compliance. Simply put,
more people took supplements than spent time in the sun.
Vitamin
D supplements are available as D2 (from plants) and D3 (from animals).
D3, mirroring the body’s sun-induced production, is often recommended
for effectively raising and maintaining vitamin D levels.
However,
Dr. Holick asserts that “physiologic doses of D2 and D3 raise vitamin D
levels in the blood the same,” effectively debunking myths about their
differing impacts on health. Additionally, he confirms that the kidneys
equally metabolize both forms.
Dr. Holick also touches on the
regulatory history of these supplements in the United States, explaining
that vitamin D2 remains the only pharmaceutical form available due to
historical U.S. Food and Drug Administration approval processes. “No one
ever got approval for D3,” he notes, highlighting a regulatory, rather
than a health-based, reason for vitamin D2’s dominance in the market.
Though
sunlight is the prime vitamin D source, its availability is
inconsistent. Diet and supplements thus serve as vital alternatives to
ensure sufficient vitamin D for optimal health.
Key Considerations for Vitamin D Supplementation
Understanding how to optimize vitamin D supplementation and reduce risks is crucial:
Fat-Soluble Nature
Contrary
to popular belief and many recommendations, Dr. Michael Holick argues
that vitamin D absorption doesn’t depend on dietary fat. He cites
studies showing better absorption from skim milk, low in fat, than from
full-fat milk. Hence, vitamin D can be taken with or without dietary
fat.
Conjunction With Other Nutrients
Vitamin K: Studies suggest taking vitamins D and K together may enhance bone health and reduce arterial calcification risks.
Magnesium: Magnesium aids vitamin D metabolism, and high vitamin D doses can deplete magnesium levels. Adequate magnesium is vital for effective vitamin D use.
Vitamin A: Vitamins A and D, both fat-soluble, work together, but consensus on taking them together has not been clearly established.
Timing of Dosage: Some suggest
aligning vitamin D intake with circadian rhythms, proposing daytime
consumption to avoid sleep disturbances. However, Dr. Holick indicates
no evidence supporting the idea that vitamin D disrupts sleep, making it
safe to take at any time.
Choice of Vitamin D Type:
While D2 (ergocalciferol) comes from plants and fortified foods and D3
(cholecalciferol) from animal products and sunlight exposure, Dr. Holick
states both forms raise and maintain vitamin D levels equally.
Consult Health Care Professionals:
Before starting supplements, consulting a health care provider is
essential to determine proper dosing and assess potential interactions
with other medications or health conditions.
While
supplements may be useful, integrating them with natural vitamin D
sources and a balanced lifestyle is crucial for overall well-being.
