Welcome to Vitamin D Dosages~New Information Part II. Yesterday, in Part I, I discussed some background about why Vitamin D is so important for optimal health. There I also reviewed how sunlight and food sources help the body manufacture Vitamin D and what the risks are when your Vitamin D level is low. Today, Part II addresses the big question: what is the best dosage of Vitamin D? Here you’ll find recommended Vitamin D dosages  from current sources and how to safely monitor your Vitamin D levels.

Vitamin D levels in your body are most accurately measured by the blood test:   

            25-hydroxyvitamin D.**

**Please note this is NOT the same lab test as 1,25-dihydroxyvitamin D [1,25(OH)₂D].                           1,25-dihydroxyvitamin D [1,25(OH)₂D] is considered less accurate for Vitamin D measurement because it is directly impacted by the brain’s regulation of calcium and does not reflect Vitamin D deficiency until it is very severe.

The beauty of this test is that it can cost as little as $32 for the test and lab draw. As a licensed acupuncturist in California, I often order this lab work for my patients. If you are taking Vitamin D supplements but are not quite sure how your body is absorbing them, blood testing every 2-3 months is a perfect way to keep tabs on your Vitamin D level and only take a safe amount. Additionally, blood draws will help you determine your body’s unique response to the amount of Vitamin D dosage supplementation you are taking. I advise guidance of a health care professional with this process.

Lab work reference levels

Your lab work will show your Vitamin D levels measured in nanomoles per liter (nmol/L) or nanograms per milliliter (ng/ml). Later in this article you will see recommended ranges.

What dosage of Vitamin D should I take?

Many respected sources disagree with NIH recommendations for Vitamin D dosages citing that they are too low.

This is not an easy answer because there are multiple recommendations from well-respected sources. As I mentioned in Part I, there is also ongoing debate in the medical community about this topic. For example: the National Institutes of Health (NIH) recommendations are far lower than other sources. I will provide you the recommended doses per the NIH and Harvard Medical School as well as some authors who contest the NIH positions. Also, integrative and functional  medicine practitioners advocate higher levels of Vitamin D.

The following Recommended Dietary Allowances (RDAs) are the daily dosage recommendations for Vitamin D taken from Table: 2 in the newly released Vitamin D Fact Sheet for Health Professionalsby the National Institutes of Health Office of Dietary Supplements ¹

Dosage debates

The Institute of Medicine (IOM) committee of the National Institutes of Health previously concluded that: Practically all people are sufficient at levels ≥50 nmol/L (≥20 ng/mL); the committee stated that 50 nmol/L is the serum 25(OH)D level that covers the needs of 97.5% of the population.²

It does not take a wide review of research to discover there are strong medical community opinions about optimal blood levels of Vitamin D needing to be higher. There is great debate that Vitamin D blood levels of  ≥50 nmol/L (≥20 ng/mL) is too low. The IOM committee also stated that it did not know if there are non-skeletal benefits with respect to Vitamin D levels.

Biology tells us that Vitamin D is necessary for the many tasks in the human body, not just bone health. Additional functions are: improving immune status, maintaining cellular health, reduction of inflammation and controlling overgrowth of cancerous cells. All of these are important mechanisms for health of your body. Thus, it makes sense that the committee could not make any concrete statements as to the blood levels that would support best Vitamin D levels in other body tissues. However, making a statement that 20ng/L is enough does not logically follow. It is more accurate to say that we are not exactly sure what other body tissues need as far as serum blood levels and we cannot rule out that it is necessary.

Respectful and logical dissention of NIH recommendations

Two members who participated on the same Institute of Medicine (IOM) committee noted above wrote a 2011 article of respectful dissention. In that article the authors, Robert P Heaney and Michael F Holick, state:

… during the evolution of human physiology, the intake to which, presumably, that physiology is fine–tuned. So far as can be judged from numerous studies documenting the magnitude of the effect of sun exposure…the primitive intake would have been at least 4000 IU/day and probably two to three times that level, with corresponding serum 25(OH)D levels ranging from 40 to 80ng/mL. The fact that primitive levels would have been higher than current IOM recommendations does not, of course, prove their necessity today. But such intakes should be given the presumption of correctness, and the burden of proof must be placed on those who propose that lower intakes (and lower serum levels) are without risk of preventable dysfunction or disease. The IOM, in its report, has utterly failed to recognize or meet that standard.³

Furthermore, the authors state that an intake of 600 IU of Vitamin D per day will produce only negligible increases in individuals who are overweight or obese.⁴

There exists a “rule of thumb” in the science world that

for each 100 IU of Vitamin D per day you take in,

your serum 25(OH)D levels will only increase by about 1ng/ml.

Other studies reflect that it might not even be a full 1ng/ml increase. Those studies show only 0.7ng/ml increase for every 100IU of Vitamin D consumed. This means that if you have severely low Vitamin D levels and take just 600IU of Vitamin D per day as a supplement your levels may not raise much.

Interestingly, the 2011 IOM panel acknowledged that intakes of up to 10,000 IU/day are

Supplementing with 600IU of Vitamin D per day will likely only raise your Vitamin D blood levels by 0.7-1ng/mL. People with low Vitamin D deficiency are typically in need of much more of an increase.

probably safe for everyone, yet they only officially stated a Total Upper Intake Limit (TUIL) of 4,000 IU/day.⁴ In contrast the Harvard School of Medicine states that up to 2,000 IU/day of Vitamin D is considered safe.⁵

Functional medicine ideal ranges of Vitamin D levels

Functional medicine practitioners currently tend to encourage 25(OH)D blood levels in the range of greater than 50 ng/ml and more toward 80 ng/ml.

Safe ways to gauge the best Vitamin D dose you need

Clinically, over the years I have seen many patients who require larger Vitamin D supplementation to maintain their serum Vitamin D levels over 50ng/L. These are patients who started supplementing at lower dosages but did not see increases in their Vitamin D blood levels until they increased their daily dosage. These are patients who also consistently monitored their blood levels through laboratory blood draws at intervals over time and had no complaints about any negative side effects of too much Vitamin D.

Vitamin D can become toxic in excessive doses

Amid the confusion with respect to dosage of Vitamin D, I encourage patients to be careful, consistent, and seek guidance. By monitoring your blood work, you will see what your blood level is and how your body responds to supplementation over time.

Side effects of taking too much Vitamin D can be grogginess and constipation or even death with exessive intake. Monitoring Vitamin D levels with regular blood draws can help you determine what dose is best for your body.

Follow up blood work is key. Taking too much can cause side effects such as grogginess or constipation. Massive doses can cause extreme toxicity which leads to elevated calcium levels in the blood. The Harvard Medical School cites that it can even cause death.⁶ It is best to be under the care of a licensed health care practitioner to be sure you take the right amount of Vitamin D that you need.

I hope this two-part blog series on Vitamin is useful information for you. Thank you for reading! •Please leave any questions you may have here and I am happy to answer them.

• If you found this article helpful, I would appreciate liking my Facebook page at:

https://www.facebook.com/KarenReynoldsLAc

I write all the content in this blog. My goal is for it to be helpful to you as you strive for great health. If you want to share or repost this content, please include the link for this blog entry to credit me as the author.

For scheduling information and appointment availability, do please visit my website at: http://www.kreynoldsacupuncture.com/

Be well!

~Karen Reynolds, RN, MS, LAc

We encourage you to become fully informed from multiple reliable sources about all health related topics and/or practices or products discussed on this blog. Please consult a team of licensed and trusted health care professionals before making health related decisions for yourself, family or loved ones. The information here is for educational purposes only and is not intended as medical advice.

¹ National Institutes of Health Office of Dietary Supplements. Vitamin D Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

² Heaney, R.P., Holick, M.F. (2011). Why the IOM recommendations for vitamin D are deficient. Retrieved from the American Society for Bone and Mineral Research Online Library website: https://asbmr.onlinelibrary.wiley.com/doi/full/10.1002/jbmr.328

³Ibid

⁴Ibid

⁵Harvard Health Publishing Harvard Medical School. Vitamin D and your health: Breaking old rules, raising new hopes. https://www.health.harvard.edu/staying-healthy/vitamin-d-and-your-health-breaking-old-rules-raising-new-hopes

⁶Ibid

Just last week the National Institutes of Health Office of Dietary Supplements released a new Vitamin D Fact Sheet for Health Professionals pertaining to Vitamin D dosages. This comes on the heels of two decades of continuous debate within the medical community about the advisable daily intake amount of Vitamin D. Debate on this is still going strong.

You may have heard that Vitamin D deficiency is alarmingly common in the United States.

Limted, safe sun exposure will help you make Vitamin D.

This is true. Formerly we were a farming and agricultural centered society. That being the case: we naturally got our Vitamin D while tending gardens or working outside. Because modern society transitioned to city dwelling and indoor offices and manufacturing, this now means most of us don’t get the natural sunlight that our bodies need. Because we cannot produce Vitamin D on our own, if we can’t be outside to receive it from sunlight, the other option is through certain foods or supplements.

Part I of this blog discusses how your body makes Vitamin D, how to improve it, and how to identify the signs of deficiency related to low Vitamin D. Part II (to be released tomorrow) discusses how to easily check, improve, and monitor your Vitamin D levels as well as Vitamin D dosages.

Most people know we need Vitamin D for strong bones. However, Vitamin D is also important to build our immunities that help us avoid colds and flu.

Vitamin D is necessary for optimal cell functioning. It prevents cell overgrowth which happens in cancer.

Adequate Vitamin D also helps reduce inflammation and aids proper cellular functioning. It also has an enormously important role in healthy cell growth and limiting the overgrowth of cancer cells. This all means that quite literally everycell in your body needs access to Vitamin D to be healthy.

Part I

How sunlight helps your body manufacture Vitamin D

Small, safe amounts of sunlight exposure will help your body produce Vitamin D.

Your body cannot make Vitamin D on its own. There are two ways to get it:

Sunlight exposure and by consuming foods or supplements that contain Vitamin D dosages.

How Vitamin D is received through sunlight:

The pros and cons

When the UVB part of sun’s rays hits your skin this causes a chemical reaction which makes what is called D₃. This D₃ is processed in your liver and kidneys to make it into the type of Vitamin D which your body can use. If you wear sunscreen, the UVB is blocked UVB and this process will not ocurr.

This does not mean keep away from sunscreen—we all need to use it to avoid skin cancer. However, as you’ll see noted below, it is difficult to eat enough of the foods that contain Vitamin D to get our daily necessary dose. That being the case, you may want to consider having limited sun exposure on certain areas of your body which normally are not exposed to the sun. As a matter of daily life, our faces, forearms and chest typically get the most sun exposure, but in as little as 10 minutes a day, some sun on your legs or back can give you your daily dose of Vitamin D without huge risk. If you have very fair skin it is advisable to do this before 10AM or after 2PM.

Please Note: if you have darker skin, you probably do need to be taking a Vitamin D supplement regularly. The darker your skin is, the less the UVB rays are processed in your skin. It is estimated that over 90% of nonwhite populations are at risk of reduced Vitamin D production, simply due to their skin pigmentation.¹

Foods that Contain Vitamin D

Vitamin D is found in surprisingly few foods and generally in very small quantities in those foods. The highest Vitamin D level is found in cod liver oil. The next highest amounts are found in fatty fishes such as sockeye salmon, swordfish and tuna fish. The smallest naturally occurring amounts of Vitamin D are found in beef, liver, and egg yolks.

In the 1930s it became standard to enrich milk

Since the 1930’s milk products have been enriched with Vitamin D.

with Vitamin D in order to prevent the childhood disease called rickets. Milk and infant formulas are still Vitamin D enriched in both the U.S. and Canada.² Many products such as breakfast cereals, yogurt and orange juice also have Vitamin D added.

The thing about foods that contain Vitamin D is that it is very hard to consume enough of those foods to get adequate amounts of Vitamin D.

VITAMIN D CONTAINING FOODS                                  IUs PER SERVING

Cod liver oil, 1 tablespoon **                                                                             1360

Cooked swordfish, 3 ounces cooked                                                                  566

Sockeye salmon, 3 ounces cooked                                                                      447

Tuna fish, canned in water 3 ounces                                                                  154

Orange juice, 1 cup                                                                                                 137

Milk nonfat, reduced fat, whole & Vitamin D fortified 1 cup                        115-124

Egg, 1 large (Vitamin D contained in the yolk)                                                  41

Ready-to-eat cereals, 1 cup                                                                                    40

Swiss cheese, 1 ounce                                                                                                6

** Please note the Harvard Medical School article Vitamin D and your health: Breaking old rules, raising new hopesstates that cod liver oil should not be taken daily because it has high levels of Vitamin, A which can be toxic.^{3, 4}

What happens if you don’t have enough Vitamin D?

Too little Vitamin D in your body greatly increases the possibility of bone fractures and even osteoporosis. Studies indicate that lack of Vitamin D leads to higher rates of hip or back fractures.

Many people think Vitamin D is more important for women because women are more prone to osteoporosis; however, a connection to prostate cancer has been found in men who do not get enough Vitamin D. As I mentioned earlier, Vitamin D is necessary for healthy cell growth and preventing overgrowth or abnormal growth like that of cancer cells. The tissue of the prostate is at higher risk for overgrowth especially in people with low levels of Vitamin D.

In general, risks of colon, breast and other types of cancers are higher in populations which are farther from the equator. It is proposed that less sun exposure and thus lower Vitamin D levels may be part of why this occurs.⁵

This concludes Part I of Vitamin D Dosages~New Considerations. Stay tuned for Part II about recommendations for Vitamin D dosages and best ways to monitor your levels to be both safe and healthy!

Thank you for reading!

• Please leave any questions you may have here and I am happy to answer them.
• If you found this article helpful, I would appreciate liking my Facebook page at:

https://www.facebook.com/KarenReynoldsLAc

I write all the content in this blog. My goal is for it to be helpful to you as you strive for great health. If you want to share or repost this content, please include the link for this blog entry to credit me as the author.

For scheduling information and appointment availability, do please visit my website at: http://www.kreynoldsacupuncture.com/

Be well!

~Karen Reynolds, RN, MS, LAc

We encourage you to become fully informed from multiple reliable sources about all health related topics and/or practices or products discussed on this blog. Please consult a team of licensed and trusted health care professionals before making health related decisions for yourself, family or loved ones. The information here is for educational purposes only and is not intended as medical advice.

¹Harvard Health Publishing Harvard Medical School. Vitamin D and your health: Breaking old rules, raising new hopes. https://www.health.harvard.edu/staying-healthy/vitamin-d-and-your-health-breaking-old-rules-raising-new-hopes

²National Institutes of Health Office of Dietary Supplements. Vitamin D Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

³IBID

⁴Harvard Health Publishing Harvard Medical School. Vitamin D and your health: Breaking old rules, raising new hopes. https://www.health.harvard.edu/staying-healthy/vitamin-d-and-your-health-breaking-old-rules-raising-new-hopes

⁵IBID