Vitamin D – Part 2
In the first article of this series, I explained what is vitamin D, why do we need this vitamin, what is the best way to know if an individual is deficient in vitamin D, what is the definition of vitamin D deficiency, what is considered a healthy vitamin D level, and what vitamin D deficiency can cause.
In this article, I am going to talk about the common risk factors for vitamin D deficiency, the increased use of supplements, the risks of mega doses of vitamin D, vitamin D toxicity or hypervitaminosis D, symptoms of vitamin D toxicity, vitamin D and coronavirus pandemic, and what is the recommended vitamin D levels during the pandemic.
Common risk factors for vitamin D deficiency
. Limited sunlight exposure and time spent outdoors
. Habitually wear long-sleeved or protective clothing or stays in the shade or use of sunscreen with an SPF of 8 or higher
. Winter season
. Geographic latitude (where the solar angle is low must of the year)
. Darker skin pigmentation
. Inadequate consumption of vitamin D in the diet
. Low calcium intake in the diet
. Malabsorption syndrome or other conditions such as obesity, diabetes, chronic kidney disease, etc.
. Taking drugs that have interaction
. Taking drugs that decrease absorption
. Sedentary lifestyle (1, 2, 3)
The increased intake of vitamin D in the form of supplements
In the last decade some factors contributed to the increased intake of vitamin D in the form of supplements:
. The growing awareness of the beneficial health effects of this vitamin
. The increased number of people deficient in vitamin D as a result of radical changes in our modern diet and lifestyle (indoors habits)
. The over-the-counter availability of vitamin D, easily found in pharmacies, markets, vitamin stores, etc
. Growing in the number of medical prescriptions using therapeutic doses, including megadoses, without any medical monitoring
. To the fact that the population in general is not informed that
high blood levels of vitamin D can be toxic, and keep taking supplements in the long-term, without any medical monitoring. (4, 5)
But are high doses or mega-doses of vitamin D safe?
As you saw in the first article, there is a great deal of controversy over the lower adequate 25(OH)D level. Likewise, there is no consensus around healthy community about the upper adequate 25(OH)D level.
However, if we go to the scientific studies currently available, there is a consensus that high doses of vitamin D in the long term might result in a greater risk of hypervitaminosis D with symptoms of hypercalcemia. Also known as vitamin D toxicity.
In fact, vitamin D, like many other nutrients, follows a U-shaped curve, what means that both low levels and very high levels are associated with negative health outcomes and can be dangerous to our health. Or the excess of something good potentially creates stress, and what is needed is the proper balance of each of our nutrients. (6, 7, 8)
Have you heard about vitamin D toxicity or hypervitaminosis D?
Vitamin D toxicity (VDT) or hypervitaminosis D occurs because of excess of vitamin D, and is a clinical condition characterized by severe hypercalcemia that may persist for a prolonged time, leading to serious health consequences.
Hypervitaminosis D might raise blood levels of calcium which increases the risk of vascular and soft tissue calcification, with subsequent damage to the heart, blood vessels, and kidney.
There are scientific evidences that 25(OH)D at levels of 56 ng/mL showing symptoms of toxicity. However, most toxicity cases are associated with levels higher than 150-200ng /mL. Anyways, it is prudent to keep the 25(OH)D levels at much lower levels, as we are going to see below. (9, 10, 11)
Severe hypercalcemia in vitamin D toxicity is related to:
. Malfunctions of the vitamin D metabolism
. Excessive long-term intake of vitamin D mega doses
. The existence of coincident disease that produces the active vitamin D metabolite locally (granulomatous disease)
. Gene CYP24A1 mutations
Symptoms of vitamin D toxicity
Vitamin D toxicity can cause non-specific symptoms that can vary greatly from person to person, as you can see below:
. Low bone density
. Heart attack
. Kidney stone
. Mental confusion
. Recurrent vomiting
. Abdominal pain
. Acute kidney injury, etc.
Also, some laboratory testing during routine clinical examinations may reveal asymptomatic hypercalcemia caused by the intake of vitamin D even in doses recommended for the general population and considered safe. That phenomenon, called hypersensitivity to vitamin D, reflects dysregulated vitamin D absorption.
That is why it is very important to be aware of the side effects of excessive vitamin D supplementation, commonly overlooked. And be informed about the possible harmful effects of self-medicating with high doses of nutrients that are widely available to us. (12, 13, 14)
Vitamin D and coronavirus pandemic
There are numerous evidences that vitamin D plays an essential role in the immune system as It has antimicrobial activity against bacteria, fungi, viruses, etc. Besides, it inhibits the production of pro-inflammatory cytokines and increases the production of anti-inflammatory cytokines.
So, considering the current pandemic of COVID-19, where it is essential or even mandatory to protect our immune system, as we have no effective preventive and curative medicine available, it seems that vitamin D has gained even more notoriety.
However, as mentioned before, some nutrients, including vitamin D, follows an U-shaped curve, where both very low levels and very high levels are associated with negative health results. And individuals with vitamin D levels at the base or at the bottom of the U curve seems to be the ones with less complications. (15, 16)
What is the recommended vitamin D levels during the pandemic?
As you could see above, the ideal 25(OH)D levels was a controversial topic even before the pandemic, and continues the same, with a multitude of different opinions. And it can be stressful and confusing when we have to decide who to believe or not.
For this reason, below there are recommendations from health professionals I trust because they are totally based on exhaustive research:
According to one of my teachers and mentor Chris Kresser,a renowned expert, leading clinician, and top educator in the fields of functional medicine and ancestral health, there is no scientific evidence that 25(OH)D levels above 60 ng/mL can provide any additional protection. On the other hand, he says that there is some evidence that levels higher than this might increase the risk of COVID-19 infection with more serious complications.
So, Chris says that “there is a weight of the research pointing to a 25(OH)D minimum of 30 ng/mL and a possible maximum of 60 ng/mL” as ideal levels. Also, you can learn a lot in his page about this topic (here).
According to Dr. Chris Masterjohn, PhD nutritional biochemist, specialist in conducting and interpreting scientific research, reconsidered that "although the risks COVID-19 levels are higher when vitamin D levels are low, similarly, there is a point where even though vitamin D is at higher levels, it also increases the risk of COVID-19 with serious complications.
Dr. Masterjohn says that "the seemingly ideal 25(OH)D levels at the present time is between 30-40 ng / mL". And he recommends the use of supplements only when the individual needs to stay in this range between 30-40 or the bottom of the U-curve. And you can find amazing information in his website (here)
As we all know, nature has its own wisdom, and our body needs the right balance or amount of nutrients to be perfectly effective.
As you could see, it is imperative to be aware of the possible harmful effects of self-supplementing with high doses of some vitamins and minerals. A topic commonly overlooked by the health community..
I hope it was helpful to you. And please, leave a comment or question at the link below.
See you soon