Forms of Vitamin D and The Side Effects of Toxicity

There is strong evidence that vitamin D is essential for the functioning of numerous physical processes. In fact, these neuroregulatory steroidal hormone influences close to 3,000 gene expressions in the body, meaning that it affects nearly every cell in the body.

Ensuring that your vitamin D intake exceeds minimum requirements should be a high priority for everyone, no matter their age, skin color or health status. However, is it possible to take unsafe amounts? Is one source of vitamin D necessarily healthier than others?

Understanding the details of vitamin D toxicity and the safety of different sources of vitamin D will help you know for sure.

How Does Vitamin D Toxicity Happen?

As the term implies, vitamin D toxicity (hypervitaminosis D) is caused when concentrations of the compound in the body are high enough to cause physical harm.

While this condition is extraordinarily rare, it can happen if levels build up in the body over time. Most vitamin D toxicity is triggered by excessive doses of supplements.

It's known that vitamin D acts similarly to a steroid hormone. This means that it can turn genes on and off, potentially overwhelming natural signaling processes if the levels get too high.

For example, vitamin D can alter is the digestive system's ability to absorb calcium, leading to hypercalcemia, or elevated calcium levels in the blood. This high calcium concentration consequently binds to other tissues like the kidneys and damages them.

Symptoms of Vitamin D Toxicity

How can you tell if you've taken in too much vitamin D? The symptoms of vitamin D toxicity are often a sign.

Symptoms of excessive calcium concentrations can include nausea, constipation, general weakness, and vomiting. As the condition develops, it can also lead to excessive thirst, high blood pressure, kidney stones, and even hearing loss. While the situation is usually reversible if you stop taking supplements, severe cases can lead to kidney failure and calcification of the arteries.

Research also shows that elderly patients prescribed too much vitamin D are more likely to fall and suffer fractures, and the condition can also lead to kidney stones and irregular heart rhythms.

Detecting vitamin D toxicity can be difficult. Some people experience hypercalcemia without any adverse symptoms, while others can experience toxicity symptoms without medical evidence of elevated calcium levels.

This is because vitamin D is a fat-soluble vitamin, meaning that the body can't get rid of excess supplies as quickly as it can with water-soluble vitamins like vitamin C. Instead of being removed from your system through urination, vitamin D clings to body fat until it's used, which can reach potentially toxic levels over time.

A single massive dose of vitamin D won't cause these symptoms as it needs to build up over time. Likewise, reducing your vitamin D intake won't immediately eliminate the symptoms of hypercalcemia. However, you can help hasten the process by stopping your supplementation, cutting fish and dairy from your diet, and avoiding sun exposure on any unprotected skin. In extreme cases, an IV can help increase your salt levels to correct excessive calcium levels.

How Much Is Too Much Vitamin D?

Understanding the daily level of vitamin D that leads to toxicity isn't easy, as it takes a long time to build up to toxic levels in your body.

While it's difficult to define an extract threshold for when toxification occurs, many researchers use blood levels above 150 ng/ml as a benchmark.

Regarding daily supplementation, the Institute of Medicine states that doses between 1,000- 4,000 IU is safe for regular intake, while levels up to 10,000 have been evaluated not to cause problems. According to the Mayo Clinic, taking 60,000 IU of the compound daily for several months will put you at risk for toxicity.

Beyond toxicity, are there other concerns about vitamin D intake? Looking at the safety of sunlight and oral consumption for the compound will answer that question.

Safety of Sunlight-Derived Vitamin D

Sunlight is the predominant way most people produce vitamin D. Exposing a third of unprotected skin (no clothes or sunscreen) to direct sunlight for up to 30 minutes a day is usually considered enough to stay healthy.

However, there are mixed opinions about how safe this sun exposure is. Ultraviolet B(UVB) light is the component in the sunlight that stimulates human skin for vitamin D production, but it is also the primary cause of sunburns and skin cancer.

Sunburns are responsible for many health risks, so its best to make avoiding them a primary goal while still giving skin 30 minutes to soak in rays without a sunscreen barrier.

Fair-skinned people can best re-expose themselves to sunlight for vitamin D if they do so slowly. Limiting exposure for the first few days allows the skin's melanocyte cells to rev-up to produce melanin pigment, causing it to develop both a tan and sunburn protection.

Darker skin can handle longer sun exposure, especially early and late in the summer season.

Unsafe Sunlight Habits

Some sun exposure behaviors will raise your risk of skin damage, including the following.

Low Sun Exposure

When the sun is lower than 50 degrees above the horizon, exposing your skin to it won't generate valuable amounts of UVB rays. However, it does increase exposure to more dangerous UVA rays, which more efficiently penetrate through clouds and the ozone layer and significantly increases your risk of prematurely aging skin and developing skin cancer.

Tanning through a Window

Enjoying sunlight through a window instead of outdoors exposes you to more harmful UVA rays because their longer wavelength lets them penetrate the glass more easily than UVB rays.

UVA rays have been shown to destroy stored vitamin D within the body, meaning that working next to a window or spending time in your car can negatively affect your overall levels. This leads to significant health problems, as it raises your risk of oxidative stress, skin cancer, and photoaging of the skin.

Safety of Vitamin D Supplements

The primary cause of vitamin D toxicity today is due to an increase in the use of vitamin D supplements. However, this doesn't mean that these supplements are innately dangerous.

Due to high levels of vitamin D deficiency, many doctors are prescribing doses up to 50,000 IU per week. Doses at this concentration can cause a massive buildup in the blood leading to the complications of vitamin D toxicity.

Safety of Food

Besides sunlight and supplements, it's also possible to take in trace amounts of vitamin D from your diet. However, not all food sources offer the same quality of vitamin D. Plant sources provide only vitamin D2, while animal-based foods like fish, egg yolk, and fortified milk contain vitamin D3.

The type of dietary vitamin D you take will make a difference in your body. A meta-analysis of the mortality rates of almost 100,000 people who increased their levels of vitamin D2 compared to vitamin D3 found that vitamin D3 was correlated with a six-percent relative risk reduction, while D2 led to a two percent increase in mortality risk.

Further analysis revealed that vitamin D3 is about 87 percent more effective at raising vitamin D concentrations in your body and triggers nearly three times the storage capacity than vitamin D2.

While the evidence is still forthcoming, this might be the first verifiable evidence that the source of dietary vitamin D makes a significant difference in how it affects you physically.

The current evidence shows that taking in vitamin D3 from fatty fish, cheese, egg yolk, beef liver, and fortified foods is good for your health. And, because the amounts are minuscule compared to supplements, there's almost no reason to worry about taking in more than you should.

Do Other Vitamins Affect Vitamin D Toxicity?

One popular hypothesis is that fat-soluble vitamins like vitamin K and vitamin A are directly connected with vitamin D toxicity. Because vitamin K helps regulate the body's use of calcium, high amounts of vitamin D can deplete the body's stores. Vitamin A might work to prevent this process by preventing vitamin K levels from getting drained.

For this reason, some doctors recommend taking vitamins A, K, D, and magnesium together to improve bone health while also reducing the chance of hypercalcemia.

Staying Safe with Vitamin D

In light of this information, how should you best ensure that your vitamin D levels are where they should be? As a general guideline, taking 5000IU of Vitamin D3 per day is considered safe.

If you are concerned about toxicity from Vitamin D supplements, ask your doctor for a vitamin D test.