Will Excess Vitamin D Increase the Risk of Other Health Concerns?

There's little debate that vitamin D is vital for your health. This fat-soluble vitamin helps your body absorb calcium and reduces your risk of health problems like osteoporosis and rickets. However, too much vitamin D can be just as dangerous as too little. Specifically, excessive levels can raise your risk of vitamin D toxicity.

Health Risks from Excessive Vitamin D Intake

Hypervitaminosis D, or vitamin D toxicity, is a rare but dangerous health condition caused by too much vitamin D in your body tissues. The situation is almost always caused by excessive supplement intake, as it's nearly impossible to take in too much vitamin D from natural sources like sunlight or food.

While you are highly unlikely to overdose on vitamin D after a single use, the compound can build up in the body over weeks or months before you experience symptoms. The most significant concern with vitamin D buildup is elevated calcium levels in the blood. This can lead to health problems that range in severity from weight loss to kidney failure.

Some of the specific conditions that are linked to excessive vitamin D levels are below.

Calcium Buildup

Hypercalcemia (excessive calcium buildup) is the primary health concern with vitamin D toxicity, and it can trigger numerous health problems. Vitamin D is responsible for helping your body absorb calcium from food, but when intake is too high, it allows calcium levels in the blood to reach unsafe levels.

The normal range for blood calcium is between 8.5-10.2 mg/dl. In one study, two men who took excessive amounts of vitamin D supplements raised their blood calcium levels to 13.2-15 mg/dl, and it took a year for their levels to return to a safe range afterward.

This calcium buildup can lead to vascular and tissue calcification, which can trigger damage to the cardiovascular system over time.

Kidney Stones and Kidney Failure

Vitamin D intake is linked with kidney disorders because blood toxicity will cause you to urinate more, putting extra strain on the kidneys. In extreme cases, the kidneys can even fail entirely and require patients to undergo dialysis or seek out a transplant.

Excessive amounts can also trigger the formation of calcium-composed kidney stones. Research shows that supplementing both calcium and vitamin D can raise the risk of kidney stones in postmenopausal women by 17 percent over a seven-year timeframe.

In one instance, a man who received vitamin D injections from his doctor was soon hospitalized for kidney failure and elevated blood calcium levels.

Skin Cancer

While excessive sun exposure won't lead to vitamin D toxicity, it can be a recipe for skin cancer for light-skinned people.

According to the CDC, over 9,000 Americans die from skin cancer each year, and fair-skinned Europeans have ten times the risk of African American populations. If you are susceptible to sunburns, it's best to protect your skin with long clothing or sunscreen when spending significant amounts of time in direct sunlight.

Increased Risk of Fractures

While calcium is vital for strong bones, a symptom of vitamin D toxicity is weaker bones and a stronger likelihood of suffering from fractures. Too much vitamin D is often an indicator that vitamin K2 levels are low, as vitamin K2 is responsible for keeping calcium in bones instead of the bloodstream. Likewise, it's believed that high levels of vitamin D will reduce vitamin K2's effectivity.

Without calcium, bones begin to weaken and disintegrate, putting you at higher risk or diseases like bone cancer, rickets, and osteoporosis. In one study, elderly patients given vitamin D supplements were more likely to fall and suffer fractures.

Taking vitamin K2 supplements can help alleviate this risk, as well as consuming K2-rich foods like grass-fed beef and dairy.

Chronic Fatigue

Excessive calcium in the bloodstream is a known cause of chronic fatigue. This is because low calcium levels in bones can prevent other nutrients like iron and protein from getting incorporated into the muscles, leading to exhaustion.

This means that vitamin D toxicity often triggers flu-like symptoms like heavy and lethargic muscles and non-location specific pain.

Digestive Problems

High calcium levels from vitamin D toxicity can trigger problems by making it hard for your digestive system to pass materials or form solid stools. Nausea and stomach cramps are common side effects of the condition, as is inexplicable weight loss. This weight loss leads to further problems like a loss of bone density, muscle mass, and vital nutrients.

While high calcium levels might directly cause these problems, they might also be linked to the body's inability to absorb other nutrients when overexposed to them.

One study of people experiencing vitamin D toxicity found over half the participants suffered nausea and vomiting or a general loss of appetite. Other research also backs up these symptom reports of nausea and vomiting after excessive supplementation.

Dealing with Vitamin D Toxicity for Better Overall Health

Vitamin D might be essential for healthy functioning, but too much can lead to physical problems like kidney problems, increased skin cancer risk, excessive calcium buildup, heightened fracture risk, chronic fatigue, and digestive issues.

To avoid these concerns, health professionals recommend keeping your vitamin D supplementation levels below 10,000 IU per day unless you get permission from your doctor to take more.