The Benefits vs. Side Effects of Vitamin D (2024)

Vitamin D, also known as calciferol, is a fat-soluble vitamin essential for physical and mental health. The two primary forms of vitamin D are vitamin D2 (ergocalciferol), found in plants, and vitamin D3 (cholecalciferol), found in animal tissues.

Vitamin D is essential for immune system function and bone health. It may also influence mood regulation and reduce the risk of several chronic health conditions.

This article looks at vitamin D's benefits and side effects, deficiency symptoms, and how much you should consume each day.

Effect of Vitamin D on the Body

Vitamin D helps the body retain and absorb calcium and phosphorus, which are important for building and maintaining healthy bones and teeth. Your nerves need vitamin D to carry messages between your brain and body, your immune system needs it to fight off bacteria and viruses, and your muscles need it to move.

Studies have shown that vitamin D may affect our mental health by reducing negative emotions. Researchers noted that individuals with major depressive disorder and vitamin D deficiency are most likely to benefit from supplementation.

Vitamin D deficiency can lead to decreased bone density, which can eventually cause osteoporosis and broken bones. In adults, a severe deficiency can also result in osteomalacia, which causes muscle and bone pain and weakness.

While more research is needed, several studies link vitamin D deficiency to several health conditions, including:

• Diabetes
• Cancer
• High blood pressure (hypertension)
• Autoimmune diseases like multiple sclerosis
  

Different Ways to Get Vitamin D

Your body makes vitamin D when it’s exposed directly to sunlight. However, prolonged sun exposure is advised against because it can increase your risk of other ailments, such as premature aging and skin cancer. Additionally, most people get less vitamin D during the winter months because of insufficient exposure to sunlight.

This makes it necessary to get vitamin D from other sources. Because vitamin D is not naturally present in many foods, fortified foods provide most of the vitamin D in the American diet.

Dietary sources of vitamin D include:

• Fatty fish, such as tuna, salmon, and mackerel
• Mushrooms
• Egg yolks
• Beef liver
• Cheese
• Fortified dairy products
• Fortified breakfast cereals and orange juice
  

What Are Signs You Need Vitamin D?

Vitamin D deficiencies are relatively common throughout the United States. Many people with vitamin D deficiency have no symptoms. However, a deficiency may cause the following symptoms:

• Muscle pain
• Muscle weakness
• Dental problems
• Fatigue
• Bone pain
• Depression
• Cognitive impairment

Risk Factors

You may have a greater risk of developing vitamin D deficiency if you take medications that interfere with vitamin D metabolism or if you have the following conditions:

• A history of gastric bypass surgery (a type of weight-loss surgery)
• Celiac disease (immune reaction to the protein gluten found in wheat, barley, and rye)
• Osteoporosis (reduced bone mineral density causing weak and brittle bones)
• Chronic kidney disease or liver disease
• Crohn's disease (an inflammatory bowel disease causing chronic inflammation of the digestive tract)
• Sarcoidosis (autoimmune disease causing collections of inflammatory tissue in parts of your body)
• Histoplasmosis (infection caused by breathing in fungal spores)
• Tuberculosis (infectious lung disease mainly caused by a bacterium)
• Hyperparathyroidism (parathyroid glands release too much hormone, raising calcium levels)
  

Your healthcare provider can order a blood test to measure the level of vitamin D in your blood. If your levels are low, your provider will likely recommend taking a vitamin D supplement to correct the deficiency.

Side Effects of High Vitamin D Levels

Vitamin D toxicity is unlikely to occur from diet or excess sun exposure since your body can control the amount of vitamin D it makes from the sun. In most cases, toxicity occurs due to the overuse of vitamin D supplements.

The main side effect of vitamin D toxicity is a condition called hypercalcemia, in which too much calcium builds up in the blood, causing symptoms like:

• Nausea, vomiting
• Confusion
• Muscle weakness
• Decreased appetite
• Generalized pain
• Excessive thirst and urination
• Dehydration
• Kidney stones

Dosing Vitamin D

Vitamin D intake is measured in international units (IU) and micrograms (mcg). The amount of vitamin D you need daily depends on your age and other health factors.

The daily vitamin D requirements are: