Dietitians Explain the Differences

Vitamin D refers to a group of essential chemical compounds necessary for bodily functions, according to Courtney Pelitera, M.S., R.D.N., C.N.S.C.. The two principal forms you will encounter on store shelves are vitamin D2 and vitamin D3, although some labels may simply state “vitamin D.”

Vitamin D is a fat-soluble vitamin vital for bone health, immune system function, and communication between the brain and muscle cells. Pelitera explains, “It is crucial for calcium absorption and essential in preventing bone diseases like osteoporosis.” Additionally, vitamin D assists in the absorption of magnesium and phosphate in conjunction with calcium, as noted by Melissa Mroz-Planells, D.C.N., R.D.N..

Increasing your vitamin D levels has been associated with numerous health benefits, including reducing the risk of heart attacks and contributing to the prevention of type 2 diabetes.

Vitamin D3, or cholecalciferol, is termed the “sunshine vitamin” for good reason. It is synthesized in the body upon exposure to sunlight, as explained by Mroz-Planells. Additionally, D3 is present in animal-derived foods such as butter, fatty fish, egg yolks, and liver. Although vitamin D3 is an inactive form of vitamin D, the body must convert it to calcitriol, which is the active form that offers health benefits.

On the other hand, vitamin D2, also referred to as ergocalciferol, is another inactive form found in both food and supplements, according to Mroz-Planells. This variant is commonly found in plant sources such as mushrooms, yeast, and fortified products.

If you decide to supplement with vitamin D, you will need to choose between D2 and D3. Even if the product label states “vitamin D,” the ingredient list will specify either D2 or D3.

Both forms are effective in raising blood vitamin D levels, according to Pelitera. Nonetheless, some research indicates that vitamin D3 may be slightly more effective at increasing serum levels.

“Vitamin D status is assessed through measurements of 25-OH Vitamin D, or ‘serum,’” Pelitera explains. When these levels are low, vitamin D3 supplementation is often recommended for its superior efficiency.

However, Mroz-Planells stresses that more research is necessary to definitively conclude which form is preferable for serum vitamin D levels. “Your healthcare provider may start treatment with a higher dose of vitamin D2 if your levels are low and then transition to a lower maintenance dose of vitamin D3,” she elaborates.

Adults deficient in vitamin D may develop a condition known as osteomalacia, which causes the bones to soften and may lead to osteoporosis, as noted by Mroz-Planells.

Pelitera adds that other symptoms of vitamin D deficiency may include:

• Muscle or bone pain
• Heightened sensitivity to pain
• Tingling sensations in the hands or feet
• Frequent bone fractures
• Muscle spasms or twitches
• Muscle weakness

Severe vitamin D deficiency in infants and children can lead to a condition known as rickets, Mroz-Planells explains. “This condition results in bowed limbs as the bones fail to develop correctly.”

Several factors can increase the risk of vitamin D deficiency, such as limited sun exposure, advanced age, specific health conditions, and skin pigmentation, notes Mroz-Planells. If you suspect that you might not be obtaining adequate amounts of the sunshine vitamin, “consult your healthcare provider about checking your serum vitamin D level,” she advises. Upon receipt of a low test result, you may need to take measures to enhance your vitamin D intake.

According to the National Institutes of Health (NIH), the recommended vitamin D intake for healthy adults ranges from 600 to 800 IU. This can be achieved through a mix of food sources, sunlight exposure, and supplements, whether you choose D2 or D3.

The most effective way to increase vitamin D levels is through consistent sun exposure, asserts Pelitera. Nonetheless, it may not always be feasible to obtain sufficient vitamin D from sunlight alone, depending on your location and lifestyle.

As such, incorporating vitamin D-rich foods is a vital strategy to guard against deficiency, according to Mroz-Planells. Some excellent sources of vitamin D include:

• Salmon
• Mackerel
• Sardines
• Eggs
• Mushrooms
• Fortified products such as milk and cereals

Supplements are also an effective way to enhance vitamin D intake when necessary, notes Pelitera. Current research does not favor one form over the other for supplementation. “Both D2 and D3 can be used effectively to address low serum vitamin D levels, and we receive both types through our diet and sun exposure,” remarks Mroz-Planells.

Regardless of which option you select, be mindful of potential interactions. Certain medications might affect how vitamin D supplements work and may need to be taken separately. This includes medications like statins, orlistat, steroids (like prednisone), and some diuretics, as highlighted by Mroz-Planells.

Ultimately, if your goal is to improve low vitamin D levels, supplementing with vitamin D3 may yield the most significant results. However, it’s crucial to consult your physician before incorporating new supplements into your routine.

Dietary supplements are intended to complement the diet and are not substitutes for medical treatment. They are not designed to diagnose, mitigate, treat, prevent, or cure diseases. Always be cautious when taking dietary supplements if you are pregnant, nursing, or considering them for a child, unless directed by your healthcare provider.