Vitamin D3, D2 & K2: Supporting Strong Bones This Fall

As days get shorter and we spend more time indoors, vitamin D deserves a little extra attention. Your skin makes vitamin D when exposed to sunlight, but production can drop during fall and winter, especially in northern climates. Supplementing with a high quality Vitamin D3 can help you meet your needs through the colder months. 

Why vitamin D matters

Vitamin D helps your body absorb calcium, a key building block of strong bones and teeth. Too little vitamin D can lead to soft, weak bones and muscle weakness. Getting enough vitamin D and calcium helps maintain bone health as you age. 

Its benefits extend beyond your skeleton. Vitamin D also supports normal muscle function, nerve signaling, and immune function. Think of it as an essential nutrient for everyday health, not just a “bone vitamin.”

Vitamin D3 vs. D2: What’s the difference?

Vitamin D supplements come in two main forms:

• Vitamin D2, also called ergocalciferol.

• Vitamin D3, also called cholecalciferol.

Both raise vitamin D levels in your blood. However, D3 generally raises levels more effectively and keeps them elevated longer than D2. Your body processes the two forms differently. Both must be converted into 25-hydroxyvitamin D, the main circulating form measured on a vitamin D blood test. 

Where does vitamin K2 fit in?

Vitamin D and vitamin K have complementary roles in bone health. While vitamin D helps you absorb calcium, vitamin K, including K2, helps activate proteins such as osteocalcin that are involved in maintaining bone. K2 is found in foods such as natto, a fermented soybean food, and some cheeses, and is available in supplements.

Part of your fall and winter checklist

Shorter days are a good reminder to make bone health part of your wellness routine. Vitamin D3 helps your body absorb calcium, while K2 helps activate proteins involved in keeping bones healthy. This fall, take stock of your vitamin D intake and current supplements to identify where you may need additional support. Small, consistent steps today can help you care for your bones throughout the year.