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The D-List: Answering Vitamin D FAQs

Last updated: October 27, 2025

With vitamin D known as the sunshine vitamin, it’s easy to see why people living in northern states might be more likely to have low levels.

“In the fall and winter months, it’s often difficult to maintain adequate vitamin D levels,” says Andy Kubisch, a Family Medicine Physician Assistant with ThedaCare Physicians-Neenah. “Vitamin D is important for many reasons, and the good news is that you can take steps to boost your level.”

Here, Kubisch answers top questions surrounding vitamin D.

1. Why do we need vitamin D?

Vitamin D helps the body absorb calcium from foods and supplements, so it’s crucial to bone and tissue health. This is critical early in life as kids’ bones are developing. It’s also important in later in life, to reduce the risk of osteoporosis. In addition, vitamin D supports immune health and helps keep muscles and brain cells working.

2. Who’s at risk for vitamin D deficiency?

  • People with obesity
  • Individuals with dark skin
  • Infants who are only fed breast milk
  • People who are homebound or rarely go outside
  • Individuals who have undergone weight loss surgery
  • People who take certain medications

3. What happens if I don’t get enough vitamin D?

People of all ages, from infants to older adults, can have vitamin D insufficiency or deficiency. In severe cases, adults can develop osteomalacia (soft bones). This can lead to an increased risk of of osteoporosis and bone fractures. Children can develop rickets, a type of demineralization that leads to bowed or bent bones.

4. What are the symptoms of vitamin D deficiency?

Children may experience:

  • Incorrect growth patterns due to bowed or bent bones
  • Muscle weakness
  • Bone pain
  • Joint deformity (rare)

In adults, the symptoms often are subtle. They may experience:

  • Fatigue
  • Bone pain
  • Muscle weakness, aches or cramps
  • Mood changes, like depression

5. Can I get enough vitamin D through my diet?

It’s often difficult to get vitamin D through diet alone. Foods that naturally contain vitamin D include:

  • Fatty fish such as salmon, tuna and mackerel and sardines
  • Rainbow trout
  • Beef liver
  • Mushrooms
  • Egg yolks
  • Cod liver oil

Other types of food are fortified with vitamin D. These include:

  • Milks (dairy and plant-based)
  • Yogurts
  • Cheeses
  • Cereals
  • Orange juice

6. Should I take a supplement?

Because many people in Wisconsin have either a vitamin D insufficiency or deficiency, Kubisch often recommends a vitamin D3 supplement to his patients. Your doctor or advanced practice provider can advise on dosage and whether you may need to have vitamin D level tested. Because vitamin D supplements are fat-soluble, it’s best to take them with food.

7. Can I just spend more time in the sun?

Sunlight is a major source of vitamin D. At the same time, the sun’s rays can harm your skin and increase the risk of skin cancer. It’s important to protect your skin with sunscreen any time you spend time outdoors, according to the Skin Cancer Foundation. Furthermore, between the months of October and April, the sun provides minimal to no vitamin D, regardless of time spent outdoors. Instead, strive to get sufficient vitamin D through diet and supplementation.

Your Proactive Partner

Whether you’re concerned about your vitamin D level or another issue, your primary care physician or advanced practice provider is here for you.

“We’ll take into account your overall health picture to make recommendations tailored to your individual needs,” Kubisch says.

Have a care need?

Schedule a primary care appointment today.

Tags: bone health osteoporosis Primary Care rickets supplements vitamin D deficiency

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