Prioritizing Vitamin D for strong bones, optimum health

Vitamin D, often referred to as the “sunshine vitamin,” is crucial for maintaining healthy bones and a robust immune system. Recent trends and lifestyle changes, however, have led to a widespread deficiency. Studies have shown that roughly 40% of Americans have low levels. People often don’t notice any symptoms, which makes it a silent challenge.

Kelly Wirfel, MD, an endocrinologist at UT Physicians Multispecialty – Bellaire Station, has observed a decline in vitamin D levels among her patients. Common signs of deficiency include muscle weakness and bone pain. Many aren’t getting enough sunlight due to increased indoor activities. Hot summers in Houston certainly don’t help.

“In the past 15 or 20 years, it’s become more in vogue to test and to supplement, so patients pick up on that and want their levels checked,” said Wirfel, associate professor of endocrinology at McGovern Medical School at UTHealth Houston. “As physicians, we know who’s likely to be insufficient, and it’s important to get that population back up to baseline.”

People who might need extra vitamin D

These are some of the populations that might need additional vitamin D:


A staggering 50%-70% of children aged 1-11 show vitamin D deficiency. This is attributed to dietary habits, such as low milk consumption and the extensive use of sunscreen. While sunscreen is important to protect the skin and help prevent skin cancer, it blocks the skin’s ability to convert sunlight to vitamin D.

“This is particularly concerning for individuals with darker skin tones and those who cover up for cultural reasons, as they are at a higher risk of deficiency,” Wirfel said. “These could lead to future bone health issues, including osteoporosis, as children may not reach optimal peak bone mass.”

Older adults

Similar to children, older adults also face challenges with vitamin D intake due to dietary restrictions and less exposure to sunlight. This group’s deficiency can manifest quickly, emphasizing the need for fortified foods or supplements.

People who are overweight

Wirfel said people who are overweight tend to require more vitamin D for bone health. Testing for their levels might show they need two to five times the dose to get them to a normal range. Follow-up is important to ensure they’re corrected.

Women during menopause

Women tend to experience a more pronounced loss of bone mass during this time. Monitoring vitamin D levels provides the best chance of maintaining a stable density and decreasing the risk of fractures and osteoporosis.

“We should be counseling women to achieve that peak bone mass in their 20s and ensuring their calcium and vitamin D is sufficient in their 20s, 30s, and into their 50s,” Wirfel said.

She suggested that testing may not be necessary for those with previously sufficient levels, advocating for consistent dietary intake or supplementation instead.

Get your daily servings

Three daily servings of vitamin D-rich foods, such as a cup of milk, a cup of yogurt, or a 2-ounce serving of cheese, are Wirfel’s recommendations. For those unable to meet these dietary needs, a supplement of 1,000 IU daily is advised. She cautioned against the common belief that more is always better. 

Dr Eisenstein's Daily Minimum Recommendation for Vitamin D intake

  • Get a Vitamin D blood test25(OH)D
  • Make sure your whole family has adequate blood levels of Vitamin D this flu season (>50 80ng/ml). Most children and adults Vitamin D blood level is <30ng/ml.
  • Adults .................................. 5,000 IU daily
  • Children ............................... 1,000 IU/25lbs
  • Chronic conditions....................... 10,000IU daily
  • At the first symptoms of a cold or flu 1,000IU/ lb. daily for 7 days.

    50 lb daily 50,000IU daily. 
    100 lb daily 100,000IU daily.
    150 lb daily 150,000IU daily.
    200 lb daily 200,000 IU daily


Taking too much vitamin D is rarely toxic but can lead to hypercalcemia (higher-than-normal calcium levels in your blood) in predisposed individuals. And it’s happening. Emergency department visits have increased by more than 50% for cases regarding vitamin D, as reported to the U.S. National Poison Data System from 2012 to 2022.

Wirfel reiterated the importance of vitamin D for bone health for everyone, regardless of age or life stage. Maintaining normal levels is essential for overall health.