Most adults need at least 600 IU of vitamin D every day to maintain healthy levels. Blood levels of vitamin D below 12 ng/mL are considered deficient and can be harmful to health. Vitamin D helps the ...

Testing vitamin D levels in the blood is not prohibited, but including it in routine blood tests is not medically justified, the Health Insurance Fund says.

Scientists are still untangling why the nutrient gap persists—and what it reveals about how women’s health is studied and treated.