What are the reasons for being unable to raise vitamin D3 levels?

Vitamin D3 deficiency may result from insufficient sun exposure, inadequate dietary intake, obesity, malabsorption syndrome, chronic liver disease, and other factors. This can be improved through increased sun exposure, dietary adjustments, weight management, medication, and treatment of underlying conditions. If levels remain low despite long-term supplementation or if symptoms such as bone pain occur, prompt medical attention is necessary.

1. Insufficient Sun Exposure: Prolonged indoor activity or excessive sun protection reduces skin exposure to ultraviolet radiation, impairing the body's ability to synthesize adequate vitamin D3, which may lead to fatigue and poor mental well-being. It is recommended to expose arms and legs to sunlight for 15–30 minutes daily between 10:00 and 15:00, avoiding peak UV hours, and minimizing the use of sunscreen during this period.

2. Inadequate Dietary Intake: A diet low in vitamin D3-rich foods (such as fatty fish, egg yolks, and animal liver) fails to meet the body’s requirements and may impair calcium absorption. It is advised to adjust the diet by consuming fatty fish (e.g., salmon, cod) 2–3 times per week, including moderate amounts of egg yolks and organ meats, or choosing vitamin D3-fortified milk and cereals.

3. Obesity: Excess body fat can sequester large amounts of vitamin D3, reducing its bioavailability in the bloodstream, often accompanied by overweight and reduced exercise tolerance. Patients may use medications such as orlistat capsules, liraglutide injection, or semaglutide injection under medical supervision, along with lifestyle changes involving diet and exercise to reduce weight.

4. Malabsorption Syndrome: Abnormal intestinal mucosal function impairs vitamin D3 absorption, often presenting with diarrhea, bloating, and poor nutrient uptake. It is recommended to use digestive enzyme supplements such as compound digestive enzyme capsules, lactase tablets, or bifidobacterium triple viable capsules under medical guidance to alleviate symptoms, while adjusting the method of vitamin D3 supplementation as directed by a physician.

5. Chronic Liver Disease: Impaired liver function hinders the conversion of vitamin D3 into its active form, leading to utilization disorders, often accompanied by fatigue, loss of appetite, and jaundice. Follow medical advice to use medications such as diammonium glycyrrhizinate enteric-coated capsules, silybin capsules, or polyene phosphatidylcholine capsules to improve liver function, and supplement with active vitamin D3 formulations under medical supervision.

Daily care should include maintaining regular sleep patterns and avoiding late nights; engaging in moderate physical activities such as brisk walking or jogging to enhance vitamin D3 utilization; and undergoing regular monitoring of vitamin D3 levels to adjust supplementation strategies accordingly.