Diet gun

25-hydroxyvitamin D3 or 25 (OH) D3 or cholecalciferol is one of the two main forms of vitamin D used to assess vitamin D status in our body.

Vitamin D, whether obtained from the diet or synthesized in the skin, is transported to the liver where it is metabolized to 25-hydroxyvitamin D. Measurements of 25-hydroxyvitamin D in the blood are helpful in assessing vitamin D status.

Low levels of 25-hydroxyvitamin D are indicative of vitamin D deficiency associated with low calcium, low phosphorus, hyperparathyroidism, rickets in children, osteomalacia in adults, and risk of acute ischemic stroke (AIS).

An AIS is a life-threatening condition caused by a sudden blockage (thrombosis or embolism) in an artery supplying the brain, retina, or spinal cord. This abruptly deprives brain tissue of oxygen and glucose, leading to rapid neuronal dysfunction.

Recent research published July 2, 2026 in MDPI titled Serum 25-Hydroxyvitamin D Concentration as a Biomarker and Immunomodulator in Patients with Acute Ischemic Stroke: A Retrospective Single-Center Study showed, once again, that higher 25(OH)D concentrations in AIS patients are associated with better survival and lower levels of inflammatory markers and disability at hospital discharge.

Compared with patients in the lowest quartile of 25(OH)D concentrations, those in the highest quartile had shorter hospital stays and a lower risk of death from any cause.

Along with the increase in 25(OH)D, there was a decrease in neutrophil count, a decrease in glucose, a decrease in glycosylated hemoglobin, a decrease in albumin, a decrease in C-reactive protein (CRP) and CRP-to-albumin ratios, β-lymphocytes, β-neutrophils, and β-platelets, lower neutrophil-to-lymphocyte ratios, and β-albumin, and there were also lower markers of systemic immune inflammation and systemic inflammatory response.

The following medications DECREASE vitamin D levels: glucocorticoids (cortisone), cholestyramine (used to lower high blood cholesterol levels), rifampicin (an antibiotic used to treat various types of bacterial infections), phenobarbital (a barbiturate used in the management of seizures), dilantin (used primarily to control seizures), phenytoin (used to control seizures), isoniazid (an antibiotic drug specifically designed to treat tuberculosis).

Foods that contain vitamin D are:

Fatty fish such as mackerel (300 IU/100 gr), salmon (250-650 IU/100 gr), herring (220 IU/100 gr), sardines (300 IU/100 gr), tuna (240 IU/100 gr), egg yolk (30 IU/yolk) and mushrooms (40-120 IU/100 gr).

Cod liver oil has a very high amount of vitamin D, 1300 IU/1 tablespoon.

Note that we can only absorb 50% of the vitamin D contained in foods.


Sources and articles that may help:
Vitamin D3 and Ischemic Stroke: A Narrative Review
Vitamin D and ischemic stroke – Association, mechanisms, and therapeutics
Vitamin D Deficiency Associated with Increased Stroke Severity in Acute Ischemic Stroke Patients
The Effect of Vitamin D Supplementation on Functional Outcomes in Patients Undergoing Rehabilitation After an Ischemic Stroke: A Prospective, Single-Blind, Randomized, Placebo-Controlled Study
2026 Guideline for the Early Management of Patients With Acute Ischemic Stroke: A Guideline From the American Heart Association/American Stroke Association
Ischemic Stroke
Vitamin D