This means:
“A pharmacist is warning people who take vitamin D that there may be something important they need to know about its use, dosage, side effects, or interactions.”
Breakdown
“Pharmacist” = a healthcare professional who specializes in medicines and supplements.
“Issues warning” = gives a caution or alert about a possible risk.
“Anyone who takes Vitamin D” = the warning is directed at people who use vitamin D, usually as a supplement.
Tone
This is a health-warning/clickbait headline. It creates urgency but doesn’t reveal what the warning actually is, encouraging you to click or read further.
Vitamin D is an essential nutrient, but too much supplemental vitamin D can be harmful, potentially causing excessively high calcium levels and kidney problems. The appropriate amount also varies by individual circumstances.
A simpler version:
“A pharmacist has an important safety warning for people who take vitamin D supplements.”
