This means:
“A pharmacist is warning people who take vitamin D that there may be an important safety issue they should know about.”
Breakdown
“Pharmacist” = a healthcare professional who specializes in medicines and supplements.
“Issues a warning” = gives a caution about a possible risk, side effect, dosage problem, or interaction.
“Anyone who takes Vitamin D” = the warning is directed at people who use vitamin D supplements.
The headline doesn’t reveal what the warning actually is, which encourages people to click or read further.
Important point
This doesn’t mean vitamin D is generally dangerous. Vitamin D is an essential nutrient, but taking excessive amounts of supplements over time can cause toxicity and dangerously high calcium levels.
A simpler version:
“A pharmacist has an important safety warning for people who take vitamin D supplements.”
