Almost half of the women here could have an iron deficiency and not even know it, going by the results of a recent survey.
It was done by voluntary welfare organisation Sata CommHealth, which screened 600 fit, healthy women who took part in a running event earlier this month.
Doctors said this could be because many women tend not to realise that certain symptoms point to iron deficiency.
These include physical and mental fatigue, hair loss and brittle fingernails, which the women put down to stress and a lack of sleep.
Associate Professor Carolyn Lam of the National Heart Centre Singapore said: "People can be tired all the time, and they just think that they're not resting enough, but that's not always the case."
Professor Toby Richards of the University College London said: "The condition is insidious, chronic and unrealised in most people."
Both were speaking at a press briefing yesterday organised by pharmaceutical firm Vifor Pharma ahead of World Iron Day today.
According to the World Health Organisation, iron deficiency is the most common nutritional disorder in the world, even in developed countries.
It is more often found among women, who are at risk if they suffer from heavy menstrual bleeding or are pregnant.
Doctors say that those with the symptoms of iron deficiency rarely consult a doctor or think that it is a cause for worry as the effects are not always noticeable.
But Prof Lam, who specialises in treating heart failure, said patients with iron deficiency tend to fare much worse than those without it.
She added that when iron deficiency is corrected, " they feel better, and they also do better in terms of staying out of hospital and overall survival".
While iron supplements may be readily available, doctors say a balanced diet is the best way to keep one's iron levels up.
"For the average healthy person, a balanced diet is No. 1," said Associate Professor Yong Tze Tein of the Singapore General Hospital, who was also at the briefing.
This article was first published on November 26, 2015.
Get a copy of The Straits Times or go to straitstimes.com for more stories.