Overdosing on vitamins and mineral supplements could lead to toxic accumulation in the body.
President of the Nutrition Society Dr Tee E. Siong said taking supplements several times a day, above the limit for a long period of time could cause this effect.
He said most consumers did not need the supplements, but had inculcated the habit of taking the pills without fail.
"Malaysians are seen to overuse health supplements, particularly vitamins and mineral supplements," Dr Tee told the New Straits Times.
He said the benefits of some of these supplements were doubtful because they were not backed by scientific proof.
"Most of the nutrients are available when healthy eating habits are practised, so there is no need to rely on supplements."
Dr Tee said it would be the worst case of misuse if people started taking supplements thinking that they could replace main meals.
"Supplements should never be used to replace main meals as they will not provide all the nutrients a person needs.
"The word 'supplement' means to add on, not to replace."
He said different individuals required different vitamins and the public should learn what should be consumed before blindly purchasing the various vitamins off the shelf.
"The elderly who do not eat well and are not able to change their eating habits may need some supplements, while pregnant and lactating women require others."
Dr Tee added that health supplements also help to speed up the recovery of children who fall sick and post-surgery patients.
"But these vitamins should be given after consulting a nutritionist or dietitian on what vitamins, how much and for how long to consume them."
He said the public was especially worried about contracting chronic diseases, such as diabetes, heart diseases and cancers.
"However, they think that by taking such supplements, it will help prevent them from contracting such diseases."
Dr Tee said many of these supplements had no scientific basis of being able to prevent such diseases.
"Many consumers also take these supplements as a 'just in case' approach, hoping they are not missing out on some nutrients or other substances from food. This is an incorrect and unnecessary way of taking supplements."