Many widely consumed nutritional supplements, including lutein, milk thistle, and protein supplements, lack sufficient scientific evidence to support their claimed benefits, experts have pointed out.
According to the medical community on the 25th, Park Kyung-hee, a professor of family medicine at Hallym University Sacred Heart Hospital, recently appeared on KBS's "Pursuit 60 Minutes" to explain the effects of lutein.
Park said of lutein, "There are research findings that it can slow the progression in cases of eye diseases such as macular degeneration, so if a hospital says it's fine, you can take it." However, she added, "If taken without any disease, the effect of improving eyesight is very lacking."
She continued, "Lutein is a pigment located in the macula at the back of the eyeball with only antioxidant action, so it may help slow the progression of macular degeneration, but it is impossible for eyesight to become brighter just by taking it."
Jung Jae-hoon, a pharmacist and author of the book "Health Subscription Society," referred to milk thistle, known as a representative liver health supplement. Jung said, "Milk thistle or silymarin components cannot change drinking behavior, but many people take them out of concern for liver health," adding, "It is difficult to find research findings that they protect the livers of drinkers."
He explained, "Supplements grant a pardon through the 'moral licensing effect,'" adding, "Many people take them because of the mindset that 'I took milk thistle, so it should be okay to drink.'"
Lee Seung-hoon, a professor of neurology at Seoul National University Hospital, raised questions about the practice of selling protein supplements in the form of nutritional supplements. Lee pointed out, "Protein supplements aside, making them into nutritional supplements is a very unscientific business," and "It is strange that the makers do not know the basic fact that protein is broken down into amino acids when consumed."
He also explained that height-growth supplements have limited effects. Lee stated, "What determines height is 80% genetics and 20% environmental influence." He continued, "Growth hormone helps children with short stature when used at a young age, but because it is a protein, there is the unfortunate reality that it must be administered daily by subcutaneous injection," adding, "Research findings clearly show that replacing it with oral ingredients has no practical effect."
The point that the verification standards for health functional foods are lower than those for pharmaceuticals was also raised. Jung said, "Pharmaceuticals require studies of thousands of people, but health functional foods can be approved with 1,000 people or even fewer, so the level of evidence is lower." He added, "Diet ingredients such as green tea extract are also often approved based on small-scale trial results."
Lee explained the nature of health functional foods, saying, "If the pharmacological action had been certain, it would have been designated as a prescription drug long ago," and "Supplements are an area that has been permitted in cases where natural ingredients originally present in the body or food are predicted not to be harmful."
He then said, "People mistakenly think it suits their body well because there are no side effects, but in fact they simply feel nothing."
Cases were also found in which people choose supplements over pharmaceuticals and miss the timing for treatment. Park said, "There are people who try supplements first because of the burden they feel about medication, and end up making their illness worse," adding, "There are also cases where people refuse diabetes medication and only take supplements, then come to the emergency room with hyperglycemic coma because their blood sugar was not controlled."
Jung also stressed, "There are people who are afraid to take statins when their LDL cholesterol levels are high and choose supplements instead," adding, "Even if health functional foods lower cholesterol, there is no evidence whatsoever that they reduce the risk of cardiovascular disease."
However, opinions emerged that vitamin D may need to be supplemented depending on an individual's lifestyle and condition. Lee said, "People who spend a lot of time indoors or apply sunscreen well cannot synthesize vitamin D, so their risk of fractures increases as they age."
Park also drew a line, saying, "Because our country is located in the northern hemisphere, there are many cases of vitamin D deficiency," while adding, "Healthy people who eat well do not need to go out of their way to take it for preventive purposes."
Experts pointed out that many modern people purchase products after concluding through advertisements or media that they are deficient in certain nutrients.
Jung said, "The likelihood that an ordinary modern person is deficient in nutrients is not high," adding, "Many people are swayed by products, tracing backward through media or YouTube ads to wonder, 'Could this be what I'm lacking?'"
Lee said, "To take supplements wisely, you need to think that food comes first," adding, "Health is not easily obtained through supplements."
