Taking vitamin C as a supplement to prevent lung cancer?… "No effect and harmful to health"

Research has revealed that consuming vitamin C through food reduces the risk of lung cancer, but taking it in supplement form, such as dietary supplements, has no effect.

Professor Myung Seung-kwon, Director of the International Cancer Graduate School at the National Cancer Center (Dean of Graduate School and specialist in Family Medicine), announced on the 27th that a meta-analysis of 20 cohort studies published in international academic journals from 1992 to 2018 confirmed this finding.

This study involved Dung V. Tran, a graduate student at the National Cancer Center International Cancer Graduate School from Vietnam, as the first author, with Graduate School Dean Myung Seung-kwon serving as the corresponding author. It was published online on the 10th in the SCIE international journal of oncology, 'Oncology Letters'.

Director Myung, an expert in meta-analysis, conducted a meta-analysis by synthesizing the results of 20 cohort studies selected through literature searches in major medical databases PubMed and EMBASE. As a result, consuming vitamin C through food or supplements was not associated with the risk of lung cancer.

However, vitamin C intake through food reduces the risk of lung cancer by 18%, but taking it in supplement form, such as dietary supplements, had no effect.

Director Myung stated, "Based on epidemiological studies conducted worldwide over the past several decades that observe humans, it is known that sufficient intake of fruits and vegetables can reduce the incidence of cancer and cardiovascular diseases by about 30%," and added, "One of the reasons is that fruits and vegetables are rich in antioxidants that suppress reactive oxygen species, which can cause cancer."

He explained that "Vitamin C is one of the powerful antioxidants, and consuming fruits and vegetables rich in vitamin C can prevent many types of cancer, especially lung cancer, which accounts for the highest cause of death from cancer," but also noted that "there was a difference in the effectiveness of lung cancer prevention depending on whether vitamin C was obtained through food or supplements. Therefore, a meta-analysis of cohort studies was conducted to determine if there are differences based on the source of vitamin C."

Director Myung explained, "There are several hypotheses as to why there is a difference in lung cancer incidence depending on whether vitamin C is consumed through food or supplements. When vitamin C is obtained through food, other antioxidants and nutrients are also ingested, which may contribute to cancer prevention effects. However, taking vitamin C supplements alone may not produce the same effect."

Another point is that reactive oxygen species can cause cancer or cardiovascular diseases, but conversely, they have a positive function of removing microorganisms or external substances. However, long-term intake of antioxidants like vitamin C may actually weaken defense and immune functions against external substances, ultimately being harmful to health.

Director Myoung emphasized, "To prevent lung cancer, quitting smoking is absolutely essential, and it is recommended to consume antioxidants like vitamin C and various nutrients in the form of a balanced diet rather than supplements. Furthermore, common health supplements such as vitamins, omega-3 fatty acids, probiotics, calcium, and glucosamine have little to no evidence or only weak evidence from recent clinical trials and meta-analyses to support their health benefits. In fact, they may even be harmful. Therefore, avoid wasting time and money on health supplements without clinical evidence, and instead focus on eating a balanced diet, maintaining a healthy weight through regular exercise, and adopting proper lifestyle habits to prevent cancer and maintain health."

<Source: Money Today>