13/08/2025
There is considerable controversy over the clinical usefulness of vitamin D supplementation. This mainly revolves around the discrepancy between observational studies (that show associations between low vitamin D levels and an extraordinarily large range of health problems) and randomised controlled trials that often fail to show clear benefits from supplementation. Hence mainstream medical “experts” often make sweeping generalisations, rejecting its value in modern health care.
But these generalisations ignore the many trials with vitamin D that have demonstrated important and valuable clinical outcomes. For example, results of a recent clinical study in Brazil suggest that low-dose vitamin D supplementation nearly doubled the response of breast cancer patients to chemotherapy.
The research included 80 women over the age of 45 who were preparing to begin treatment at the oncology outpatient clinic of the general and teaching hospital (“Hospital das ClĂnicas”) at the Botucatu School of Medicine at SĂŁo Paulo State University. The women were divided into two groups: one group of 40 received 2,000 IU (international units) of vitamin D daily, while the other 40 received placebo tablets.
Most of the participants in the study had low blood levels of vitamin D, defined as less than 50 nmol/L (20 ng/mL). After six months of cancer treatment and supplementation, 43% of the women taking vitamin D saw their tumours disappear following chemotherapy, compared to 24% in the placebo group. All participants underwent neoadjuvant chemotherapy, a treatment used to shrink tumours before surgery.
“Even with a small sample of participants, it was possible to observe a significant difference in the response to chemotherapy. In addition, the dosage used in the research [2,000 IU per day] is far below the target dose for correcting vitamin D deficiency, which is usually 50,000 IU per week,” says Eduardo Carvalho-Pessoa, president of the São Paulo Regional Brazilian Society of Mastology and one of the authors of the article published in the journal Nutrition and Cancer.
For more information see: https://scitechdaily.com/vitamin-d-boosts-breast-cancer-treatment-success-by-79-study-shows/