In the News: Ineffectiveness of Vitamin Supplements

New analysis and recommendations from the US Preventive Services Task Force (USPSTF) question the efficacy of vitamin and mineral supplements. With the global market for dietary supplements being assessed At more than $140 billion, the USPSTF’s findings, along with new data on the role of vitamins in various pathologies, garnered a lot of attention this week. Notably, the USPSTF analysis of 84 studies found minimal benefits and serious concerns.

Vitamin E and being ta-caroting do not die advised

The USPSTF has specifically advised against the use of vitamin E and beta-carotene for the prevention of heart disease, stroke, and cancer. [1,2] “We recognize that more than half of Americans take some type of vitamin supplement every day and 30% take a combination of vitamins and minerals,” said the Dr. John Wongmember of the USPSTF, to Medscape Cardiology. “We searched for evidence, reviewing a total of 84 studies. But we didn’t find enough evidence for or against taking any vitamins, with the exception of beta-carotene and vitamin E, which we don’t recommend. No take,” he added.

In a editorial accompanying the statement, the Drs Jenny Jia, Natalie Cameron and Jeffrey Linder of the Northwestern University Feinberg School of Medicine of Chicago, note that the results included an additional 52 studies that were not available when the last USPSTF recommendation was published in 2014. [3]. In response to these new data, the doctor perry wilson (Yale School of Medicine) recalled the “nephrological” adage: “Vitamins only make expensive urine. He raised serious questions about the significance of the only benefit found by the USPSTF, that multivitamins were associated with a 7% relative reduction in cancer incidence. Dr. Wilson explains that “the relative risks really tend to overestimate the magnitude of the effect. In absolute terms, multivitamins reduced the incidence of cancer by approximately 0.2%. This means that 500 people would have to be treated with a multivitamin to prevent 1 case of cancer. » [4]

Vitamin C : disappointing data on septic shock

According to an article published in the New England Journal of Medicine, patients with septic shock who received vitamin C infusions were more likely to die or have more severe organ failure than those who received a placebo. These results come from theLOVIT study [5]a randomized placebo-controlled trial involving 863 patients from Canada, New Zealand, France, and other countries.

In the study, 872 patients were randomized to receive vitamin C infusion every 6 hours for 4 days (n=435) or placebo (n=437). After 28 days, 191 of 429 patients (44.5%) in the vitamin C group had died or had persistent organ dysfunction, compared to 167 of 434 (38.5%) in the placebo group. This corresponds to a therapeutic effect of 1.21 (p = 0.01). “This is an unexpected result and secondary analyzes (which included evaluation of 5 biomarkers of tissue dysoxia, inflammation, and endothelial damage measured up to 7me day) did not identify the established mechanism of adverse effects”, explained the researchers, led by the Prof Francois Lamontagne (University of Sherbrooke, Quebec) and the Professor Neill Adikhari (University of Toronto, Ontario).

Vitamin D deficiencies

However, the effect of vitamin deficiencies is still important. Vitamin D deficiency was recently found to significantly increase the risk of miscarriage. In an analysis of 10 studies [6]women with vitamin D deficiency (<50 nmol/L) tenían casi el doble de riesgo de aborto espontáneo que aquellas con niveles adecuados de vitamina D (>75nmol/L; OR 1.94; 95% CI, 1.25 to 3.02). Low vitamin D levels have also recently been associated with a higher prevalence of diabetic foot ulcers in elderly patients in a preliminary preliminary study. [7]

On the other hand, as a reminder, vitamin D supplementation has been shown to be ineffective in reducing the risk of developing type 2 diabetes in the general population with prediabetes. The new findings come from the prospective DPVD trial [Diabetes Prevention with active Vitamin D] conducted with more than 1200 Japanese participants with glucose intolerance. [8] Treatment with 0.75 μg/d eldecalcitol, an active vitamin D analog, for 3 years did not prevent progression from prediabetes to type 2 diabetes, nor did it improve the rate of regression to normoglycemia compared with placebo.

Towards evidence-based prevention measures

Nearly 60% of the American population (and 46% of the French) consume some type of dietary supplement, often for the prevention of cardiovascular disease. For editorialists who commented on the USPSTF report [3]These data confirm that the best strategy is not to focus on vitamin supplements but to reinforce low-risk, high-benefit measures such as healthy eating, regular exercise, maintaining a healthy weight, and smoking cessation.

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