Supplements of vitamin D and omega-3 fatty acids (often sold as fish oil) do not help people with type 2 diabetes ward off chronic kidney disease, according to findings from the largest clinical study to date of the supplements in this patient population.
The paper was published on Friday, November 8, 201
"We were hopeful for both of these efforts, vitamin D and fish oil , but they don't seem to be particularly effective for this purpose, "Dr. Ian de Boer, paper's leading author. He is a professor of medicine at the University of Washington School of Medicine and assistant director of the Kidney Research Institute, a collaboration between UW Medicine and the Northwest Kidney Centers.
Of the 28 million Americans living with type 2 diabetes, de Boer said, about 40 percent develop chronic kidney disease, a condition where the kidneys cannot adequately remove waste and fluid from the body. This interferes with a person's health in many ways and can develop into kidney failure. It also increases the risk of cardiovascular events and deaths.
Previous animal model and cell culture studies have suggested that vitamin D and fish oil supplements have anti-inflammatory and other properties that can prevent or curb type 2 diabetes in chronic kidney disease. Research has also found a connection between people's kidney decline and lower levels of vitamin D and lower dietary intake of fish.
"Many people use the supplements in the hope that there are beneficial effects on the kidneys and cardiovascular system," said de Boer. "We wanted this study to clarify if these supplements have any real kidney benefit in adults with diabetes. Although that is not the result we hoped for, closing a chapter is useful for both patients and clinicians and researchers."
The study was conducted as part of the nationwide VITamin D and OmegA-3 TriAl (VITAL). The investigators designed a five-year study of renal function in 1,312 adults with type 2 diabetes in the trial. The adults (men of age
Participants provided blood and urine samples to determine an estimated glomerular filtration rate – eGFR, a measure of renal waste filtration performance – and the presence of protein in the urine. They were then randomly assigned to one of four treatment groups:
- 370 people were given vitamin D and omega-3 fatty acids (fish oil)
- 333 received vitamin D and a fish oil placebo
- 289 received a vitamin D placebo and a capsule of fish oil
- 320 received two placebos
Blood and urine samples were collected two years and again four or five years after randomization. On average, renal function decreased by approximately 15% during the study. The amount of decline did not vary significantly whether participants were assigned vitamin D or placebo, or omega-3 fatty acids or placebo. There were also no significant differences in urinary protein excretion.
"The VITAL study evaluates the overall benefits and risks of these supplements, and the effects on kidney function are an important part of the puzzle. The current study answers a key question that helps promote public health," Dr. JoAnn Manson, the study's senior author and head of the main VITAL trial. She is Head of Preventive Medicine at Brigham and Women's Hospital and Professor of Medicine at Harvard Medical School.
Vitamin D and Omega 3 supplements do not reduce the risk of systemic inflammation: study
JAMA (2019). DOI: 10.1001 / jama.2019.17380
University of Washington Health Sciences / UW Medicine
Supplements do not preserve kidney health in type 2 diabetes (2019, November 8)
Retrieved November 8, 2019
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