Low Vitamin D Linked to Depression in Young Women
New research by Oregon State University scientists suggests there’s a relationship between low levels of the “sunshine vitamin” and the risk of clinical depression among otherwise healthy young women. Even after controlling for other potential confounding factors, such as time of year, physical activity level, and time spent outdoors, the relationship between low vitamin D and risk of depressive symptoms persisted.
"Depression has multiple, powerful causes and if vitamin D is part of the picture, it is just a small part," said lead author David Kerr, an associate professor in the School of Psychological Science at OSU. "But given how many people are affected by depression, any little inroad we can find could have an important impact on public health.”
Vitamin D is an essential nutrient that comes from certain limited food sources, such as salmon, fortified dairy, and mushrooms. It’s so important for so many aspects of health that the body also generates its own supply through the activity of summer sunshine striking bare skin. Problem is, a majority of Americans still don’t have enough vitamin D circulating in their bloodstreams at any given time. Experts speculate that various aspects of modern life may be interfering with our natural ability to shore up vitamin D, which actually behaves like a hormone in the body.
Exposure to ultraviolet radiation from sunshine has been linked to an increased risk of developing skin cancer, as well as sun-damaged, prematurely-aged skin. Skin doctors have done a good job of encouraging people to wear hats, avoid the sun altogether during peak burning hours, and slather on sunscreen before venturing out-of-doors. But this advice may be working a little too well.
The problem is compounded by the fact that official recommendations regarding optimal amounts of supplemental vitamin D3 have recently been called into question. The Institute of Medicine (IOM) recommends most adults get just 600 IU vitamin D3 per day to stay healthy. But other experts claim these recommendations are based on faulty math. In fact, say these concerned scientists, IOM is off by a factor of 10. Most adults need up to 7,000 IU of vitamin D3 daily.
If the higher amounts are accurate, it might explain why studies have repeatedly shown that a majority of Americans have insufficient, or deficient, levels of vitamin D. We’re simply not spending enough time in the sun—or taking enough supplemental vitamin D—to make up the difference.
In the past, doctors knew that vitamin D is crucial for bone health. But in recent decades, they’ve discovered that vitamin D also plays an essential role in regulating the immune system and maintaining good mental health, among other crucial functions. Which may explain why low vitamin D levels appear to be linked to the risk of depression among otherwise healthy young women.
In any event, ”Vitamin D supplements are inexpensive and readily available,” Kerr said. "They certainly shouldn't be considered as alternatives to the treatments known to be effective for depression, but they are good for overall health.”
David C.R. Kerr, David T. Zava, Walter T. Piper, Sarina R. Saturn, Balz Frei, Adrian F. Gombart. Associations between vitamin D levels and depressive Symptoms in healthy young adult women. Psychiatry Research, 2015; DOI: 10.1016/j.psychres.2015.02.016
Paul Veugelers, John Ekwaru. A Statistical Error in the Estimation of the Recommended Dietary Allowance for Vitamin D. Nutrients, 2014; 6 (10): 4472 DOI: 10.3390/nu6104472