Vitamin D is created from direct sunlight on the skin when outdoors. From about late March/early April to the end of September, most people should be able to get all the vitamin D they need from sunlight. Some people are at risk of running a vitamin D deficiency, however. While it is well understood that a lack of the vitamin can cause bone problems, it may come as a surprise that it can impact the body in another way too.One study, published in the Journal of Inflammation, has found that vitamin D deficiency is associated with inflammation, a negative response of the immune system, in healthy women.Increased concentrations of serum TNF-α, an inflammatory marker, were found in women who had insufficient vitamin D levels.This study is the first to find an inverse relationship between vitamin D levels and concentrations of TNF-α in a healthy, non-diseased population.This may explain the vitamin’s role in the prevention and treatment of inflammatory diseases, including heart disease, multiple sclerosis and rheumatoid arthritis.As medical website LiveStrong explains, inflammation is an immune system response that can trigger fluid buildup and swelling.Vitamin D deficiency: Study suggests a lack of the vitamin can trigger an inflammation response (Image: Getty Images ) Low vitamin D levels negatively impact inflammation and immune responseCatherine Peterson, assistant professor”The findings reveal that low vitamin D levels negatively impact inflammation and immune response, even in healthy women,” said Catherine Peterson, assistant professor in the MU College of Human Environmental Sciences.Adding: “Increased inflammation normally is found in people with obesity or chronic diseases; a small decrease in vitamin D levels may aggravate symptoms in people who are sick.”People may also experience a sign in their hair. Who is at risk of a vitamin D deficiency?Some people won’t get enough vitamin D from sunlight because they have very little or no sunshine exposure throughout the year.The Department of Health recommends that a person takes a daily supplement containing 10 micrograms of vitamin D throughout the year if they:Aren’t often outdoors – for example, if you’re frail or houseboundAre in an institution like a care homeUsually wear clothes that cover up most of your skin when outdoorsIf a person has dark skin – for example if they have an African, African-Caribbean or south Asian background – they may also not get enough vitamin D from sunlight, advised the NHS.Vitamin D: Oily fish is a rich source of vitamin D (Image: Getty Images )Vitamin D: Taking too many vitamin D supplements can cause bone, heart and liver complications (Image: Getty Images )People who fit this profile should consider taking a daily supplement containing 10 micrograms of vitamin D throughout the year, the health site added.Vitamin D is also found in a small number of foods.Sources include:Oily fish – such as salmon, sardines, herring and mackerelRed meatLiverEgg yolksFortified foods – such as most fat spreads and some breakfast cerealsAs the NHS noted, vitamin D can also be topped up with dietary supplements. The health site warns against exceeded the recommended dosage, however: “Taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body (hypercalcaemia). This can weaken the bones and damage the kidneys and the heart.”If a person chooses to take vitamin D supplements, 10 micrograms a day will be enough for most people, noted the health site.Exceeding 100 micrograms of vitamin D a day could be harmful, it added.