Tiredness and weak muscles can be a sign of vitamin D deficiency, research finds.
As a result, people with low levels of vitamin D are at double the risk of mobility issues with age, scientists have found.
Other signs of vitamin D deficiency include poor sleep, symptoms of depression and headaches.
The vitamin is thought to play a role in regulating serotonin, a neurotransmitter important for mood.
Around half the world’s population is deficient in vitamin D.
The conclusions about mobility issues come from a study including 2,099 people aged 70-79 whose vitamin D levels were measured.
Dr Denise Houston, the study’s first author, explained the results:
“We observed about a 30 percent increased risk of mobility limitations for those older adults who had low levels of vitamin D, and almost a two-fold higher risk of mobility disability.”
Vitamin D is vital for muscle function and low levels have been linked to diseases including high blood pressure, diabetes and cardiovascular disease.
Dr Houston said:
“Higher amounts of vitamin D may be needed for the preservation of muscle strength and physical function as well as other health conditions.
However, clinical trials are needed to determine whether increasing vitamin D levels through diet or supplements has an effect on physical function.”
Vitamin D is critical to the functioning of the whole body.
From October to March many people in northern climes do not get enough vitamin D.
Vitamin D is found in oily fish, egg yolks, fortified cereals and some margarine spreads.
Most people need around 10 micrograms per day, which can also be obtained from supplements.
Vitamin D supports the mineral density of bones and aids neuromuscular function as well as reducing the risk of fracture.
The study was published in The Journals of Gerontology: Series A (Houston et al., 2012).