Back in May, one of my blogs focused on some evidence which suggests that vitamin D has the capacity to improve a range of measures of physical function, including fitness, muscular strength, balance and reaction time. Strange though this may seem, there indeed appears to be evidence that simply sitting the sun may be all it takes to get fitter and healthier.
Of course, not everyone has the opportunity to sit out in the sun. Some parts of the World, particularly during colder seasons, don’t get that much sun. And even in places where the sun is shining, some individuals may be shielded from it through clothing or by the fact that they’re sitting inside. One subset of the population prone to problems here is the elderly. As people get older they can also get out less, perhaps at least partly because of increasing infirmity or disability. Some elderly individuals can end up a bit institutionalised, even in their own home.
This, in theory, may set up a bit of a vicious cycle. As people get increasingly infirm they are less likely to get out, and are more likely to become vitamin D deficient as a result. This, in its own way, may contribute to weakness and infirmity, which makes venturing out into the light even less likely. And so the cycle repeats.
I thought about this recently on reading about a study in which institutionalised Brazilian individuals aged 60 or more were treated with calcium, plus either vitamin D (D3) or placebo [1]. Vitamin D was given at a dose of 150,000 IU once a month for two months, followed by 90,000 IU once a month for a further four months. Two muscle tests were performed at the start and end of the study. One of these tested the muscles that flex the hip (the motion of lifting the knee in the standing position). The other tested the strength of the ‘knee extensors’ (straightening of the leg at the knee).
The calcium/placebo supplemented group did not see improvements in either of these two measurements. The group taking did:
Hip flexion strength increased by 16.4 per cent
Leg extension strength increased by 24.6 per cent
Both improvements were statistically significant.
The authors of the study conclude that The suggested cholecalciferol [D3] supplementation was safe and efficient in enhancing 25(OH)D [vitamin D] levels and lower limb muscle strength in the elderly, in the absence of any regular physical exercise practice.
Here again, it seems we have evidence that vitamin D has the capacity to improve muscle strength. This, I think, has important implications for those who could do with a bit more muscle strength such as many elderly individuals.
Remember, vitamin D has been linked with improved reaction time and balance too. Higher vitamin D levels may therefore help protect the elderly against falls ” something that could help to prevent injury, including broken bones, and even death.
References:
1. Moreira-Pfrimer LD, et al. Treatment of Vitamin D Deficiency Increases Lower Limb Muscle Strength in Institutionalized Older People Independently of Regular Physical Activity: A Randomized Double-Blind Controlled Trial Ann Nutr Metab 2009;54(4): 291-300
