Vitamin D 'boosts child muscles'

Higher levels of maternal vitamin D during pregnancy have been linked to better muscle development in children, say researchers.
The study on 678 children, published in Endocrine Research,  showed vitamin D levels in the womb were linked to grip strength at the age of four. The team at the University of Southampton say the muscle boost could persist throughout life. Trials are taking place to see how effective pregnancy supplements are.
Most vitamin D is made by the skin when exposed to sunlight and supplements are offered during pregnancy.Some doctors have  voiced concerns about vitamin D deficiency as people become more "sun aware" and have linked it with a range of health problems.
The team at the University of Southampton investigated the impact of the vitamin in pregnancy. Blood samples were taken 34 weeks into the pregnancy and the vitamin D levels were compared with how tightly their children could squeeze a device in their hand at the age of four. The results showed that women with high levels of vitamin D in the late stages of pregnancy were more likely to have children with greater muscle strength.
Dr Nicholas Harvey told the BBC that: "There's some evidence that 'fast' muscle fibres go down in vitamin D deficiency and you get more fat in muscle. If there is deficiency in utero then they may end up with a lower number of numbers of these 'fast' muscle fibres."