Vitamin D, glucose metabolism and muscles
In a recent study evaluating the link between obesity, diabetes and vitamin D, lower serum 25(OH)D levels were found in pre-diabetic and diabetic groups regardless of their weight, suggesting that a vitamin D deficiency may be linked more closely with carbohydrate metabolism than with obesity.
As vitamin D is required to produce insulin and to utilise glucose for energy, a deficiency can create poor glucose handling. This research further supports the above-mentioned importance of the need for supplementation of vitamin D in type II diabetes. Serum vitamin D levels should at the very least be greater than 60nmol/L.
Interestingly, studies consistently show that vitamin D also increases muscle strength by increasing the size of muscle fibres and the rate of protein synthesis. Indeed a recent study involving six randomized trials found an increase in muscle and limb strength in 18–40 year olds who supplemented with high dose vitamin D.
In older people supplements of 1,000 IU of vitamin D daily for two years improved serum vitamin D from a deficient range to the sufficient, and reduced falls by 58%, reduced muscle atrophy (wastage) and increased muscle strength.