As we grow older, our levels of circulating vitamin D decrease. This is due to a number of factors such as poor diet, poor renal function, poor digestion, less exposure to sunlight, decline in vitamin D reduction and increased degradation. When it comes to supplementation, it is common for doctors to recommend a bottle of standard 1000IU capsules and to take as directed on the label (1 daily). However, some of the questions we need to ask are, is this enough?
According to experts, vitamin D deficiency is defined as less than 50nmol/L. Under 29nmol/L is classified as moderate deficiency, whereas less than 12.5nmol/L is severe deficiency. In patients with such low levels of vitamin D, supplementation with only 1000IU daily will prove difficult to increase serum levels. When advised to take 3 to 5 of 1000IU capsules daily, compliance is usually low. In this situation, 3000 to 50 000IU capsules can be compounded to not only increase compliance but also cost-effectiveness. 3000IU capsules to be taken once daily can be compounded for ~$30/month, or 50 000IU capsules to be taken every 4 weeks for around $10/month.
These high doses of vitamin D may sound alarming, however, high doses of up to 600 000IU have been evaluated for safety and are currently used intramuscularly as a yearly dose in Canada. A study also found no evidence of hypercalcaemia from giving 50 000IU orally daily for 8 weeks.
As well as recommending the right level of supplementation, it is important to remember to learn the importance of correct sunlight exposure. During summer in Brisbane weather, it is recommended to obtain 6-7 minutes of sunlight for fair skin and 20-45 minutes for dark skin per day. In winter this should be increased to 10 minutes for fair skin and 30-60 minutes for dark skin. It should also be noted that an area of the body such as the arms should be exposed (not covered with sunscreen). This should also be done during mid-morning or mid-afternoon (~10am or ~2pm) to avoid the peak UV times.
References available on request