Have you thought about whether or not you are getting enough vitamin D? Studies suggest that more than 50% of adults in the UK have insufficient levels of vitamin D. It is difficult to get enough vitamin D from sunlight, particularly during the winter months (Oct-May).
Referred to as a fat-soluble vitamin but it is actually a hormone. A vitamin is a ‘nutrient’ that cannot be made in our bodies but helps our bodies to function. The body can synthesise vitamin D but only in the presence of sunlight.
How much should we be getting?
Although your body can make some vitamin D, the amount produced through sunlight will only last in your body for a few weeks. Therefore, you need an adequate amount in your diet to supplement levels over winter. The dietary recommendation for individuals not getting any sun exposure is 400 IU a day (10 micrograms). According to research, it is possible to get 8-9 mcg from a portion of oily fish.
It is difficult to exceed the recommended levels of vitamin D from your diet or through sunlight as your body only makes as much as it needs. However, according to NHS guidelines supplements should not exceed 25 micrograms (0.025mcg) a day. Taking vitamin D supplements over a long period of time can result in more calcium being absorbed than can be excreted, which can damage your kidneys.
Why do we need it?
It is vital for good bone health because it promotes the absorption of calcium in the gut. Vitamin D also maintains adequate serum calcium and phosphate concentrations to enable normal mineralisation of bone.
Even if your diet is rich in calcium it cannot be absorbed efficiency without the presence of vitamin D. Other nutrients that play a role in bone health include phosphorus, magnesium, and vitamin K.
There are claims that low levels of vitamin D are linked to many illnesses including cancer and heart disease. Further research is required, in many cases, it is unknown whether low levels of the vitamin have caused the disease.
Good sources of vitamin D include:
- Oily fish (sardines, salmon, pilchards, trout, kippers) are a good source of vitamin D. Evidence suggests higher levels of vitamin D and omega-3 fatty acids from wild rather then farmed fish). The government recommends having between 2-4 portions of oily fish a week (2 for children and during pregnancy and breastfeeding), due to levels of contaminants in some fish.
- Cod liver oil contains significant levels of vitamin D (not recommended during pregnancy because of high levels of vitamin A).
- Egg yolks, meat (particularly liver) and milk contain some but this varies between seasons.
- Fortified foods including some breakfast cereals, dairy products and tofu (advised to check food labels to ensure vitamin D fortification and sugar content, foods containing more than 15g of sugar per 100g).
Adults over the age of 65, pregnant women or those who are breastfeeding may be advised to take a vitamin D supplement. Always consult your doctor if you are unsure.