Vitamin D is important for keeping our bones, teeth and muscles healthy, as it regulates the amount of calcium and phosphate in the body. Find out more about vitamin D, symptoms of deficiency and the best supplements and vitamin D foods.
During the warmer months (late March through to early September) our bodies should make enough vitamin D from exposure to the sunlight. But, during the colder months (October through to early March) we need to seek our vitamin D source from elsewhere. One way we can do this is by taking supplements or consuming foods that contain vitamin D.
Benefits of vitamin D
While vitamin A foods can help the appearance of our hair and skin, vitamin D helps regulate the amount of calcium and phosphate in the body. These nutrients are needed to keep bones, teeth and muscles healthy. A lack of vitamin D can lead to bone deformities such as rickets in children, and bone pain caused by a condition called osteomalacia in adults.
Vitamin D can also affect liver function through the vitamin D receptor (VDR). VDR is naturally present in the liver cells and its higher expression can reduce inflammation in chronic liver diseases. It also has anti−fibrotic, proliferative, and inflammatory effects on the liver.
Vitamin D foods include:
1) Oily fish
Oily fish including salmon, sardines, herring and mackerel are high in long-chain omega-3 fatty acids, which may help to prevent heart disease, plus they're a good source of vitamin D. In fact, vitamin D is best absorbed when taken with a meal containing fats or oils, so fish oil can only help with that.
Some oily fish contain bones that you can eat. These include whitebait, canned sardines, pilchards and tinned salmon (but not fresh salmon). These fish can help keep our bones strong because they are sources of calcium and phosphorus.
2) Red meat
For those whose diets will allow it, red meat, offal and liver can provide additional vitamin D. One 25g steak, for example, contains around 15 IU of vitamin D.
Red meat and meat products can contribute meaningfully to the mean daily intake of vitamin D. Beef and lamb can contain vitamin D3 and 25-hydroxyvitamin D3 [25(OH)D3] but also potentially vitamin D2 and 25-hydroxyvitamin D2 [25(OH)D2], all of which contribute to meat's vitamin D activity.
Pork in general is also high in vitamin D. Cuts that pack the most punch include back fat (138 IU per four ounces) and spareribs (103 IU per four ounces).
3) Liver
Beef liver contains vitamin D, and while it's known for being lower in calories than other meats it's also worth noting it's high in cholesterol. A cooked, 2.5-ounce serving of beef liver has 36 IU of vitamin D.
Liver also includes several other nutrients such as vitamin A, iron, and protein.
4) Egg yolks
Eggs are a convenient way to get vitamin D. They're popular in many breakfast, lunch, dinner, and dessert recipes. Since the vitamin D in an egg comes from its yolk, it's important to use the whole egg—not just the whites. One yolk will give you about 40 IUs.
Research has shown that when eggs are baked for 40 minutes, they may lose up to 61% of their vitamin D, compared to up to 18% when they're fried or boiled for a shorter period of time. However, even though cooking eggs reduces these nutrients, eggs are still a very rich source of vitamins and antioxidants.
5) Fortified foods
Some fat spreads, breakfast cereals and plant based milks have vitamin D added to them and can contribute to your vitamin D intake. Cereal manufacturers can add up to 560 IU of vitamin D3 per 100 grams in breakfast cereals and 400 IU of vitamin D3 per 100 grams in cereal bars.
If you're not sure whether your usual breakfast cereal includes vitamin D, check the list of ingredients which will tell you how much vitamin D is included.
However, it’s important to note that while the above are vitamin D foods, it is only very small amounts and you'll never be able to make enough vitamin D from scoffing these foods alone. This is why it’s best to take supplements as your main source when the sun isn’t shining.
How much Vitamin D do I need?
During those warmer months your body should be able to make enough vitamin D from the sunlight on your skin and a nutritious, balanced diet including the vitamin D foods above, but during the autumn and winter the sun just isn’t strong enough and foods with vitamin D don’t contain enough of it. Therefore, the NHS recommends that adults should take 10 micrograms of vitamin D a day. If you already take a multivitamin or vegan multivitamin it may be worth checking if it contains vitamin D, if not it could be a good idea to take this as a separate supplement. Remember to always talk to your GP before starting a new supplement regime.
A lack of vitamin D can lead to bone pain and deformities, but equally too much can lead to too much calcium building up in the body (known as hypercalcaemia), which can damage your kidneys and heart and weaken the bones.
Vitamin D deficiency symptoms
The majority of people with a vitamin D deficiency do not present with symptoms. However, a chronic deficiency may cause hypocalcemia, a calcium deficiency disease, and hyperparathyroidism, where the parathyroid glands create a hormone imbalance that raises the blood calcium levels.
These conditions can lead to secondary symptoms including:
• bone fragility, especially in older adults
• osteoporosis
• bone pain
• fatigue
• muscle twitching
• muscle weakness
• myalgias, or muscle pain
• arthralgias, or joint stiffness
The joint issues a lack of vitamin D causes, and the fact that it's hard to find vitamin D foods, is why it's included in many joint supplements. If Vitamin D deficiency continues for long periods, it may result in complications, such as:
• cardiovascular conditions
• autoimmune problems
• neurological diseases
• infections
• pregnancy complications
• certain cancers, including breast, prostate, and colon
If you notice any of the above symptoms or are concerned about your vitamin D intake it could be worth talking to your doctor about introducing a vitamin D supplement. Whether you opt for the convenience of capsules or prefer the ease of a liquid supplement, you have multiple options to ensure your body receives this vital nutrient.
Stephanie Anthony is the Deputy Digital Editor of Yours.co.uk. Having worked across a variety of topics, from travel and food to pharmaceuticals, she also has a particular interest in mental health and wellness.