As summer slides away and the days start to get shorter, it’s time we started to think about vitamin D. A lot has been written about the benefits of vitamin D and how much it is needed. Vitamin D is actually a complex hormone rather than a vitamin, with many functions in the body, such as regulation of the immune system and bone health. Most people refer to it as a vitamin however.
Unlike other vitamins, vitamin D is made in the skin from exposure to sunlight. The ultraviolet B rays of the sun cause a reaction in the skin that produces pre-vitamin D3. This is then, first by the liver, then by the kidneys, converted to the active form of vitamin D. It then binds to vitamin D receptors all through your body, so it can do its job in different places.
But vitamin D is also found in foods. Vitamin D3 can be found in foods such as oily fish, liver, egg yolk, red meat, cheese, butter, cod liver oil, and fortified foods (foods with added vitamin D).
There is not only vitamin D3, that is found in humans and animals, there is also vitamin D2. Vitamin D2 is formed by UV radiation in certain plants and can be found in mushrooms or sprouted seeds for instance.
For us humans, vitamin D3 is better absorbed and used in the body than vitamin D2. In the mitochondria, the powerhouses of the cells, certain enzymes convert vitamin D3 five times faster than vitamin D2.
So what are the top vitamin D foods?
Oil fish contains not only vitamin D but it is also high in omega 3 fatty acids. Omega-3 fatty acids reduce inflammation, are good for brain health and help prevent and manage cardiovascular diseases.
Best oily fish? SMASH…….Sardines, Mackerel, Anchovies, Salmon and Herring.
Whilst it is not everyone’s favourite food, liver is a nutrient-dense food that is full of vitamins and minerals, a good source of protein and low in calories. Liver is not only a good source of vitamin D, it is the best source of vitamin B12! The only downside of eating liver is that it is very high in vitamin A, of which you shouldn’t get too much, as high levels can be toxic. Always make sure you buy organic liver as the liver is the organ of detoxification. So, stay clear of liver from animals reared in a toxic environment.
One medium egg contains 32% of the recommended daily allowance of vitamin D!
Half of the protein of the egg is found in the yolk, plus many other vitamins, omega 3 fatty acids and antioxidants, and yes, cholesterol. Cholesterol is much needed in the body. For example, it is part of the cell membranes and is used to make hormones. Research has shown that the cholesterol from eggs can increase your good cholesterol (HDL).
Butter doesn’t only contain vitamin D, it also has vitamin K2. The D3 & K2 team is great for strong bones and healthy arteries. Vitamin D3 looks after the calcium in your blood and K2 helps it to get to the right places. Another benefit of butter is the butyrate it contains. This saturated short-chain fatty acid keeps your gut lining healthy and is anti-inflammatory. It is needed for a healthy gut. Always go for organic, grass-fed butter.
Vitamin D in red meat is highly bioavailable, much better absorbed and used by the body than other vitamin D food sources. However, there isn’t as much vitamin D in red meat as there is in oily fish and eggs.
Good news for the vegetarians and vegans, there is a source of vitamin D for you (although it is not as well absorbed and used by the body as vitamin D3)!
Mushrooms make vitamin D2 by being exposed to the sun’s UV radiation, just like human beings. That’s why mushrooms that have been grown indoors, in the dark, have very small amounts of vitamin D, but the wild mushrooms contain a lot more. Luckily, growers have started to expose the mushrooms to UV lamps, but you can even put the mushrooms you bought on the windowsill, so they can sun-bath and increase their vitamin D level. Crimini, Maitake, Portobello and white button mushrooms are the highest in vitamin D2.
It is hard to get enough vitamin D from foods. If you think that 1 tablespoon of butter only contains 60IU of vitamin D and a maintenance dose of vitamin D supplementation contains 1,000IU, then you can imagine that you have to eat a lot of vitamin D containing foods to keep your level optimal.
Because it is so difficult to get enough vitamin D from food, some foods have been fortified with the vitamin. Think of milk alternatives such as almond milk, soya products, dairy products, fruit juices, cereals and even bread.
Is supplementing necessary?
Only about 10-20% of our vitamin D3 intake is from foods, the other 80-90% should come from exposure to sunlight. And that’s where the problem begins. How often do we have enough sunshine, and can we expose ourselves enough to get the required intake of this valuable vitamin?
My advice is to make sure you get enough sun exposure. I don’t mean spending the whole day sunbathing. Vitamin D production actually happens quite quickly. In about half the time it takes for your skin to get sun-burned, you can make a good amount of vitamin D. But you need to expose a bit more than just your face and arms. The more skin you expose, the more vitamin D you can make.
People with a very light skin only need about 15 minutes of decent sun exposure to obtain the vitamin D they need. However, people with a dark skin will need up to 2 hours to produce the same amount of vitamin D.
Secondly, I advise people to eat foods that contain vitamin D and get their vitamin D level checked to see if it is sufficient (especially people who don’t eat animal products or people who are not outdoors very much). This is no luxury, given that almost 50% of the world’s population doesn’t get enough vitamin D. Around 1 billion people worldwide are suffering from vitamin D deficiency.
If your vitamin D level is insufficient or deficient, you will have to supplement. You can check with your GP or a nutritional therapist what supplement, at what strength, is best for you.