What does Vitamin D do?
Probably one of the most talked-about vitamin in Canada is vitamin D, and for good reason!
Vitamin D is known as a vitamin but it is actually a hormone that is manufactured in our skin when we come in direct contact with ultraviolet rays from sun exposure.
As you can imagine, here in Canada we don't always have so much of that which is why the risk for vitamin D deficiency is typically higher in the Northern Hemisphere.
So why is vitamin D important? The benefits of vitamin D in the body are vast as it plays an influential role in many health outcomes. Vitamin D plays a significant role in overall health but particularly in immune and bone health. It is needed for the absorption of calcium and bone mineralization as it enhances the absorption of this mineral in the intestines (3).
Too little levels of vitamin D can result in low calcium levels in the blood, which can decrease bone density and increase the risk of brittle bones and bone diseases. In combination with calcium, having adequate vitamin D levels is essential for strong and healthy bones.
Vitamin D is involved in the innate and adaptive immune responses and deficiency in vitamin D has been associated with an increased risk of autoimmunity and infections (4). If you notice that you are often sick in the wintertime, it might be worthwhile to get your vitamin D status checked in order to avoid potential vitamin D deficiency.
How much Vitamin D do I need?
It is best to test your blood levels before supplementing to get a better idea of your optimal vitamin D intake. However, the daily recommended dose for the average adult is 600 International units of vitamin D per day.
This dosage will increase to 800 IU a day of vitamin D for older populations above the age of 70 (5).
Keep in mind there are different types of vitamin D that will also impact its effectiveness at raising blood levels to adequate levels which we will discuss later in this article.
What foods have Vitamin D?
Though you can obtain vitamin D from certain foods such as wild fatty fish, dairy milk and cheese products, egg yolks, beef liver, and mushrooms, the best way to maintain a sufficient vitamin D status is from sunlight exposure or supplementation (6).
The richest food sources of vitamin D will be found in fatty fish such as halibut, salmon, tuna, mackerel, sardines, and trout. Many foods may also be fortified in vitamin D such as almond milk, soy milk, orange juice, milk, yogurt and cereals.
It is not always possible to meet the daily requirements through food alone.
Tips on getting vitamin D for infants
Breastfed babies are said to be at a greater risk of being vitamin D deficient because though breast milk does contain some vitamin D it is typically not enough for optimal health thus an infant's diet may need to be supplemented additionally (7).
Supplementation usually doesn't start before 1 year of age however it is always best to verify with your doctor to determine the best course of action (8).
For babies that are bottle-fed, infant formula will be fortified with sufficient vitamin D to meet their daily requirements and therefore a supplement will likely not be needed.
Tips on getting vitamin D for children and adults
For children who are eating solid foods as well as adults, eating vitamin D-rich foods such as the ones we mentioned above will help to raise vitamin D levels, however, this is not always enough.
Safe sun exposure can also significantly raise vitamin D levels but it's important to take precautions depending on where you live. Without regular exposure to sunlight, it's very difficult to obtain enough vitamin D from your diet alone.
Supplementation is an effective way to boost low levels and maintain adequate vitamin D status, especially during the winter months. Healthy levels of vitamin D are essential for children and adult health and should therefore be monitored regularly. If you are not sure if you need to supplement or not it would be most prudent to check in with your doctor for an assessment of vitamin D levels.
Tips on getting vitamin D for adults 50 and over
Vitamin D supplementation will often be the most appropriate treatment option for the older adult population which will have an increased need for vitamin D intake.
It's especially important for these populations to pay attention to their vitamin status as vitamin D insufficiency has been associated with cognitive decline, depression, and conditions associated with low bone mineral density like osteoporosis (9).
Do I need a vitamin D supplement?
In order to determine if a person has adequate levels of vitamin D or not, we would need to measure their blood circulating level of 25(OH)D.
Most experts agree that a 25-hydroxyvitamin D level below 20 ng/ml is considered to be a deficiency whereas a level between 21-29 ng/ml is considered to be insufficient (10).
If you find yourself below the recommended levels you will likely need a vitamin D supplement and your doctor will be able to assist you in finding the most appropriate dosing in order to meet the requirements.
Many people do not need a supplement if they are spending time in the sun on a daily basis but supplementation will often be required during the colder and darker months of the years or for individuals who may be at an increased risk of deficiency.
These may include:
- those with gastrointestinal disorders
- populations over 50
- pregnant women
- breastfeeding women
- vegan and vegetarian diets
- lack of sunlight exposure
- dark skin
Common symptoms of too low vitamin D may include lack of energy, low mood, frequent infections, hair loss, chronic muscle pain, slow wound healing, poor bone health conditions such as rickets or risk of osteoporosis.
If you think you might be at risk of vitamin D deficiency we suggest consulting with your doctor to verify your level of vitamin D and assess if a daily vitamin would benefit you.
On an additional note, vitamin D is often recommended to be taken alongside vitamin K2 as these two vitamins work synergistically. This can also help to prevent cardiovascular and bone problems as K2 helps to deliver vitamin D3 as well as serum calcium into the tissues where it is needed, such as the bones, instead of potentially building up in the arteries (11). For this reason, calcium supplements are not recommended to be taken alone but should always be combined with vitamin D, vitamin K, and magnesium. These vitamins and minerals are essential in the maintenance of strong bones and the prevention of osteoporosis as well as other medical conditions (12)(13).
Vitamin D by itself may become problematic when taking higher doses (14).
Do I need a vitamin D supplement if I'm vegetarian?
It is already not that easy to obtain sufficient vitamin D content through dietary intake alone but it will also be more challenging with a plant-based diet as the richest dietary sources of vitamin D are found in animal foods.
The other important thing you need to know as a vegan or vegetarian is there are different types of vitamin D. Vitamin D3 is found exclusively in animal foods, and is also the form of vitamin D that is manufactured through your skin when exposed to sunlight, and vitamin D2 is typically the form found in plant sources.
Make sure you pay attention to the label and consider choosing vitamin D3 over vitamin D2 for improved vitamin D absorption.
Algae is now a popular dietary supplement for vegetarians because it provides vitamin D3 but is entirely plant-based. This is an ideal option for vegetarians who are not obtaining sufficient amounts of vitamin D3 and want to find a vegan-friendly alternative.
If you are not getting daily sun exposure then it probably will be a good idea to look into a daily supplement and find your optimal dose with your doctor.
Can I get vitamin D from sunlight?
The short answer is yes! It is for this very reason that it is called the sunshine vitamin.
How cool is it that we can make a vitamin from coming into contact with the sun? I'd say it might even be a superpower!
But seriously, vitamin D synthesis is triggered in the skin in response to contact with ultraviolet rays and is therefore considered the most "natural" form of the vitamin. Most people will be able to get enough vitamin D during the summer months with just 15 minutes of exposure but it may vary depending on skin type, time of day, how much skin is exposed, and location.
However, according to researchers, the benefits of sunlight don't just stop at vitamin D production and a tan. There is fair evidence that points to exposure to sunlight activating feel-good chemicals in the brain as well as promoting nitric oxide production and optimal melatonin later at night (17).
This is why most people won't need to take a vitamin D supplement during the summertime but might bring it back into their supplement routine in the wintertime. This may also be one of many reasons why our mood may tend to lower in the darker winter months compared to the bright and sunny summer months (18).
Keep in mind skin pigmentation can impact serum 25-hydroxyvitamin D concentrations as fair-skinned individuals have been shown to more efficiently convert sunlight into the vitamin compared to darker skin tones (19).
If you find you still are lacking adequate amounts of vitamin D then you might need to supplement to boost your vitamin D intake.
Is more vitamin D better?
When you start increasing your vitamin D dosage this can potentially cause problems. More is not necessarily better and not always needed. Again, this is why we recommend testing your own vitamin D level in order to properly assess the adequate intake for you.
As vitamin D is a fat-soluble dietary vitamin it can be stored for longer in the body and high levels can potentially lead to vitamin D toxicity and adverse effects.
What are the vitamin D guidelines? Daily intake is recommended at 600 IU of vitamin D per day and shouldn't exceed the upper intake level of 4,000 IU for most healthy individuals unless recommended and monitored by your doctor as sometimes higher levels will be needed to correct a vitamin D deficiency. In order to reach toxic levels, this will typically require a much higher daily dose of vitamin D.
Toxicity of vitamin D may be associated with symptoms and conditions such as hypercalcemia, nausea, vomiting, diarrhea, constipation, excessive thirst, high blood pressure, kidney failure, or hearing loss.
Though too little vitamin D can pose a problem too much can also result in adverse health effects. More is not always better!
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