What is vitamin D good for?
Vitamin D contributes to the immune system and plays an important role in the process of cell division, which is why it is so common in colds and flu research.
Vitamin D actually refers to a family of compounds that includes vitamins D1, D2, and D3.
Vitamin D3: From sunlight & animal-sourced foods
Vitamin D3, also known as cholecalciferol, is the form of vitamin D that is produced by our bodies when our skin is exposed to sunlight. I'm sure you are all aware by now that sufficient sunlight exposure on our skin is how we must obtain the bulk of our vitamin D intake, but did you know that it is actually the cholesterol contained within our skin that synthetizes vitamin D when it is irradiated with the sun's ultraviolet waves? Well now you do! The connection between vitamin D, calcium and cholesterol is also hinted at in cholecalciferol's peculiar name.
While healthy and regular sunlight exposure is the easiest and most efficient (and arguably the cheapest) way to reach our required intake of vitamin D, vitamin D3 can also be found in certain animal-sourced foods such as fatty fish, liver and eggs, although it is not feasible to achieve the entirety of our vitamin D intake through diet alone.
To put it into perspective, approximately half an hour of exposure to direct sunlight (provided clothing, seasonal and meteorological conditions are met) can easily give you the full daily quota of recommended vitamin D, while you would need to eat more than half a kilogram of fatty fish in order to achieve this through diet alone. Obviously, in reality, we naturally eat much less than that.
That said, every little helps, and you should definitely seek to include fatty fish in your diet often, if not for its complementary vitamin D3 content, then at least for the range of other areas it appears in.
Vitamin D2: An inferior synthetic alternative
Vitamin D2 on the other hand is the synthetic form of vitamin D, and it is often used for fortifying foods, such as cereals and plant-based milk alternatives, due to its low cost. Vitamin D2 can also be found in certain species of mushrooms that have been exposed to ultraviolet radiation.We are able to absorb both types of vitamin D, however research has shown that vitamin D3 is more efficient, both at raising as well as maintaining, adequate vitamin D levels in our body.
Sufficient sunlight exposure
However, it is important to remember that anything that interferes with our body's ability to create vitamin D through our skin, including liver disease, kidney disease, increased melanin, or simply our lifestyle choices or obligations of remaining indoors and/or covered up, can cause vitamin D deficiency.In fact, if you live far from the equator, there's a definite possibility that you are deficient in vitamin D to some degree, and this is where vitamin D supplementation comes in handy, especially during the winter months.
Vitamin D deficiency
So, now that you know how to get your daily dose of vitamin D, let's dig deeper into what vitamin D does, or rather, the effects that result from vitamin D deficiency.Low levels of vitamin D have been associated with heart disease, hypertension, heart failure and strokes in the research, and the same work looks at respiratory infection. In fact, that is one of the reasons the winter months get so much attention in vitamin D research, when sunlight, and the vitamin D it makes, is in short supply.
Vitamin D deficiency is also associated with an increased risk of type 1 and type 2 diabetes, arthritis, and autoimmune diseases such as inflammatory bowel disease. Studies have looked at vitamin D supplementation in people who have pre-diabetes, and the results there sound promising.
We're not done yet, it gets worse. A deficiency in vitamin D has been linked to an increased risk of developing several types of cancer.
Role in mental health
Furthermore, researchers have observed that many people that suffer from depression have low Vitamin D levels, although low Vitamin D levels are also in turn associated with lower outdoor activity and overall unhealthier lifestyles, making it hard to distinguish the correlation from the causation within the context of depression.That said, studies have looked at how vitamin D sits in the research on mood regulation and depression. A study featuring over 7,500 people looked at vitamin D supplementation and symptom measures in those who were experiencing negative moods and emotions.
I think we all intuitively know that being outside in the fresh air and sunlight lifts our mood, but the scientific explanation for that, or at least one of the main reasons, might be as simple as vitamin D.
When should I take vitamin D?
Vitamin D is best taken early in the day if possible, and as it is a fat-soluble vitamin, it is recommended to take it together with a meal that incorporates dietary fat, such as fatty fish or meat, dairy products, avocados, nuts or seeds, in order to maximize its absorption.
What does vitamin D combine well with?
Vitamin D with ox bile, taken together, for fat-soluble absorption
If you take ox bile, it belongs in the same sitting as vitamin D when the meal actually contains fat, because bile salts form the mixed micelles that carry vitamin D to the gut wall, facilitating its absorption.Vitamin D with Vitamin K, taken together, for bone and calcium handling
Vitamin D and vitamin K are taken together because between them they cover bone and calcium handling, with each one carrying a different part of that job. As mentioned earlier in this article, vitamin D and vitamin K work together as a team to ensure calcium is distributed correctly throughout the body.One of vitamin D's primary functions is to ensure that your blood has adequate levels of calcium, while vitamin K promotes the accumulation of calcium in your bones (and not elsewhere), which is why a supplemental combination of vitamin D and vitamin K is a familiar pairing in bone-health supplements.
Vitamin D with boron, taken together, for bone and calcium handling
Vitamin D does the absorbing and boron does the retaining: vitamin D raises calcium uptake from your gut, and boron has been studied for reducing how much calcium and magnesium leave your body in urine. A bone and calcium routine carrying both is taking one nutrient for each half of that job, and the two can share a meal because both are fat-soluble-friendly.What else pairs well with vitamin D?
Also taken with omega-3, for cardiovascular health
As vitamin D is best taken along with a meal that includes high-fat foods, it is a common habit to combine it together with your omega-3 supplement of choice, such as fish oil or krill oil, if you are taking any.Furthermore, combined supplementation of vitamin D with omega-3 fatty acids has been studied against insulin levels, inflammation and HDL "good" cholesterol levels.
Also taken with magnesium, for bone, muscle & cognitive health
Magnesium is also known to combine well with vitamin D, and for a variety of reasons. The primary reason is that the enzymes that are responsible for metabolizing vitamin D all require a certain amount of magnesium to work.In other words, if you don't have enough magnesium in your body, you will not be able to make the most of any vitamin D supplement. In fact, magnesium deficiency can result in insufficient levels of vitamin D, which may result in low intestinal calcium absorption, and lead to brittle bones, an increased risk of fracture, and increased risk of developing osteoporosis.
In addition to this, taking magnesium with vitamin D matters for muscle health, as both are involved in regulating normal muscle function. Specifically, vitamin D helps regulate muscle contraction, while magnesium helps regulate muscle relaxation.
The combination of magnesium and vitamin D is also known to promote neurotransmitter production, which helps regulate mood. Studies show that depression during adolescence could be caused by vitamin D deficiency for this precise reason.
Also taken with zinc, for increased absorption
Another mineral that combines well with vitamin D is zinc, as they share a synergistic relationship. Specifically, zinc is known to enhance the activity of vitamin D, while vitamin D is known to influence zinc's absorption, but with the benefit of not needing to take both at the same time.Also taken with ubiquinol
Research also looks at combining vitamin D with CoQ10, which you may also know as ubiquinol. Some studies look at this combination for supporting cardiovascular health and kidney health, and one animal study in rats with raised blood pressure reported synergy between both components, especially in regards to their antioxidant properties.Also taken with ubiquinol, astaxanthin and vitamin B12
Another study suggests that supplementing ubiquinol and vitamin D together with astaxanthin and vitamin B12 is studied for energy levels, physical endurance and muscle health. This is especially relevant for those who are on a diet that is low in vitamin B12, such as people following vegan or vegetarian diets.Also taken with quercetin, for cell-function research
Some studies have looked at vitamin D and quercetin together, and at their effect on how cancer cells divide.Also taken with olive leaf extract, for blood pressure and immune system
Taken together, vitamin D and olive leaf extract cover bone health, immune system and blood pressure, so the two are usually kept side by side, each for its own share of the purpose.Also taken with fish oil or krill oil, for heart health
Vitamin D and fish oil are paired for heart health and bone health, with each one carrying its own half of the purpose, and the same applies to krill oil, which also brings with it the added astaxanthin benefit mentioned earlier.What should I avoid taking vitamin D with?
Avoid taking vitamin D at the same time as calcium
These two can share the day, though not the same time slot: keep a few hours between them so the calcium load stays a reasonable size. While it is known that one of vitamin D's main functions involves assisting in the absorption and distribution of calcium, it is not necessary to take them at the same time, and in fact one study reported an increased risk of stroke when vitamin D and calcium are taken together in supplemental doses.While these two supplements are often recommended to be taken together, and some supplement formulations even combine the two, taking high doses of both can lead to a condition known as hypercalcemia, which means that there is too much calcium in the blood.
In addition to cardiovascular issues, and the risk of calcium being deposited in the artery walls, this condition can also increase the risk of kidney stones.
So, in order to avoid any potential interaction, it would be advisable to take your calcium and vitamin D supplements separate, at least two hours apart.
What are natural sources of vitamin D?
If you are interested in obtaining your daily vitamin D through your diet, you can often find it in:
Only a few select foods, such as the flesh of fatty fish, or certain species of mushrooms that have been exposed to UV light, naturally contain anything above trace amounts of vitamin D, and dietary intake is estimated to account for roughly only 10% of a person's total Vitamin D intake. We must get the vast majority of our Vitamin D through sunlight exposure, or alternatively, via supplementation.
Who should avoid taking vitamin D?
Before taking vitamin D supplements, check with your trusted healthcare professional if any of the following apply to you:
- Granulomatous disease
- Hypercalcemia
- Kidney stones
High calcium and kidney stones
Vitamin D raises calcium absorption, so a granulomatous disease such as sarcoidosis, a previous high calcium result, or a history of calcium kidney stones are the situations where a standard dose can cause an overshoot.Remember to always discuss any vitamins or supplements with your trusted healthcare professional if you are suffering from any health conditions.
Possible side effects of vitamin D
Possible side effects from taking vitamin D supplements may include (but are not limited to) the following:
- Nausea
- Vomiting
- Muscle weakness
- Dehydration (excess)
If you are experiencing negative side effects from taking vitamin D supplements, stop taking them immediately and reach out to your trusted healthcare professional.
Drug interactions with vitamin D
The medicines listed below are the ones most often named in interaction reports for vitamin D, but it is by no means a comprehensive list:
- Corticosteroids
- Digoxin
- Diuretics
- Orlistat
If you are taking any prescription drugs or medication, check with your trusted healthcare professional before taking vitamin D supplements.
Can I take vitamin D while pregnant or breastfeeding?
Vitamin D is needed for your baby's skeleton, and 600 IU a day is the standard pregnancy amount, with low levels linked to neonatal hypocalcemia and rickets. Plenty of us enter pregnancy with a low level, particularly in winter, which is why the level gets checked rather than assumed.
Remember to always discuss any vitamins or supplements with your trusted healthcare professional while pregnant or breastfeeding, or while attempting to conceive.
What are deficiency symptoms of vitamin D?
Possible signs of vitamin D deficiency may include (but are not limited to) the following:
- Bone pain
- Muscle weakness
- Rickets in children
Bone pain, proximal muscle weakness, and in children bowed legs are the hard signs. Dosing still belongs with a result and a trusted clinician.
If you are experiencing abnormal symptoms, reach out to your trusted healthcare professional as soon as possible.
Where should I store vitamin D?
For optimal shelf life, it is recommended to keep vitamin D supplements stored in the cupboard. Always make sure the bottle or container is tightly closed, and kept away from sources of light, heat and humidity.
Vitamin D data sources & further reading
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