Vitamin D is linked to so many vital processes, including calcium absorption, that it acts more like a hormone than a vitamin.

Osteoporosis has many links besides low vitamin D levels - calcium dominance due to magnesium deficiency as well as boron & vitamin K2 deficiencies + estrogen in menopausal women.

The most interesting stat I have seen recently is most cancer patients test low in vitamin D (10-40 ng/mL) & recommendation of supplementation to increase levels up to 60+.

I agree with Jacquie, I remember speaking to a large group in Michigan about nutrition and living longer when a nurse came up to me after my talk and said how glad she was that I brought up Vitamin D. She sees patients every day whose Vitamin D levels are so low that now they automatically prescribe it.

Vitamin K2 is another vitamin that many people end up lacking, especially in women who are going through or have gone through menopause. I started taking it when I noticed that I had restless leg syndrome - it was gone after taking Vitamin K2.

As a Nutritionist, I recommend taking both supplements from a reputable supplier and always follow label directions for recommended dosage.

Agreed with Jacquie & Sherry.

As a holistic nutritionist and natural health practitioner my recommendation is always go with the natural source first - sunshine & food rich in Vit D like salmon/fatty fish or shiitake mushroom. 15 min sunshine a day is good enough and you can easily get it from a brief walk or with the window down and let the sun ray shine on your hand during driving (many people worry about UV - if one eat a good diet with much antioxidants like colorful veggies and fruit, the body can take care of the free radicals).

That said,, when we age, and due to constraints from lifestyle (e.g. always stay indoor, short day light time in Winter, anemic, etc.), it's wise to take Vit D supplement for many good reasons. Do some math though - if you eat fortified cereal, milk, orange juice, etc. then beware of over-dosage.

Echoing Sherry's feedback, since there's no regulation in the industry, we need to buy any supplement from reputable companies (you can find supplements in Dollarama!),

You're right Carla - all make-up these days has sunscreen in it as well as most daily moisturizers. On sunny days, if time permits, I make a point of getting outside without make-up or sunscreen on for 15 minutes, but that is not always possible. Glad you are able to make the adjustments!!

Here there is the link to an interesting article in which authors published results of a clinical trial designed to obtain, for the first time, evidence-based recommendations on the efficacy of vitamin D3 supplementation, a safe, non-costly therapeutic strategy, in improving physical performance, decreasing fatigue and increasing HRQoL in patients with advanced cancer in palliative care

https://bmjopen.bmj.com/content/4/12/e006128

Thank you all for your input about Vit D. I thought I was getting enough by being outside for 15 minutes but once I realized that sunscreen was reducing my absorption I adjusted things to get the Vit D I need.

Well, It depends on a variety of factors.
Environmental factor. People living in place that encounter 4 seasons or at extreme latitude might need to increase their vitamin D intake during the autumn/ winter as sun exposure is less. Moreover people tend to use more protective clothes during winter time which further decrease the total exposure surface of the skin towards sun light decreasing the amount of vitamin D.  
Lifestyle such as usage of sunblock, indoor activity or any related lifestyle that reduces the sun exposure might need oral intake of vitamin to meet the daily requirement. Diet also play a vital role. Cultural diet does influence one bone density and also basal vitamin D intake. Just like what Colin Johanson has commented. Scandinavians who live in a higher latitude with low sun light exposure during winter month but poses higher bone mass density due to higher vitamin D intake from oily fish consumption as their cultural staple food. Besides, i believe that Scandinavian diet which are high in Dill, thyme and various herbs that aid in vitamin D metabolism and bone health.
Biological factors. People who are have darker skin usually need more vitamin D compare to others because they produce a higher amount of melanin which reduces the amount of sun light to reach the lower dermis needed for vitamin D production. Not only age, sex, body predisposition and past medical history does influences the amount of vitamin D needed for our body and also production of vitamin D. For example, younger patient especially during growth spur period need more vitamin D to support the rapid growth acceleration curve. Elderly patient might need more vitamin D intake because of less vitamin D production from the skin due to natural physiological skin aging atrophy. Female might need more in vitamin D because they might spent more time indoor or biologically, their bone mass is lower than man and poses a higher bone mass loss post-menopausal. Furthermore, they might exert less weight bearing activity though out their life thus more vitamin D might be needed to prevent bone loss. Lastly, pregnancy and lactation both biological process that increase the vitamin D requirement. Studies have been suggesting that patient with a higher BMI value tend to lack of vitamin D. Patient with kidney disease/ nephropathy might need more vitamin D as they body are unable to activate Vitamin D effectively. Patient with Diabetes Mellitus, Cardiovascular diseases and Depression might need more vitamin D because studies have linked that these disease might be attributed/ related to Vitamin D deficiency.
Regarding taking vitamin D supplement of consuming natural food with high concentration of vitamin D. I would strongly suggest to consume natural food with high concentration of vitamin D such as Oily fishes (salmon,tuna…), Oyster, Egg yolk, Liver, Cheese, For vegen, one might opt for fortified cereals. The reason I prefer natural food over Vitamin D supplement is due to the reason that
1.      Vitamin D is a fat soluble vitamin in which consuming it with fatty acid from food will enhance their absorption compare to supplements capsules.
2.      Since it is a fat soluble vitamin where it can store in the body for a longer period, supplements usually come with mega dose. This increase the predisposition of vitamin D toxicity.
3.      Consuming food high in vitamin D contain other healthy substances such as vitamins, minerals, antioxidants that all that works in unison to promote good skeletal health.
However, some people might prefer supplement because they might need a higher dose of vitamin D in one go or they might have limited food choice such as vegetarian or a lifestyle that does not permit a variety of food selection.
In a nut shell, To vitamin D or not to Vitamin D depends on a variety of factors.

Great information Lawrence!!

I agree with much of what has been said. Vitamin d3 supplementation is vital, how much depending on where you live. Stress is such a common factor in the body breaking down in many ways and one of the many benefits is it reducing the stress levels that contribute greatly.

I've read some new studies also that darker colored skin may not be letting in Vit d and causing many issues with mood, so that group may need even more supplementation.

Nancy

Vitamin D

Over used, over prescribed and predicated on fearful marketing. Go outside, use a sunscreen and WALK. 

Where I live access to sun isn't an option many months of the year, especially to get the needed D you need to be able to expose more of your body. We have had numerous amazing results supplementing, as most people where I live are very low, lethargic, depressed, SADD, the the D turns it around.