CardiAction Vitamin D Test

As with all nutrients, our bodies need vitamin D from the environment (through food or sunlight in this case) to function properly. Vitamin D has a particularly important role in bone health by helping with calcium absorption. This is a very clear relationship as its classic deficiency symptoms are diseases of “soft bones” – rickets in children and osteoporosis and fractures in adults (Bilke DD, 2014). However, with the discovery of vitamin D receptors in virtually every type of cell in the body (Pludowski et al. 2018), we have found that vitamin D affects many other parts of the body, like the immune system (Ginde 2009) and the cardiovascular system (Michaelsson et al. 2010). This combination of health benefits may be why several studies have found that those with higher vitamin D blood levels live better for longer (Garland et al. 2014). So, we need vitamin D to build and keep our bones strong, but also to help the rest of our body work like it should.

Vitamin D3 is the primary raw material to make active and usable vitamin D. It is produced when the body is exposed to sunlight (ultraviolet B radiation sunlight). Our bodies are amazingly efficient when it comes to producing vitamin D3; brief sunlight exposure of the arms and face will enable our body to produce 200 international units (IU) of vitamin D3. The precise amount of vitamin D3 produced will vary depending on factors such as skin type, geographical location, season, and time of the day. Vitamin D can also come from our diet but there are very few foods in nature that contain it. The best sources of Vitamin D in nature are fatty fish like salmon, tuna, mackerel, as well as cheese, mushrooms, apples, egg yolks, sardines and fortified foods. Finally, supplements are a potent source of Vitamin D and raise blood levels effectively.

It depends! OmegaQuant recommend aiming for a Vitamin D blood level >30 ng/mL, but that can be achieved in several ways. Some people may be able to reach this level through exposure to the sun, while some may achieve it through a high-fish diet and fortified foods, and others may take a supplement. Still, most will need a combination of two or three of these. If you go the supplement route, the US Institute of Medicine recommends taking no more than 4000 IU per day on average, but, beyond that, how much supplemental vitamin D you should take depends on your blood level.

The best way to know what you need to do to maintain a desirable blood level of vitamin D is to test regularly and change your habits accordingly. There is a seasonal variability in blood levels depending on your latitude, so your levels could drop during the darkest part of the year and you might want to supplement during that time. On the other hand, during the summer you might get enough through vitamin D through sun exposure and not need any supplemental vitamin D.

There is not yet an agreed upon “optimal” Vitamin D level in the scientific community. This mostly comes from a disagreement on “deficiency” (Taylor C, et al. 2018) vs “optimal” blood levels (Holick MF. 2017) and what endpoint is being considered, i.e. bone health vs. infection risk. OmegaQuant we recommend aiming for a level of at least 30 ng/mL. The evidence for the 30 ng/mL cut off is demonstrated by Garland et al. 2014 where the hazard ratio for mortality plateaus around 30 ng/mL, by Michaelsson et al. 2010 where the lowest risk for death from all-causes, cancer and cardiovascular disease is at 30 ng/mL, by Ginde et al. 2009 where those with levels >30 ng/mL have the lowest risk of upper respiratory tract infections, and by Miliku et al. 2016 where pregnant women with levels >30 ng/mL were at the lowest risk of preterm birth, as well as babies born with low birth weight and small for gestational age. This seems like an excellent target level for several different populations and health states.

You may notice that none of these outcomes are related to bone health (rickets in kids and osteoporosis/hip fracture risk in adults), the primary health outcome related to a deficiency in Vitamin D. For this endpoint, according to the Institute of Medicine, a serum level of >20 ng/mL is considered sufficient and <12.5 ng/mL is deficient. From OmegaQuant’s perspective, optimal vitamin D levels are considered more from a “whole health” perspective rather than specific to bone health, thus the higher target of at least 30 ng/mL.

You can take a Vitamin D test at any time. This test is a long-term stable view of your Vitamin D intake and will not be affected by any short-term dietary or supplementary changes. A test will simply tell you if your diet is delivering enough Vitamin D to maintain an optimal level.

The cost of a Vitamin D test is $79. This includes a collection kit, a replied paid envelope to send your blood spot, a detailed report of your results and access to the CardiAction app. Your results will include your Vitamin D level along with suggestions of how to get to an optimal level.

Item descriptYes! Even those who live in sunnier climates and/or take Vitamin D still might be falling short, because there are so many individual factors that can affect your blood level. In New Zealand, the amount of sunlight each part of the country receives varies considerably. If you live in the South Island you are much more likely to be insufficient in Vitamin D.

The only way to truly know if your diet or environment is delivering what you need is to take a test. https://www.osteoporosis.foundation/educational-hub/topic/vitamin-d

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Spending time outside in the sun may not improve your blood levels as individual factors such as genetics can affect how well you manufacture and respond to Vitamin D. While some genetic combinations are more beneficial in the Vitamin D response, others may not respond as favourably and require targeted lifestyle choices to increase Vitamin D levels.

For example, individuals of Maori and Pasifika descent tend to have a less favourable Vitamin D receptor. This can lead to an inefficient response to Vitamin D and may contribute to inflammation.