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| Spring in the mountains |
Who is at risk of low vitamin D?
- Children born to mums with low level of vitamin D.
- People with darker skin tones – pigment melanin stops UVB rays penetrating the skin and this is needed to make vitamin D.
- People who avoid sun exposure or those who do not have time to get outdoors often enough.
- People who do spend enough time outdoors but
- cover up their skin with UV filters, also found in most ‘anti-ageing’ moisturisers and make-up
- cover up most of skin with clothes
- after each sunbathing wash most of their skin with soap
- usually wear sunglasses – it is thought that there is some connection between light frequency signal in the eye and formation of vitamin D
- People with an excess weight. Fat cells can soak up the fat-soluble vitamins and keep them locked, while there is less available in blood stream.
- People with absorption problems such as those with Coeliac or Crohn’s disease, cystic fibrosis and also during long term stress, which lowers excretion of digestive juices including bile, crucial for fat emulsification.
- People with kidney disease have problem to convert inactive D from food or supplements to active form.
- The most extreme form is rickets, softening of bones. It is known mostly as malnutrition disease from the past but in recent decades we can see rickets returning and number of cases rising. Although vitamin D is the main missing vitamin, forming of healthy bones also depends on other nutrients such as another fat-soluble vitamin K2, minerals in food, mainly magnesium, silica, boron and organic forms of calcium.
- Immune system malfunction – from frequent colds and flu, asthma, eczema, to autoimmune diseases such as arthritis and multiple sclerosis and even cancer.
- Osteoporosis and osteopenia – vitamin D is known to help absorption and processing of minerals such as magnesium and calcium, important for bone building.
- Low vitamin D is a risk factor in heart disease and diabetes. Also, there is a connection with low thyroid hormones – vitamin D is more hormone-like substance and any low hormone can skew up the rest of hormonal balance.
Vitamin D as immune balance regulator
A 2010 study on 400 school age children has shown that those who took 1200 IU of vitamin D3 during the flu season (December-March) had 42% less cases of flu virus (8).
In 1994 study 20,000 people were followed during 6-year period and respiratory problems (such as cough and cold) were observed. It was found that low level of vitamin D in blood correlated with more respiratory problems. 24% of people with level of 25(OH)D below 10ng/ml had respiratory infections, while those with level of from 10-30ng/ml had respiratory infections in 20% cases and those above 30ng/ml had problems only in 17% of cases. It would be interesting to see, if even higher level of 25(OH)D would manage prevent infection even further.
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If the amount of one type of T-helper cell increases, the amount of other type automatically drops. Examples of situations when Th1 are called upon are during fighting off intracellular bacteria, mycotoxins or cancer cells. Th2 fight bacteria and parasites outside of cells and in the blood stream.
If Th2 become too active, this results in increased allergic reactions, asthma, eczema and systemic autoimmune diseases. Other side of immune swing - Th1 – drops in amount and this can cause less active natural killer (NK) cells, resulting in increased risk of infection in the internal cell environment (bacterial, viral, fungal).
If Th1 become too active, the result is autoimmunity of specific tissues (rheumatoid arthritis, multiple sclerosis, thyroid autoimmunity, Crohn’s disease, psoriasis, lupus...). However, these are often situations which can have paradoxically dominant Th2. Therefore it is important to communicate with doctors and request special tests for various types of lymphocytes. This can be very helpful in choosing the right diet, as there are some common foods and herbs which are known to support only one side of immune balance (i.e. Echinacea, green tea, quercetin).
In contrast with some other nutrients, vitamin D can balance Th1/Th2 depending on actual needs and it does not specifically support one side of immunity only. This way it has ability to influence many health problems.
What to look at when reading vitamin D tests
1. Units used – several types
· nmol/l
· ug/l (can be written as mcg/l)
· ng/ml ( ug/l = ng/ml )
· pg/ml a pmol/l – used for 1,25(OH)2D
2. Forms of vitamin D
· D2 (ergocalciferol)
· D3 (cholecalciferol)
· D2 + D3 = total D
D3 – is made from cholesterol in the skin on exposure to sunlight. This is an active form of the vitamin. Tests for total D give us useful information about serious deficiency but they do not tell us exactly how much of usable form of vitamin we have and if we already reached the optimum level.
· 25 hydroxyvitamin D - 25(OH)D
· 1,25- dihydroxyvitamin D - 1,25(OH)2D
25(OH)D is a form of vitamin D considered most accurate for testing in majority of people. Exceptions are blood samples of people with osteoporosis – they do not seem to convert enough D to 1,25(OH)2D form. It is thought this is due to deficiency in magnesium and boron. Their test can therefore show as false negative for existing deficiency.
1,25(OH)2D is a part of active form with very short half-life of only 14 hours. This amount can artificially increase in case of very low level of D – when activation of PTH (parathyroid hormone) happens and rises conversion 25(OH)D to 1,25(OH)2D.
3. Values for deficiency, normal and optimum
TOTAL 25(OH)D – differences in literature
nmol/l
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ug/l = ng/ml | |
Deficiency
(4)
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<50 nmol/l
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<20 ng/ml
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Deficiency (3)
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<63 nmol/l
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<25 ng/ml
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Normal (4)
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>50 nmol/l
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>20 ng/ml
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Normal (3)
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>63 nmol/l
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>25 ng/ml
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Normal (2)
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97-250 mmol/l
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39-100 ng/ml
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Optimum (1)
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>75 nmol/l
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>30 ng/ml
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Optimum (3)
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80-120 mmol/l
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32-48 ng/ml
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Optimum (2)
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175-250 mmol/l
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70-100 ng/ml
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TOTAL 25(OH)D - table by Nutri (6)
nmol/l
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ug/l = ng/ml | |
Deficiency
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<50 nmol/l
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<20 ng/ml
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Below normal
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52-72 nmol/l
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21-29 ng/ml
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Optimum
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75-150 nmol/l
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20-60 ng/ml
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Toxic
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>374 nmol/l
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>150 ng/ml
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Reference tables for D3 are not available as each laboratory has its own ranges which they consider normal.
Why there are such large differences in recommended values?
Many recommended values for vitamin D (both daily intake and blood levels) were taken from historical information based on the lowest amount of vitamin needed to prevent the most serious symptom – rickets.
It is now known that vitamin D functions in more similar way to our hormones, rather than the vitamins. It helps to keep immune balance, mineral absorption balance and can also directly interfere with our genes. Optimal levels of cholecalciferol (D3) were shown to reduce risk of cardiovascular diseases, diabetes, osteoporosis and cancer.
It is becoming more widely accepted today that rickets is not the only problem caused by low blood levels of vitamin D and therefore the recommended values have been accordingly adjusted by some medical establishments around the world but not by all.
It is also important to realise that ‘normal’ values just mean prevention of known illnesses but ’optimal’ values can actually mean more than just prevention. Absence of symptoms does not necessarily mean that our health is optimal. Many problems develop slowly over the years, such as in cases o many cancers, where it can take decades for any symptoms to show up.
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| Sunset near Ullapool |
As I mentioned before, vitamin D is known to act more like a hormone rather than a vitamin. Too much of hormonal action is not always the best but once depleted, it is very hard to get the levels up.
The best source of vitamin D is sunlight on the skin, which should not be covered by clothes or skin products with UV filters. Formation of D in this way is self-regulating and body stops producing it when there is enough. We also need to have sufficient levels of cholesterol and sulphur in our skin to produce vitamin D from light. About 20-30 minutes daily over the Summer months is enough for most people. For the Winter months and for people living in colder darker regions of the world, the nature offered sources of D in form of fish liver (we polluted it to the extreme its not completely safe any more) and animal foods such as butter, meat and eggs. However, if the animals are farmed and kept inside, the amount of D they produce may not be sufficient.
Supplements
D3 – cholecalciferol (not D2 - ergocalciferol) is direct active form. The best form is sublingual spray, tablets or drops as these are not affected by absorption in digestive tract and get into the blood by absorption through the mucosa of the mouth. If taking ordinary tablets, it is important to have them with food which contains some fat.
Amount needed is individual and depends on existing blood levels, personal risk factors, time of the year and climate. Therapeutic levels need to be taken along with other nutrients. Vitamin D will increase absorption of minerals such as calcium, and this may not be desirable in some case. Always test and speak to an experienced health professional.
SOURCES
1. http://www.powerofvitamind.com/diagnosis_of_vitamin_d_deficiency.html
2. J.E.Williams, K.Gianni - How to Read Your Blood Tests. Renegadehealth.com (2010)
3. Nutri Clinical Application Series (2011) Immune System Balance / Lecture Notes
4. http://www.vitamindtest.org.uk/vitamindbackground.html
5. http://emedicine.medscape.com/article/2088672-overview
6. Nutris Guide to Vitamin D Range – Clinical Guide Series
8. Urashima, M et al (2010) Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren, American Society for Nutrition.
9. Ginde AA, Marshbach JM, Camargo CA (2009) Association Between Serum 25-Hydroxyvitamin D Level and Upper Respiratory Tract Infection in the Third National Health and Nutrition Examination Survey Arch Intern Med. 2009;169(4):384-390
