Vitamin D – The Sunshine Vitamin

Vitamin D, often called the „sunshine vitamin", plays an important part in our health, particularly in bone metabolism and the immune system. It is one of the vitamins our body can make itself with the help of the sun. Interestingly, vitamin D is classed as a vitamin but, judging by what it does, is really more of a hormone — and it is vital to us. Vitamin K2, calcium, magnesium and boron all play a very important part alongside it, which is why this article also looks at how these five vital nutrients work together.

There are several vitamin D compounds, and our body absorbs some better than others.

There is vitamin D2 (ergocalciferol), formed in plants by UV radiation. And there is vitamin D3 (cholecalciferol), likewise formed by UV radiation but in our skin, or in the skin of animals, from a precursor of cholesterol into provitamin D3, and then converted into its active form in the liver (calcidiol) and the kidneys (calcitriol). These two hormones, formed in the liver and the kidneys, have very different effects.

Studies have shown that the D3 form is more effective than D2 at raising and maintaining the vitamin D level in the blood. D3 also stays active in the body longer than D2 and therefore needs to be taken less often. D3 is more stable as well, meaning it keeps longer in food supplements and fortified foods. For supplementation, D3 is therefore the form to prefer.

Lichens can produce the D3 form too, incidentally. Many D3 supplements are lichen-based and so manage without animal ingredients such as fish oil or lanolin from sheep's wool.

There are also the forms D1, D4 and D5, which are made artificially and are often added to food. D2 can be made artificially as well.

Vitamin D in bone metabolism

Vitamin D supports the absorption of vitamin A, calcium and phosphorus, all of which are essential for healthy bones and teeth.

One of vitamin D's key tasks is therefore to maintain a healthy calcium and phosphate balance in our blood.

When our need for calcium rises, vitamin D can regulate in three ways:

• by increasing calcium absorption in the gut
• by increasing how much calcium the kidney takes back up
• and by mobilising calcium from the bones and teeth

Vitamin D also stimulates bone formation by activating the bone-building cells. That already shows how closely calcium and vitamin D work together.

Enough vitamin D means healthy calcium absorption in the gut and works in favour of bone mineralisation. In short, vitamin D channels calcium into the bones and firms them up that way. Where calcium is lacking, it is drawn out of the bones and they become porous.

How vitamin D affects our immune system

Vitamin D matters a great deal to our immune system too. It stimulates the formation and maturing of immune cells and thereby prevents frequent infections. Studies show that people with adequate vitamin D levels (60–90 nmol/l) get noticeably fewer infections than those with a deficiency, and that daily supplementation is more effective than occasional high doses.

Vitamin D and its part in inflammation

Vitamin D plays an important part in regulating inflammatory processes in the body. Scientific research has shown that a vitamin D deficiency leads to raised markers of inflammation, while improving the vitamin D level can reduce the risk and the severity of chronic conditions with an inflammatory component. Vitamin D inhibits the production of pro-inflammatory cytokines such as interleukin-12 while encouraging the formation of anti-inflammatory ones such as interleukin-10. This anti-inflammatory effect reduces inflammatory molecules in the body and activates defence cells, which can matter particularly where inflammation is chronic.

Vitamin D and blood pressure

Vitamin D also plays an important part in regulating blood pressure. According to studies, a vitamin D deficiency is associated with a raised risk of high blood pressure, while an adequate supply can have a positive effect on it. The blood-pressure-lowering effect is put down partly to vitamin D inhibiting the activity of messengers such as angiotensin II, which contribute to narrowing the vessels. Where blood pressure is high, it is therefore worth checking vitamin D status and, if need be, improving it through supplementation in consultation with a doctor.

What else vitamin D does in our body

Vitamin D is involved in countless metabolic processes as well and is responsible for regulating the expression of hundreds of genes.

The cancer-inhibiting effect of vitamin D counteracts an unchecked rate of cell division, something many studies have observed particularly in bowel cancer.

An adequate amount of vitamin D can moreover

• improve fertility
• protect pregnancy
• help with weight control
• prevent stroke and dementia
• boost memory and mental performance
• support muscle strength
• support hormonal balance
• reduce oxidative stress in the body
• bring better sleep, and much more.

In childhood, a vitamin D deficiency leads to rickets, for example. That is the picture of inadequate bone growth, inadequate bone mineralisation and delayed tooth development, caused by too little calcium reaching the body. Symptoms are deformities of the spine and skeletal muscles and a greater tendency to break bones.

In adults a vitamin D deficiency can lead to decalcification of the skeleton, osteoporosis (loss of bone), to bone pain and to a raised risk of fractures.

A deficiency affects the muscles too. It brings twitching, trembling, vibrating, cramping and pain, as well as muscle weakness. What is simply missing here, because of the vitamin D deficiency, is calcium (hypocalcaemia).

A loss of energy, weakness, chronic exhaustion, low spirits, listlessness and fatigue syndrome can often be caused by a vitamin D deficiency as well.

The nervous system can be affected too. A disturbed nervous system can cause sleep problems, constant tiredness, a high need for sleep, inner restlessness, trouble concentrating, headaches, coordination problems and changes in behaviour.

Our nerves need an electrical charge, and calcium ions are among the things that charge depends on. Activating nerve cells, just like activating muscle fibres, depends on calcium. Because the charge is missing when calcium is short as a result of a vitamin D deficiency, performance drops right across the nervous system.

This is a very, very important point for our health and wellbeing generally. Our body runs on electrical charge. When the vital nutrients needed to build that charge are present in too small an amount, communication in the body breaks down and illness follows. Put the other way round: a sufficiently high electrical charge in the body means health and vitality.

Feeling cold, particularly in the arms, hands, legs and feet, along with circulation problems, can likewise be a sign of a vitamin D deficiency. Here too the charge for the flow of energy is missing. That can also lead to persistent headaches.

It is easy enough to see: where vitamin D is missing, calcium is missing too. Even if we take in enough calcium, the body cannot make proper use of it when vitamin D is short.

Another classic sign of deficiency is a greater tendency to infection. The risk of colds affecting the upper airways then rises by a full 40%, for instance.

Mood swings and anxiety can be signs of a vitamin D deficiency as well. Some studies suggest that a low vitamin D level is linked to a raised risk of depression and anxiety disorders. Those affected may experience unexplained mood swings, irritability or heightened anxiousness.

A vitamin D deficiency also correlates with cardiovascular disease, with diabetes and autoimmune conditions, with various kinds of cancer, arteriosclerosis, with chronic inflammation, with psoriasis, with rheumatoid arthritis and neurological disease, and with raised mortality.

The greater part of the German population, whatever their diet, does not reach the recommended vitamin D intake and is undersupplied, especially in the winter months.

As already hinted, our body is able to make vitamin D itself with the help of sunlight. Sunbathing for about 15 to 20 minutes several times a week is enough for a good supply. It is not enough to let the sun reach your face alone, though — the arms and legs should be included at least. For it to work, the UV-B radiation has to be strong enough to set the synthesis going in the body. At our latitudes in northern Europe that is not possible all year round, because of the seasons and air pollution. In winter the atmosphere filters the radiation out very heavily. An adequate supply in the months from October to March is not possible here.

Nor can vitamin D be stored for weeks or months at a time. Incidentally, sun creams and skin creams with a sun protection factor inhibit the formation of vitamin D. A protection factor of 10 already lowers vitamin D production by 95%. So sunbathe without sun cream or other protection factors. Older people, people who are very overweight and people with darker skin are less able to form vitamin D and are affected by a deficiency more often still.

Hormonal changes in the body during the menopause and in pregnancy can also lead to a vitamin D deficiency. Liver disease can bowel disease such as Crohn's and kidney disease can encourage a deficiency too.

Vitamin D can of course also be taken in to a certain degree through animal products, particularly by eating fish. Fish today, though, is heavily contaminated with toxins, microplastics and heavy metals. Eating it would mean taking those toxins into our body and storing them there.

According to the German Nutrition Society, the need for vitamin D is 20 micrograms (800 IU) a day. That is a figure which might just avoid a deficiency disease. In illness, or in older people, this dose will tend to be too low.

Because it is difficult to cover the need for vitamin D naturally outside the summer months, a vitamin D3 supplement is worth taking. A D3 preparation from a plant source would be best. As mentioned, these are mostly obtained from lichens and have good bioavailability. D2 supplements of plant origin unfortunately have lower bioavailability.

Let us look at the vitamin D level in the blood as well. Across the year, without a vitamin D supplement, we reach an average level of 16 nanograms/ml — lower in winter, somewhat higher in summer. Values below 20 ng/ml can already cause complaints.

The optimal vitamin D level in the blood is 50–90 ng/ml. The recommended upper limit is 100 ng/ml. Deficient values are 30 ng/ml and below, and anything under 12 ng/ml is an extreme deficiency.

Dosing vitamin D

The dose in vitamin D supplements is usually given in IU (international units), rarely in micrograms. One microgram corresponds to 40 IU.

The German Nutrition Society's recommendation for vitamin D

The German Nutrition Society gives the following recommendation for vitamin D:

infants (0 to under 12 months): 400 IU a day

children (1 to under 15 years): 800 IU a day

adolescents and adults (15 to under 65 years): 800 IU a day

adults from 65 years: 800 IU a day

pregnant women: 800 IU a day

breastfeeding women: 800 IU a day

Source: German Nutrition Society

Recommended vitamin D dosage in orthomolecular medicine

The experts of orthomolecular medicine, who rely on high-dose vital nutrients to prevent and treat illness, give the following recommendation for vitamin D supplementation.

babies up to their first birthday: 400 IU a day

children from their first birthday: 1,000 IU a day

adolescents, per 12 kg of body weight: 1,000 IU a day at a body weight of 70 kg

adults, by body weight: 2,000–5,000 IU a day (depending on body weight)

pregnant and breastfeeding women: 4,000 – 6,000 IU a day

It is worth knowing that the vitamin D level builds up relatively slowly, even with supplementation. Where there is a severe deficiency, the dose should therefore be adjusted together with a therapist and with regular blood checks, so that the level can be built up faster. With vitamin D there is really no blanket recommendation. It is so individual, because the dose also depends on other cofactors. So if you have your vitamin D level measured, do please have calcium, magnesium, K2 and boron measured as well. That way your doctor can see whether the other nutrients that matter here should be supplemented too, for vitamin D supplementation to work properly.

Where there is a deficiency, supplementation should happen in two phases: a filling phase and a maintenance phase. In the filling phase the vitamin D store is refilled, and that calls for a higher dose over a certain period, depending on the deficiency. Once the desired blood level is reached, the maintenance phase begins: the dose is turned down to the point where the level reached can be held over the long term.

In a groundbreaking large study on vitamin D by the University of California, the University of San Diego School of Medicine and the Creighton University School of Medicine in Omaha, even a long-running daily intake of 10,000 IU (250 micrograms) a day produced no toxic effect. The study concluded that a blood level of up to 150 ng/ml should rather be regarded as an optimal supply. If you plan to supplement vitamin D at a higher dose, please seek advice from a therapist.

If you would like to read up in more detail on dosing vitamin D and other vital nutrients, I recommend the two books by Dr Helena Orfanos-Boeckel: Nährstoff-Therapie - Orthomolekulare Medizin & Bioidentische Hormone and Nährstoff-Therapie - Der Praxisleitfaden.

Vitamin D supplements

Vitamin D3 preparations come as tablets, capsules and drops. In liquid form, often as oil drops, vitamin D tends to be absorbed faster and more efficiently, because it is already dissolved and can be taken up by the body directly. That can be particularly helpful for people with digestive problems.

Capsules, especially oil-filled ones, also have high bioavailability. The fat in the capsule helps with the uptake of fat-soluble vitamin D.

Tablets are a widespread and inexpensive option but may have somewhat lower bioavailability than liquid forms, since they first have to dissolve in the digestive tract.

Before you supplement vitamin D, it makes sense to have your blood level tested.

Signs of overdosing on vitamin D supplements

Vitamin D is a fat-soluble vitamin and can therefore be stored in the body. That also means an overdose is possible. Anything above a blood value of 150 ng/ml can be toxic.

Signs of poisoning can be deposits of calcium in the blood vessels, on the heart, in the kidneys and in the lungs. The risk of kidney stones and loss of kidney function rises.

Serious poisoning has been described in the literature above 300 ng/ml.

An oversupply of vitamin D from sunlight, incidentally, is not possible. Our body is an autonomous regulator and simply breaks the vitamin D it makes itself back down beyond a certain level.

Now, we still had vitamin K2 and calcium. Why look at those as well? Because vitamin D, vitamin K2 and calcium work together. That is why so many vitamin D supplements are combined with vitamin K2.

For using calcium and for activating the proteins that are formed, vitamin D depends on an important partner: vitamin K2.

Vitamin K2 makes sure the calcium taken in is transported and used correctly. It also activates important proteins such as matrix GLA protein and the peptide hormone osteocalcin.

Osteocalcin plays an important part in building new bone and makes sure the calcium taken in really does end up in the bones. Matrix GLA makes sure no calcium is deposited in organs or vessels, by binding it and carrying it away. Without vitamin K2 these two important proteins would stay inactive, and calcium would settle in the body as waste, leading to many kinds of illness.

Vitamin K2 is formed by bacteria in the gut. However, if we take a higher dose of vitamin D as a supplement, we also need a higher dose of vitamin K2, because more of it is then used up in activation. If you supplement calcium, you should certainly take vitamin D and vitamin K2 alongside it. A calcium deficiency arises mostly through a vitamin D deficiency. Supplementing calcium is therefore not necessary. If you do it anyway, then be sure to supplement vitamin D and vitamin K2 at the same time.

Vitamin K2 of course has other important functions in the body as well. Here, though, we are keeping to how it works with vitamin D and calcium.

Besides vitamin K2 and calcium, magnesium plays an important part alongside vitamin D. Magnesium is an essential cofactor for the enzymes that convert vitamin D into its active form. That process is called hydroxylation.

So if we want our body to convert the vitamin D3 it has taken in into calcidiol and calcitriol, we need magnesium. The enzymes vitamin D 25-hydroxylase and 1-alpha-hydroxylase, responsible for hydroxylating vitamin D in the liver and kidneys, depend on magnesium. Magnesium lets these enzymes work properly and so lets the body use vitamin D effectively. A magnesium deficiency can lead to inefficient vitamin D metabolism even when there is enough vitamin D.

Magnesium also helps regulate the calcium level in the blood and supports the mineralisation of the bones.

So what part does boron play? Boron can influence the activity of enzymes involved in converting vitamin D into its active forms, and so raises its bioavailability. Boron can also reduce the loss of calcium and magnesium through the urine.

Beyond that, it can influence the production of hormones such as oestrogen and testosterone, which in turn influence vitamin D metabolism and bone health. Natural sources of boron are nuts (almonds and walnuts, for example), dried fruit (raisins, prunes), avocados, berries and pulses. Boron preparations should only be taken after consulting a therapist.

Vitamin D supplements can interact with some medicines. If you take medicines, it is always advisable to discuss high-dose food supplements with your doctor. Vitamin D preparations can interact with the following medicines and groups of medicines, among others: diuretics, cardiac glycosides (such as digoxin), corticosteroids (such as prednisone), anticonvulsants (antiepileptics), cholestyramine, orlistat.