D for Deficiency

Recently, The Irish Times reported that nutritional rickets has once again been observed by dieticians in Irish maternity and paediatric hospitals after a long respite. Rickets is a deficiency disease that manifests in childhood if vitamin D is severely lacking. In the 1600s it was known as an illness that softened and deformed bones. In the 1800s it was treated with cod liver oil, which we now know is rich in vitamin D. But it was not until the 1930s that vitamin D deficiency was discovered as the cause of this debilitating condition. Dr Mary Flynn, chief specialist in public health nutrition at the Food Safety Authority of Ireland (FSAI), told The Irish Times that rickets is the tip of the iceberg in terms of actual nutritional deficiency and an advance warning of wider vitamin D deficiency in the population that might not be so severe. She also said that virtually every study where blood has been drawn to look at vitamin D status has found deficiency levels during the winter. So what is vitamin D? Why is it so important? How does it work? Why are we lacking in it? And what can we do about it? What is vitamin D? Described as a fat-soluble vitamin but technically not a vitamin, vitamin D is in a class of its own. It is a pro-hormone – a substance that can be converted into hormones in the body. The term 'vitamin D' is confusing, as anything with vitamin D activity tends to be covered by the description. According to the Vitamin D Council, vitamin D3 (cholecalciferol) is the only true vitamin D. It is made when UVB rays from the sun react with cholesterol in your bare skin (or wool, fur or feathers, if you have any). Why do we need D lovin'? Vitamin D3 is essential for bone formation and mineralisation, controlling calcium and phosphorous metabolism, and maintaining several organ systems. It also sports immunosuppressive functions and anti-tumour activities, maintains the blood-brain barrier, and regulates gene expression (where the magic begins…!). Current research has implicated vitamin D deficiency in the pathology of cancer, heart disease, stroke, high blood pressure, autoimmune diseases (e.g. MS), diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, influenza, periodontal disease, and more. Researchers have also found that people who live in sunny climes, where their skin makes oodles of D3, suffer less from chronic illnesses. How does it do what it does to you? Vitamin D3 converts to two hormones in the body: calcidiol and calcitriol. If Nature has her sunshine-y way, we make D3 in ample amounts. It flows to the liver, where it is metabolised into calcidiol, or 25(OH)D. Calcidiol is the storage form of vitamin D; it fills up your vitamin D tank. Calcidiol then follows one of two pathways. The first pathway leads to your kidneys, which convert calcidiol to calcitriol. Calcitriol circulates in your blood and regulates serum calcium levels. It is vital for bone strength and good cellular functioning. If you do not have enough calcitriol in your blood, calcium levels will dip and illness will ensue. This pathway is crucial to survival. If you are deprived of vitamin D, the kidneys will make calcitriol from the small amount of calcidiol you produce to make sure these jobs get done. Now for the second pathway. You return home from Honduras, say, lightly toasted. You've made heaps of D3 and your liver has stashed some nice calcidiol in your fleshly tank. Your kidneys are happily doin' their thing and you have excess calcidiol to play with. The overflow now takes the second pathway straight to your cells, where tissue calcitriol is made. This is the exciting bit! Over the past 10 years, researchers have discovered myriad health benefits associated with vitamin D. These are born of the second pathway. Calcitriol is the most potent steroid hormone in the human body. A steroid hormone is any molecule made from cholesterol that acts to turn your genes on and off. Calcitriol does so at a vertiginous rate, unlocking binding sites on the human genome. The human genome contains more than 2,700 binding sites for calcitriol, which reside near genes involved in virtually every known major disease. Genes are either making proteins that fight disease or proteins that promote illness. Adequate tissue calcitriol prevents genes from expressing negative traits. Vitamin D receptors have been found on intestinal, bone, liver, kidney, hematopoietic, skin, muscle, heart, pancreatic, adrenal, brain, reproductive, lung, pituitary, thyroid and cartilage tissues and on lymphocytes, monocytes and macrophages. Such a wide range of receptor sites suggests the importance of vitamin D to good health. If, for example, your family is genetically predisposed to a certain illness, you may be able to stop its expression in you by optimising your vitamin D levels! If you have enough calcidiol, your cells convert it to tissue calcitriol with aplomb! Other steroids limit their own production by inhibiting the very chemical reactions that create them. But not tissue calcitriol. It just keeps on keepin' on… So how does the body guard against too much of a good thing? There are two mechanisms that stop calcitriol from flying too close to the sun. One is catabolism, or breakdown. The more calcitriol you make, the more you metabolise and excrete in your bile. But the most important negative feedback loop is your skin! Sunbathing without sunscreen in your togs in summer until your skin glows pink will create, on average, 20,000 units of vitamin D. Once optimum levels have been reached, the sun's rays start breaking D3 down, leaving less to convert to calcidiol and calcitriol. Why, where's it gone? In modern times, our main problem is not getting too much vitamin D, but too little. Humans are living with historically low levels of calcidiol in their blood and calcitriol in their cells. While no one factor can be blamed for chronic illness, we are suffering from diseases of civilisation that optimum levels of vitamin D could help to alleviate. So why are we so D-deprived that rickets is sneaking back on stage to ruin the play? In times past, humans lived and worked under the sun and prized D-rich foods, such as organ meats, wild fatty fish and egg yolks. Since the industrial revolution, however, we have been moving steadily indoors. Heavier clothing, glass windows and tall shady buildings block the UVB spectrum, so we make less D3 through our skin. And our move away from traditional foods has diminished our supplementary source of vitamin D. Sunscreen and sun avoidance, however, are major players. Over the past 25 years, increased skin cancer fears have caused governments to adopt aggressive anti-sun policies, especially in hot countries that are home to citizens of fair-skinned origin, such as Australia. Sun avoidance means less vitamin D, for a start. Also, until recently, sunscreens blocked D-making UVB rays because (a) they burn the skin if people sunbathe recklessly and (b) they were believed to cause skin cancer. However, recent research has shown that the UVB spectrum does not cause skin cancer after all; it protects against it by making vitamin D. The skin cancer award goes to UVA rays, which are more abundant, penetrate the skin more deeply, and wreak more havoc. All this time, while sunscreens have been barring protective UVB rays, they have been issuing guest passes to cancer-causing UVA rays. So skin cancer rates have risen and vitamin D status has dropped through the floor. Also, the further you live from the equator, the harder it is to make vitamin D. As latitudes rise, UVB weakens, the angle of the sun is not as good for D-ing, and cloud cover stops UVB getting through, as it cannot penetrate cloud, smog or fog. Add to the pot sunshine policy advice based inappropriately on the Aussie model (cover up, avoid the sun, wear lots of high SPF sunscreen, etc., while forgetting that there's lots of sun down under and very little up here…!) and you begin to see why we suffer from such a dearth of vitamin D. Ideally, we should fill up our D-tanks in summer to see us through the winter; instead, our winter levels are showing that we are becoming dangerously deficient. Whaaat caaan we do about it? (Ovine Aid) First, if at all possible, get your vitamin D levels tested to determine your current status. Clinical Nutritionist and vitamin D researcher Krispin Sullivan states that as a pro-hormone, too much supplementary vitamin D has the potential to harm. She advocates testing, treating (if necessary) and re-testing until you find the right amount to meet your daily needs. The test you need is vitamin D (D3 (25-OH)). It measures your calcidiol levels – how much you have in your tank. This is the correct test for vitamin D deficiency. Do not accept a vitamin D (1,25(OH)2D3) test for calcitriol. Calcitriol levels should never be used to determine if you are deficient in vitamin D, as they fluctuate depending on what's going on in your body at the time of testing. You may want to get a vitamin D3 test done as part of a wider panel that checks levels of other key nutrients too. Vitamin D works with co-factors in the body, the most important being magnesium. It is common for rising vitamin D levels to exacerbate an underlying magnesium deficiency. Vitamin D toxicity may be suspected, when the problem lies in a mineral imbalance caused by the orchestra of synergy swaying out of tune. However, vitamin D from supplements does have the potential to cause overdose. On the other hand, you might need significant doses of vitamin D3 to restore optimum levels if you are deficient, so knowing your individual starting point is very useful. Contact Heather Leeson and Sally Milne at Positive Nutrition, Rathmines, Dublin 6 for more information on vitamin D3 testing. Contrary to popular advice, both Krispin Sullivan and the Vitamin D Council argue that sunbathing for vitamin D should involve naked or near-naked sun worshipping when the sun is high in the sky (midday, summer) until your skin jusssst starts to go pink (not red!). And no sunscreen! As a guide: get regular midday sun exposure between 10am and 2pm in late spring, summer and early autumn, exposing as much unprotected skin as possible for 20-120 minutes (fair skin 20 minutes or less; dark skin up to a max. of 120 minutes but be ultra-careful not to burn!) to form adequate vitamin D before burning occurs. Don't shower, bathe or swim for at least one hour afterwards, or you'll wash all that lovely D down the drain. The skin oils in which vitamin D is produced can also be stripped away by chlorine in swimming pools. If you are not vegetarian or vegan, grass-fed organ meats, fatty fish, naturally raised poultry and free-range organic egg yolks contain some vitamin D, depending on how they were reared, but you can't meet your need for D with diet alone. To deter deficiency, supplements are the way to go. Preferably, get a vitamin D3 test done first. Then pop into The Hopsack, where d nice girls and boy will help you choose the right one for you. Vitamin D supplements range from omnivore (cod liver oil) to vegan. Some of the best are vegetarian, such as BetterYou's D Lux 1000 and several of Solgar's D3 products, which are made from the lanolin on sheep's wool. Animals with coats (designer only!) and birds make vitamin D3 in their wool, fur or feathers, since sunlight cannot reach their skin. Interestingly, mammals and birds then eat their own D3 by grooming their fur or rubbing their beaks on their feathers. So, when you take this form of vitamin D3 by mouth, you are really just licking a sheep. A note to the kind: vegan D Vegan vitamin D supplements tend to be D2 (ergocalciferol). Most studies have found D3 to be safer and more effective than D2. According to the Vitamin D Council, D2 is a vitamin D-like, patented drug that is not naturally present in the human body. It is derived from fungal and plant sources by activating ergosterol with ultraviolet light. It is only half as potent as D3 and may even block some of D3's beneficial effects. It is more toxic and the cause of most reported cases of vitamin D toxicity. However, all is not lost … ta raa! Dr Brian Clement of the Hippocrates Health Institute in Florida has formulated a vegan vitamin D3 supplement called LiveGive Sun-D. You can read about it here and order it here. Did you know? Scientists have discovered that red hair and fair skin offer evolutionary advantages to people whose ancestors parked in the Brrrritish Isles. Pale skin lets the sunshine in, which equals more vitamin D, less rickets and TB, and a greater chance of growing the family tree. Selecting a fair maid (or mate) meant choosing for vitamin D and an edge for survival. In Scotland and Ireland, which sport a higher proportion of redheads (and beautiful strawberry blondes 😉 ), the sun is shrouded in cloud for much of the year. Those creamy complexions that burn to a crisp in the tropics are a gift from the gods in the grey lands of northern Europe.