Older New Zealanders might remember receiving a daily dose of cod liver oil as children. But do you remember why? Cod liver oil is a rich source of vitamin D, and was considered an easy way of preventing rickets, a bone-softening condition causing bowed legs or knock knees in children. Today, a low blood level of vitamin D may not be severe enough to cause rickets, but it may increase the risk of bone fractures due to its important role in bone health where it is essential for calcium absorption from food. Concern about vitamin D deficiency has re-emerged in New Zealand as a result of health messages to reduce sun exposure and encouragement to use ultraviolet (UV) sun screens, reducing the skin’s ability to produce vitamin D. How much vitamin D do we need? Pregnant and breastfeeding women Who needs more and why? Older people, particularly those who are housebound with limited exposure to sunlight. Those with a darker skin colour, e.g. Maori and Pacific Islanders, or people who are veiled.
Those living in the South Island during the winter. Which foods contain vitamin D? Vitamin D is in oily fish, such as canned tuna and salmon, eggs, lean meat and dairy products. There are now margarines, milks and yoghurts fortified with vitamin D available in New Zealand. Unlike any other nutrient, most vitamin D (up to 80%) is formed as a result of sunlight exposure on our skin. The most recent national surveys showed about one in three New Zealand children had too little vitamin D in their blood; nearer a half of adults. During summer, being outdoors before 11am and after 4pm should allow enough sunlight to be absorbed to meet your vitamin D needs. We still need to practice good sun protection (sunscreen, hats and coverage) during the summer months. In winter, longer periods are required, around 30 minutes per day, with those people living in the south island of New Zealand needing more exposure because of the lower UV levels. Talk to your doctor if you are concerned about your vitamin D levels or if you have limited exposure to the sun.
Supplements popular but health claims rarely met, research finds Vitamin D supplements provide little - if any - health benefits, a study shows. The Auckland University report analysed multiple existing studies focused on the effects of vitamin D. It found they failed to reduce the risk of heart attacks, strokes, cancer or bone fractures in the general population by more than 15 per cent. Vitamin D supplements are commonly associated with better health and the prevention of various medical conditions. However, an emerging body of research is beginning to debunk these beliefs. A study published last month in The Lancet Diabetes & Endocrinology journal concluded low levels of vitamin D were a result, rather than a cause, of ill-health. The latest study, led by Dr Mark Bolland from the university's Department of Medicine, analysed comparisons of individuals who took calcium with their vitamin D supplements and those who didn't. Calcium is essential for healthy bones and teeth. Some of Bolland's research indicates an increased risk of hip fractures with vitamin D supplementation.
It follows studies that showed vitamin D supplements made no difference in preventing osteoporosis in most healthy adults. Arapera Salter took supplements two years ago when she had low vitamin D levels and she stands by the decision. A prescription from her family doctor for three high-dose supplements, taken once a month, cost $5. The 32-year-old paediatric registrar, who had her first child five weeks ago, wanted her vitamin D levels right before getting pregnant. "I wanted to have good levels before I was pregnant because if you've got low vitamin D then your baby will get low vitamin D." Salter said she intended to have her vitamin D levels retested once she stopped breastfeeding and, if needed, begin taking the supplements again. "I definitely don't feel like I've wasted my money. "Even though [the research] doesn't show that it prevents fractures, it's something that is down the line, like when you've got frail bones. I would rather try to prevent her [daughter Aniwa] from having that."
Salter lives in Dunedin with partner Tom Wolfenden and their daughter. In New Zealand, about 12 per cent of people aged over 50 - 5 per cent of the population - receive state-funded vitamin D supplements. This figure does not include over-the-counter purchases. In residential care facilities, 74 per cent of elderly residents are given the supplements, which are even more prevalent in the US.Welcome to MS Research Australia, skip to: PrevANZ is a world-first clinical trial that will test whether vitamin D supplementation can prevent MS in those at risk of developing the disease. The Phase IIb randomised, double blind, placebo-controlled trial will focus on the possibility of using vitamin D supplementation to prevent a diagnosis of MS following a person’s presentation with a first episode of symptoms that may be a precursor to MS, such as blurred vision (optic neuritis) or limb weakness (transverse myelitis) (these symptoms may be described as a first demyelinating event, or clinically isolated syndrome (CIS).
PrevANZ will also test appropriate dosage levels and safety. The need for the PrevANZ trial has arisen from a now significant body of evidence for the role that vitamin D deficiency plays in MS. However, to date there has not been a clinical trial conducted to provide the necessary evidence on the benefits that can be expected from vitamin D supplementation or the correct dose. MS Research Australia and our colleagues in the MS research community see this trial as a high priority and an area in which the expertise in Australia and New Zealand can contribute significantly to the prevention and better treatment of MS globally. A steering committee of clinicians and researchers from Australia and New Zealand, with expertise in MS neurology, MS clinical trials, endocrinology and epidemiology has been assembled to oversee the trial. The trial will be coordinated and funded by MS Research Australia. This has been made possible by generous support from the state MS organisations, particularly, WA, QLD and Tasmania, as well as Foundation 5 Million+, the Trish MS Research Foundation, and the John T Reid Trust.
A collaborative team of neurologists, lead by Professor Helmut Butzkueven from the Department of Medicine, University of Melbourne, and Professor Bruce Taylor, Menzies Institute for Medical Research, will undertake this study across 20 sites in Australia and New Zealand. PrevANZ commenced recruitment in June 2013. The trial will run for four years over 2013-2016. It is expected that results will be available in 2017. PrevANZ will test 3 dosage levels of daily oral vitamin D3 supplements (1000, 5000 & 10,000 International Units) against placebo (dummy tablets) in a total of 240 people. The role of vitamin D in MS The evidence for the role of vitamin D deficiency in MS is now very strong and was reinforced by the internationally important Australian study (Ausimmune, 2004-2007), comparing MS patients in with CIS in Brisbane, Newcastle, Geelong and Hobart. Vitamin D deficiency is thought to play a role in MS since geographical areas of lower levels of UV radiation, and hence lower vitamin D synthesis in the skin, have higher incidences of MS. Variations in genes involved in the vitamin D metabolism pathway have been implicated in susceptibility to MS and vitamin D deficiency has also been shown to be associated with a higher rate of relapses in people with established MS.
Taking part in the PrevANZ trial People with CIS who are interested in taking part should discuss participation with their neurologist. The sites for the trial are listed below. Full details of the trial, including eligibility criteria for participants can be found here Please note people who have already been diagnosed with MS are not eligible to participate in the trial. People with MS who are concerned about their vitamin D levels should seek advice from their GP or neurologist. Brain Mind Research Institute Wendy Hayes or Michelle Allan Griffith University/Gold Coast Hospital Australian Neuromuscular Research Institute 09 307 4949 Ext 25816 Professor William Carroll, Sir Charles Gairdner Hospital, Perth Professor Helmut Butzkueven, University of Melbourne Professor Bruce Taylor, Menzies Institute for Medical Research Professor Anne-Louise Ponsonby, Murdoch Children’s Research Institute, Melbourne Professor Simon Broadley, Griffith University, Queensland