Sun For Gawler
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Sun For Gawler

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Sun For Gawler Sun For Gawler Presentation Transcript

  • Adequate sun exposure is essential for optimal health George Jelinek Professor of Emergency Medicine University of Western Australia
  • Overview
    • The controversy
    • Background
      • Sunlight and UV light
      • Vitamin D
    • The evidence
    • Conclusions and recommendations
  • The message
    • A lot of data but a simple message:
    • Avoiding the sun makes us sick
    • Most of us need more sunlight to be really well
  • The controversy
    • Growing debate about public health messages regarding sun avoidance*
    • Growing burden of disease related to inadequate vitamin D
      • Without sun, there would be no life on earth: why continue regarding sunlight as poison?
            • * Lucas RM, Ponsonby AL. Ultraviolet radiation and health: friend and foe. Med J Aust 2002; 177:594-8
            • Ness AR, Frankel SJ, Gunnell DJ, et al. Are we really dying for a tan? BMJ 1999; 319:114-16
  • Changing mainstream opinion
    • ‘ The paradox of Vitamin D deficiency emerging as a public health issue in sunny Australia’*
    • ‘ It is no longer acceptable to assume that all people in Australia receive adequate Vitamin D from casual sunlight exposure’+
            • * Ebeling PR. Megadose therapy for vitamin D deficiency. Treating the paradox of an important emerging public health problem. Med J Aust 2005;183:4-5
            • + Nowson CA, Diamond TH, Pasco JA, et al. Vitamin D in Australia. Aust Fam Phys 2004;33:133-138
  • Background
    • Sunlight composition
      • Mixture of infrared, visible and ultraviolet
      • Ultraviolet comprises UVA, UVB, UVC
    • UVB
      • Only about 5%
      • Blocked by glass, passes through water
      • Acts on skin to form vitamin D
  • Formation of vitamin D
    • Amount of vitamin D formed depends on:
      • Area of skin exposed to sunlight
      • Length of time exposed
    • Upper limit of 10 000 to 15 000 IU after which no more produced
      • This takes all over exposure for 10-15mins at midday on a UV index 7 day
  • UV index
    • Each point on UV index scale equivalent to 25mW energy per square metre
    • So if UV index 14, you need half the time for the same amount of vitamin D as if UV index 7
    • UV index in Melbourne about maximum 12 in summer, 1 in winter
  • Vitamin D
    • Main action is to increase absorption of calcium from gut and deposition in bone
    • More recently found that vitamin D has profound effects on immune system
    • Other effects on muscle, balance, mood
    • Impossible to get adequate amounts from diet alone
  • Effects of vitamin D deficiency
    • Calcium effects
      • Ricketts, osteoporosis, fractures
    • Hypertension, depression, weakness, falls#
    • Immune effects
      • Increased incidence and severity of autoimmune diseases and cancers*
            • # Bischoff HA, Stahelin HB, Dick W, et al. Effects of vitamin D and calcium supplementation on falls: a randomised controlled trial. J Bone Miner Res 2003;18:343-51
            • * Ponsonby AL, McMichael A, van der Mei I. Ultraviolet radiation and autoimmune disease: insights from epidemiological research. Toxicology 2002; 181-182:71-8
  • US UV exposure
  • Breast cancer
  • Colon cancer
  • MS prevalence WW2 veterans at entry into armed forces by latitude
  • Diseases from low vitamin D
    • Cancers*
      • Digestive tract cancers
        • Esophageal, gastric, colon, rectal
      • Breast and reproductive system cancers
        • Breast, cervical, endometrial, ovarian, vulva
      • Urogenital cancers
        • Bladder, kidney, prostate, renal, testis
      • Other cancers
        • Gallbladder, laryngeal, pancreatic, Hodgkin’s lymphoma, non Hodgkin’s lymphoma
    • Autoimmune disorders
      • Multiple sclerosis, rheumatoid arthritis, insulin dependent diabetes, SLE
    • Bone disorders
      • Ricketts, osteoporosis, osteomalacia, fractures, poor fracture healing
    • Mood disorders
      • Depression, seasonal affective disorder (SAD)
    • General health
      • High BP, CHD # , irritable bowel, Crohn’s disease, falls, muscle weakness
            • * Grant WB. Ecologic studies of solar UV-B radiation and cancer mortality rates. Recent Results Cancer Res 2003; 164:371-7
            • # Grimes D., Hindle E., and Dyer T., Sunlight cholesterol and coronary heart disease. QJM 1996; 89;579-589
  • Current vitamin D recommendations
    • Current mod/severe deficiency <25nmol/L
    • Current mild deficiency <50nmol/L
      • Considerable evidence that this is too low*
    • Even at these levels, large proportion of population has low levels
      • Low levels correlate with osteoporosis, falls, fractures, autoimmune disease and cancer
            • * Vieth R. Why the optimal requirement for Vitamin D(3) is probably much higher than what is officially recommended for adults. J Steroid Biochem Mol Biol 2004; 89-90:575-9
  • Vitamin D deficiency
    • 80% of women, 70% of men in hostels and nursing homes in VIC, NSW, WA are vitamin D deficient
      • 97% had blood level below median of healthy reference range*
    • In Geelong women, 30% had vit D level <50nmol/L in summer and 43% in winter#
            • * Flicker L, Mead K, MacInnis RJ, et al. Serum vitamin D and falls in older women living in residential care in Australia. J Am Geriatr Soc 2003;51:1533-38
            • # Pasco JA, Henry MJ, Nicholson GC, et al. Vitamin D status of women in the Geelong Osteoporosis Study: association with diet and casual exposure to sunlight. Med J Aust. 2001;175:401-5
  • Current vitamin D recommendations
    • RDA now 200IU to prevent deficiency
      • Equivalent to about 5 seconds all over sun in Perth summer at midday!
    • Where these diseases uncommon blood levels are around 100-140nmol/L
      • 4 000IU/day gives level of 100nmol/L
      • 10 000IU/day gives level of 140nmol/L
  • Current vitamin D recommendations
    • Current ‘LOAEL’ is 2 000IU per day
      • Good evidence that supplementing with 10 000IU per day perfectly safe*
      • Only published toxicity is from >40 000IU/day
    • Potential toxicity relates to high calcium
      • Currently much work on vitamin D analogues to get immune effect without calcium effects
      • Flawed thinking: nature provides the balance
            • * Vieth R. Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety. Am J Clin Nutr 1999; 69:842-56
  • Benefits of high normal vitamin D levels
    • Not only prevents ricketts, osteomalacia, osteoporosis, autoimmune diseases, cancer, hypertension, depression*
    • Prevents complications of these diseases, such as osteoporosis from inactivity, falls (49% drop), fractures, muscle weakness#
            • * Deluca HF, Cantorna MT. Vitamin D: its role and uses in immunology. Faseb J 2001; 15:2579-85
            • Zittermann A. Vitamin D in preventive medicine: are we ignoring the evidence? Br J Nutr 2003; 89:552-572
            • # VanAmerongen BM, Dijkstra CD, Lips P, Polman CH. Multiple sclerosis and vitamin D: an update. Eur J Clin Nutr 2004
  • How to get adequate vitamin D
    • Diet not enough
    • Simplest and cheapest is adequate sunlight
    • Probably also helpful in other ways besides vitamin D (melatonin, etc)
    • Solarium if no sun, but in very small doses
    • Supplements
      • Can take a one-off supplement to get levels up
  • Risks of adequate sunlight
    • Probably none!
    • Risks are from excessive sunlight
      • Various skin cancers
      • But, for every melanoma prevented by sun avoidance we incur about 6.6 internal cancers*
      • Adequate vit D probably prevents melanoma#
            • * Grant WB. Ecologic studies of solar UV-B radiation and cancer mortality rates. Recent Results Cancer Res 2003; 164:371-7
            • # Garland FC, White MR, Garland CF, Shaw E, Gorham ED. Occupational sunlight exposure and melanoma in the U.S. Navy. Arch Environ Health 1990; 45:261-7
  • Recommendations: sunlight
    • 10-15mins sunlight all over (in speedos) 3-5 times a week UV index 7 day (spring)
      • Proportionately more or less in winter and summer
      • Solarium a reasonable alternative
      • Usually about 3mins in a 10min solarium
      • Check that has both UVA and UVB
  •  
  • May 2005 ANZ osteoporosis recommendations for sun exposure
    • Melbourne summer: ‘6-8min of sun at 10am or 2pm on hands, face and arms’*
    • Melbourne winter: ‘25mins of sun at midday on hands, face and arms’*
      • Very similar to mine except only 15% of body exposed: 6-7 times the dose with mine for optimal effect: clearly considered safe exposure
            • * ANZ Bone and Mineral Society, Endocrine Society of Australia and Osteoporosis Australia. Vitamin D and adult bone health in Australia and New Zealand: a position statement. Med J Aust 2005;182:281-5
  • Recommendations: supplements
    • Supplement with 4 000IU per day (or more, up to 10 000IU) if no sun
    • One off dose if levels low
      • 50 000-500 000IU if <25nmol/L
        • Single dose of 600 000IU raised levels to 73nmol/L for people with levels <12.5nmol/L*
      • 25 000-250 000IU if <50nmol/L
            • * Diamond TH, Ho KW, Rohl PG, Meerkin M. Annual IM injection of a megadose of cholecalciferol for treatment of vitamin D deficiency. Med J Aust 2005;183:10-12
  • Target blood levels
    • Check levels each autumn
      • Aim for at least 70nmol/L if well
      • Aim for 100-140nmol/L if sick
      • Probably up to 200nmol/L really optimal*
      • Evidence that 135-225nmol/L normal in sunny countries where these diseases rare
            • * Grant WB,Holick MF. Benefits and requirements of Vitamin D for optimal health: a review. Altern Med Rev 2005; 10:94-111
  • Getting the supplements
    • Vitamin D3 unavailable in Australia
    • Don’t try to get it from cod liver oil (vitamin A toxicity)
    • Ostelin R 1 000IU available on prescription but vitamin D2 (synthetic)
    • Try www.healthau.com for 5000IU capsule
    • Or PSM Healthcare for 50 000IU monthly
  • Final recommendation
    • Enjoy your time in the sun!