Tips for Better Bone Building, Part 2: What is the “Real” Vitamin D Requirement?

This is part of our ongoing The Best Kept Secrets to Healthy Aging spotlight. Each week, we will be posting some of the great information that’s packed into our book, The Best Kept Secrets to Healthy Aging.

Today’s topic:
Tips for Better Bone Building, Part 2: What is the “Real” Vitamin D Requirement?

The true test of vitamin D adequacy is whether it prevents the parathyroid glands from secreting parathyroid hormone (PTH). What does the scientific evidence say? Daily intakes of vitamin D much greater than the recommended 400 IU are required to minimize PTH secretion and optimize skeletal health. The results of a statistical analysis of published research published recently in the Journal of the American Medical Association (JAMA) found that men and women over 60 years of age who routinely consumed double the RDA (about 800 IU of vitamin D daily) suffered 25% fewer hip fractures than those who stuck to the RDA.5 Consistent with this analysis, the results of the Women’s Health Initiative Study published recently in the New England Journal of Medicine proved that the RDA for vitamin D was no better than vitamin D deficient diets in protecting the skeleton.6 As shown in the results of another study published recently in the British Medical Journal, even 800 IU daily may not be enough vitamin D for every elderly person.7

Scientists now conclude that an average vitamin D intake of 1000 IU daily is needed by most adults (some may require more) and that an average daily vitamin D intake of 2600 IU would be required in order to ensure that very few older women could become functionally vitamin D deficient. A pioneer of vitamin D research, Dr. Hector F. DeLuca of the University of Wisconsin, has advised all adults to consume 2000 IU of vitamin D daily to optimize health.8 As detailed in the vitamin D chapter later on in this book, many researchers feel that a number of people may need much higher amounts. The FDA also agrees about the importance of achieving adequate intake of vitamin D along with calcium throughout life. In a claim they’ve approved about the relationship between vitamin D and calcium together, they state that, “Adequate calcium and vitamin D throughout life, as part of a well-balanced diet, may reduce the risk of osteoporosis.” Calcium is the structural backbone for skeletal health and vitamin D controls its incorporation into tissues. Both are vital to promoting healthy bone structure and density.

Next Best Kept Secrets to Healthy Aging topic:
Tips for Better Bone Building, Part 3: Vitamin C

References:
5. Bischoff-Ferrari HA, Willett WC, Wong JB, Giovannucci E, Dietrich T, Dawson-Hughes B. Fracture prevention with vitamin D supplementation: A meta-analysis of randomized controlled trials. JAMA 2005;293:2257-2264.
6. Jackson RD, LaCroix AZ, Gass M, Wallace RB, Robbins J, Lewis CE, Bassford T, Beresford SA, Black HR, Blanchette P, Bonds DE, Brunner RL, Brzyski RG, Caan B, Cauley JA, Chlebowski RT, Cummings SR, Granek I, Hays J, Heiss G, Hendrix SL, Howard BV, Hsia J, Hubbell FA, Johnson KC, Judd H, Kotchen JM, Kuller LH, Langer RD, Lasser NL, Limacher MC, Ludlam S, Manson JE, Margolis KL, McGowan J, Ockene JK, O’Sullivan MJ, Phillips L, Prentice RL, Sarto GE, Stefanick ML, Van Horn L, Wactawski-Wende J, Whitlock E, Anderson GL, Assaf AR, Barad D; Women’s Health Initiative Investigators. Calcium plus vitamin D supplementation and the risk of fractures. N Engl J Med 2006;354:669-683.
7. Porthouse J, Cockayne S, King C, Saxon L, Steele E, Aspray T, Baverstock M, Birks Y, Dumville J, Francis R, Iglesias C, Puffer S, Sutcliffe A, Watt I, Torgerson DJ. Randomised controlled trial of calcium and supplementation with cholecalciferol (vitamin D3) for prevention of fractures in primary care. BMJ 2005;330:1003 (6 pages). doi:10.1136/bmj.330.7498.1003 (http://bmj.com/cgi/content/full/330/7498/1003).
8. DeLuca HF. Overview of general physiologic features and functions of vitamin D. Am J Clin Nutr 2004;80(Suppl.):1689S-1696S.