June 1, 2009
For years, doctors and scientists have told the public to drink milk, eat dairy products and take calcium supplements to improve bone health and prevent osteoporosis. The problem is they're wrong, according to a new book co-authored by a UNC Asheville researcher.
Amy Lanou, UNC Asheville assistant professor of health and wellness, and noted health writer Michael Castleman’s new book, "Building Bone Vitality: A Revolutionary Plan to Prevent Bone Loss and Reverse Osteoporosis," dispels the calcium myth using the latest clinical studies and medical information. Published by McGraw Hill, the book hits shelves this month.
"Building Bone Vitality" provides readers with practical advice to strengthen bones, reduce the risk of fractures and prevent osteoporosis. Readers will also learn why there's no proof of dairy's usefulness in bone health, despite what doctors say, and why eating low-acid foods and taking daily walks are the most effective ways to prevent bone loss.
The authors' suggested eating plan includes six to nine daily servings of fruits and vegetables and no more than one or two servings of high-protein foods such as meat, dairy and eggs daily. Why? Because protein is composed of amino acids. As the body digests high-protein foods, the blood becomes more acidic, leaching calcium from the bones.
For example, have you ever taken Tums for acid indigestion? Its active ingredient, calcium carbonate, neutralizes stomach acid because it's highly alkaline. To neutralize excess acid in the bloodstream, the body draws the same compound from bone. A high-protein diet of meat, dairy and eggs draws calcium from bone and eventually causes osteoporosis, the authors say.
Of course, fruits and vegetables also contain some protein, but much less than meat, dairy and eggs. Fruits and vegetables also contain a great deal of alkaline material. When you eat these foods, only a small amount of acid enters the bloodstream along with a great deal of alkaline material, which neutralizes the acid. Therefore, the body does not have to draw calcium compounds out of bone.
"Fruits and vegetables keep calcium in bone where it belongs," said Lanou.
To further back up their theory, Lanou and Castleman pored over completed human clinical trials and found that they also refute the calcium claim. Since 1975, 140 clinical trials have explored calcium's effects on osteoporotic fracture risk. Two-thirds of these studies show no benefit from high calcium intake. Overall, the clinical trials dealing with fracture prevention run two-to-one against calcium, the authors noted.
Finally, the authors reviewed research on the impact of exercise on bone health. They found that the consensus of research shows that just 30 to 60 minutes of daily walking is enough exercise to build strong bones.
"The good news is that you don't have to join a gym or sweat buckets," said Castleman. "But you do have to walk every day."
Lanou, who holds a doctorate in human nutrition from Cornell University, joined the UNC Asheville faculty in 2005. She has played an instrumental role in creating programs and coursework for UNC Asheville's North Carolina Center for Health & Wellness, which focuses on childhood obesity, workplace wellness and healthy aging. Previously, she taught nutrition at Cornell University and Ithaca College. She is the author of "Healthy Eating for Life for Children" and has written or delivered more than 50 scientific articles, reports and presentations on bone health, dairy products or the health benefits of plant foods. Lanou also serves as senior nutrition scientist for the Physicians Committee for Responsible Medicine, a Washington, D.C.-based nonprofit organization dedicated to preventative medicine through good nutrition.