People’s Pharmacy: Caffeine stunting growth?

Q. I’m 18 now, a male, 5 feet 9 inches tall. I began drinking caffeinated sodas in great excess (1 liter or more a day) when I was 10 or 11. By the time I was 13, I had completely stopped growing.

My height isn’t that unusually small until you compare me with the rest of my family. My father is 6 feet 8 inches, my brother 6 feet 10 inches, and all my male cousins are at least 6 feet 4 inches. My own mother is 5 feet 11 inches. I do believe caffeine played a significant role in stunting my growth.

A. A liter of soda a day is a lot of caffeine for a 10-year-old. Studies such as the Penn State Young Women’s Health Study (Journal of the American College of Nutrition, October 1998) don’t show a connection between caffeine intake and height, but experts often warn that substituting soda instead of milk could lead to suboptimal calcium intake. That, presumably, would have a negative effect on bone development. Perhaps that is why you ended up so much shorter than the rest of your family.

Q. I use sunscreen daily because I have red hair and fair skin, but I love the outdoors. A lab test shows that I am vitamin D deficient. How can I balance my need for sunscreen and the need for sun exposure to make vitamin D?

A. Vitamin D has been getting far more attention in recent years, as scientists realized that it is critical for many other functions in addition to building strong bones. Recent studies show that adequate vitamin D in early childhood reduces the risk of developing type 1 (juvenile) diabetes (Archives of Disease in Childhood, June 2008; Diabetologia online, June 5, 2008).

Vitamin D is also important for controlling blood pressure and preventing several types of cancer. In older adults, low levels of vitamin D have been linked to falls as well as muscle and joint pain (Journal of the American Geriatrics Society, May 2008).

With your fair skin, you need to be careful to avoid sunburn. But it just takes a few minutes of sun exposure daily without sunscreen for your skin to manufacture the building block for vitamin D.

To learn more about the consequences of low vitamin D and how to replenish it, you might want to listen to a radio show we did focusing on this topic. We interviewed Drs. James Dowd and Michael Holick about the research and clinical evidence regarding vitamin D. Anyone who would like to order this one-hour CD may send $16 to: Graedons’ People’s Pharmacy (CD-672), P.O. Box 52027, Durham, NC 27717-2027. Show No. 672 is also available as a free podcast at www.peoplespharmacy.com.

Q. You wrote recently about the dangers of carrying germs around on your shoes or bare feet. Because of studies on the germs found on women’s purses, I avoid putting my grandchildren’s backpacks on the kitchen table.

Who knows where those book bags have been? They’ve at least probably been on the floor of the school bus, along with germs from school restrooms and goodness knows where else.

A. Your decision is prudent. Dr. Charles Gerba, a professor of microbiology at the University of Arizona in Tucson, did the research showing how shoes carry many nasty germs. He told us he now refrains from propping his feet on his desk. It’s smart to keep shoes, purses or backpacks away from any surfaces where you might want to put your hands – or your lunch.