A study from the University of Warwick in England shows that more time in the sun can help older people avoid diabetes and heart attacks (Diabetes Care, July 2009). They evaluated 3,262 people aged 50-70 years old in Beijing and Shanghai, China, and found that 94 percent were low in vitamin D and 42 percent of those had metabolic syndrome: abdominal obesity, high triglycerides, low HDL and high blood sugar levels. This is consistent with world- wide studies that show that as people age their skin atrophies, reducing their ability to make vitamin D from sunlight. Seniors also usually exercise less so they do not go outside as often. Since they are more susceptible to cold, they usually wear more clothing when they do go outside. Inadequate vitamin D increases risk for heart attacks, strokes, certain cancers, arthritis, auto-immune diseases and many other health problems.
A major function of vitamin D is to increase absorption of calcium from food. When vitamin D levels are low, body levels of ionized calcioum drop. This forces the parathyroid glands to increase production of parathyroid hormone that blocks insulin receptors, to raise blood sugar levels markedly and increase production of insulin. High levels of insulin constrict coronary arteries to cause heart attacks.
Vitamin D deficiency occurs when the concentration of D3 (25-hydroxy-vitamin D) is less than 75 nmol/L. If you are deficient, you need to expose skin to more sunlight or take at least 2000 IU of vitamin D3 per day. To address skin cancer concerns, protect the most frequently exposed areas, since it is cumulative life-long exposure to sunlight that increases risk for skin cancer. For most people, this means you should use sunscreen or wear clothing to cover your face, scalp, neck, tops of the ears, forearms and hands whenever you will be in the sun for more than 30 minutes.
Dr. Gabe Mirkin is a Villages resident.
