Health & Fitness

How does light pollution affect health?; Type 2 diabetes and fruit


King Features Syndicate

Q: I read that 80 percent of Americans can’t see the Milky Way because of all the lights at night. Does that kind of light pollution affect my health? -- Suzi C., Clearwater, Florida

A: We can shed some light on that! Light pollution can interfere with your sleep-wake cycle (that’s your circadian rhythm, which controls 10 to 15 percent of your genes), and that can throw off your metabolism. It’s also associated with changes in brainwave patterns and cell regulation, and it’s linked to depression, insomnia, cardiovascular disease and cancer. A 2007 report from a National Institute of Environmental Health Sciences meeting even suggested that there may be a relationship between increased light pollution and an increase in the risk for breast and prostate cancers, obesity and early-onset diabetes.

The American Medical Association has come out with an advisory, telling cities to turn down new LED streetlights: “High-intensity ... blue-rich LED streetlights [that appear white to the eye] operate at a wavelength that most adversely suppresses melatonin during night. It is estimated that white LED lamps have five times greater impact on circadian sleep rhythms than conventional street lamps. Recent large surveys found that brighter residential nighttime lighting is associated with reduced sleep times, dissatisfaction with sleep quality, excessive sleepiness, impaired daytime functioning and obesity.”

How can you protect yourself?

1. Get light-blocking shades and curtains for your bedroom.

2. Use nightlights with RED wavelengths only.

3. Keep blue-light-emitting digital devices and TV out of your bedroom.

4. Talk to your city council about turning off buildings’ lights at night; turning down LED streetlights and turning off high-intensity lights around empty ballfields and shopping malls.

The researchers in Science Advances suggested that not seeing the Milky Way is a “profound alteration of a fundamental human experience -- the opportunity for each person to view and ponder the night sky. Even small increases in sky brightness degrade this experience.”

Q: I’ve just been diagnosed with Type 2 diabetes. I know fruits are full of carbs and are loaded with fructose/sugar, so can I still eat them? -- Claudia C., Houston

A: Every diet should contain some fruit. It’s packed with fiber and heart-, brain- and gut-healthy phytonutrients, along with a sugar called fructose. As to how fruit will figure in your diet, well, everyone with Type 2 diabetes responds a little differently to various types of fruit, and you’ll have to experiment to see how different types affect your blood glucose levels.

For a general guideline, however, you can use a food’s glycemic index, or GI. On a scale of 1 to 100, it ranks how quickly a food’s carbohydrates (fructose is a carb) turn to sugar; 100 is pure sugar. A 120-gram apple (GI 39) raises your blood sugar more slowly than a 120-gram slice of watermelon (GI 72); 120 grams is around 4 ounces. Generally, most fruits have a low GI.

But remember, the index isn’t a precise measure. So much depends on how the fruit was grown, the type it is (there are around 2,500 varieties of apples grown in the U.S., for example), how it’s prepared and what you ate beforehand. (Eating a little healthy fat -- six walnuts, for example -- slows absorption of sugar, making that piece of fruit cause less of a spike in your blood sugar level.) So stick with unprocessed and uncooked fruits; dried fruit and fruit juices are considered processed.

Knowing your portion size is another way to make sure you can eat fruits without too rapidly increasing your blood sugar level. Get a scale, and weigh your fruit. After a while, you will be able to tell what a serving of 120 grams/4 ounces (or half of that) looks and feels like.

But the single smartest move you can make if you’re newly diagnosed with diabetes is to make an appointment with a certified diabetes educator (find one at and work together to develop a personalized meal plan. Insurance almost always covers it.

Mehmet Oz, M.D. is host of “The Dr. Oz Show,” and Mike Roizen, M.D. is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. Email your health and wellness questions to Dr. Oz and Dr. Roizen at