The 1991 film "Night on Earth" tells the story of five taxi rides in five locations around the world, from Los Angeles to Rome. Most of the characters, including Corky (Winona Ryder) and Angela (Rosie Perez), seem determined to avoid the light of day.

That's something familiar to the 1 billion people around the globe who don't have healthy levels of vitamin D because of lack of sun exposure.

The repercussions of vitamin D deficiency are significant because it regulates the functions of more than 200 genes that control growth and development.

Deficiency has also been linked to obesity, hypertension, depression, osteoporosis, and Alzheimer's. It also might contribute to development of breast, prostate, and colon cancers.

And now it seems that low D is more likely to contribute to Type 2 diabetes than being overweight! (And we know that is a major risk factor.)

Spanish researchers looked at folks (some lean, some obese) and found two things: Lean people with diabetes had lower vitamin D levels than lean folks without diabetes; and obese people without diabetes had higher levels of vitamin D than obese people with diabetes.

So for a diabetes-free health plan — in addition to maintaining a healthy weight, eating plenty of fresh produce, and walking 10,000 steps a day — get your vitamin D levels checked and take 1,000 IU of D3 a day.

If you're D-ficient, bring it up with extra supplements and 15 minutes of sunshine daily.

Remember, sunscreen doesn't interfere with your body making vitamin D, but night on Earth does!