It's a little funny to hear a nutritionist lash out against supplements right around the time one of the world's most prominent medical schools comes out in favor of one of them.

Researchers at the Harvard Medical School have identified vitamin D as the one nutrient that most people even with ideal diets won't be able to get enough of through food.

Vitamin D is called the sunshine vitamin, but who really sees the sun anymore? Most folks dash from the home to the office to the mall, getting exposed to sunlight for 10 seconds here or 30 seconds there – not nearly enough to help the body produce the amount of D it really needs.

Even when we are out in the sun, most people wear shirts, hats, sunglasses, and sunblock, which makes it even tougher to get your daily D from sunlight alone. It's literally impossible to get enough vitamin D from the sun in winter in many areas.

So it makes perfect sense for most folks to take a high-quality D supplement. Harvard recommends at least 1,000 IU per day, and I've seen with my own eyes how a steady source of D can work wonders.

Vitamin D plays a critical role in helping your body hold onto calcium. So even if you think you're getting enough calcium, a lack of vitamin D could cause your body to come up short – increasing your risk for bone conditions like osteoporosis.

That dynamic D can also help your body fight infections, beat cancer, reduce your risk for heart attack and stroke, ease asthma and prevent colds and the flu. Vitamin D has even been shown to help people live longer.

You really can't go wrong with this one – and you won't get enough of it from your food.

So while we can thank the sun for introducing us to all those benefits, your body will thank you for using a supplement to make sure you actually get them.