Originally associated with the childhood disease rickets, vitamin D has reemerged as an important factor in health and disease prevention. The studies are so convincing, health organizations and our government are considering officially increasing the recommended daily requirement for vitamin D in the diet. It is estimated that 75 percent of US teens and up to 60 percent of adults are deficient in vitamin D.
What is Vitamin D?
Vitamin D is actually a type of steroid hormone that affects many cells and systems in the body. We obtain vitamin D from the diet and from the sun striking unprotected skin. Unfortunately, getting adequate vitamin D from the diet is difficult. Milk and oily fish are good sources but few other foods provide significant amounts. Traditionally humans got all the vitamin D they needed from the sun. When sun strikes skin, the body is able to make vitamin D.
Levels typically plummet in winter when people spend more time covered up and indoors. Our skin is more exposed in summer, but sunscreen blocks the skin from making Vitamin D. Getting your vitamin D from the sun also poses a significant risk of skin cancer. However, this issue is hotly debated as some experts recommend 10-15 minutes per day of sun exposure as the best way to keep levels up. In the case of vitamin D, supplements seem to be the best option. Supplements are inexpensive and easily available in grocery stores and pharmacies.
So why is this vitamin so important?
Vitamin D is usually associated with bone health. However, new research has found that vitamin D may be helpful in preventing certain cancers such as colorectal cancer. Vitamin D also plays a role in the proper functioning of the immune system and may prevent the development of autoimmune diseases like Type 1 Diabetes and rheumatoid arthritis. People with Multiple Sclerosis are often vitamin D deficient. In fact, the risk of MS is much higher the farther one lives from the equator. Vitamin D is also believed to play a role in heart health, cholesterol levels, hypertension and Type 2 diabetes.
Do I need more Vitamin D?
The first thing you should do is find out your vitamin D level with a simple blood test called a “25OH Vitamin D.” A result of 32 ng/dl or above is considered adequate. If your levels are very low, your physician may order Vitamin D once weekly with a recheck in 6-8 weeks.
How can I get more Vitamin D in my diet?
Most people do not need a prescription and can easily maintain adequate levels with vitamin D supplements found over the counter. Taking 1000 IU of vitamin D daily along with a multivitamin that contains 200-400 IU during the spring and summer months should be enough. More may be needed in winter. Over this past winter I took a total of 2000 IU per day and my level was only 50ng/dl in May—a normal reading.
Remember that everyone is different and you may require more or less. For this reason, working with your physician and getting levels checked regularly is important. Be careful not to take mega doses without your doctor’s recommendation. Vitamin D can be toxic in very high amounts, so more is not necessarily better.
Lori Stevens RD, LDN, CNSC, is a dietitian with WakeMed Cary Hospital. The Outpatient Nutrition Services Department at WakeMed Cary Hospital offers nutrition counseling. For more information, or to schedule an appointment, please call or have your physician fax a referral. Phone: (919) 350-2358; Fax (919) 350-2319.