What You Need to Know About Vitamin D
By Gunjan Tykodi, M.D.
Board-certified endocrinologist with Kaiser Permanente medical offices
Open any health magazine these days and you are likely to see an article on vitamin D. I'm sure that's why so many of my patients ask about it. It's an important topic, especially here in the Northwest where the sun in the winter months is too weak to help us make as much vitamin D as our bodies need.
There have been many claims about the benefits of boosting your vitamin D to a high level — from protecting against cancer, allergies, and cardiovascular disease to fighting off viruses.
But such claims are just that. Most haven't yet been definitively supported by scientific evidence. How vitamin D actually affects many conditions will take much more investigation. Until then, here are some things to think about.
Skeletal health: Vitamin D plays a key role in skeletal health, helping to absorb calcium which ensures adequate mineralization of your bones. Without enough vitamin D, you're at risk for weak bones and possibly also weak muscles which may increase your risk of falling.
Sun exposure: There is debate over how much sun exposure is safe for your skin. Most dermatologists recommend always wearing sunscreen. If you are light skinned or are at higher risk for skin cancer, that's probably excellent advice. Other medical specialists believe most people can safely receive up to 10 minutes of sun exposure on their legs and arms without sunscreen to ensure their body makes some vitamin D.
Higher risk: Those at higher risk for low levels of the vitamin include people with darker skin; the elderly and those living in institutions such as nursing homes; those who are obese; those who have osteoporosis (weak bones); and those whose bodies don't absorb nutrients well because of gastric bypass surgery, bowel diseases such as celiac disease (which causes problems breaking down foods containing gluten), or inflammatory bowel disease such as Crohn’s disease.
Food and Daily Needs
Vitamin D is naturally found in only a few foods including fatty fish, eggs, and cod liver. When consumed in the usual amounts, none of these foods are high enough in the vitamin to meet your daily needs. Some foods such as milk, orange juice, yogurt, and some cereals are fortified with vitamin D, but amounts vary.
For most people, especially those living in the Northwest, a vitamin D supplement is a good idea. A vitamin D3 supplement, as opposed to vitamin D2, is preferable whenever available.
How much is enough? If you don't have a risk factor for low vitamin D levels look for a daily supplement with 400 to 800 international units (IU) of vitamin D. If you're over 65, aim for the higher end of this range. Those in a higher risk group for low levels may need 2,000 units daily or even more. But be sure to talk with your doctor first. Taking too much vitamin D can lead to problems like kidney stones.
If you're concerned about your vitamin D level, ask your doctor if a blood test is warranted. Future studies will hopefully further clarify the optimal amount of vitamin D that is best for your overall health.
This article was originally published in 425 magazine in July 2014.