How can we here in sunny California be low in vitamin D? Vitamin D is known as the sunshine vitamin, as we get most of it from exposure to sunlight. Yet, disturbingly, many children and adults all over the country, as well as locally in the Central Valley, are deficient in vitamin D.
Why is this important? Well, vitamin D is not technically a vitamin at all, but is actually a hormone, with effects on every organ system in our bodies. Being deficient in vitamin D can increase our risks of many different illnesses, including heart disease, diabetes, Alzheimer’s, Multiple Sclerosis, osteoporosis, thyroid disease, and cancer.
It can also lead to growth stunting in children. Early symptoms of Vitamin D deficiency can be headaches, fatigue, bone pain, sweaty heads in infants, severe period cramps in women, and anxiety or depression in some susceptible people. The symptoms are so varied because Vitamin D is so important to so many parts of the body and brain.
Years ago, it was thought that this vitamin was important only for bone growth, and it was recognized that Rickets, a severe disease of bone in children, was due to deficiency of vitamin D. As a result, our milk was fortified so that children would receive enough vitamin D to prevent Rickets.
So why are we having an epidemic of vitamin D deficiency? There are many factors that affect an individual’s levels of vitamin D, but the primary factor is the amount of sun exposure. Exposure has to be at the right time of day (10 a.m. to 3 p.m., when the sun is at the proper angle), the right time of year (April through September in the Modesto region), and even the right weather conditions and air quality conditions (clouds and fog block vitamin D absorption, and so does air pollution).
So here in the Valley, most people who are either working or at school during the middle part of the day are not receiving enough natural sun exposure to keep their vitamin D levels in a healthy range. We also use sunscreen liberally here, as at our elevation there are more UVA rays, which cause sunburn, than there are UVB rays, which give us vitamin D. And sunscreen very effectively blocks absorption of vitamin D.
Besides that, many children, teens and adults are not just indoors for school and work, but stay indoors a majority of the time, watching TV or playing video games, or doing homework.
Although people do consume some vitamin D in fortified foods, such as milk, it is difficult to get enough D from food, as it is not present in large amounts. For instance, it would take 20 cups of milk each day to give sufficient D for a school age child who is not getting any sun exposure. And many children no longer drink milk, substituting juice, soda, and sports drinks instead. Furthermore, when people get overweight or simply start to age, their absorption and processing of vitamin D alters, so they are even more likely to become deficient. So in reality, most people here in the Central Valley have one or more risk factors for being deficient in the sunshine vitamin.
Yet maintaining a healthy level of vitamin D does not have to be difficult. Vitamin D is available in drops and chewable tablets for children, and in capsules for adults. The most recent recommendations from the Vitamin D Council suggest that a newborn should get 400 IU of vitamin D, a toddler 800 IU, a 40 pound child 1,200 IU, a 60-80 pound child/pre-teen about 2000 IU, and a teen or adult between 3,000 and 5,000 IU daily. Children’s vitamins routinely have only 400 IU in them, and many adult multivitamins have 400 to 800 IU.
So, unless you are someone who works, lives, and plays outdoors, without constant shade or sunscreen, it is wise to supplement with vitamin D.
Yvonne Brouard is a pediatrician at Sutter Gould Medical Foundation in Modesto.