Integrative Pediatric and Adolescent Health: Educational Web Column

Other Topics in this Series

• November 2009:
  Vaccinating our
  Children for Influenza
• April 2009: Eating
  Disorders
• January 2009: The
  Cold and Flu Season
• October 2008: Self-
  Regulation
• September 2008:
  Herbs and
  Supplements, Part II
• August 2008: Herbs
  and Supplements,
  Part I
• July 2008: The Benefits
  of 'Free Play'
• June 2008:
  Communicating With
  Your Provider

What does Vitamin D do?

Many decades ago when the Recommended Daily Allowance of vitamin D was established, the most important known function of the vitamin was bone health. A certain amount of vitamin D (and calcium) are necessary to prevent rickets–a condition characterized by weakened bones. Today, we know quite a bit more about other important functions of the vitamin, but we are still learning. For example, a number of studies have shown that it plays a vital role in the function of our immune system. Vitamin D supplementation has been shown to reduce the risk of influenza in winter months, and adequate levels of the vitamin may also be important for mental health, particularly in depression.

So far, studies suggesting these roles for vitamin D are retrospective–meaning we cannot draw firm conclusions from them. In the future, long-term prospective studies will help us understand how much vitamin D in our bodies is optimal and how we should best achieve this level.

How do we get our Vitamin D?

The main source of vitamin D in humans starts with a chemical process that occurs when our skin is exposed to the sun (specifically ultraviolet B wavelengths). The final production of active vitamin D requires the action of both the liver and the kidneys. The only significant natural dietary sources are fatty fish and fish liver oils. Several food sources are fortified with Vitamin D, including cow’s milk, infant formula and some soy, rice and other milks, but you should check the labels on these. In order to get the current recommended quantity (400 IU daily), an infant or child would need to drink 1 liter (about 34 ounces) of formula or cow’s milk every day. Some older infants may occasionally take this much formula, but children over a year of age should not take in more than about 20 ounces of milk a day because it can be irritating to the intestines and may replace other essential foods. This causes a bit of a challenge and emphasizes the importance of supplementation.

The same UV radiation that helps us make vitamin D can also damage our skin if we get too much of it, and using sunscreen of SPF 8 reduces vitamin D production by 98%. Generally speaking, we are now very well conditioned to use appropriate clothing, hats and sunscreens to protect us from the dangers of excessive sun exposure. In addition, our modern lifestyle has meant much more time indoors and less sun exposure. But this appears to have come at the cost of insufficient production of vitamin D.

It is very hard to give advice on how much sun exposure is ideal for making enough Vitamin D. Many factors go into determining how much is enough: the time of day and the season of the year (i.e., angle of the sun), cloud cover, skin tone, body surface area exposed, air pollution levels and one’s location on the globe (also related to the angle of the sun). We do know that there is no risk of overdosing on Vitamin D with lots of sun exposure. Also, if you’re taking a supplement, no amount of additional sun exposure will cause you to get too much Vitamin D.

While it is far from clear at this point, getting a certain amount of regular, ultraviolet sunlight exposure may have benefits beyond those associated with vitamin D. A low level of sun exposure has both pros and cons. It is clear that less UV exposure is linked to lower risk of skin cancers, but a number of studies associate higher risks of some autoimmune conditions (e.g., multiple sclerosis, type I diabetes and rheumatoid arthritis) in regions of the world with less sun exposure. Generally speaking, getting even a mild sunburn means you’ve had too much sun exposure at any one time. It’s difficult to give clear guidelines on how much is okay–you need to learn your own body’s tolerance and pay attention to the local conditions when you’re out. If you can avoid getting burned you should be alright.

Even though you can’t get an overdose of Vitamin D by sun exposure, you can if you take too much of it in the form of supplements. Too much Vitamin D by supplements can cause calcium levels to rise–causing deposits and affecting the functioning of muscles including the heart. But there is controversy over how much is too much. For adults and adolescents, 2,000 IU is certainly safe. Below are several recommendations for younger children.

Pregnancy and breastfeeding

Vitamin D deficiency is present in a wide range of populations in the U.S., including pregnant and breastfeeding women. It is clear that vitamin D levels during pregnancy impact the health and development of the fetus. Babies born to mothers with low levels of vitamin D have low levels themselves. Supplementation during pregnancy adequate to bring the mother’s blood levels up to at least 30–40 ng/L are enough to ensure appropriate levels in newborns. Breastmilk naturally contains very little vitamin D. During breastfeeding, mothers would have to take at least 6,000 IU of vitamin D in order to provide a “supplement” dose to their infants equivalent to giving the currently recommended 400 IU daily. While taking 6,000 IU daily during pregnancy and/or breastfeeding is likely safe, the science to date to back this up is insufficient.

What about cod liver oil?

For the last several years I have been recommending cod liver oil supplements to the families in my primary care practice. There are many forms of cod liver now available. Many have vitamin D and vitamin A either as natural components or added back in after a ‘deodorizing’ process. Some have the vitamin D and A removed completely. In an upcoming column I’ll discuss omega 3 fatty acids. I’ll address reasons for and against cod liver oil then. For now, be sure to read the labels to know what you’re giving to your child.

Recommendations:

During Pregnancy and Breastfeeding:

1. Talk with your obstetrician about Vitamin D early in your prenatal visits. 1,000 IU daily is a good goal. In addition, you might consider asking your obstetrician to include a vitamin D level in the routine blood tests done for screening to see if you may need more than 1,000 IU daily.

For Infants:

1. The American Academy of Pediatrics recommends a daily supplement of 400 IU starting days after birth for all infants, whether you are breastfeeding or using formula. The amount of vitamin D currently in infant formula is not enough without this supplement.
2. Moms who are breastfeeding and taking supplemental vitamin D still need to supplement their infants. It takes at least 6,000 IU daily for a breastfeeding mom to increase the amount of vitamin D in their breast milk. Talk with your doctor before taking this amount of Vitamin D.

For Children 1 Year and Older:

1. If your pediatrician does routine blood tests for anemia or lead exposure at around 1 year of age and you have not been giving 400 IU most days of the week, ask to include a vitamin D test as well (specifically, “25-hydroxy-vitamin D level”).
2. Some pediatricians do not perform routine screening blood tests (most important information can be gathered by asking you questions about iron sources and lead exposure, for example). In this case, if your child has blood drawn for other reasons, consider asking that a screening test for vitamin D be added.
3. If your child has a chronic health condition or significant emotional or behavioral concerns, it would be reasonable to check a vitamin D level.
4. The American Academy of Pediatrics recommends a daily supplement of 400 IU throughout childhood regardless of sun exposure or other dietary sources. In my opinion, 1,000 IU daily is more appropriate for older children and teens. However, it is too early to be able to conclusively recommend this. So if you choose to supplement at this level, be sure to talk with your doctor in case further monitoring is deemed necessary.

There are two forms of vitamin D: Vitamin D2 (ergocalciferol, made by plants) and Vitamin D3 (cholecalciferol, made by mammals). This part can get confusing and it is not essential that you know the difference. Most over-the-counter vitamin D products contain D3. Fortified milk might contain either one. And prescription forms of vitamin D are only D2. There is disagreement among scientists as to whether D2 or D3 is better. I reviewed a number of articles on the topic and do not see enough reason to recommend one over the other.

Over-the-counter Vitamin D supplements come in a number of formulations. Conveniently, there are liquid products dispensed in droppers that are easy to use for infants and small children. I do not have recommendations for specific products.

References*

Wagner CL, Greer FR. Prevention of Rickets and Vitamin D Deficiency in Infants, Children, and Adolescents. Pediatrics. 2008; 122(5):1142-1152.

Mitka M. More Evidence on Low Vitamin D Levels Fuels Push to Revise Recommended Intake. JAMA. 2009; 302(23):2527-2528. (Note: Subscription required to view article)

Greer FR. Vitamin D Deficiency—It’s More Than Rickets. Journal of Pediatrics. 2003; 143:422-3.

Lucas RM, Ponsonby A-L. Considering the potential benefits as well as adverse effects of sun exposure: Can all the potential benefits be provided by oral vitamin D supplementation? Progress in Biophysics and Molecular Biology. 2006; 92:140–149

*Note: Subscription may be required to view article

About the Column

This column presents an integrative medicine view on a range of topics relevant to children, teens and early adolescents including: nutrition, herbs & supplements, mind-body and self-regulation skills, and general health and wellness.

If you’re new to the concept of integrative medicine, take a few minutes to browse the UCSF Osher Center web site, particularly the page what is integrative medicine? 

Broadly speaking, integrative medicine is practicing good medicine. It is an approach to a child’s health that:

• places illness in the context of the child, rather than the child in the context of illness;
• takes into account family and environmental factors;
• neither rejects conventional medicine nor accepts complementary or alternative medicine (CAM) uncritically.

Integrative pediatric consultations are available at the Osher Center with Kevin Barrows, MD, Rick McKinney, MD, and Priscilla Abercrombie, RN, NP, PhD, AHN-BC. To make an appointment, please call the main clinic line at 415.353.7720.

David Becker, MD, MPH is an Assistant Clinical Professor in the Department of Pediatrics at the University of California, San Francisco, and Affiliate Faculty at the Osher Center for Integrative Medicine at UCSF. He started the Pediatric Integrative Pain Clinic in July 2008. This is a referral-based service for children and adolescents with chronic pain. For questions about referrals, please contact the main Mt. Zion Pediatric number: 415.885.7478.

In addition, we offer two healthy parenting stress reduction classes: Mind in Labor and Mindfulness-Based Childbirth and Parenting.