Vitamin D and Bone Health from our Physician Assistant Kristina Stanson

Most people are aware that calcium is vital for supporting bone health and preventing fractures, but did you know that vitamin D is just as important? Vitamin D mediates the absorption of calcium and phosphorus, which are essential elements in building strong bones.  In addition to bone health, vitamin D also plays a role in cardiovascular health, cognitive function, musculoskeletal development and maintenance, immune function, and more!

Unfortunately, vitamin D deficiency is very prevalent. It is estimated that up to 1 billion people worldwide are vitamin D deficient or insufficient.  Smoking, obesity, race, inactivity, age, lack of sun exposure, diabetes, cancer, malabsorption, kidney and liver disease, and several other chronic medical conditions can contribute to vitamin D deficiency.

There is new evidence that vitamin D deficiency is associated with adolescent idiopathic scoliosis. A 2016 study by Mehmet Balioglu et al published in the Journal of Pediatric Orthopaedics found that patients with adolescent idiopathic scoliosis (AIS) had significantly lower vitamin D levels than the control group. The researchers concluded that there is a correlation between vitamin D deficiency and scoliosis, though further studies are needed to determine if there is a causative relationship. A Chinese team published a study in 2018 that showed evidence that daily calcium and vitamin D supplementation can prevent curve progression in some female patients with adolescent idiopathic scoliosis.

While more research still needs to be done, this is a promising discovery! As more conservative methods of managing scoliosis are developed, we can do more to prevent progression of curves and the potential need for surgery.

HOW MUCH VITAMIN D DO I NEED?

The National Osteoporosis Foundation (NOF) set forth the following guidelines for target calcium and vitamin D intake for adults:

The Vitamin D Council published the following chart which compares the recommended daily intake of vitamin D from several US organizations:

As you can see, there is quite a bit of variation between the different medical societies’ recommendations. At Hey Clinic, we typically advise our patients to supplement with 2,000 IU of vitamin D per day, and get vitamin D levels checked with their primary care provider (PCP) via a simple blood test. If the vitamin D level is <50 ng/mL, supplementation can be increased to 5,000 IU for a short period of time, with close follow-up with the PCP.

HOW CAN I INCREASE MY VITAMIN D?

Sunlight promotes vitamin D3 (cholecalciferol) production in the skin and is the most natural way of increasing vitamin D. The actual amount of vitamin D your skin will produce depends on your skin type, location, position of the sun and sunscreen use.  Of course, too much sun exposure can increase the risk of skin cancer, so it is not always the safest option.

It is difficult to get enough vitamin D through food alone. Fortified milk, orange juice and cereals, as well as fatty fish and egg yolks are good options, but are unlikely to satisfy your total daily need.

Vitamin D supplements are widely available over-the-counter and tend to be affordable. Calcium supplements often contain some vitamin D, though you will likely need a separate vitamin D supplement to reach the 2,000 IU dose.

WHAT IS THE DIFFERENCE BETWEEN VITAMIN D3 AND D2?

Vitamin D3, also known as cholecalciferol, is the form of vitamin D that the body naturally produces. This is the form that the Vitamin D Council recommends, and the form contained within the majority of over-the-counter vitamin D supplements.

Vitamin D2, also known as ergocalciferol, is primarily found in plants. Some sources claim that at high doses D2 may be less effective than D3.

IS IT POSSIBLE TO GET TOO MUCH VITAMIN D?

Yes, though it is unlikely. Vitamin D is a fat-soluble vitamin, meaning that it can be stored in adipose (fat) tissue making it more difficult for the body to excrete. (It is absorbed best when taken with high fat foods). If taken in very high doses, it is possible for vitamin D to build up to toxic levels. Vitamin D toxicity is most likely to occur in adults who take 40,000 IU per day for >3 months. The cutoffs for children vary by weight:

• For children that weigh 25 lbs or less, more than 50,000 IU in 24 hours or 2,000 IU/day for over three months is too much and potentially toxic.
• For children that weigh between 25 and 50 lbs, more than 100,000 IU in 24 hours or 4,000 IU/day for over three months is too much and potentially toxic.
• For children that weigh between 50 and 75 lbs, more than 150,000 IU in 24 hours or 6,000 IU/day for over three months is too much and potentially toxic.
• For children that weigh between 75 lbs and 100 lbs, more than 200,000 IU in 24 hours or 8,000 IU/day for over three months is too much and potentially toxic.

High dose vitamin D supplementation is contraindicated for people taking certain medicines or with certain medical conditions. Always discuss with your primary care provider before starting supplementation and get your blood levels checked to be sure you are in the proper range.

Sources:

• https://www.aafp.org/afp/2009/1015/p841.html
• https://www.vitamindcouncil.org/review-establishes-vitamin-d-deficiency-risk-factors-prevalence-and-treatment-for-individuals-worldwide/#.XSkU2uhKiM8
• https://aims.cuhk.edu.hk/converis/portal/Publication/78022768?auxfun=&lang=en_GB
• https:www.nof/org/patients/treatment/calciumviatmin-d/
• Balioglu, M. et al. Vitamin-D measurement in patients with adolescent idiopathic scoliosis. Journal of Pediatric Orthopaedics, 2016.
• https://www.vitamindcouncil.org/about-vitamin-d/am-i-getting-too-much-vitamin-d/#.XSkabuhKiM8
• https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/