Bone Health, Vitamin D, and Obesity - Again!

Vitamin D deficiency is common with obesity. When vitamin D is deficient, calcium tends to be deficient, too. But the body has a way of keeping the calcium level in the blood looking normal. That is, by raising the level of a hormone called "parathyroid hormone" (has nothing whatsoever to do with thyroid hormone), calcium is actually taken away (say, stolen away) from the bones, to keep its level looking normal in the blood. The bones lose calcium, and become weaker, more fragile and more likely to break. We are talking osteopenia and osteoporosis.

A new study from the University of Nebraska Medical Center, Omaha, was published recently in the Journal "Obesity Surgery". The study found out that vitamin D deficiency is common in obese patients at the time of bariatric (weight loss) surgery and is also accompanied by an increased level of parathyroid hormone, approximately half the time. So, vitamin D deficiency after bariatric surgery is not purely a complication of bariatric surgery. It is, at least in part, caused by vitamin D deficiency before the surgery itself. To reach those conclusions, the authors did blood tests to measure the levels of 25-hydroxyvitamin D, iPTH (intact parathyroid hormone), and calcium in 41 patients before undergoing Roux-en-Y gastric bypass. Then, they compared them to healthy non-obese matched controls. About half of the pre-bariatric surgery patients had elevated hyperparathyroid hormone level, compared to only 2% of controls. Levels of vitamin D (25-hydroxyvitamin D) were significantly low in more than half of the obese patients.

This actually reminds us of a previous study that we reported here. In that study, from Maine, before bariatric surgery, 34% of patients had suboptimal levels, and 54% had deficient levels, of 25-hydroxyvitamin D in their blood. By one year after Roux-en-Y gastric bypass surgery, the vitamin D deficiency improved remarkably with the intake of vitamin D supplements. The researchers actually recommended higher-than-average doses of vitamin D supplementation.

Reference Article:

Goldner WS, Stoner JA, Thompson J, Taylor K, Larson L, Erickson J, McBride C. Prevalence of vitamin d insufficiency and deficiency in morbidly obese patients: a comparison with non-obese controls. Obes Surg. 2008 Feb;18(2):145-50. [PMID: 18175194] (Abstract)

More References:

Nelson ML, Bolduc LM, Toder ME, Clough DM, Sullivan SS. Correction of preoperative vitamin D deficiency after Roux-en-Y gastric bypass surgery. Surg Obes Relat Dis. 2007 Jul-Aug;3(4):434-7. [PMID: 17400028] (Abstract)

Vitamin D supplements and Obesity

Did you know that there is a high incidence of vitamin D deficiency with obesity? The reason is probably that vitamin D is fat-soluble, so it deposits in the fat stores, and becomes less available to the body. There is a possibility that lack of adequate sun exposure, which is common in Seattle area and in the Northern regions, could contribute to a baseline vitamin D deficiency. This means that a typical patient most likely has a deficit of vitamin D before bariatric (weight loss) surgery. A study from the University of Maine, that was recently published in the journal "Surgery for Obesity and Related Diseases" (1) , showed the results of evaluating how adequate the correction of vitamin D deficiency is, one year after gastric bypass surgery. Before surgery, 34% of patients had suboptimal levels, and 54% had deficient levels, of 25-hydroxyvitamin D in their blood. By one year after Roux-en-Y gastric bypass surgery, the vitamin D deficiency improved remarkably with the intake of vitamin D supplements. Remember, nutritional supplements after weight loss surgery are not optional, they are a must. The researcher recommended higher doses of vitamin D than the average.



Vitamin D is essential for bone health. Calcium absorption requires vitamin D. Lack of calcium leads to osteopenia and osteoporosis. So, when you take your supplements, particularly after bariatric surgery, make sure that they include calcium and vitamin D. Actually, it may be better to start before having the surgery. Notice, though, that there are medical conditions in which taking extra calcium may be contraindicated. Therefore, make sure that your physician is OK with it. Also, after gastric bypass, the general recommendation is to take the calcium supplements in the form of calcium citrate, not carbonate. There is some controversy in that issue, but taking calcium citrate will keep you on the safer side, with regards to calcium absorption.



So, make sure that you take your nutritional supplements regularly, and stay healthy.



Reference:



(1) Nelson ML, Bolduc LM, Toder ME, Clough DM, Sullivan SS. Correction of preoperative vitamin D deficiency after Roux-en-Y gastric bypass surgery. Surg Obes Relat Dis. 2007 Jul-Aug;3(4):434-7. [PMID: 17400028]