Sunday, July 29, 2007

Fat Soluble Vitamins---Vitamin D---Part IV

This is the last in our ongoing discussion concerning Vitamin D. We'll focus on the research as it pertains to WLS. Check out the earlier posts (Part I, II, III).

First we look at this research concerning Vitamin D deficiency in those people even BEFORE they have WLS. As I posted in Part II, obesity is a risk factor for deficiency.

Prevalence of vitamin D depletion among morbidly obese patients seeking gastric bypass surgery:

BACKGROUND: Abnormalities in calcium and vitamin D metabolism have been reported after bariatric surgery. The purpose of this study was to evaluate vitamin D nutritional status among morbidly obese patients before gastric bypass surgery.
METHODS: We prospectively studied 279 morbidly obese patients seeking gastric bypass surgery for vitamin D nutritional status as assessed by serum 25-hydroxyvitamin D level. In addition, serum samples were analyzed for calcium, alkaline phosphatase (AP), intact parathyroid hormone (PTH), and 1,25-dihydroxyvitamin D.
RESULTS: Mean patient age was 43 +/- 9 years; 87% of the study patients were women, and 72% were white. Serum calcium and AP levels were normal in 88% and 89% of the patients, respectively. Vitamin D depletion, defined as serum 25-hydroxyvitamin D level < .001). Vitamin D depletion was significantly more prevalent in the African-American patients than in the white patients (91% vs 48%; P < .001).
CONCLUSIONS: Before gastric bypass surgery, a majority of morbidly obese patients have vitamin D depletion and secondary hyperparathyroidism. Studies evaluating the effects of gastric bypass on vitamin D metabolism must consider preoperative vitamin D nutritional status.
So....this means I was probably deficient in Vitamin D before I ever had my WLS. With the added problem of malabsorption after WLS, I am more than likely to still be deficient. So what risks am I taking by continuing to ignore the nutritional science available.

Effect of gastric bypass surgery on vitamin D nutritional status.

BACKGROUND: We previously reported a 60% prevalence of vitamin D (VitD) depletion, defined as a 25-hydroxyvitamin D (25-OHD) level of < or ="20">
METHODS: We prospectively studied 108 morbidly obese patients who had undergone GB. Routine postoperative supplementation consisted of 800 IU VitD and 1500 mg calcium daily. Serum calcium, parathyroid hormone, and 25-OHD were measured before and 1 year after GB.
RESULTS: The mean patient age was 46 +/- 9 years, 93% were women, and 72% were white. Preoperatively and at 1 year postoperatively, the prevalence of VitD depletion and hyperparathyroidism (HPT) and the mean 25-OHD level was 53% and 44%, 47% and 39%, and 20 and 24 ng/mL, respectively. One year after GB, the percentage of excess weight loss was 67% and demonstrated significant correlations both positively with 25-OHD and inversely with parathyroid hormone. At both intervals, blacks had a greater incidence of VitD depletion than did whites, and, at 1 year after GB, HPT was more common in patients with VitD depletion (55% versus 26%, P = .002).
CONCLUSION: With customary supplementation, VitD nutrition is improved after GB, but VitD depletion persists in almost one half of patients, and blacks are at a significantly greater risk than whites. HPT did not improve, and those with VitD depletion had a significantly greater rate of HPT. Additional prospective studies are needed to determine how to optimize VitD nutrition and avoid potential long-term skeletal complications after GB.

The majority of the research on WLS and Vitamin D, focuses on it's relation to calcium. So it looks at the effects on your bones. As pointed out in the previous posts, Vitamin D plays a part in many aspects of the human body. So don't forget that either.

Bone and Gastric Bypass Surgery: Effects of Dietary Calcium and Vitamin D

Objective:To examine bone mass and metabolism in women who had previously undergone Roux-en-Y gastric bypass (RYGB) and determine the effect of supplementation with calcium (Ca) and vitamin D.
Research Methods and Procedures: Bone mineral density and bone mineral content (BMC) were examined in 44 RYGB women (>=3 years post-surgery; 31% weight loss; BMI, 34 kg/m2) and compared with age- and weight-matched control (CNT) women (n = 65). In a separate analysis, RYGB women who presented with low bone mass (n = 13) were supplemented to a total 1.2 g Ca/d and 8 µg vitamin D/d over 6 months and compared with an unsupplemented CNT group (n = 13). Bone mass and turnover and serum parathyroid hormone (PTH) and 25-hydroxyvitamin D were measured.
Results:Bone mass did not differ between premenopausal RYGB and CNT women (42 ± 5 years), whereas postmenopausal RYGB women (55 ± 7 years) had higher bone mineral density and BMC at the lumbar spine and lower BMC at the femoral neck. Before and after dietary supplementation, bone mass was similar, and serum PTH and markers of bone resorption were higher (p>0.001) in RYGB compared with CNT women and did not change significantly after supplementation.
DISCUSSION: Postmenopausal RYGB women show evidence of secondary hyperparathyroidism, elevated bone resorption, and patterns of bone loss (reduced femoral neck and higher lumbar spine) similar to other subjects with hyperparathyroidism. Although a modest increase in Ca or vitamin D does not suppress PTH or bone resorption, it is possible that greater dietary supplementation may be beneficial.

Metabolic bone disease after gastric bypass surgery for obesity.

BACKGROUND: The popularity of gastric bypass surgery for treatment of morbid obesity has been increasing in recent years. Osteomalacia and osteoporosis are commonly observed in patients who have had partial gastric resections for treatment of peptic ulcer disease. Recently, we encountered four patients with previous gastric bypass surgery who had metabolic bone disease similar to that reported in the older literature in patients who had partial gastrectomies.
METHODS: Review of clinical data of four patients who developed osteomalacia and osteoporosis 9 to 12 years after gastric bypass surgery for morbid obesity.
RESULTS: All subjects were women, 43 to 58 years old. Three had Roux-en-Y gastric bypass, and the other had a biliopancreatic diversion 9 to 12 years prior to presentation. Weight loss averaged 41.8 kg. Patients reported fatigue, myalgias, and arthralgias. They had symptoms for many months or years before the correct diagnosis was established. All were osteopenic or osteoporotic with hypocalcemia, very low or undetectable 25-hydroxyvitamin D levels, secondary hyperparathyroidism, increased 1,25-dihydroxyvitamin D levels, and increased serum alkaline phosphatase. CONCLUSIONS: Relatively little has been published in the general medical literature about this postoperative complication of bariatric surgery. Yet, nearly all patients after bariatric surgery will receive their long-term follow-up from a primary care physician. Physicians and patients need to be aware of this complication and take measures to identify and prevent it.

As you can see many things can come about because of the malabsorption associated with WLS. Vitamin D is just one of the major players. So get your levels checked properly and take heed of these docs advice.

Remember what I said in Part II---I'd also like to stress that when taking a Vitamin D supplement, you must look at what kind it is. D3 (cholecalciferol) is the preferred form. Vitamin D found in multivitamins and calcium/vitamin D combinations is D2(ergocalciferol) and useless. It is also more associated with Vitamin D toxicity. But as I pointed out in the Part I of this series, Vitamin D must be taken in an oiled base formula NOT pills.

This ends it for Vitamin D. Hope you take the info and use it. It is just too important not to listen to the science. Look for more posts coming about vitamins.