bone health redo

Protect Your Bone Health If You’ve Had WLS

November 2, 2016

Baratric surgery can be effective in treating severe obesity, and even at times reverse some complications of obesity such as Diabetes (Type 2). However, it is important to note that there is a risk of bone loss after bariatric surgery. The reasons for this continue to be explored, but one potential explanation is that individuals with obesity may have higher rates of deficiency in certain vitamins and minerals. Some of these – such as calcium and vitamin D – are required for bone health, so even when weight is lost after bariatric surgery, these individuals are at an even greater risk for bone disease.

As stated, vitamin D is a crucial nutrient required for reaching optimal bone mass. It has been consistently shown that increased body mass index (BMI) and increased body fat is associated with lower serum 25-hydroxyvitamin D (25D) concentrations. A deficiency such as this can then worsen after surgery if the individual is not eating and supplementing correctly. (1-3)

It is also important to note that certain procedures seem to increase the risk for low bone mineral density (BMD) more than others.

Roux-en-Y gastric bypass (RYGB) can result in greater risk for low BMD and fractures as compared to the laparoscopic adjustable gastric band (LAGB) and sleeve gastrectomy (SG), as RYGB is a more malabsorptive procedure. (1,2)

Recommendations to Protect Bone Health

Before surgery, it is important for those planning to undergo bariatric surgery to meet with their physician and dietitian to be sure that vitamin and mineral labs are reviewed, and the patient is supplemented accordingly. After surgery, it is crucial that the patient follows up with their physician and dietitian regularly based on the program’s protocol to ensure that he or she is receiving adequate nutrition and is taking the correct supplements. Appropriate supplementation will vary based on the individual and the procedure.

According to the American Society for Metabolic and Bariatric Surgery, following the LAGB, calcium supplementation is generally 1200-1500 mg/day; this should be taken in 2-3 separate doses and 4-5 hours apart to help promote maximal absorption. Vitamin D supplementation should be age-specific; this would be 600 International Units of vitamin D daily from age 19-70 years old and 800 International Units/day for those greater than 70 years old. Your physician and dietitian will monitor this lab value, and increase the dosage as needed; the goal is for this vitamin level (25D) to be greater than 30 ng/mL. These recommendations also apply for the sleeve gastrectomy. (1)

These same recommendations once again apply for those who have undergone gastric bypass (GB); however, it is important to note that in GB, calcium citrate is especially recommended as it is better absorbed than calcium carbonate due to the reduced gastric acid that results in this surgery. (1)

Foods that Promote Bone Health

Although supplementation is necessary after bariatric surgery, it is also beneficial to be aware what foods contain the nutrients that promote bone health. Calcium is necessary to build and maintain bones; this nutrient is also required for optimal function of both the circulatory and nervous system. We usually think of calcium as being in dairy products like cheese, milk, Kefir, and yogurt. However, it can also be found in figs, blackstrap molasses, legumes, sardines and other fish in which you eat the bones, as well as green leafy vegetables.

As mentioned earlier, vitamin D is required for adequate bone mass. Vitamin D helps the body to absorb the calcium that you ingest. Although vitamin D is found in some foods – such as fatty fish, fortified dairy and orange juice, and mushrooms – it is much better absorbed when taken in from the sun. However, we have to balance that need with our desire to keep safe from skin cancer. This is why supplementation with vitamin D3 is usually the best bet in meeting our vitamin D needs.

Another nutrient that isn’t always thought about as being important in maintaining bone health is vitamin C. Vitamin C acts as an antioxidant, helping to reduce bone breakdown as well as promote bone growth and maintenance. Food sources of vitamin C include citrus fruits, bell peppers, broccoli and Brussels sprouts, berries, and tomatoes. Adequate phosphorus – found in animal products and dairy as well as nuts and nut butters – is also necessary for bone health. Magnesium – sometimes included in calcium supplements, but also found in dark green leafy vegetables, whole grains, nuts and seeds – is necessary for bone formation as well.

Your Take-Away

Although bariatric surgery can lead to weight loss and even improvements in medical conditions, there is an associated risk for bone loss. This is why it is crucial to meet with your physician and dietitian prior to surgery, and then continue to follow up with these clinicians as stated in your program’s protocol, in order to reduce your risk for developing bone loss. It is necessary not only to aim to consume the discussed “bone-protecting” nutrients in the foods that you eat but also to supplement according to your specific surgery type and individual needs.


(1) Kim J. & Brethauer S. (2014). Metabolic bone changes after bariatric surgery. American Society for Metabolic and Bariatric Surgery

(2) Stein E.M. & Silverberg S.J. (2015). Bone loss after bariatric surgery: causes, consequences, and management. Lancet Diabetes Endocrinol, 2(2): 165-174.

(3) Vanlint S. (2013). Vitamin D and obesity. Nutrients, 5(3): 949-956.



Lauren C. Kelly, MS, RD, CDN earned her Masters of Science in Clinical Nutrition at Hunter College in New York. She received her Registered Dietitian credential from North-Shore LIJ, completing most of her clinical rotation at Lenox Hill Hospital in Manhattan. Lauren currently works as a Clinical Dietitian at New York Weill Cornell Medical Center. There, her passion lies in developing new educational materials and methods to more effectively communicate nutritious behaviors to her patients, with the goal for these behaviors to seamlessly continue at home.