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Post-Bariatric Surgery Supplement Savvy

While weight loss surgery can and does change lives for the better, it requires lifelong lifestyle changes. This includes taking supplements of important vitamins and nutrients to stave off deficiencies that can be caused by the surgery.

Some bariatric surgeries — such as gastric bypass, biliopancreatic diversion (BPD) and duodenal switch (BPDDS) — work by malabsorption, meaning that the body blocks the absorption of certain vitamins and minerals. This can result in serious nutritional shortfalls. Other restrictive procedures — such as Lap Band — also may cause nutritional shortfalls because people can no longer eat certain types of food and must restrict the volume of those foods that they can tolerate.

Nutritional needs vary based on the individual as well as the type of surgery, but here’s a primer on your post-bariatric surgery nutritional needs.


Most bariatric surgeons will suggest a daily multivitamin after weight loss surgery. However, multivitamins alone may not meet your specific nutritional needs. Talk to your doctor to see if you have to supplement your supplement.

Tip: Chewable and liquid multivitamins are the most easily absorbed, and are recommended after all bariatric surgery procedures. They are also less likely to cause heartburn and ulcers after gastric banding and gastric bypass surgery.


You must consume sufficient amounts of protein after bariatric surgery. Protein speeds wound healing, preserves lean body mass and enhances fat-burning. Most registered dieticians (RDs) recommend eating high protein foods first to avoid becoming too full, too fast, and not having room later on. Most people need to eat approximately four ounces (or more) of protein each day. Specific recommendations vary. Talk to your doctor or an RD.


Anemia is common in the months and years following weight loss surgery. Iron deficiency is the most common cause of anemia after bariatric surgery. This risk is heightened after gastric bypass and other malabsorptive surgeries in women who are still menstruating, and in the super-obese (body mass index of 50 or above). Some people may need more than what is found in their multivitamin. Talk to your doctor about how much iron you need.

Tip: Do not take iron supplements with tea, cola, coffee, calcium citrate or the thyroid medicine levothyroxine because they can interfere with absorption. Taking vitamin C with your iron supplements aids iron absorption. Either a Vitamin C pill or glass of orange juice can do the trick.

Vitamin B12

Most multivitamins do not contain adequate levels of B12. Some surgeons may suggest (and offer) monthly vitamin B12 shots. Others may recommend 500 micrograms of B12 taken under the tongue (sublingually) daily. These are readily available at many drug stores. Regardless of the form, vitamin B12 may help boost your metabolism, and enhance your weight loss efforts as you begin your life after bariatric surgery.


Folate or folic acid is another B-vitamin. Folic acid is known to prevent neural tube defects in pregnant women. It also prevents anemia, certain cancers and heart disease. Your multivitamin should contain 400 to 800 micrograms of folate. Ask your doctor if you need more. Foods that are rich in folic acid include leafy green vegetables, citrus fruits, berries and melon, dried beans, peas and nuts. Enriched breads, cereals and other fortified grain products also contain folic acid.


Calcium is important for bone health. After weight loss surgery, you may be at risk for the brittle bone disease osteoporosis and related fractures. This is a direct result of the nature of the surgeries. To compensate, most surgeons recommend a diet rich in calcium, combined with 1,200 to 1,500 milligrams of calcium supplements, split into two doses and taken twice daily. Older women may require more calcium.

Tip: Do not take calcium with your iron supplements as the two interfere with one another.Calcium and iron should be taken at least two hours apart.

Vitamin D

Vitamin D aids the absorption of calcium, which is needed to build strong bones after weight loss surgery. It is known as the sunshine vitamin because the human body produces it only when exposed to sunlight. Vitamin D also is added to multivitamins and milk.

Vitamin D deficiency is linked to a host of chronic diseases, including certain cancers, heart disease, osteoporosis, stroke, diabetes, immune system problems and inflammatory diseases. What’s more, obesity increases risk of Vitamin D deficiency.

Recommendations for vitamin D supplements are tiered based on blood levels. Most surgeons recommend supplementation starting at 2,000 international units per day. Get tested to see where you stand.

Vitamin A

Some people may become deficient in vitamin A following weight loss surgery. This fat-soluble vitamin is important for vision, particularly at night. The risk of vitamin A deficiency is heightened after BPD and BPDDS. Your surgeon should test your levels and suggest supplements accordingly.


Zinc deficiency may occur after bariatric surgery. This mineral is an essential building block for hair, skin and teeth. Make sure your multivitamin contains adequate amounts of zinc.

Vitamin B1 (Thiamine)

Thiamine deficiency may occur after weight loss surgery due to reduced acid production, restriction of food intake and frequent vomiting. This may lead to nerve problems and memory loss. Make sure your multivitamin contains sufficient thiamine, especially if you are vomiting frequently after surgery.

There are many companies that manufacture supplements specifically for people who have had bariatric surgery. See if there is a specific product line that your surgeon recommends. These supplements will likely be needed for the rest of your life. Do not stop taking them without discussing it with your bariatric surgeon or primary care doctor.