What Happens If I Don’t Take Vitamins?

When our patients start their weight loss surgery journey, we try to stress the importance and permanence of the commitment they are making. Not only does bariatric surgery permanently change your body, it is ultimately changing the way your gastrointestinal system works. Whether you choose a gastric sleeve or gastric bypass, you will be eating differently than before and your body will now react to food differently. Because of this, we want to be very aware of how your body is maintaining levels of certain vitamins and minerals that we know can be affected by weight loss surgery. If you don’t take your vitamins, they can’t help you. So, what happens if you don’t take the recommended vitamins and minerals?


Stomach acid is reduced following weight loss surgery, except with the lap-band. Because of this decrease in acid, it becomes difficult to convert dietary iron obtained naturally from foods like meat, beans, greens, or nuts, to usable forms of iron. To compound this, gastric bypass patients also have a portion of the small bowel responsible for absorption of iron rerouted and eliminated from the digestive process.

Iron deficiency, often referred to simply as anemia, is not uncommon. In fact, many patients find they are iron deficient before undergoing surgery. Initially, those with low iron tend to feel more lethargic and weak. Iron is vital to the creation and support of red blood cells in your body, which carry oxygen to all of your vital organs, muscles, and tissues. Iron is also important to the body’s metabolic processes as well as key functions like healing, detoxification and growth. Patients with anemia may also notice changes in the hair, skin and nails. More seriously, deficiency in iron may also lead to shortness of breath and heart palpitations.

B Vitamins

Processes in the stomach normally allow the body to draw usable b12 from your diet. Because the stomach is altered in the sleeve and bypass, both stomach acid and an additional substance created in the stomach, called Intrinsic Factor, are reduced and b12 absorption is reduced. B12 deficiency typically develops slowly, and could take years to present. Long term supplementation and monitoring of B vitamins is important beyond the first year. Many patients will notice high levels of b12 while supplementing, but this may not mean that your body’s stores are adequately built up.

Pernicious anemia is the medical term used to describe the deficiency of vitamin B12. Weight loss surgery patients can also develop deficiencies in B9, known as Folate deficiency, when levels of Folic Acid dip below the acceptable range. Thiamin (Vitamin B1) can also become depleted. Initially, B12 deficiency may present as tiredness, weakness, paleness and lightheadedness. While these may not be immediately noticed or attributed to your b12 levels, it is an important factor to consider because as the stores become depleted, ailments included nerve problems, depression, memory problems, numbness or tingling, and vision loss.

Calcium & Vitamin D

When we don’t supply enough Calcium to the body, it begins to steal the mineral from other parts of the body. This includes our teeth and bones. For bariatric patients, we are already concerned with loss of bone density. Inadequate calcium levels lead to degenerative conditions like osteoporosis as well as increased risk of bone fractures. Calcium regulates heart rate and nerve transmission and without it, serious complications can occur. Vitamin D is necessary for the body to absorb Calcium. It also has links to cancer prevention as well as reducing risk of dementia. Vitamin D deficient patients can experience chronic pain, weakness, and frequent infections or depression.

How Do You Avoid Deficiencies Post-Op?

For most patients, avoiding vitamin deficiencies is easy. You simply follow a healthy diet and take your recommended supplements. However, everyone is unique, and some will find their bodies struggle to absorb and retain vitamins at healthy levels. Most patients find bariatric formulated vitamins help them most easily meet their goals. While these vitamins are tailored specifically for weight loss surgery patients, they can come with a higher cost, but are very much worth it.

Ultimately, preventing a deficiency from occurring is much easier than treat them once they become symptomatic. Because vitamins are stored in different ways by our bodies, some deficiencies can take several months or even years for serious symptoms to show. This is one of the many reasons we stress the importance of follow up, even years after surgery, and encourage you to keep in touch with us and attend support groups. We want you to notify us of changes, even if you don’t think they are related to your surgery. The human body is a complex system and the gut plays a large role. If you had bariatric surgery years ago and have not recently followed up, we encourage you to come in for a check-up. No matter what your weight loss status or amount of time since we’ve seen you, our goal is to support you and help you find and maintain your health.

Our Surgical Weight Loss Program and Bariatric Surgery Center's mission is to deliver safe and effective surgical solutions with a compassionate touch. Our bariatric program is operated by NYU Langone Long Island Surgical Associates, P.C., a network of leading physicians and surgeons that provide comprehensive care for patients.

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