Why is it Important?
Vitamin D is important for calcium absorption, bone health and plays a role in prevention of certain types of cancer, heart disease and other chronic disorders. Supplemental Vitamin D, combined with calcium, is essential because bone loss is a common problem following weight loss surgery.
Studies have found that 60% to 80% of bariatric pre-op candidates have low Vitamin D.
Vitamin B12 is an essential nutrient required for healthy blood cells and to preserve normal nerve function. Changes created in the gut by gastric bypass surgery result in depleted Vitamin stores because absorption from food is limited and ultimately results in a Vitamin B12 deficiency.
There are two key steps necessary to absorb Vitamin B12:
- Vitamin B12 in food is always bound to a carrier. Once food containing Vitamin B12 reaches the stomach, the acidic environment is ideal to break the Vitamin B12 from the carrier.
- Also, intrinsic factor, a compound needed for active absorption of Vitamin B12, is synthesized in the stomach. Both of these steps in Vitamin B12 absorption are hindered because weight loss surgery reduces the size of the stomach, the acidity of the stomach and the ability to produce enough intrinsic factor.
It is possible to absorb Vitamin B12 without intrinsic factor if intakes are very high. A limited set of studies have shown that individuals given high levels of Vitamin B12 can absorb about 1%-2% even in a low acid environment and without intrinsic factor.
Vitamin B12 deficiency can result in permanent damage to the nervous system.
Thiamin, Riboflavin, Niacin and Vitamin B6
All of these “B” vitamins have important roles.
It is particularly important to supplement with Thiamin because the “reserves” in the body are small, and need daily replacement. In one study, 15% of pre-bariatric surgery patients were low in thiamin.
Folic acid is an important B-complex vitamin. Deficiencies can lead to weakness, fatigue, difficulty with concentration, and irritability. However, overdoses have risks as well. Overdoses can mask B12 deficiency.
Iron deficiency anemia is the most common nutritional deficiency in the world.
Your entire body needs oxygen, and every cell depends on red blood cells to deliver that oxygen. To build red blood cells, iron is essential. Supplemental iron is needed to prevent anemia, a common side effect of weight loss surgery.
Common symptoms of anemia are fatigue, and reduced capacity to exercise. Getting enough iron is difficult because the body normally absorbs only 10% of iron from foods. Iron absorption is greatest in an acidic environment. Weight loss surgery reduces the size of the stomach and its ability to make enough acid for the best iron absorption. Plus, gastric bypass usually bypasses the duodenum and proximal jejunum, the most efficient absorption sites.
A note about Iron in multivitamins, and calcium: Calcium blocks iron absorption depending on how much calcium is present.
Vitamin A is important to maintaining good vision, gene expression, growth and immune function and more. At the same time, excessive Vitamin A can be toxic as well; chronic toxicity can cause reduced bone density, disorders of the brain and spinal cord, and liver abnormalities. For these reasons, it is most important to get Vitamin A dosage right.
A 2009 study in Obesity Surgery reports that almost 50% of pre-surgery patients are deficient in Vitamin C. Vitamin C deficiency has also been reported after gastric bypass surgery.
Sufficient calcium is essential to maintenance of healthy strong bones. The duodenum and proximal jejunum are important sites for calcium absorption, and these are usually bypassed in RNY Gastric Bypass Surgery. As a result, because bone loss is a common problem following weight loss surgery, use of a calcium plus Vitamin D supplement is essential.
Because higher doses of calcium inhibit iron absorption which is why Calcium and Iron should be taken at separate times of the day.