Vitamin Deficiencies After Bariatric Surgery & Ocular Consequences

Vitamin Deficiencies After Bariatric Surgery & Ocular Consequences

Bariatric Surgery? Nutritional Vigilance Wise

More than 60% of U.S. adults now meet the criteria for being overweight or obese, and bariatric surgery has become a popular way to combat this problem. Despite complications such as nutrient deficiencies that are associated with weight loss surgery, it’s estimated that the number of obesity surgery patients in the U.S. will exceed 1 million in the next few years.

Most bariatric surgery centers offer guidelines for how to eat and drink to avoid complications post-op, as well as how to consume nutrient-dense foods for the long haul. Surgeons also emphasize the need for multi-nutrient supplementation, which should begin prior to surgery, and continue for life. But the problem is that many patients don’t follow up with their surgeons as advised. Thus, nutritional vigilance by all health care professionals is increasingly important.

What Are Common ‘Problem’ Nutrients?

According to the most recent reviews, bariatric surgery patients are commonly at risk for deficiencies of water-soluble vitamins B12, B1, folate and C; fat-soluble vitamins A, D, E and K; and the minerals iron, zinc, selenium, calcium, magnesium and copper. Deficiencies of vitamin B12 and iron are perhaps the most commonly observed, but shortfalls of the fat-soluble vitamins can also occur. Keep in mind, too, that these patients are more likely to have marginal levels or deficits of multiple nutrients rather than a single deficiency.

The risk for micronutrient depletion is highest after surgeries that affect digestion and absorption, such as the Roux-en Y gastric by-pass (RYGB), the most frequently preformed type of weight-loss surgery. RYGB greatly increases the risk for vitamin B12 deficiency. But other B vitamins – especially B1 – as well as minerals can also be affected.

Biliopancreatic surgeries (BPD), the second most frequently conducted, increase the risk for a number of nutrient shortfalls. The risk for fat-soluble vitamins A, D and K appears to be higher, as fat malabsorption is induced with this procedure.

In the past it was thought that nutrient deficiencies wouldn’t be a problem in patients undergoing “restrictive” types of surgery such as the adjustable gastric band or “lap banding”. However, poor food choices, food intolerances and the limited size of food portions can all contribute to the risk of vitamin and mineral shortfalls. Deficits of thiamine (B1), folate and others have been reported – especially in “banding” patients experiencing vomiting, inadequate food intake or rapid weight loss.

Signs & Symptoms: Vitamins B1 and A Deficiencies

Deficiencies of vitamins B1 and A can sometimes include ocular signs. One early symptom of low vitamin B1 levels is fatigue since this vitamin is required for the energy-yielding metabolism of carbohydrates. Overt deficiency can lead to dry beriberi and even Wernicke encephalopathy which affects the nervous system. A patient with “bariatric beriberi” may have weakness, dizziness, blurred vision, peripheral neuropathies (often beginning with a tingling in the toes and hands), and difficulty walking.

One central neurologic complication of B1 deficiency is Wernicke encephalopathy which classically presents as mental confusion, memory loss, rapid or abnormal eye movements (nystagmus), and an unstable gait. Many of these symptoms can be mistaken for stroke, so it’s important to know a patient’s surgical history. Treatment is considered a medical emergency, entailing rehydration as well as IV administration of thiamine to avoid long-term mental impairment.

Vitamin A is another example. Night blindness, drying of the conjunctiva with Bitot’s spots, dry skin and poor wound healing can be early symptoms of deficiency. More advanced deficiency symptoms include corneal damage, softening and degeneration of the cornea (keratomalacia), inflammation of the ocular cavities and adjacent structures (endophthalmitis), rough dry skin (xerosis) and hyperkeratinization of the skin. Some treatment guidelines call for 10,000-25,000 IU of vitamin A orally for several weeks when there are no corneal changes. When corneal changes are present, higher levels (50,000-100,000 IU) are sometimes given intramuscularly for several weeks.

Shortfalls of Lutein and Zeaxanthin?

Eye care professionals are in a unique position to monitor the status of lutein and zeaxanthin – two non-vitamin, but important fat-soluble nutrients. This might be accomplished by assessing a patient’s macular pigment density, and recommending supplemental lutein and zeaxanthin where warranted or even as a cautionary measure.

Concentrations of these macular pigments decline naturally with age, which is thought to increase the risk for AMD. It’s possible that post-bariatric malabsorption of lutein and zeaxanthin could exacerbate that risk over time. Since only the status of traditional vitamins and minerals are routinely monitored, there’s scant information about the impact of weight-loss surgery on the status of nutrient such as lutein and zeaxanthin. Nor are many primary care physicians or bariatric surgeons aware of this potential issue.

How Can Eye Professionals Help?

In addition to watching for nutrient deficiency signs and symptoms, here are several tips for helping weight-loss surgery patients keep on track:

• Ask whether a patient is keeping up with his/her recommended supplement regimen.

Non-compliance with taking recommended supplements is often what gets patients who’ve undergone bariatric surgery in trouble. Supplementation must be continued for life, and the supplemental level required to prevent deficiencies for many nutrient far exceeds what any healthy diet can supply.

• Remind patients to visit their primary care physician regularly for nutrient status assessments.

Even those already taking supplements should be closely monitored for vitamin deficiencies.

Some deficiencies, such as vitamin B1, can occur rapidly, while deficiencies of fat-soluble vitamins can take much longer to develop. Many patients also require extra supplements of specific nutrients in addition to a daily multi-vitamin and mineral. For example, current recommendations for gastric by-pass patients include: 10,000 IU vitamin A, 50-100 mg B1, 300-500 mcg of B12 (some may also require B12 injections), 300 mcg daily of vitamin K, 800-1200 IU vitamin D and 1200-1800 mg of calcium.

References

1. Aasheim ET. Wernicke encephalopathy after bariatric surgery. Annals of Surgery 248:714-720, 2008.
2. Aills L et al. ASMBS Allied Health Nutritional Guidelines for the Surgical Weight Loss Patient. Surgery for Obesity and Related Diseases 4:S73-108, 2008.
3. Matrana MR and Davis WE. Vitamin deficiency after gastric bypass surgery: a review. Southern Medical Journal 102:1025-1031, 2009.
4. Matrana MR and Davis WE. Vitamin deficiency after gastric bypass: Why multivitamins aren’t enough. Clinical Nutrition Insight 36:1-4, August, 2010.
5. Shankar P, et al. Micronutrient deficiencies after bariatric surgery. Nutrition, April 2nd, 2010 [Epub ahead of print].