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Lactating mothers and their infants have special nutrition needs. Can women with limited food intake after bariatric surgery meet those needs?

An outpatient dietitian at Bellevue Woman’s Hospital in Niskayuna, N.Y., Karann Durr, RD, CDN, searched the Internet, consulted personal resources, and contacted other RDs for advice and information. She was left with nothing substantial. In the end, she and her hospital’s lactation consultant were forced to make professional guesses on the issue—lactation after gastric bypass surgery.

Durr explained, “I had to take the evidenced-based practice guidelines for lactation and the nutrient recommendations for gastric bypass and put the two together. Basically, because this is new, people are reluctant to venture there.”

The human body can adapt to the changing demands of lactation by increasing nutrient intake, improving absorption, decreasing excretion, or using tissue stores. For the patient who has undergone bariatric surgery, it is questionable whether the body’s natural adaptations for lactation can overcome the physiological changes the surgery has created.

According to Jeanne Blankenship, MS, RD, an expert in bariatric surgery and reproductive health from the University of California, Davis Medical Center, “We need to promote breast-feeding to this population—more than 80% of the women who have surgery are of child-bearing age. The numbers are going to keep going up.”

Blankenship further elaborates that “we do know that obese women are less likely to initiate breast-feeding and, if they do, they are less likely to make it to the major marks—three and then six months—let alone one year. What we don’t know is if a woman who was previously obese behaves like an obese woman or like a normal-weight woman in terms of lactation. There are definitely success stories, but I think a lot of these women fall through the cracks.”

Gail Hertz, MD, IBCLC, pediatrician and certified lactation consultant, points out that not all healthcare practitioners may be familiar with the long-term effects of bariatric surgery. “The average pediatrician probably isn’t aware of the impact of gastric bypass on nutrition because typically our patients aren’t undergoing the procedure themselves. In our practice, we do ask breast-feeding mothers about any breast reconstruction or reduction, but if the mother doesn’t volunteer information about her past surgeries, we may not know.”

Surgical Ramifications
Weight-reduction surgeries are classified as restrictive, malabsorptive, or a combination of the two. Operations such as vertical banded gastroplasty (VBG) and gastric banding aim to limit the amount of food that can be ingested and reduce the emptying rate of the stomach.

The Roux-en-Y gastric bypass (RYGB), bilio-pancreatic diversion (BPD), and the now uncommon jejuno-ilial bypass combine restriction and malabsorption. The RYGB utilizes a 30- to 50-milliliter pouch, formed by surgically separating the stomach. A gastrojejunostomy is created by anastomosing the stomach to the distal end of the jejunum.1

The BPD utilizes a subtotal gastrectomy to create a larger pouch than the VBG or RYGB. As a more complicated surgery, the small intestine is divided to create a gastroileostomy, bypassing the lower stomach, duodenum, and jejunum and leaving only the distal ileum for nutrient absorption.2

Due to the surgical alteration of the gastrointestinal tract using the RYGB and BPD approaches, patients require perpetual supplementation to meet minimal nutrient needs. If eating habits are too restrictive after VBG or laparoscopic banding, deficiencies may occur.3

Habits Under Investigation
Conduct a survey of bariatric practitioners and you will find varied vitamin and mineral prescriptions. In terms of pregnancy and lactation, the general nutrient recommendations may not meet increased requirements. Additionally, compliance with recommended supplements can be poor.4,5

Total weight loss averages 25% to 35% of initial body weight at 18 months after surgery.6,7 Pregnancy is not recommended within the first 18 to 24 months after surgery due to the active weight loss occurring. After 24 months, weight loss has stabilized or regain may begin to occur. Several articles have been published that address the needs of pregnancy after gastric bypass.8-12

Calorie consumption has been shown to be approximately 1,100 calories per day at one year post-op and 1,300 calories per day at 18 months.13 Post-gastric bypass patients’ diets have also been shown to be low in nutrients vital to pregnancy and lactation, such as iron, calcium, and folate.14 Actual vitamin deficiencies, other than vitamin B12 and folate, have yet to be quantified.15

Due to the absence of standardized follow-up of patients after surgery, there is inadequate information regarding the effects of bariatric surgery on many aspects of health.3 Women who have achieved healthy pregnancies face challenges when it comes to breast-feeding. Limited data exists to help practitioners guide mothers in the right direction.

Will the Maternal Diet Affect Milk Production?
Human milk is a symphony of nutrients that varies between mothers and changes with lactation duration or even time of day.16 In studies of lactation during famine conditions, malnourished mothers were able to produce sufficient breast milk and support normal growth in their infants.17,18 In several instances, maternal nutrition stores suffered as breast milk quantity and quality remained adequate.17,19

“It is definitely true that there is no reason that they can’t breast-feed if their diet is adequate. Compliance with vitamins and minerals is important. It really depends on the type of surgery, how long it has been since surgery combined with their breast-feeding history, age, and, of course, all the factors that affect breast-feeding in the general population,” explains Blankenship. When combining breast-feeding with a history of bariatric surgery, there are several key nutrients practitioners must focus on to achieve success in the breast-feeding relationship.

Calories
For lactation, the dietary reference intake is 500 calories higher than guidelines intended for women who are not breast-feeding. This recommendation of 2,700 calories per day is based on energy needed for milk production, energy mobilized from fat stores, and estimated metabolic rate. It is assumed that 66% of calorie needs will be provided by oral intake and 34% will come from fat stores gained during pregnancy.20

In one study, participants consumed approximately 1,500 calories per day for the first six months of lactation. Although these women had not undergone weight-loss surgery, their low calorie intake did not affect breast milk production and prolactin levels remained within normal limits.21

Vitamin B12
Several important steps in vitamin B12 absorption are affected by RYGB. Deficiencies have been discovered in 30% to 70% of patients one to nine years after RYGB.22-25 Hemoglobin or mean corpuscular volume levels may not reveal this deficiency.26
Secretion of hydrochloric acid may be nearly absent in the surgically created pouch.27 With decreased acid and pepsin exposure, vitamin B12 can not be cleaved from foods such as meat, milk, and eggs. B12’s attachment to glycoproteins and subsequent coupling with intrinsic factor is also hindered by the pathophysiology of the RYGB.6,28

Mothers who are B12 deficient during pregnancy may give birth to infants with subnormal B12 stores. Further depletion may occur as the infant is undersupplied via human milk from a B12 deficient mother.29

In a case study presented in 1994, a 10-month-old, exclusively breast-fed infant was found to have a vitamin B12 deficiency. Two years prior, the mother had undergone bariatric surgery. Although the mother was asymptomatic, she was also deficient in vitamin B12.30

In a similar scenario, a 12-month-old, exclusively breast-fed infant of a semivegetarian mother, presented with developmental delay, macrocytic anemia, low folate and B12 levels, a positive urinary methylmalonic acid peak, and a high homocystine level. The infant’s B12 deficiency was corrected parenterally. Two months later, the mother revealed she had undergone bariatric surgery six years earlier. Although the mother consumed vitamin B12 and iron supplements, the vitamin B12 level of her milk was found to contain only 42 picomoles per liter compared with a normal level of 184 to 812 picomoles per liter.31

Folate
Absorbed primarily by the proximal one third of the small intestine, folate absorption must now occur in a smaller surface area under modified conditions. Folate deficiency has been documented in up to 40% of patients after RYGB and is of great concern in regard to the onset of neural tube defects. Both serum folate levels and red blood cell counts should be evaluated to detect deficiencies and patients supplemented appropriately.3,23,32

Calcium
Due to the circumvention of the duodenum in RYGB, the primary absorption site for calcium is omitted. Passive diffusion of calcium must occur along the remaining small intestine. Serum levels may remain stable, as calcium is leeched from maternal stores.6 Reductions in maternal bone content occur during the first three to six months of lactation, but this loss is replaced in later lactation and after weaning.33
Breast milk calcium secretion does not appear to depend on the current calcium intake of the mother, nor does the intake of phosphorus, magnesium, or sodium. Maternal intake during pregnancy may predetermine the calcium content of breast milk after delivery.33-35

Vitamin D
The ideal amount of calcium and vitamin D gastric bypass patients need to maintain stable parathyroid hormone and 25-hydroxyvitamin D has yet to be determined. Typical amounts of 800 to 1,000 international units (IUs) are provided upon initiation.36,37,3

Infants may be influenced more by the vitamin D status of the mother during pregnancy and by the amount of sun exposure received rather than by vitamin D levels in breast milk. Human milk naturally contains low levels of vitamin D. Additionally, there is little evidence to suggest that lactation increases vitamin D needs in the mother.38-40

Guidelines have previously encouraged two hours per week of direct sun exposure or 30 minutes per week wearing only a diaper to stimulate adequate vitamin D production in the exclusively breast-fed infant.41 The American Academy of Pediatrics now recommends that infants less than 6 months old be kept out of direct sunlight to limit UVA light exposure and suggests that “all breast-fed infants receive at least 200 IU of vitamin D per day beginning in the first two months after delivery.”42

Iron
Decreased intake of sufficient sources of heme iron, a reduction in the acidic environment required to release heme iron, and changes in absorptive surface area impact iron stores.3,6 Iron deficiency may occur in up to 50% of patients after RYGB, especially in women who are still menstruating.6,22-26 Amenorrhea from sustained lactation can actually benefit women as decreased blood loss via the menstrual cycle can boost depleted iron stores.42

Although breast milk is a poor iron source, iron from human milk is better absorbed than formula.43 Lactoferrin, a whey protein connected with infant immune response, has been found in greater concentration in breast milk from iron-deficient women. It has been hypothesized that this increase may help protect the infant from iron deficiency.44-46

Some evidence suggests that standard multivitamins will not prevent a deficiency after bariatric surgery.13,22,23,25 Women who have undergone restrictive procedures may not require additional iron beyond the standard recommendations.47

Fat-Soluble Vitamins
Vitamin A deficiencies have only been reported to occur after biliopancreatic diversion in the nonpregnant population.15 Vitamin A levels should be tested early in pregnancy and patients should be counseled to consume adequate amounts of vitamin A via food. Women who oversupplement may be at risk of consuming intakes of preformed vitamin A in amounts greater than 5,000 IUs, which may cause birth defects.37 Fat-soluble vitamin content of breast milk has been found to be minimally impacted by recent intake of the mother.17

Water-Soluble Vitamins
Maintenance of adequate water-soluble vitamin levels in the body, especially thiamine, requires a continuous supply in the diet. Even patients who have undergone restrictive procedures can develop a deficiency if oral intake is inadequate.12,48,49

Vitamin C, niacin, thiamine, riboflavin, and vitamin B6 levels in human milk are greatly influenced by the mother’s diet. In studies of maternal supplementation of water-soluble vitamins, vitamin levels increased in human milk and then leveled off.17 High doses of vitamin B6 should be avoided as production of prolactin may be inhibited.50

Protein
No consensus has been reached on the extent to which protein energy malnutrition may develop after gastric bypass surgery. A protein intake of 65 grams per day is recommended for the first six months of breast-feeding.17 Patients’ diets and lab values should be evaluated, and patients should be encouraged to focus on high-quality protein sources to meet minimal guidelines.51

According to Kelly O’Donnell, MS, RD, CNSD, nutrition support specialist with the University of Virginia Medical Center, “Our average patient, two to three years out, is consuming about 900 to 1,000 calories per day. Specific food choices are one of the most essential points to stress. Snacks become very significant. Choosing low fat, high protein choices, which are good calcium sources, are very important.”

Fat
Lipid comprises one half of breast milk calories and is highly variable.16,52,53 The total lipid content of human milk is not affected by daily intake in normal mothers, although it has been correlated with maternal fat stores.54

Breast milk contains arachidonic acid (ARA) and docosahexaenoic acid (DHA), which have been associated with improved cognition, growth, and vision in children.55 Some experts recommend supplementation of ARA and DHA in the diets of both pregnant and lactating mothers, especially for those with limited diets.

A patient who failed to follow nutrition guidelines provided after her gastric bypass several years earlier suffered from anemia during her pregnancy and gave birth to an infant weighing little more than 5 pounds. Growth milestones were not reached and, upon assessing the mother’s breast milk at four months postpartum, an analysis of the fat content, or creamatocrit, revealed a low mean fat and calorie content. After the mother supplemented with formula, adequate growth was displayed in the infant at 6 months of age.56

Should We Wait for Weight Loss?
Exaggerated concern with reinitiating rapid weight loss after birth may cause some women to forgo breast-feeding altogether. Blankenship points out that there may be significant psychological issues to consider. “Many pregnancies are unplanned and women just want to get back to the weight loss. Patients have misconceptions about weight loss during lactation and they want to be able to drastically cut calories.”

Regardless of the fact that many studies have reviewed the impact of lactation on weight maintenance, true consensus has not been reached. Greater weight loss has been shown in breast-feeding mothers vs. women who choose to use formula, while other studies have been inconclusive.57-61

Gradual weight reduction, in amounts no greater than 1 pound per week, does not appear to negatively affect the quantity or quality of breast milk produced, though environmental pollutants stored in maternal fat tissue may be released into breast milk with extended weight loss.62,17

Vitamin and Mineral Supplements
Women of childbearing age should be advised to consume a prenatal vitamin containing 1 milligram of folate, 350 to 500 micrograms of crystalline vitamin B12, plus calcium citrate in amounts of 1,200 to 1,500 milligrams and vitamin D. Patients who have had gastric bypass surgery should consume 40 to 65 milligrams iron in the ferrous form daily.8,37 Some guidelines suggest that, during pregnancy, the prenatal vitamin should be given in addition to, not instead of, a daily multivitamin.10 The consumption of two prenatal vitamins may not be advisable because some combinations may exceed vitamin A and iron guidelines.37

Maternal lab values, including CBC, albumin, folate, vitamin B12, calcium, phosphorus, and 25-dehydroxy-vitamin D, should be tested during pregnancy and after birth to detect deficiencies and supplemented accordingly. Infants should be evaluated for appropriate growth, adequacy of B12, calcium, and folate levels throughout the duration of breast-feeding.

Careful Monitoring Equals Success
Carla Woodard, MSN, WHNP, nurse practitioner with the University of Tennessee Medical Center, emphasizes the importance of educating both patients and practitioners. “The challenge for healthcare providers lies in educating women pre- and post-operatively regarding the ramifications of stopping vitamin supplements, which a good number do. Lifelong B vitamin and calcium supplementation is a must for these patients, especially those planning a pregnancy. Pediatricians and pediatric nurse practitioners, as well as women’s healthcare providers, should also be made aware of these dangers.” The increased risk of nutritional deficiencies induced by bariatric surgery, coupled with the demands of lactation, requires careful monitoring by knowledgeable professionals familiar with both bariatric surgical procedures and the nutritional needs of lactating mothers and their infants.

— Julie Stefanski, RD, LDN, CDE, is a clinical dietitian, adjunct professor, and freelance writer in York, Pa.

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