Restriction diets associated with reduced growth among children with milk, other allergies
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Key takeaways:
- Infants and children with cow’s milk and other allergies consumed less calcium than those with no allergies.
- These allergies were associated with significantly low weight and height z scores.
Infants and children with cow’s milk allergy and multiple food allergies had high gaps in nutrition, decelerated growth and unbalanced bone metabolism, according to a study published in Annals of Allergy, Asthma & Immunology.
Children with cow’s milk allergy should receive balanced nutritional support as soon as possible after diagnosis, Cansin Sackesen, MD, professor, division of pediatric allergy, Koc University School of Medicine, and colleagues wrote.
“In clinical practice, it is a well-known observation, studied in the literature, that children with cow’s milk allergy exhibit low growth parameters, namely weight and height, due to the necessity of eliminating milk from their diet, which is a mainstay of treatment,” Sackesen told Healio.
However, she continued, the mechanism behind this bone metabolism remains uncovered.
“Despite widespread vitamin D supplementation, lower height and weight persist,” Sackesen said. “Thus, we aimed to investigate a new biochemical marker to serve as a predictor of the impairment of bone metabolism.”
Study design, results
The study included 125 children aged 6 months to 18 years with an IgE-mediated food allergy, including 66 (52.4%) with cow’s milk allergy alone and 59 (47.2%) with other food allergies such as egg, tree nuts, peanut, sesame, wheat, legume, beef, chicken and banana in addition to cow’s milk allergy. The cohort also included 69 children with no food allergy.
The children with cow’s milk allergy were put on diets that eliminated foods that included cow’s milk, and those with cow’s milk and other allergies were put on diets that eliminated those other foods as well.
The children with multiple food allergies including cow’s milk had the lowest z scores for weight, height and BMI, and those with cow’s milk allergy alone had the next lowest z scores in these metrics, compared with the controls (P < .001, P = .004, P = .002, respectively).
Also compared with the controls, weight and height z scores were significantly lower for
infants aged 6 to 24 months with cow’s milk allergy alone (P = .007) and multiple allergies including cow’s milk (P = .036).
Similarly, children aged 2 to 18 years with cow’s milk allergy alone (P = .007) and multiple allergies including cow’s milk (P = .03) had significantly lower weight and height z scores compared with the controls as well.
When the researchers compared the z scores for height and weight between children with and without atopic dermatitis, they said they did not see any differences between children who did and who did not have cow’s milk allergy.
Across the full cohort, children who had asthma or wheezing (n = 35) had similar weight z scores compared with the children who did not have asthma or wheezing (n = 159), but their height z scores were significantly lower (P = .011).
The groups did not differ in overall daily energy intakes, the researchers continued. But compared with the controls, the allergy groups had significantly lower percentages of protein (P < .001), fat (P < .005), vitamin B2 (P < .001), vitamin B12 (P < .01), niacin (P = .043), calcium (P < .001) and phosphorous (P < .001) intake and significantly higher mean percentages of carbohydrates (P < .001).
Sackesen said that these lower percentages among children with cow’s milk allergy represented a “nutrient gap” among these children.
The allergy groups also had normal blood calcium levels, but they were significantly lower compared with the controls (P = .01). The researchers also categorized the levels of calcium as significantly low in infants aged 6 to 24 months but not among children aged 2 to 18 years in the allergy groups (P = .001).
Children aged 2 to 18 years with cow’s milk allergy alone had the highest levels of parathyroid hormone (PTH) at 51.9 (33.8-61.9), followed by the multiple allergy group at 43.4 (31.2-61.8) and then the controls at 29.3 (25-39.4; P = .003).
Also, the allergy and control groups all had similar levels of vitamin D.
The researchers further said that there was a negative correlation between serum calcium level and age in the control group based on the Spearman correlation test (r = –0.627; P < .001) and the allergy groups (r = –0.248; P = .006).
PTH levels increased with age with a significant positive correlation in the allergy groups (r = .0591; P < .001) but not in the control group (r = .058), also in Spearman correlation testing.
Among the allergy groups, children who did not take calcium and/or vitamin D supplementation had significantly higher PTH levels than those who did use these supplements (P < .001).
“While [PTH] levels remained similar between controls and [cow’s milk allergy] affected children up to the age of 2, PTH was significantly higher in the [cow’s milk allergy] group thereafter,” Sackesen said.
These findings suggest that PTH secretion is notably elevated in older children with cow’s milk allergy compared controls aged 2 and older, she continued.
“The significantly higher PTH secretion in older children with [cow’s milk allergy] may contribute to maintaining a similar level of serum calcium as in controls who do not eliminate calcium-rich milk-containing foods,” Sackesen said.
Also, children who used calcium and/or vitamin D supplementation had significantly higher serum 25(OH)D vitamin levels than those who did not in the control group (P = .024) and in the allergy groups (P < .001).
Food allergy, eosinophil percentage, serum calcium level, asthma, and carbohydrate and calcium intake in 3-day nutrition all were individually significant in a univariate linear regression model, the researchers said.
Intake of fat percentage in nutrition (= 0.036; P = .006) and asthma (= 0.661; P = .036) had significant associations with z scores for height in a multivariate-adjusted linear regression model as well.
The researchers further called food allergy, calcium supplementation, and energy, protein, carbohydrate, fiber, folic acid, magnesium, phosphorus, calcium, and vitamin E, K, B2 and B6 intake individually significant in the univariate-adjusted linear regression model.
The multivariate-adjusted linear regression model found significant associations with weight z scores and food allergy diagnosis (= –0.964; P = .008) and calcium (= 0.002; P = .045), phosphorous (= –0.005; P = .012) and magnesium (= 0.012; P = .018) intake.
The researchers also called food allergy, multiple food allergies, eosinophil percentage, serum vitamin D level, and energy, protein, carbohydrate, fat, fiber, folic acid, magnesium, phosphorous, copper, and vitamin E, K, B2, and B6 intake in the 3-day food diary individually significant in the univariate-adjusted regression model as well.
Finally, the researchers found significant associations between BMI z scores and eosinophil percentage (= –0.083; P = .045), serum vitamin D level (= –0.026; P = .044), and fat (= 0.113; P = .041) and magnesium (= 0.01; P = .033) intake in the multivariate-adjusted linear regression model.
Conclusions, next steps
These associations between cow’s milk and other allergies and weight, height and BMI z scores in infants and children indicate a need for vigorous programs including calcium and vitamin D supplementation that families could enroll in as soon as these allergies are diagnosed to help them overcome these challenges, the researchers said.
“These findings imply that PTH may compensate for the low nutritional intake of calcium, and PTH levels could serve as a promising indicator for maintaining balanced nutrition, encompassing calcium, phosphorus, vitamin D, and supporting healthy growth in school children with [cow’s milk allergy],” Sackesen said.
Considering the associations between cow’s milk allergy and asthma also found in this study, the researchers additionally called for bigger longitudinal cohort studies to better understand the impact of atopic comorbidities on growth in children with food allergy.
“Our study was not conducted longitudinally and did not assess whether the children experienced prolonged elevation of PTH or a transient increase in response to low calcium levels,” Sackesen said.
Also, recurrent elevation in PTH secretion or prolonged high PTH levels can present a risk for bone resorption to maintain serum calcium equilibrium, she continued.
“While infants may not face this risk, children older than 2 years may be susceptible to bone resorption due to elevated PTH secretion, with this association potentially becoming more pronounced with increasing age,” Sackesen said.
“Future research investigating the impact of calcium supplementation across different age groups could elucidate the relationship between PTH secretion, dietary calcium supplementation and serum calcium levels in patients with [cow’s milk allergy,” she said.
For more information:
Cansin Sackesen, MD, can be reached at csackesen@yahoo.com.
Perspective
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These results are not surprising to me at all considering how restricted diets are one of the most common ways that nutrient deficiencies show up in both adults children. It also is not surprising that these infants and children had unbalanced bone metabolism and low blood calcium, as dairy products are the source of calcium in children’s diets in the United States.
Working with children in the past, it was common to see those with allergies and multiple food restrictions struggling more with growth, nutrient deficiencies and even behavioral issues as a result of poor nutrition. Infancy and childhood are particularly sensitive times due to the extra nutrition needs required for growth. Kids who do not get adequate nutrition during these years may struggle even past childhood with health concerns such as poor cognition and cardiometabolic disease risks if inadequate intake is not dealt with quickly enough.
Doctors can help with referrals to dietitians who can work with these kids and families to learn what nutrients they may be missing in their diet and what foods they can add to make up for these deficiencies. In tougher cases, doctors may also chat about supplementation if kids and their families have a hard time consuming enough of these missing micronutrients through diet alone.
If children are avoiding milk due allergies, calcium and vitamin D are top priorities to try to get through other sources. Foods canned beans, eggs, hummus, salmon, sardines, tahini, figs, bok choy, collard greens and cooked spinach are all examples of nondairy foods high in calcium. Fatty fish salmon and sardines are also great natural sources of vitamin D, but nondairy milk, orange juice and certain cereals are often fortified with this nutrient as well.
In future studies, I would love to see a cohort given diet education to see if dietary changes recommended by a professional have any outcome in changes in dietary patterns and growth outcomes.
The study also noted that the mean percentage of carbohydrates was significantly higher in the cow’s milk allergy group vs multiple food allergy groups compared with controls, so I would like to assess (based on NOVA food classification system scores) if there is a correlation between a higher processed/high carbohydrate diet and growth outcomes.
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