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Two new studies point to diet deficiencies in celiac disease

July 16, 2020

Lack of nutrients and knowledge about a healthy diet common in celiac disease

By Amy Ratner, Medical and Science News Analyst

Recent research into nutrition in the gluten-free diet found celiac disease patients lacking, with one study concluding vitamin and mineral deficiencies are common and another that patients’ focus on avoiding gluten interferes with their attention to overall healthy eating.

Researchers from the Netherlands found people with celiac disease on an established gluten-free diet continue to lack sufficient iron, zinc, and vitamins D and B6. Newly diagnosed patients also lack folic acid and calcium and vitamin B12. Investigators’ observations were based on a review of studies of celiac disease and nutrient deficiencies done around the world since 1960.

Osteoporosis, anemia and neurological symptoms can be indications of impaired nutritional status, the study, published in the journal Nutrients, found. In children, delayed growth highlights the impact the of vitamin and mineral deficiencies.

Meanwhile, researchers in Italy who surveyed people with celiac disease and people with inflammatory bowel disease (IBD) about their nutritional knowledge found that celiac disease patients were less aware of overall nutrition recommendations and tended to focus their diet mainly on avoiding gluten. IBD patients tended to follow a healthier diet, probably because they believe diet plays a major role in regulation of inflammation and consequent symptoms, according to the study, also published in Nutrients.

“Nutrient deficiencies can be an important contributor to some of the extra-intestinal clinical manifestations of celiac disease, such as anemia, premature bone loss, and neurological symptoms and failure to thrive,” said Salvo Alesci, Beyond Celiac chief scientist and strategy officer. “Yet, they remain poorly understood and researched.”

The two new studies highlight the limitations and challenges of the gluten-free diet as the only available option for celiac disease patients, Alesci said. They demonstrate that the diet may not only fail to resolve some of the nutrition deficiencies in celiac disease, but may inadvertently worsen the situation by becoming more of a focus for patient than healthy eating, he added. “These findings also point to the need for physicians, dietitians and healthcare providers to better educate celiac disease patients about nutrient deficiency and its consequences once the diagnosis is made,” Alesci noted.

Lack of nutrients

Nutritional challenges in celiac disease have long been recognized, but the Dutch study that reviewed previous research found that the causes of nutrient impairment are poorly understood. About 70 percent of the studies in the review were conducted in Europe, but 13 percent were done in North America. Others were done in India, Israel, Australia and South America.

“Despite their clinical significance, consensus is lacking on the pattern and frequency of nutrient deficiencies in celiac disease, the usefulness of their assessment at the time of diagnosis and during follow-up,” the study says.

For example, iron deficiency in newly diagnosed patients was described in six to 82 percent of adult patients and in 12 to 82 percent of children.

The authors call for research that explores differences between adults and children and between untreated and, “more importantly,” treated celiac disease. More long-term investigation of the prevalence of certain nutrient deficiencies, their resulting health complications and the potential role of nutrient supplements is needed, wrote the authors, all of whom are from Maastricht University Medical Centre.

Currently, evidence is inconclusive regarding whether nutrient supplements help with healing of the intestine, correction of vitamin and mineral deficiency or recovery from other conditions, they note. Future studies could provide evidence of the time it takes for celiac disease patients to recover from nutritional deficiencies and which factors influence the process.

“This may shed light on the questions of whether we should strive to achieve a more rapid recovery of nutrient levels in celiac disease patients after diagnosis,” the authors wrote, noting that studies could also clarify whether diet alone is enough or if supplements are needed.

People following the gluten-free diet who do not have celiac disease could serve as valuable controls in future studies seeking to determine the cause of nutritional deficiencies, that is whether it is diet or disease.

Related: Following a healthy gluten-free diet 

The study says nutrient deficiencies in newly diagnosed celiac disease patients may result from the loss of the absorbing lining of the intestine. Improvement in the intestine occurs gradually and recovery of nutrient levels after diagnosis takes time Vitamin B12, folic acid, calcium and magnesium appear to generally improve in celiac disease patients on a gluten-free diet.

The gluten-free diet appears to reduce the prevalence and severity of iron deficiency anemia, but iron deficiency was still found in 14 to 41 percent of adult celiac patients. “A considerable group of micronutrient imbalances improve yet remain a prevalent problem on a gluten-free diet, iron deficiency being a chief example,” the study says.

Even patients on a gluten-free diet who have biopsy-proven remission, may still lack in vitamins and minerals because they are not consuming a sufficient amount. And some nutritional deficiencies, for example Vitamin B6, may become even more prominent on the gluten-free diet, according to the study.

“The goal of [future studies] should be to relieve symptoms, recover the intestinal mucosa and reverse the consequences of celiac disease related malabsorption while enabling patients to secure a nutritionally adequate gluten-free diet,” the study says.

Lack of nutritional know how

Investigators from the University of Padua recruited about 100 patients each with asymptomatic celiac disease or IBD in remission from the University of Padua outpatient clinic, along with 65 healthy controls. All study participants filled out a questionnaire to measure their nutritional knowledge.

Celiac disease patients were less able to choose healthy food compared to both IBD patients and controls. Additionally, they were less aware of nutritional recommendations compared to healthy controls and less able to identify source of nutrients compared to IBD patients.

Treatment of celiac disease is focused on avoiding gluten-free food, with less emphasis given to the nutritional quality of the diet, the study says. When patients are diagnosed, doctors should focus not only on what foods to avoid, but also on a balanced diet, study authors wrote. They noted that their results support the Dutch researchers’ conclusion that dietitians should focus on a balanced diet for celiac disease patients and not only on eliminating gluten.

While IBD patients view diet as a crucial component in disease management, more than half have reported not receiving any information about diet, an earlier study had found. Despite that lack of information, the IBD patients in the Padua study tended to have better dietary knowledge compared to those with celiac disease.

The study is thought to be the first to evaluate nutritional knowledge using a validated questionnaire in a large group of celiac disease patients and comparing the results to those from patients with another immune-mediated disease involving the gastrointestinal tract, the authors wrote. A limitation of the study based on surveys might be that nutrient levels were not measured through blood samples, something that would give researchers a real idea of how nutritional deficiencies correlated to nutritional knowledge.

You can read more about these studies here and here.



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