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Side Effects of the Gluten-Free Diet

Impact on Cholesterol Levels, Vitamin Status, and Weight


Updated May 28, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

For celiac patients -- even those with no obvious symptoms -- adhering to the gluten-free diet can prevent serious, life-threatening complications. But just avoiding gluten does not guarantee that your diet is completely healthy. Keep the following issues in mind as you shop and plan your meals.

You Will Probably Gain Weight

Many of us were gaunt and sickly before we were diagnosed. Damage to the villi that line the small intestine -- a hallmark of celiac disease -- meant that food (and calories) couldn't be absorbed. After some time on the gluten-free diet, when the intestines begin to heal, the nutrients (and the calories) in foods can be absorbed. Even though we may not be consuming any more calories now than we did when we were eating gluten, it's likely that we're going to gain weight. In fact, hard as it may be to imagine for people who were too thin before their diagnosis, studies have shown an increased risk for obesity on the gluten-free diet. It's important to start counting calories.

You're At Risk for Poor Vitamin Status

Patients with newly diagnosed celiac disease often have nutrient deficiencies. Complicating that problem, gluten-free products are often low in B vitamins, calcium, vitamin D, iron, zinc, magnesium, and fiber. Few if any gluten-free products are enriched or fortified with these nutrients. When Swedish researchers studied adult celiac patients who had been gluten-free for 10 years, half of the patients had vitamin deficiencies, including low levels of vitamin B-6 or folate, or both, and high levels of homocysteine (a risk factor for heart attacks, vascular disease, and strokes). Before the study, all the patients had biopsies to prove their intestines were healed and healthy, so these vitamin deficiencies could not be explained by malabsorption. Italian researchers have found similar deficiencies in gluten-free adolescents. When it's time for an annual check-up, celiac patients should ask their doctor whether their vitamin status needs to be measured, and whether they should be taking folic acid and vitamin supplements.

Your Cholesterol Levels Will Probably Rise

For the first four decades of my life, while I was still eating gluten, my doctors always told me I had the lowest cholesterol levels they'd ever seen. It retrospect, it's easy to see why -- my intestines weren't absorbing any of the cholesterol in the foods I was eating. Those days are over. Now I have to watch my cholesterol levels along with everyone else. When I check food nutrition labels for the presence of gluten, I also check the fat and cholesterol content. It's very important to choose low-fat, low-cholesterol foods. Packaged gluten-free products are often higher in fat than their gluten-containing counterparts. This is especially true of packaged gluten-free cookies, crackers, and cakes. The American Heart Association points out that foods that are high in soluble fiber have been shown to help lower cholesterol -- so look for beans, peas, rice bran, citrus fruits, strawberries, apple pulp, and gluten-free oats.

You Might Experience Constipation or Diarrhea

If you replace the bread and pasta in your diet with only processed white rice, the low-fiber diet may lead to constipation. Conversely, if fiber-rich grains and beans are added to your diet in large amounts too quickly, you might develop gassiness and diarrhea.

Some People Actually Lose Weight

Dietary changes to eliminate gluten-containing foods can also lead to a decrease in caloric intake and weight loss.


Gluten-Free Diet Guide for Families. Children's Digestive Health and Nutrition Foundation/North American Society of Pediatric Gastroenterology, Hepatology and Nutrition.

Hallert C, Grant C, Grehn S, et al. Evidence of poor vitamin status in celiac patients on a gluten-free diet for 10 years. Alimentary Pharmacolology & Therapeutics 2002;16:1333-1339.

Kupper C. Dietary guidelines and implementation for celiac disease. Gastroenterology 2005;128(4 Suppl 1):S121-7.

Mariani P, Viti M, Montouri M, et al. The gluten-free diet: a nutritional risk factor for adolescents with celiac disease? Journal of Pediatric Gastroenterology and Nutrition 1998;27:519-523.

American Heart Association

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