Risks of rice on a gluten-free diet


Many gluten-free diets rely on rice as their staple grain for a number of reasons: it's inexpensive, readily available, and (perhaps most importantly) in most ready-to-eat gluten-free foods. Free foods like breads, cereals, cookies, and mixes.

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But research increasingly shows that those who eat a lot of rice, such as those with celiac disease and gluten intolerance, may be at risk of consuming problematic levels of arsenic, a toxic metal that tends to accumulate in rice. Additional research shows that other so-called "heavy" metals, including mercury, are also found in higher concentrations in people who eat gluten-free.

According to Trisha Thompson, a nutritionist and expert on celiac disease and gluten-free diets, the information about arsenic in those who do not eat gluten is concerning. Thompson, head of food testing services at Gluten-Free Watchdog, told Get Meds Info that she "took a close look" at the data she and other researchers collected.

"I am convinced that inorganic arsenic consumption among gluten-free people is a serious concern and deserves our attention," says Thompson.

Why does arsenic accumulate in rice?

You probably know arsenic as a poison; in fact, it has long been used as an invisible weapon. But you may not realize that arsenic exists in small amounts around us as a natural part of our rocks and soil, and as a result, it can be found in our water and even in the air.

Since arsenic is present in the soil, the plants that grow in that soil can absorb it, and when they do, they cannot easily remove it. Thus, it tends to accumulate in the grain, which is part of the plant that we end up eating.

The rice plant is more effective than most plants, including wheat, barley, and rye that contain gluten, at accumulating heavy metals such as arsenic. That's why rice eaters, like people who don't eat gluten-containing grains, may have higher levels of arsenic and other heavy metals.

There are two types of arsenic: organic arsenic and inorganic arsenic. Scientists agree that the inorganic type is more dangerous than the organic type. Unfortunately, this is the kind that tends to build up in rice.

As with rice, our bodies are not very efficient at getting rid of toxic substances like arsenic, so it also tends to build up in us, which can cause serious health problems.

Arsenic in large amounts can poison someone, but lower amounts of arsenic have been linked to many different cancers , including cancers of the skin , lungs , bladder , kidney , and liver . It is also associated with cardiovascular and neurological problems and, in fact, can affect many systems in the body.

Arsenic cannot be completely avoided; again, it is found in our soil, water, and air. Therefore, the FDA has established safety standards for the amount of arsenic that can be found in drinking water and has proposed standards for other foods, including apple juice.

People who follow gluten-free diets are at particular risk of exposure to arsenic

There is no question that many people on a gluten-free diet eat a lot of rice in a wide variety of ways. A quick inspection of the supermarket's gluten-free aisle reveals that rice, in one form or another, is an ingredient in about three-quarters of finished gluten-free cereals.

Therefore, with the rise in popularity of eating gluten-free foods, researchers began to focus on the levels of arsenic in both the food and the people who consume it. Thompson is one of those researchers: She and a colleague surveyed people with celiac disease to find out how much rice they eat each week to assess the effects of arsenic on them.

Researchers have found that people with celiac disease get rice from a variety of sources, including plain rice, gluten-free rice bread, and rice-based snacks, and a higher intake can put them at risk of overconsumption arsenic.

"A hypothetical person consuming average amounts of each food category would consume 10 servings of rice each week," the study said. "Based on these rice consumption patterns, some people with celiac disease may be at risk of consuming more than the EPA standard dose for chronic oral exposure to inorganic arsenic."

Another study from the Mayo Clinic directly looked at arsenic levels in people with and without celiac disease on a gluten-free diet. The researchers measured the arsenic content in the subjects' urine and then compared the results with the levels of people not using gluten-free supplements. They found significantly higher levels in those who did not consume gluten, whether they had celiac disease or not.

Is mercury a problem too?

Rice not only accumulates arsenic efficiently; it can also contain high levels of other heavy metals, including mercury and lead.

In fact, the Mayo Clinic study also ran blood tests to measure levels of mercury, lead, and cadmium and found higher levels of the three in gluten-free people, whether they were celiac or not. (The highest cadmium levels did not reach statistical significance in gluten-free and gluten-free people.) Additional studies have confirmed this study.

"People who follow a gluten-free diet have significantly higher levels of total arsenic in their urine and levels of mercury, lead, and cadmium in their blood than people who do not avoid gluten," the Mayo Clinic researchers concluded. "Research is needed to determine the long-term effects of accumulating these elements with a gluten-free diet."

This study does not prove that rice is the culprit in gluten-free people's exposure to heavy metals; other foods also contain high levels of these elements. For example, apple juice can contain higher levels of arsenic, and some types of fish contain too much mercury.

However, another group of researchers found that people with celiac disease had higher levels of mercury, although their fish consumption and the amount of mercury fillings were the same as in the control group. It is becoming increasingly clear that something from the gluten-free diet is the culprit, and rice is the main suspect.

What can you do to limit your risk?

Not all people on a gluten-free diet eat a lot of rice; people who tend to avoid foods like bread and pasta should be at lower risk for this problem. But there's no question that those who have replaced common gluten-rich foods like bread and pasta with gluten-free versions may be consuming a lot more rice than they realize.

Thompson offers some healthy gluten-free and rice-based diet ideas. She says that people on a gluten-free diet should consider:

  • Determination of the level of arsenic in drinking water.
  • Evaluation of your consumption of rice grains.
  • Obtain rice from low arsenic areas
  • Cooking rice as pasta in excess of water
  • Replacing quinoa or other gluten-free grains with a grain of rice
  • Evaluate your consumption of rice-based foods
  • Stop rice bran, rice milk and rice syrup

Obviously some of them will be easier to do than others. For example, some studies show that cooking rice in large amounts of water and then draining excess water can reduce arsenic levels by 40-60%. However, sourcing rice from low arsenic areas can be more challenging as arsenic levels vary widely and it is not always obvious where the rice was grown.

Well water can also contain large amounts of arsenic, so if you get your drinking water from a well, you can buy test kits that will show you how much arsenic is in a particular water.

But perhaps the simplest thing you can do to protect yourself is to replace several gluten-free whole grains, such as quinoa or buckwheat, in your diet. For example, if you normally cook a pot of rice for stir-frying, try a dish with a different grain.

You can also find gluten-free foods, including cereals, pasta, breads, and cookies, that contain little or no rice. Obviously, you have to read labels to identify these foods, but people with celiac disease and gluten insensitivity already know how.

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