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  • Writer's pictureDr Matt Kopke

Rice and arsenic: what's the story?

Updated: Dec 21, 2023

When most people hear the word arsenic, it typically insights a negative response and a feeling of having to avoid something harmful. So, when you find out that this something something harmful is present in certain types of food, no doubt, your plan is to avoid these contaminated foodstuffs. About five years ago, there was a lot of media attention around the topic of rice and arsenic. But where are we at now? Is it still a problem and something for people to be concerned about when it comes to what they eat themselves and what they choose to feed their pets?

A recent study published in Frontiers (Su et al.) reviewed the most salient concepts related to dietary arsenic exposure, with particular reference to arsenic in brown rice. Before we get into the study, though, let's start with some of the basics.

What is arsenic?

Arsenic is a naturally occurring chemical element. It is part of the earth’s crust and is found in water, air, and soil. There are two forms of arsenic, namely, an organic and inorganic form. Inorganic arsenic compounds, which do not contain carbon, appear to be the more problematic form, with higher toxicity levels and more severe adverse health effects.

What are (potential) sources of arsenic?

Arsenic in drinking water is a particular concern – especially in certain countries around the world, like Bangladesh, for example.

It may also be found in foods such as rice and some fish, due to its presence in soil or water. In other words, it gets absorbed by plants, and grasses like the rice plant are, unfortunately, pretty good at absorbing it.

Because arsenic naturally occurs in the environment, it is not possible to remove it entirely from environmental sources or the food supply.

It is also important to note that arsenic is tasteless, colorless, and odorless, which necessitates testing for both detection and monitoring purposes. The U.S. Food and Drug Administration (FDA) monitors and regulates levels of arsenic in certain foods. The FDA prioritizes monitoring inorganic arsenic levels in specific foods that are more likely to be eaten by young children, such as infant rice cereal and apple juice.

What does arsenic do to humans?

Many people would have seen reports of arsenic exposure linked to skin, lung, and bladder cancer, along with type 2 diabetes, heart disease, hypertension, and even potentially, certain neurological problems.

Both short-term and long-term exposure to arsenic can cause health problems. Even at low levels, arsenic can interfere with the body’s endocrine (or hormonal) systems. Long-term exposure to arsenic from drinking water and food has been linked to certain types of cancer and skin lesions. It is for this reason that arsenic is classified as carcinogenic and mutagenic. It has also been associated with cardiovascular disease, diabetes, and even obesity.

Exposure in utero and during early childhood has been linked to negative impacts on cognitive development and increased deaths in young adults.

How about in dogs and cats?

Not much is known about long-term exposure to arsenic in either dogs or cats. Reports of arsenic toxicity or poisoning are typically acute cases with recent exposure to arsenic compounds in substances like pesticides, ant baits, and wood preservatives.

Most of the clinical signs seen in acute cases relate to the gastrointestinal tract and cardiovascular system, including diarrhea (which may be hemorrhagic), abdominal discomfort, dehydration, and weakness, to mention a few.

While there is much to be learned about the effects of long-term exposure to heavy metals such as arsenic, there have been several studies that have looked at the concentrations of arsenic and other heavy metals in commercial dog foods. While these studies have shown commercial dog foods to be safe for chronic consumption, the concentrations of heavy metals are heavily dependent on the primary protein sources used in the diets. Red meat and fish-based diets had higher arsenic content than poultry-based diets.

How can I reduce/remove the arsenic content of (brown) rice?

Brown rice has long been believed to be the healthier option to white rice, and it very well may be, but when it comes to potential arsenic exposure, brown rice has more arsenic as a result of arsenic accumulating in the husk (or its outer layer).

While its arsenic content is higher, some research has shown that the amount of arsenic absorbed by the body from brown rice is similar to that of white rice because the fiber present in whole-grain brown rice interferes with arsenic absorption.

Let’s talk about ways to try to reduce arsenic exposure when it comes to incorporating rice in your diet.

  1. Brown rice is nutritious, so consider feeding it as one of the carbohydrate sources in your pet’s diet, but perhaps not the sole source. An example of a type of rice that is lower in arsenic is white basmati rice.

  2. Some things that you can do to reduce the arsenic content of brown rice by up to 80% include:

  3. Consider some low-arsenic alternative grains or seeds, which do not absorb arsenic from the soil, such as quinoa, buckwheat and millet.

  1. Cook with turmeric, which contains curcumin. Alternatively, you can take curcumin as a supplement. Why? Curcumin has been shown to reverse the toxic effects of arsenic and protect against DNA damage.

  2. Minimise arsenic exposure during the growth period or during pregnancy by feeding diets that include alternate carbohydrate sources like barley or a mix of carbohydrate sources.

  3. Finally, something else to consider is increasing the amounts of vegetables and herbs in your diet. These are good sources of antioxidants that help replenish glutathione levels in the body, which is what exposure to arsenic typically depletes. They also provide beta-carotene, a precursor of vitamin A, which helps protect against the toxic effects of arsenic.

So, in conclusion, the health effects of arsenic exposure depend on various factors, which include the type of arsenic (inorganic versus organic), the degree of exposure, and, at least in humans, the age of the individual exposed to the arsenic. The risk-benefit ratio for whether or not it’s worth keeping brown rice as a staple in your or your pet’s diet remains to be determined, particularly in the long term. There’s no need to panic, though, especially if you feed a varied diet and alternate between different brands and flavours.

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