What is Arsenic and How Does it Get Into Food?
Arsenic is a naturally occurring metalloid found in the Earth's crust, widely distributed in rocks, soil, water, and air. It exists in two main forms: organic and inorganic. The inorganic form is the more toxic of the two and is classified as a carcinogen. Organic arsenic is less harmful and is generally found in seafood. Arsenic enters our food supply primarily when plants absorb it from contaminated soil or water. For rice, the flooding of rice paddies promotes the uptake of arsenic from the soil into the grain. Seafood accumulates arsenic from the marine environment, with the specific form depending on the type of organism and its diet. For other foods like fruits and vegetables, the concentration of arsenic is dependent on the soil quality and whether contaminated water is used for irrigation.
Foods with Trace Amounts of Arsenic
Trace amounts of arsenic can be found across various food groups. For most people, the levels are not a health concern, but it is important to be aware of the primary sources to make informed dietary choices.
Rice and Rice-Based Products
Rice is particularly susceptible to arsenic absorption because it is grown in flooded conditions that allow the element to be readily taken up from the soil. Some rice varieties and products have higher levels than others:
- Brown rice: Contains higher levels of arsenic than white rice because the arsenic accumulates in the bran layer, which is removed during the polishing process to make white rice.
- Infant rice cereal: Due to infants' higher body weight-to-food consumption ratio, they can be more susceptible to contaminants. Health authorities like the FDA have set action levels for inorganic arsenic in infant rice cereals.
- Rice milk and syrups: These products, used in many processed foods, can contain higher concentrations of arsenic than whole grains.
- Sushi rice and some basmati varieties: Some studies show certain types of rice, like sushi rice from the US and white basmati from specific regions like India and Pakistan, have lower arsenic levels.
Seafood
Seafood is another well-known dietary source of arsenic, though it mostly contains the less harmful organic form. Finfish and shellfish absorb arsenic from the marine environment.
- Finfish and Shellfish: Most fish and shellfish primarily accumulate organic arsenic, specifically arsenobetaine, which is considered non-toxic and is efficiently excreted by the human body.
- Certain Seaweed: Some types of seaweed, particularly hijiki, are known to contain high levels of inorganic arsenic. Health agencies often advise limiting or avoiding this type of seaweed.
Fruits, Juices, and Vegetables
While often containing much lower levels than rice or seaweed, other produce can also absorb arsenic from the environment.
- Fruit Juice: Apple juice, in particular, has received scrutiny for containing trace amounts of arsenic. This is primarily from the fruit itself or the water used in processing.
- Vegetables: Root vegetables like carrots and potatoes store most arsenic in their skins. Peeling them can reduce exposure. Leafy greens also absorb some arsenic.
Other Sources
Arsenic can enter other areas of the food chain through contaminated water and feed given to livestock.
- Meat and Poultry: Arsenic-based drugs historically used in animal feed (like roxarsone in chickens) promoted arsenic transfer to animal products. While this practice is largely phased out in many regions, arsenic-contaminated water and feed can still contribute to low levels.
- Dairy Products: Trace amounts of arsenic can appear in dairy from animals consuming contaminated water or feed.
Comparison of Arsenic Levels in Rice and Other Grains
| Food Type | Form of Arsenic | Common Arsenic Level Compared to Other Grains | Key Takeaway |
|---|---|---|---|
| Brown Rice | Higher inorganic | 1.5x higher than white rice | Accumulates in the bran layer. |
| White Rice | Lower inorganic | Lower than brown rice | Polishing removes the bran layer. |
| Sushi Rice (US) | Lower inorganic | Often lower than other US-grown rice | Specific varieties and regions matter. |
| Quinoa | Low | Substantially lower than rice | Excellent, low-arsenic alternative. |
| Oats | Low | Lower than rice | Good option for varying grain intake. |
Reducing Exposure to Arsenic from Food
For most people, minimizing arsenic exposure from food is about varying your diet and making smarter choices rather than eliminating entire food groups.
Dietary Diversity
- Vary your grains: Alternate between rice and other grains like quinoa, oats, barley, and farro, which are known to have lower arsenic levels.
- Diversify infant cereals: For infants, it is especially important to rotate between different cereals, such as oatmeal, barley, and multigrain, instead of exclusively relying on rice cereal.
Smart Cooking Methods
- Cook rice like pasta: Use a high ratio of water to rice (about six cups of water to one cup of rice) and drain the excess after cooking. This can remove 40-60% of the arsenic. Soaking the rice beforehand can increase the reduction.
- Check your water source: If you use private well water, have it tested for arsenic, as high levels can be absorbed by rice during cooking.
Informed Product Choices
- Select lower-arsenic rice varieties: Choose certain rice types known to be lower in arsenic, such as US-grown sushi rice or white basmati rice from India, Pakistan, and California.
- Read labels: Check for rice or brown rice syrup in processed snacks and cereals and consider alternatives.
- Limit hijiki seaweed: Due to high inorganic arsenic content, limit consumption of this specific seaweed.
Conclusion
Trace amounts of arsenic are present in many foods, with rice and some seafood being the most common sources. Understanding the difference between less-toxic organic arsenic in seafood and the more concerning inorganic form found in rice is key. By adopting varied dietary habits, using smart cooking techniques, and choosing lower-arsenic options when possible, consumers can effectively minimize their exposure. This approach ensures a balanced diet without causing unnecessary alarm over trace contaminants.
For More Information
For those interested in the nutritional and food safety aspects of this topic, the following resource is useful:
This authoritative site provides detailed information from research on arsenic contamination and how to reduce exposure in daily life.
