Arsenic is a naturally occurring element found in the earth's crust, soil, and water. It can exist in two forms: organic and inorganic. Organic arsenic, which contains carbon, is generally less harmful and is prevalent in seafood. Inorganic arsenic, which lacks carbon, is the more toxic form and is considered a human carcinogen associated with various long-term health issues. Humans are primarily exposed to inorganic arsenic through contaminated drinking water and food. Arsenic enters the food chain when plants absorb it from the soil and water where they grow, making it important for consumers to be aware of the dietary sources.
Key Dietary Sources of Arsenic
Rice and Rice Products
Rice is the single largest food source of inorganic arsenic in the U.S. diet. This is because rice plants are very efficient at absorbing arsenic from the environment, especially when grown in flooded paddy fields. The type of rice also affects its arsenic content:
- Brown rice vs. white rice: Brown rice typically contains more arsenic than white rice because arsenic concentrates in the outer bran layer. Polishing the grain to produce white rice removes this layer, along with some of the arsenic.
- Infant rice cereal: The FDA has set action levels for inorganic arsenic in infant rice cereals, as infants are a vulnerable population. Other rice products like crackers, milk, and sweeteners can also contain high levels.
Seafood and Seaweed
Seafood is another primary dietary source of arsenic, but it mostly contains the less harmful organic form, arsenobetaine. However, there are exceptions:
- Hijiki seaweed: This variety of seaweed, used in some Asian cooking, is known to contain higher levels of toxic inorganic arsenic and should be limited or avoided.
- Shellfish: Shellfish, particularly those from certain areas, can also contain higher inorganic arsenic levels. It is wise to check local advisories.
Vegetables
Many vegetables can accumulate arsenic from the soil, but levels vary depending on the plant type and the arsenic content of the soil.
- Leafy vegetables: Plants like spinach, lettuce, and kale can store higher amounts of arsenic in their leaves.
- Root vegetables: Beets, carrots, potatoes, and radishes can absorb arsenic, which is largely concentrated in their skins.
Fruit Juices and Fruits
- Juices: Some fruit juices, notably apple and grape juice, may contain low levels of arsenic absorbed from the fruit itself or potentially higher levels if mixed from concentrate with contaminated water. This is particularly concerning for children, who often consume more juice.
- Fruits: Fruits like apples, pears, and grapes can also contain small amounts of arsenic.
How Arsenic Enters the Food Chain
Arsenic contamination in food is a multi-faceted problem originating from both natural and human-caused sources.
- Natural contamination: Arsenic can leach from mineral deposits and rocks into groundwater, contaminating water supplies and soil used for farming.
- Human activities: Industrial waste, mining activities, the use of certain pesticides (especially historically), and burning coal can release arsenic into the environment.
- Contaminated water for crops: In many regions, crops are irrigated with groundwater naturally high in arsenic. This is a significant pathway for soil and crop contamination, as is using contaminated water during food preparation.
Comparing Inorganic and Organic Arsenic
| Feature | Inorganic Arsenic | Organic Arsenic |
|---|---|---|
| Toxicity | High (more toxic) | Low (less harmful) |
| Presence | Found primarily in groundwater, soil, and plants (e.g., rice, root vegetables) | Found mainly in fish and shellfish |
| Health Concerns | Carcinogenic; linked to cancer (bladder, lung, skin), skin lesions, cardiovascular disease, and developmental issues | Generally considered safe, although research on all organic forms is ongoing |
| Primary Sources | Contaminated water, rice and rice products, certain vegetables, some juices | Most finfish and shellfish |
| Noteworthy Exceptions | Hijiki seaweed and some shellfish can have higher inorganic arsenic | Arsenobetaine is a common, non-toxic organic form found in seafood |
How to Reduce Arsenic Exposure from Food
Fortunately, there are practical steps to minimize your family's exposure to arsenic from dietary sources. Diversifying your food choices is one of the most important strategies.
Best Practices for Rice Preparation
- Use plenty of water: Cooking rice with a high water-to-rice ratio (e.g., 6 to 10 cups of water for every cup of rice) and draining the excess can remove up to 60% of the arsenic.
- Soak before cooking: Soaking rice overnight, draining the water, and then cooking it in fresh, clean water can significantly further reduce arsenic levels.
- Consider low-arsenic rice: Aromatic rice varieties like basmati and jasmine often have lower arsenic levels than other types.
Strategies for Other Foods
- Vary your grains: Incorporate other grains like oats, wheat, and quinoa into your diet to reduce reliance on rice as a staple.
- Wash and peel produce: Thoroughly wash all fruits and vegetables. For root vegetables like carrots and potatoes, peeling the skin can remove most of the arsenic.
- Limit high-risk items: Reduce consumption of hijiki seaweed and certain fruit juices, especially for young children.
Ensure Safe Water
- Use water confirmed to be safe for drinking and cooking. If you use well water, get it tested for contaminants.
Navigating a Low-Arsenic Diet
- Prioritize variety: The single most effective tip is to eat a wide variety of foods from all food groups, reducing dependence on any one potential source of contamination.
- Make informed choices for infants: Because infants are more vulnerable, consider non-rice alternatives for baby cereal and read ingredient lists carefully to avoid brown rice syrup, which can be a concentrated source of arsenic.
- Understand seafood: Enjoying seafood is generally beneficial due to its nutritional value. Focus on understanding that the form of arsenic is typically organic and less harmful, but exercise caution with specific items like hijiki seaweed.
- Stay informed: Keep up-to-date with guidance from public health agencies like the FDA, especially regarding food safety regulations and monitoring efforts. The FDA's 'Closer to Zero Action Plan' focuses on reducing exposure to contaminants for babies and children.
Conclusion
While arsenic is a widespread environmental contaminant found in many foods, particularly rice, some seafood, and certain vegetables, consumers can take proactive steps to minimize their exposure. Understanding the difference between more toxic inorganic arsenic and less harmful organic arsenic is key to making informed dietary choices. By varying your diet, preparing rice with plenty of water, and ensuring your cooking water is safe, you can significantly reduce your intake of inorganic arsenic. A varied diet remains the best defense against over-exposure to contaminants from any single food source. For more information on food safety, you can consult authoritative resources like the FDA.
