Rice is a cereal grain and it is the most consumed food in the world. Since sizable portions of sugarcane and maize crops are used for purposes other than human consumption, rice is the most important grain about human nutrition and caloric intake, providing more than one-fifth of the calories consumed worldwide by humans.
Rice is a filling food that goes well with almost any type of ingredient. However, a recent study warns that eating certain kinds of rice can increase your exposure to harmful inorganic arsenic.
The study was conducted by Kan Shao and his collaborator Zheng Zhou. Both researchers are from Indiana University Bloomington. In December 2018, Zhou presented their findings at the Society for Risk Analysis Conference in New Orleans.
What Is Arsenic?
Arsenic is a toxic trace element, denoted by the symbol As.
It is not usually found on its own. Rather, it is bound with other elements in chemical compounds.
These compounds can be divided into two broad categories:
- Organic arsenic: mainly found in plant and animal tissues.
- Inorganic arsenic: found in rocks and soil or dissolved in water. This is the more toxic form.
Both forms are naturally present in the environment, but their levels have been increasing due to pollution.
For several reasons, rice may accumulate a significant amount of inorganic arsenic (the more toxic form) from the environment.
Dietary Sources of Arsenic
Arsenic is found in nearly all foods and drinks but is usually only found in small amounts.
In contrast, relatively high levels are found in:
*Contaminated drinking water: Millions of people around the world are exposed to drinking water that contains high amounts of inorganic arsenic. This is most common in South America and Asia.
*Seafood: Fish, shrimp, shellfish and other seafood may contain significant amounts of organic arsenic, the less toxic form. However, mussels and certain types of seaweed may contain inorganic arsenic as well.
*Rice and rice-based foods: Rice accumulates more arsenic than other food crops. It is the single biggest food source of inorganic arsenic, which is the more toxic form.
High levels of inorganic arsenic have been detected in many rice-based products, such as:
*Rice-based breakfast cereals
*Rice cereal (baby rice)
*Brown rice syrup
*Cereal bars containing rice and/or brown rice syrup.
Why Is Arsenic Found in Rice?
Arsenic naturally occurs in water, soil, and rocks, but its levels may be higher in some areas than others.
It readily enters the food chain and may accumulate in significant amounts in both animals and plants, some of which are eaten by humans.
As a result of human activities, arsenic pollution has been rising.
The main sources of arsenic pollution include certain pesticides and herbicides, wood preservatives, phosphate fertilizers, industrial waste, mining activities, coal burning, and smelting.
Arsenic often drains into groundwater, which is heavily polluted in certain parts of the world.
From groundwater, arsenic finds its way into wells and other water supplies that may be used for crop irrigation and cooking.
Paddy rice is particularly susceptible to arsenic contamination, for three reasons:
It is grown in flooded fields (paddy fields) that require high quantities of irrigation water. In many areas, this irrigation water is contaminated with arsenic.
Arsenic may accumulate in the soil of paddy fields, worsening the problem.
Rice absorbs more arsenic from water and soil compared to other common food crops. Using contaminated water for cooking is another concern because rice grains easily absorb arsenic from cooking water when they are boiled.
Health Effects of Arsenic
High doses of arsenic are acutely toxic, causing various adverse symptoms and even death.
Dietary arsenic is generally present in low amounts and does not cause any immediate symptoms of poisoning.
However, long-term ingestion of inorganic arsenic may cause various health problems and increase the risk of chronic diseases. These include:
*Various types of cancer
*Narrowing or blockage of blood vessels
*High blood pressure (hypertension)
*Type 2 diabetes
Also, arsenic is toxic to nerve cells and may affect brain function. In children and teenagers, arsenic exposure has been associated with:
*Impaired concentration, learning, and memory
*Reduced intelligence and social competence
Some of these impairments may have taken place before birth. Several studies indicate that high arsenic intake among pregnant women has adverse effects on the fetus, increasing the risk of birth defects and hindering development.
How to Reduce Arsenic in Rice
The arsenic content of rice can be reduced by washing and cooking the rice with clean water that is low in arsenic.
This is effective for both white and brown rice, potentially reducing the arsenic content by up to 57%.
However, if the cooking water is high in arsenic, it may have the opposite effect and raise the arsenic content significantly.
The following tips should help reduce the arsenic content of your rice:
*Use plenty of water when cooking
*Wash the rice before cooking. This method may remove 10–28% of the arsenic
*Brown rice contains higher amounts of arsenic than white rice. If you eat large amounts of rice, the white variety may be a better choice
*Choose aromatic rice, such as basmati or jasmine
*Choose rice from the Himalayan region, including North India, North Pakistan and Nepal
*If possible, avoid rice that is grown during the dry season. The use of arsenic-contaminated water is more common during that time.
Conclusion: The presence of arsenic in food is a serious problem for many people who rely on rice as a staple food. Reducing the content of arsenic is very important.
Follow a few simple cooking methods tips mentioned here to reduce the arsenic content of rice. Also keep in mind that some types of rice, such as basmati and jasmine, are lower in arsenic.