The risk of arsenic in food, is it advisable to wash rice before cooking it?

“The health concern of arsenic in food is confirmed.” This forceful phrase is the conclusion that published at the end of January by the European Food Safety Authority (EFSA) after evaluating the risks posed by exposure to this contaminant through the diet. This seems to confirm the fears of many people who, for fear of arsenic, wash rice before cooking it or discard the cooking water. However, to know if it is necessary to take these measures and before throwing our hands around, it is worth knowing some details.

The first thing to clarify is that we are not facing a food alert, a situation that occurs when the contamination of food in circulation poses an imminent risk to health. In this case, we are talking about a risk assessment, which is carried out from time to time to know the state of the situation, considering the most recent scientific knowledge and consumer habits, so that, if necessary, appropriate measures can be taken. measures aimed at protecting health.

Why does it reach food?

Arsenic is a common element in the Earth's crust, and widely spread in the environment due to both natural sources (due to volcanic emissions, forest fires, erosion of minerals and rocks, etc.), and human activity (due to emissions from the mining or metallurgical industry, insecticides, herbicides, etc.).

This means that many foods are susceptible to being contaminated with this chemical element and its compounds, although not all of them are of equal concern. For example, the presence of organic forms of arsenic is common in fish (like arsenobetaine), less worrying than inorganic forms, which are much more toxic. That is why they are also those that have been evaluated in the latest EFSA report. These are absorbed from the soil by some plants such as rice. In fact, the foods that contribute the most to human exposure to arsenic are rice and cereals, in addition to products made from them; and may also be present in drinking water.

What effects does it have on health?

Known as a potent poison since ancient times and more recently used as a pesticide, inorganic arsenic is present in much smaller doses in contaminated water and food. Even so, in this way, you can increase the risk of suffering from different types of cancer, especially the skin, bladder or lung, but also the kidney, liver and prostate. In addition, it can cause other adverse effects, such as skin lesions, neurotoxicity, cardiovascular diseases, abnormal glucose metabolism or diabetes, among others.

It is a genotoxic compound and carcinogenic, so any amount could be potentially dangerous to health. Although the dose and level of exposure matter: generally, the higher the dose and the more exposed we are, the more likely we are to suffer adverse effects. We can easily understand this if we think about the example of tobacco: when we inhale its smoke we are also exposed to genotoxic compounds, so any amount has the potential to cause an adverse effect, such as the development of lung cancer. But it is very unlikely that this will happen with a single cigarette because the dose and level of exposure play a role: the more we smoke, the more likely we are to develop that disease.

What foods to avoid?

The fact that water, rice, cereals and products made from them are the ones that contribute the most to dietary exposure to arsenic does not mean that we should avoid their consumption. Nor does it seem necessary for us to take extraordinary measures at the domestic level. This has not been specified in the EFSA report, which focuses only on evaluating the risk of arsenic, but it is what seems to be deduced from the data for the Spanish population. And we could say the same if we consult the information published in this regard by the Spanish Agency for Food Safety and Nutrition (AESAN) and that can be summarized in three points:

1. Cereals are an important source of complex carbohydrates that, combined with other foods, have a positive effect on health. For this reason, it recommends the consumption of cereals (wheat, corn, rice, oats, etc.), preferably whole grains, in an amount of between 3 and 6 servings per day, depending on energy needs.
2. Water is the drink of choice in a healthy diet and the level of arsenic is generally very low.
3. Yes, it is recommended to avoid the consumption of hiziki seaweeddue to its high content of inorganic arsenic.

To wash or not to wash

To answer the doubts and concerns that the presence of arsenic in the diet raises in the population, we can clarify some important details:

• Not all rice is likely to contain the same amount of arsenic. In general, the levels are higher in brown rice than in conventional rice (around 1.7 times more) because this compound accumulates in the bran.
• The origin also influences. There are countries, such as India and Bangladesh, where the accumulation of inorganic arsenic in rice is greater, mainly due to contamination of irrigation water. In any case, all rice marketed in the European Union must comply with the maximum limits established by European legislation, regardless of its origin.
• A simple measure with which we can reduce levels of exposure to arsenic is to follow a varied diet, alternating different types of cereals. It doesn't seem like a good idea to consume rice every day, especially if it is whole grain. This is of special interest for certain population groups, where exposure levels may be higher, such as young children or people who suffer from gluten-related disorders, such as celiac disease, given that gluten products sometimes predominate in their diet. rice base, such as drinks, pasta or pancakes. Instead of consuming these products every day, perhaps it would be better to try to alternate them with other suitable cereals, as appropriate, such as corn, for example.
• Washing the rice abundantly (for example, rinsing it six times) before cooking could eliminate between 10% and 30% of arsenic, while cooking the rice in plenty of water (1:6 ratio) and discarding the latter at the end could eliminate around 30-45% arsenic. In any case, the results depend on different factors, such as the variety or type of rice. Therefore, while some research shows that both actions lead to a reduction of up to 57% of arsenic, other studies (like the one pointed out by the AESAN in their recommendations) only achieve a reduction of 11%. On the other hand, it must be considered that these practices
  can also reduce the nutrient content of rice.

Are we exposed to dangerous amounts?

To evaluate the safety of arsenic, the European Food Safety Authority (EFSA) has considered the risk of skin cancer because it is one of the most worrying adverse effects and because it is the most conservative approach, given that it protects against the rest of the the adverse effects associated with this contaminant. With this new reference, more conservative than the one considered in its previous evaluation in 2009has concluded that the levels of exposure to arsenic through the diet are of concern in average consumers and, above all, in heavy consumers: that would mean, for example, that a person who ate rice at daily could have a 5% (or more) increased risk of developing skin cancer, compared to another unexposed person.

Now, it is important to consider that the level of exposure to arsenic in the Spanish population is lower than the European average in all age ranges studied, as pointed out by the Spanish agency AESAN. This means that the probability of suffering adverse effects such as the one indicated above is lower, so the situation is less worrying than for the population of other countries.

On the other hand, it should be noted that in younger population groups (especially children up to 10 years old) the exposure levels are higher than in adults, due to their lower body weight. From this, one might think that they are in a higher risk situation. But according to the EFSA, this is not necessarily the case, because the adverse effects of arsenic are due to long-term exposure and most epidemiological studies are conducted in adults who would also have had higher dietary exposure during their first years of life. Therefore, it is concluded that children are covered by this risk characterization.

What measures are taken?

In the field of food production, measures have been applied for years at all stages to try to reduce the presence of arsenic; For example, controls are carried out on irrigation water.

Analysis is also carried out on drinking water and certain foods to verify that they comply with the maximum arsenic limits established by legislation. Some of those limits were set for the first time in 2015 for rice and derived products; and later, in 2023, They spread to other foods and became more restrictive, in line with advances in scientific knowledge.

Now, with data obtained from the new EFSA report and in the absence of this European body evaluating the toxicity of organic arsenic and that of total arsenic (the combination of organic and inorganic) in the coming months, it is very possible that measures will be taken to try to further reduce the population's exposure to this substance. Probably, lowering even more strictly the maximum limits allowed in certain foods; or perhaps, offering consumption recommendations for the most exposed population groups.

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