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We choose to spend money on household products based on their look, feel, and taste, and we think they may make our lives better. Manufacturers apply nanotechnology, a field of technology that uses effects that occur at the nanoscale, to create the properties we want in this type of product, such as whiteness in toothpaste or preventing bacterial growth in socks. One nanometer is one billionth of a meter. Chemical and physical interactions at the nanoscale are much smaller than we can see with the naked eye. Drugs, miniature sensors, fast computers and food science are all areas where we can take advantage of nanotechnology. But some people are worried about the potential health risks posed by nanoparticles. Recently, France announced a ban on the use of a nano-scale food additive from 2020 due to a lack of evidence to prove its safety.
What are nanoparticles?
Nanoparticles are extremely tiny particles. Their external dimensions are less than 100 nm, or 0.0001 mm. That’s small. Not all nanoparticles are the same. They can be composed of a variety of different substances, like metals such as silver and gold, carbon, and even clay, and they can have different structures and chemical compositions. These properties ultimately determine the behavior, function, and safety of nanoparticles.
Nanoparticles are naturally formed and can also be manufactured. Naturally occurring nanoparticles can be found in volcanic ash, watercourses, fine sand and dust, and even in biological materials such as viruses. When used in medicine, technology, or science, nanoparticles are often manufactured to better control their performance.
The benefits of nanoparticles come from their extremely small size. For example, the material can be made into a stronger, lighter, or better electrical conductor. In medicine, nanoparticles can be made to enter hard-to-reach parts of the body. This is useful for treating or diagnosing diseases such as cancers and infections. But sometimes nanoparticles that you don’t want to ingest get into your body, or small amounts are consumed in products. This makes some people curious about how to know that they are safe?
Nanoparticles are naturally found in food
First, the nanoparticles in food are not new. Nanoparticles are naturally found in some foods: milk is a good example. Casein micelles in milk are nanospheres made of protein. By naturally gathering together, the nutrients in micelles are more easily absorbed by us.
In addition to milk, some food ingredients can be naturally assembled into nanoparticles. During the digestion process, our body uses bile from the gallbladder to “nanosize” the fat we ingest into micelles so that we can absorb them. Micelles also allow fats to mix into water more efficiently. Nanoparticles can be produced during food processing, such as during homogenization, emulsification, grinding, and milling. Over time, they also fall off from metal cutlery and other cooking tools.
Nanoparticles are present in some additives
Common additives, such as titanium dioxide (a whitening agent) and silicon dioxide (an anticoagulant), contain nanoparticles. This is because they are added in the form of powder, some of which will be nano-sized. These ingredients make up only a small portion of food, and actually only a small portion are nanoscale.
Two assessments commissioned by the Food Standards Board of Australia and New Zealand in 2015 found that current evidence suggests that titanium dioxide and silica nanoparticles do not absorb better than microparticles (particles that are 1,000 times larger), and most are excreted.
New uses are being explored
Researchers are studying how nanoparticles can bring new benefits to food. For example, adding nutrients to food can help us get better nutrition from processed foods, slow down the breakdown of nutrients, and help nutrients be better absorbed. Nano salt and sugar can make food healthier. The smaller the particles, the faster and easier they get to the taste buds on your tongue, so the less we need to eat to taste sweet or salty. Similarly, the use of nanoparticles can reduce the level of additives, making them easier to mix in the product. Nanoparticles may also extend shelf life, increase food safety, and reduce the need for added fat. Toxicity testing will be an important part of bringing these new technologies to market. But all in all, we have been eating nanoparticles for a long time, which are naturally occurring in additives, and there is no evidence that it is harmful.
References：
1.Nanopartikel-Materialien der Zukunft, Albert Rössler, Georgios Skillas, Sotiris E. Pratsinis; Chemie in unserer Zeit, 2001, 1, 32-41.