The language used to describe the foods we eat can have a big effect on how we perceive them: “organic,” “artisan,” “homemade”, and “select” sound a bit more tempting than prosaic “canned,” “rehydrated”, or “lyophilized.” Another adjective that can whet our appetite is “natural”, while we tend to associate “processed” with products with a long list of unpronounceable ingredients.
But when it comes to our health; are natural products always better than processed products?
In reality, naturalness does not automatically mean a food is healthy, says Christina Sadler, manager of the European Food Information Council and a researcher at the University of Surrey, in the United Kingdom. In fact, natural foods can contain toxins and minimal processing can make them safer. Beans, for example, contain lectins, which can cause vomiting and diarrhea. They are removed by soaking them overnight and then cooking them in boiling water.
Processing also makes drinking cow’s milk safe. Milk has been pasteurized since the late 19th century to kill harmful bacteria. Before this time, it was distributed locally, because there was no good refrigeration in the houses.
“Cows were milked every day and people brought milk into their neighborhoods to sell it”, says John Lucey, a professor of food science at the University of Wisconsin-Madison, in the United States. “But the cities got bigger, the milk moved away and it took longer to reach the consumer; this meant that pathogens could multiply”.
Growing evidence suggesting that some organisms in milk could be harmful led to the development of heating devices for milk and the invention of pasteurization, which was soon adopted in Europe and, later, in the United States.
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Milk is pasteurized to make it last longer. “It is one of the most important public health success stories of the last century”, says Lucey. “Just before World War II, about a quarter of all food and waterborne illnesses came from milk. Today, it is less than 1%”.
Processing can also help retain the nutrients in what we eat. For example, freezing, which is classified as minimal processing, allows fruits and vegetables to retain nutrients that might otherwise degrade while in the refrigerator. “Vegetables are often frozen shortly after harvest, rather than being picked, transported, and then deposited on the shelves, losing nutrients”, Sadler says.
In 2017, a group of researchers bought fresh vegetables from different grocery stores and tested their nutrient levels, including vitamin C and folic acid, the day they bought them and within 5 days of making it and having them in the refrigerator. They found that they had comparable levels of nutrients. And in some cases, the study found that frozen foods had higher levels than those stored in the refrigerator.
“There is a misconception that frozen products are not as good as fresh, but that is really inaccurate”, states Ronald Pegg, professor of food science and technology at the University of Georgia, also in the United States.
Canned tomatoes are a good example of a healthy processed food. Processing also allows vitamins and minerals, such as vitamin D, calcium, and folic acid to be added to certain processed foods, including bread and cereals. Such efforts have helped reduce various nutrient deficiencies among the general public. However, this does not necessarily make the meal nutritionally balanced.
Processing can also help preserve food and make it more accessible. Fermentation makes the cheese stable for longer and, in some cases, reduces the amount of lactose, making it more digestible for those with a mild intolerance to it.
In the past, the main reason food was processed was to increase its shelf life. For a long time, preserving food by adding ingredients like sugar or salt was crucial for people to survive the winter, says Gunter Kuhnle, professor of food and nutritional sciences at the University of Reading.
“The processing allowed us to be where we are today, because it prevented us from starving”, he explains. “Many foods need to be processed to be consumed, like bread. We could not survive on grains alone”. Adding heat, also a minimal process, makes lots of foods edible, such as potatoes and mushrooms.
Fresh vegetables can sometimes lose many of their benefits if they are kept in the refrigerator for a long time. “Canned tomatoes are a classic example that processed foods are better than their fresh versions”, says Kuhnle. “They can be harvested much later, when the product is much more mature, and they can be processed in a much gentler way”.
And while some processes can make a food less nutritious, they can still make food more accessible. Bacon, for example, does not improve health, but it gives more people access to meat by preventing food from spoiling. Processed ones also tend to be cheaper, as they can be produced at lower costs.
Say “No” to the ultra-processed food!
Several investigations have concluded that the healthiest foods are 3 times more expensive than those with high content of salt, sugar and fat; these are mostly highly processed. But these highly processed products, which are made from food-derived substances and additives, are generally not good for us.
Studies have shown that food additives can alter our gut bacteria and cause inflammation in our bodies, which is linked to an increased risk of heart disease. Additionally, research shows that people tend to overeating ultra-processed foods.
Studies have shown that people who eat ultra-processed foods consume more calories overall and gain more weight. Also, they are at higher risk of developing heart disease.
A brief 2019 study found that participants, during the 2 weeks that they ate a diet rich in ultra-processed products, consumed 500 more calories per day than during the weeks in which they ate unprocessed foods. They also gained an average of almost 1 kilogram on the ultra-processed diet.
Processed foods can be high in fat, salt, and sugar. However, the mechanisms behind ‘why’ should be better understood, say the researchers. More generally, there seems to be a consensus that more research is needed on the effects that processed foods have on our health.
For example, it is still unknown how flavonoids and polyphenols (micronutrients found in some plants that have been linked to many health benefits) in fruits are affected by processing, Kuhnle says. “There is not much information on how processing limits health benefits. A lot of research focuses on a single food, but people do not just eat apples, their diet consists of apples, smoothies, cakes, etc.”
While minimal processing has many benefits, the same cannot be said for what classification systems call “ultra-processed” foods. But there is debate among scientists regarding the definitions and terminology around what constitutes minimal and “ultra” processing.
Earlier the current year, Sadler analyzed numerous systems that seek to classify processed foods. He found no consensus on what factors determine the level of processing and states that the classification criteria are “ambiguous” and “inconsistent”.
Nova is one of the best known and most used classification systems in food research
The classification includes unprocessed or minimally processed, processed culinary ingredients, processed foods, and ultra-processed foods. According to Nova, ultra-processed foods are made up of fractionated ingredients and contain little or no whole foods.
But the definitions of ultra-processed foods vary between publications and there is an ongoing debate about these definitions. “There is no good definition of processing. The public gets the idea, when they hear the word ‘processing’, that all food is disassembled and reassembled, but it could be as simple as heating or cooling”, says Lucey.
Food processing is a broad term that describes many types of food. There is a debate about whether public health nutrition policies should focus more on the degree of food processing than on the nutritional profiles of foods.
But, is there something inherently wrong with the processing?
A group of scientists wrote in a 2017 article: “To our knowledge, no arguments have been offered as to how, or whether, food processing constitutes in any way a risk to the health of the consumer due to a possible adverse intake of nutrients or chemical or microbiological hazards”. However, it is worth noting that the lead author is on the scientific committees of food producers Nestlé and Cereal Partners Worldwide.
While ultra-processed foods typically contain fewer nutrients than minimally processed foods; fortified foods, to which micronutrients are added during production to improve public health, play an important role in production, they argue.
Some studies show that ultra-processed foods fill us up less and leave us with the need to eat more. However, the authors of the article argue that some processing is also used to reduce the number of calories in some foods, such as semi-skimmed milk and low-fat margarines.
Some ultra-processed foods can be linked to poor health outcomes, but not all processed foods are cut from the same pattern. Frozen vegetables, pasteurized milk, or boiled potatoes, for example, may be better for us than their raw counterparts.
But here is the key: All those foods also look a lot like their natural form, and this is what we need to keep in mind. As long as we can recognize that a processed food is close to its natural form, including it in our diet may even be good for us.