How chemical reactions deplete nutrients in plant-based beverages

The global market for plant-based beverages has experienced impressive growth over the past decade, during which oat, almond, soy, and rice beverages have emerged as popular alternatives to milk in coffee and oatmeal.

A possible reason why millions of liters of plant-based drinks end up in consumers’ shopping carts is because their climate footprint is often lower than that of milk. But if consumers think plant-based drinks are healthier than milk, they’re wrong. This is revealed in a new study conducted by the University of Copenhagen in collaboration with the University of Brescia in Italy.

In the study, published in the journal Food Research International, researchers investigated how chemical reactions during processing affect the nutritional value of 10 plant-based beverages compared to milk. The big picture is clear.

“We definitely need to eat more plant-based foods. But if you’re looking for proper nutrition and believe that plant-based drinks can replace milk, you’re wrong,” says the Food Science Department. says Professor Marianne Nissen-Lund of the department. Lead author of the study.

Long shelf life even at the expense of nutrition

While milk is essentially a finished product once it comes out of the cow, oats, rice, and almonds require extensive processing to make them into drinkable beverages. Additionally, each of the plant-based beverages tested underwent “ultra-high temperature” (UHT) processing, which is widely used for long-life milk around the world. In Denmark, milk is usually sold only in the refrigerated section of supermarkets and is pasteurized and subjected to milder heat treatment.

“Despite the increase in sales of plant-based beverages, sales of milk remain high. As a result, plant-based beverages are sold more than milk, which is typically sold in Denmark, in order to extend their shelf life. “But such treatments are costly,” Lund says.

UHT processing causes a chemical reaction between proteins and sugars, the so-called Maillard reaction, that occurs when foods are fried or roasted at high temperatures. Among other things, this reaction affects the nutritional quality of the proteins contained in a particular product.

“The protein content of most plant-based drinks is already significantly lower than that of milk. And the lower protein content is further denatured by heat treatment. The nutritional content of plant-based beverages varies, but most have relatively low nutritional value,” explains the professor.

For comparison, the UHT-treated milk used in the study contained 3.4 grams of protein per liter, while eight of the 10 plant-based beverages analyzed contained between 0.4 and 1.1 grams. contained protein. Levels of essential amino acids were low in all plant-based beverages. Additionally, 7 out of 10 plant-based drinks contained more sugar than milk.

Heat treatment may produce carcinogens

Heat treatment not only reduces nutritional value but also creates new compounds in plant-based beverages. One such compound, which researchers measured in four of the plant-based beverages made from almonds and oats, was found to be carcinogenic and is also found in breads, cookies, coffee beans, and fried foods such as french fries. The substance is acrylamide.

“We were surprised to find acrylamide, as it is not normally found in liquid foods. One possible source is the roasted almonds used in one of the products. “The compound has been measured at very low levels, so there is no danger. However, if you ingest small amounts of this substance from various sources, they can add up to levels that pose a health risk,” Lund said. I say.

Additionally, researchers detected alpha-dicarbonyl compounds and hydroxymethylfurfural (HMF) in some plant-based beverages. Both are reactive substances and can be harmful to human health when present in high concentrations, which is not the case here.

Nutrition professor Lars Ove Dragsted said he wasn’t particularly concerned about the study’s results, but he said it does highlight how little we know about the compounds formed during food processing. I believe there is.

“Chemical compounds resulting from the Maillard reaction are generally undesirable because they can increase inflammation in the body. Some of these compounds have also been linked to an increased risk of diabetes and cardiovascular disease. “Our gut bacteria break down some of them, but there’s a lot we don’t know or haven’t studied yet,” says Dragstead, from the School of Nutrition, Exercise and Sport. .

Professor Dragsted said: “This study highlights why we need to pay more attention to the effects of the Maillard reaction when developing plant-based foods and processed foods in general. The identified compounds are only a small fraction of the compounds we know about.” ”

make your own food

Professor Lund said the study highlights a broader problem with ultra-processed foods. “Ideally, a green transition in the food sector should not be characterized by ingesting plant ingredients, ultra-processing them, and assuming healthy outcomes. These products should not be dangerous or clearly unhealthy. No, but they’re also often not particularly nutritious for us.”

Her advice for consumers: “In general, try to minimize your use of processed foods and drinks and prepare as much of your own food as possible, even if you’re eating healthy to begin with. “You can definitely incorporate plant-based drinks into your diet.” Try to get your nutrients from other foods. ”

At the same time, Professor Lund hopes the industry will do more to address these issues: “This is a call for manufacturers to further develop their products and reconsider the extent of processing. “The shelf life of their product would be acceptable. ”