What Do Nutrient Effects Tell Us?

 

WHAT DO NUTRIENT LABELS TELL US?

Nearly all the food we eat has a nutrition label. This label presents basic values showing the total fat, carbohydrate, protein level and many other pieces of information contained in the food. But what do all these values mean and how are they measured? How can this information help us stay healthy? For example, you might drink a caramel iced coffee every morning, but if you look at the nutrition information, a large caramelized coffee from a leading fast-food chain contains 680 calories. You would need to cycle at high speed for an hour to burn these calories. But what exactly is a calorie? A calorie is a measure of energy. In reality, the calorie that people talk about is a kilocalorie and is written as Calorie with a capital C. One Calorie is the amount of energy required to raise the temperature of 1 kg of water by 1°C at sea level. The measurement of calories was determined in the late 1860s by chemist Wilbur O. Atwater. Atwater built a device called a respiration calorimeter to measure the heat released from foods consumed by people. From 1894 to 1903, Atwater served as Deputy Chief of Nutrition Research and from 1903 onwards as Chief of Nutrition Research at the U.S. Department of Agriculture. After lengthy negotiations, Atwater received funding from the government to study human metabolism and build a large respiration calorimeter. This piece of equipment, with an annual cost exceeding ten thousand dollars, was considered a dream project for the nineteenth century. The calorimeter assisted in food analysis, diet development, work energy consumption and studies related to digestible foods. By analyzing the heat and metabolic rate produced by a person performing specific physical activities, it measured the balance of human metabolism. With this machine, the dynamics of metabolism could be measured and the balance between food intake and energy production could be measured. In simpler terms, the Atwater calorimeter for nutrition diets was large enough to allow a person to enter it. With this equipment, the amount of oxygen consumed by people, the heat they released, and the carbon dioxide they produced were measured. Using this device, Atwater was able to measure the precise amount of energy contained in food substances. He found that protein and carbohydrates have 4 calories per gram and fats have approximately 9 calories per gram. This 4-9-4 rule became the main rule for how labels are determined today. If you wonder how many calories you need each day, the answer depends on your sex, age and daily activity level. For example, an active 17-year-old male should consume 2,400–2,800 calories per day. If that person has a sedentary lifestyle, this number drops to 2,200. The calories we need for daily activities are produced thanks to a process called metabolism that occurs in body cells. Metabolism is a serious chemical reaction in which foods are broken down and energy is released. When we consume excess calories, our body stores these calories as fat for later use. Metabolism refers to the entirety of biochemical processes that a living organism performs in its body to maintain life. The burning of nutrients taken into the body, the construction or repair of the body with the energy that emerges at this stage, and similar processes constitute metabolism. The amount of energy burned here is related to the metabolic rate. Basal metabolic rate refers to the energy burned by the body when it is not engaged in any activity. The amount of energy required for respiration, blood circulation, body temperature control, cell growth and renewal, and brain and nerve functions constitutes the basal metabolic rate. This amount of energy also constitutes the largest percentage of daily energy expenditure (approximately 50–80 percent). Basal metabolic rate directly affects the amount of calories a person expends daily, that is, weight gain and loss or weight control. However, how calories are produced and used varies from person to person. For this reason, it is said that people's ability to lose weight depends on their metabolism. People can change their basal metabolic rate through exercise over the long term. Furthermore, it has been reported that people with more muscle and less fat in their bodies generally have a higher basal metabolic rate. In addition to calories, the nutrition label also shows the amount of three nutrients: fats, proteins and carbohydrates. As is well known, fats are found mainly in vegetable oil products and fish. Proteins are found in milk, meat, beans and nuts. Carbohydrates are found in fruits, vegetables and wheat products. To determine fat content, foods are preprocessed and crushed, then continuously washed with appropriate organic solvents that dissolve only fats. This method is called continuous extraction with Soxhlet. The amount of fat obtained is determined. This method, used for 100 years, is used today in the production of vegetable and essential oils. However, this method is very slow and complex. As a newer method for measuring fat content, a technique called nuclear magnetic resonance is used. By exposing the food sample to radiofrequency waves, the magnetic moments of protons on atoms in the sample are caused to rotate. After the radiofrequency is cut off, the magnetic moments of the protons return to their original state. When this process is performed at low temperatures and the movement of atoms is slowed, the fat signals in the sample can be separated from the remaining signals. Thus, quantification is simplified. So how much fat should we consume? Experts have reported that 30 percent of our daily calories should come from fat. That is, if we consume 2,000 calories in a day, the mentioned 30 percent means that the calories obtained from fat should not exceed 600 calories. The standard method used to determine the amount of protein in food is called the Kjeldahl method. This test is similar to a method that measures the nitrogen content in food. This is because most proteins in food contain nitrogen atoms. In the Kjeldahl method, the sample is boiled in sulfuric acid and then neutralized with a sodium hydroxide solution. This process converts any nitrogen present into ammonia gas. The ammonia gas is collected in a bottle containing boric acid solution. The amount of acid obtained indicates how much protein is present in the sample. So how much protein do we use each day? Medical institutes recommend that adults consume a minimum of 0.36 grams of protein per kilogram of body weight daily. Thus, an adult weighing 73 kg should consume approximately 58 grams of protein. The carbohydrate content in foods is traditionally calculated rather than measured. In this method, other food components such as protein, fat and water are measured and added together. When the calculated value is subtracted from the total, the result obtained is assumed to be the total carbohydrate content. Half of consumed calories should come from carbohydrates. All this data regarding calories, protein, fat and carbohydrate can especially help overweight people make dietary decisions. According to the U.S. Centers for Disease Control and Prevention, more than one-third of adults in the U.S. are obese. In this alarming situation, it reveals the fact that sugar consumption in the average American diet is quite high. In a report presented to the Turkish Grand National Assembly by the World Health Organization in 2019, approximately 3 out of every 4 people in Turkey are overweight, overweight or obese, and 1 out of 3 is obese. Our obese population is 7.5 million, and our morbidly obese population is 2.4 million. Like in the world, there is an obesity epidemic in Turkey, and when we look at childhood obesity, it is increasing steadily. To eat healthy, you can better understand what you can eat by looking at the nutrition label. This way, you can make healthier decisions about what to include in your diet. As of 26 July 2018, certain rules have been established regarding innovations in nutrition labels. According to these: 1. Data for larger portions should be provided. 2. The total calorie amount and portion information of the food should be written in large font. 3. The amounts of vitamin D, potassium and other components necessary for the body should also be indicated. Additionally, the recommended daily dose should be updated and written. 4. The amount of sugar added to the product should be specified. Returning to the 4-9-4 rule, pick up your pen and paper and start calculating. Find the total carbohydrate and protein values on a product's nutrition label and multiply each value separately by 4. Then find the total fat value and multiply this value by 9. Add the products you calculated. This value you obtained gives the total calorie content of that food. I thank Elle Hughes, Pixabay, Daria Shevtsova and Fancycrave.com for the photographs. Sultan Funda Görkem Assistant Professor Eskişehir Technical University Faculty of Science Department of Chemistry