National Nutrition Week | Are all cheeses suitable for children and pregnant and nursing women?

In recent times, cheese has become the new favorite among dairy products.

How is cheese made? Are all cheeses a nutritious choice for children, adolescents, and pregnant and breastfeeding women?

About Cheese

In nutrition textbooks, cheese appears as a food with high nutritional value. In various versions of the Dietary Guidelines for Chinese Residents, cheese is recommended to varying degrees.

In Guideline 3 of the "Dietary Guidelines for Chinese Residents (2022)", the practical application recommendations for "How to eat more dairy products and soy" include "Children should develop habits such as drinking milk, eating cheese for breakfast, and drinking yogurt from an early age to increase sources of calcium, high-quality protein and trace nutrients"; recommended snacks for children also include "milk and dairy products (liquid milk, yogurt and cheese)."

The foreign name for cheese is chees or chees, which is the transliteration of the English word cheese. Cheese is a common food for nomadic peoples. European and American diets are essentially an extension of nomadic diets, with cheese being the main food.

Most Chinese people were unfamiliar with cheese before, because Chinese cuisine is mostly based on agricultural traditions. We are more familiar with tofu, which is actually similar to cheese, both of which are made by coagulating, filtering and squeezing protein slurries (soy milk and milk).

How cheese is made

Cheese is to Western diet what tofu is to Chinese people. Therefore, even if we don't know much about how cheese is made, it is easy to imagine that cheese should be a piece of protein that is clumped together, just like tofu.

As a nutritionist, I don't know much about cheese processing because I have no experience with it in my life. Professionally, it belongs to the field of dairy processing. Based on this mindset, I have always believed that cheese is the casein aggregate after the whey is removed, or milk concentrate. Although those water-soluble proteins are separated and taken away with the whey, there is no lactose, avoiding any trouble of lactose intolerance.

I know that most of the calcium in milk is combined with casein, so cheese should be high in protein, high in calcium, and almost lactose-free. Cheese made from skim milk will also have much lower milk fat. I have learned something new from reading materials recently, and I know that cheese is indeed like this.

but!

However, this is raw cheese, and what we discuss in nutrition textbooks and what the dietary guidelines recommend should refer to raw cheese.

As a consumer, the cheese you hold in your hands or eat is not necessarily original cheese. It is likely to be processed cheese, that is, cheese that has been further processed. In order to indulge the feeling of your mouth, they may no longer have the nutritional quality of the original cheese.

Cheese is a fermented milk product, which is usually made by skimming or not skimming milk, then pasteurizing it, adding the corresponding lactic acid bacteria starter and rennet to ferment it, similar to making yogurt. Then the protein in the milk coagulates, and the next step is similar to making tofu, and the whey is squeezed out to make cheese.

It is generally said that 1 kg of cheese requires about 10 kg of milk to make. Of course, this also depends on whether it is skimmed and the moisture content of the cheese.

As mentioned above, cheese is a traditional Western food. In the past, when there were no conditions for freezing and preservation, adding salt to cheese for preservation was a common practice. Therefore, many original cheeses are often salty.

Processed cheese

In order to obtain better cooking and processing performance, or to please our mouths and increase palatability, the original cheese is further processed by adding water, oil, sugar, flavoring substances, and possibly thickeners, preservatives, etc. This is the processed cheese mentioned above.

The advantage of processed cheese is that its cooking performance is greatly improved, it is more suitable for cooking with other foods, and it tastes better; the disadvantage is that the nutritional quality may be compromised.

When you salivate over the cheese pulled into thin strands on pizza, you may not realize that the delicious taste is still based on the contribution of fat. Data shows that most of the mozzarella cheese used in pizza processing is fat after deducting water, and a small part is protein.

The processed cheese used to make pizza does not have the lowest protein ratio. In order to make some processed cheese more delicious, oil and sugar are added. As a result, the protein obtained from a bite of cheese is less than that obtained from a sip of the same amount of liquid milk, and the energy level has soared by 3-4 times.

At this point, I need to make a special statement. This is not to say anything bad about processed cheese. In fact, it is not the fault of processed cheese. Each food has its own characteristics. Various processed foods are for us to choose from. There is nothing wrong with pursuing deliciousness. In the face of these dazzling array of food varieties, it is wrong not to make the right choice.

Cheese Choice

Whether we are nutritionists, ordinary consumers, or dairy processing practitioners, we need to stand together and examine the research and development, production and consumption of cheese from the perspective of nutritional quality, taking into account both deliciousness and nutrition, and especially understanding which cheese is best for which person.

Special and sensitive groups such as young children, older children, teenagers, and pregnant and lactating women should choose foods with high nutritional quality and high nutritional density, and choose cheese as the first choice in order to obtain rich and high-quality calcium, protein and other trace nutrients. It is very important to make a reasonable choice.

How to choose?

A look at product types

The packaging will usually indicate whether it is original cheese or processed cheese.

Original cheese is the original pure cheese. If it is labeled as cheese or original cheese, it means less water, protein and calcium are both derived from milk, and the content will be higher. If it is labeled as processed cheese, you should keep your eyes open.

2. Look at the nutrition label

That is the nutrition facts table. At present, there are not many mandatory indicators on the legal nutrition label, including energy, protein, fat, carbohydrates and sodium, but these indicators are sufficient for identifying and selecting cheese: these indicators happen to be the key to distinguishing cheese.

Due to the uncertainty of water content, we cannot simply compare the grams of protein and fat. The clearest thing is the proportion of energy provided by protein and fat to the total energy.

The method is not difficult: look at the NRV% number on the nutrition label, and compare the protein number under the column with the energy number. The higher the ratio, the better. Or look at the protein content (grams) per 100 grams of the product, then multiply it by 16.7, and then divide it by the energy data in the content (kJ/kilojoules), and convert it into a percentage. This is the energy ratio of protein; the grams of fat × 37.6 ÷ energy, convert it into a percentage, this is the energy ratio of fat.

Regardless of how the moisture content changes, the energy proportion of protein in original cheese should be around 30%, or the higher the better; the lower the fat heat energy ratio, the better.

A certain raw cheese, protein accounts for 32% of energy

More casein means more calcium, so the calcium content doesn’t even need to be a big concern. If the protein ratio is not high and the calcium content is high, it means that the calcium is added extra, not milk-derived calcium.

The sodium content is marked on the nutrition label, which is very important for cheese. The lower the sodium content, the better. High protein, high calcium, low sodium, and low fat should be the goal from a nutritional perspective.

3. Look at the ingredient list

The General Rules for Prepackaged Food Labeling (GB7718-2011) stipulates that the various raw materials and additives in the ingredient list should be sorted from most to least according to the amount used in the product formula. That is to say, the raw material with the largest amount should be listed first in the ingredient list, and the raw material with the smallest amount should be placed at the end of the ingredient list. Therefore, the raw materials listed at the front are the main raw materials of the product.

The first raw material for making original cheese should be raw cow's milk, goat's milk or pasteurized milk, followed by fermentation bacteria, rennet, salt and the like. The ingredient list is generally short and there are not many varieties of raw materials.

A certain original cheese ingredient

Processed cheese is made by adding other food ingredients to the original cheese (natural cheese, cottage cheese) to further form a more palatable and convenient product, which caters to various consumer demands, including more delicious and more suitable packaging. Therefore, the main raw materials of processed cheese are generally cheese (cottage cheese), water, butter or vegetable oil, sugar, etc., and some spices, thickeners and preservatives are also added.

Ingredients of two processed cheeses (table)

The processing of cheese is also necessary from the perspective of consumption. For example, cheese sticks suitable for children need to be processed in terms of taste, quantity, shape, and packaging. However, the key point is that the processing of cheese cannot reduce its nutritional quality too much, especially for cheese products for children and pregnant women. We cannot lose sight of the big picture and compromise the nutritional advantages to accommodate taste or reduce costs.
Obviously, in the reprocessing of cheese, it is extremely important to use original cheese as the main ingredient, use liquid milk instead of water, and avoid adding excessive sugar and fat. In order to reduce the sodium content while maintaining the taste, using potassium chloride instead of salt (sodium chloride) is also a good solution.

Therefore, even for processed cheese, cheese must be the first on the ingredient list, followed by water, and preferably raw milk; it is not that the following auxiliary ingredients cannot be used, but they should be as simple as possible, especially when butter or vegetable oil, sucrose or maltodextrin appear in the ingredient list, then you should pay attention to the indicators in the nutrition label discussed above.

In short, when choosing cheese for pregnant women and babies, it is best to choose low-salt original cheese, which is more natural and pure.

When choosing processed cheese, the main ingredient should be cheese, or the nutrition label (content and NRV%) should have a protein value as high as possible and a fat and sodium value as low as possible compared to the energy value marked.

At present, many products also choose cheese as a carrier for fortifying more nutrients. During the reprocessing, DHA, iron, vitamins A and D, carotene and lutein are added in the same way as the production of milk powder to form better nutritional supplement advantages, which is also worthy of attention.

Author: Wang Zhixu | Chairman of the Maternal and Child Nutrition Branch of the Chinese Nutrition Society, Professor of Maternal and Child Nutrition at the School of Public Health, Nanjing Medical University