National Science Popularization Day | The rainbow in the food world, do you know how to eat it?

When it comes to the most colorful food, it must be fruits and vegetables. The colorful fruits and vegetables form a "rainbow" in life.

In addition to their attractive appearance, fruits and vegetables are also a good source of nutrients such as various vitamins and minerals. Therefore, it is particularly important for children and adolescents who are in the process of rapid growth and development to eat good fruits and vegetables.

Then some parents will ask: "Our child doesn't like to eat vegetables. Since fruits and vegetables contain vitamins and minerals, I should just give him more fruits."

This statement sounds reasonable, but in fact there is a certain misunderstanding. Today, let us re-understand fruits and vegetables and master the secret of eating good fruits and vegetables!

1. Classification of fruits and vegetables

There are many types of vegetables, and each type of vegetable has different nutritional characteristics:
Leafy vegetables are rich in beta-carotene, vitamin C, etc. For example, cabbage and rapeseed are leafy vegetables.

Melon and nightshade vegetables are rich in water and contain dietary fiber, and some special phytochemicals such as lycopene play a role in them. Cucumbers, eggplants, tomatoes and other "melons" and "nightshades" are classified into this category.

Tubers, taro and root vegetables contain large amounts of carbohydrates such as starch, which means that eating vegetables such as sweet potatoes and potatoes can provide sufficient energy just like rice and flour.

Fungi and algae contain proteins and polysaccharides, and mushrooms and fungus are important components of them.

Compared with vegetables, fruits contain more carbohydrates and organic acids in the form of monosaccharides and disaccharides, such as tartaric acid, malic acid, etc., which is also the source of the unique sweet and sour taste of fruits.

Similarly, there are different categories of fruits: such as pome fruits (apples, pears, etc.), berries (grapes, kiwis, etc.), stone fruits (peaches and apricots), melons (watermelon, cantaloupe, etc.), citrus fruits (tangerines, oranges, etc.), and some tropical fruits (pineapples, bananas, etc.).

2. How should we eat fruits and vegetables?

In the "Dietary Guidelines for Chinese Residents (2022)", school-age children aged 6-17 can refer to the general population's intake, which is 300-500 grams of vegetables and 200-350 grams of fruit per day. However, as people's living standards improve, livestock, poultry, fish and shrimp are no longer luxuries, and the intake of fruits and vegetables is insufficient. According to a study involving 15 provinces, the proportion of vegetable intake of children and adolescents in my country that meets the recommendation is only 14.2%, and fruit intake is only 3.1%.

In such a big context, what we need to do is to eat more fruits and vegetables if possible!
To this end, we have summarized some tips for eating vegetables and fruits in a reasonable way. Come and take a look!

Pay attention to the type of combination

The above article mentioned the classification of fruits and vegetables. When choosing daily fruits and vegetables, you should try to eat them equally. Balanced matching is the key. You can choose 2-3 different kinds of vegetables for each meal, and 1-2 different fruits after the meal. However, there is a special type of vegetable, which is yam. Because it contains a lot of starch, it can replace some staple foods. Therefore, after choosing this type of vegetable, you must appropriately reduce the intake of rice and noodles.

Another recommendation in the guidelines is that "dark vegetables should account for 1/2 of your daily intake." What are dark vegetables? Dark vegetables include dark green, red, orange-red, and purple-red vegetables, and they are dark from the inside out. Compared with light-colored vegetables, dark vegetables contain more vitamins, minerals, and pigments. Therefore, "color" is also a basis for choosing vegetables!

Pay attention to cooking methods

The cooking process is essential to getting a delicious vegetable dish, and the right cooking method can minimize the loss of nutrients. For example, quick stir-frying or cooking with soup can shorten the cooking time and reduce the loss of vitamins due to heat or water dissolution. Starch can also be used for thickening to protect the texture and shape of the vegetables.

At the same time, good cooking skills can also improve the color, aroma and taste of dishes, and increase the appetite of children and adolescents. Mothers no longer have to worry about their children being "picky eaters".

Juice is not a substitute for fruit

Fruits are sweet and juicy. Some parents squeeze fruits into juice for their children to increase their fruit intake because their children don't want to eat fruits. This practice has good intentions and is very convenient. However, during the processing, vitamin C, organic acids and other ingredients are oxidized when exposed to air; if the residue is filtered out to obtain a better taste, most of the dietary fiber in the fruit will be lost; and juice concentrates the sugar in the fruit. Drinking a lot of juice is tantamount to drinking "sugar water", which can easily cause health problems such as obesity and tooth decay in children.

Having said so much, I believe that both adults and children have a new understanding of fruits and vegetables, and have learned how to eat more fruits and vegetables better.
Let’s start from our next meal and create a rainbow life with colorful fruits and vegetables!

Let children and teenagers grow up healthily and happily with the company of fruits and vegetables!

References:
[1] Shen Xiuhua. Food Nutrition[M]. Shanghai: Shanghai Jiaotong University Press, 2020.6.

[2] Li Li, Ouyang Yifei, Wang Huijun, et al. Vegetable and fruit intake of children and adolescents in 15 provinces of China[J]. Chinese Journal of Health Education, 2020, 36(1): 3-7.

[3] Lu Ruoqi. Dark vegetables have many advantages, so it is appropriate to eat more of them [J]. Family Medicine (Part 2), 2018(7): 40.

[4] Zhang Liuzhou. Effects of cooking on functional components and nutritional evaluation of vegetables[J]. Food Industry, 2017(4): 137.

Project source: Shanghai Science and Technology Commission Science Popularization Project Funding (Project No.: 21DZ2301800)

Author: Wang Cenyu Niu Yang | Department of Clinical Nutrition, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine