What will happen if you eat a box of blueberries every day? Will your skin really become whiter? Will your eyesight really improve?

In recent years, as a fruit with high nutritional value, blueberry has increasingly entered people's lives.

For many people, there is nothing more satisfying than grabbing a handful of fresh blueberries while walking, throwing them into your mouth, and experiencing the bursting of blueberries in every bite.

Recently, there is a hot search about what will happen if you eat a box of blueberries every day. Many netizens say that it can relieve thyroid, whiten the skin, and improve vision. Are these true?

Image source: Weibo screenshot

01

What nutrients do blueberries contain?

Blueberries are often called one of the "top ten fruits" and are also on the "superfruit" lists circulating online. But what are the nutritional properties of blueberries?

When talking about the nutrition of blueberries, people usually mention two things - anthocyanins and vitamin C.

The vitamin C content of blueberries usually ranges from 10 to 34 mg/100 g, with the highest being only 34 mg/100 g. This content is only average in the fruit and vegetable world, and is actually less than that of strawberries, kiwis, dates, etc.

Copyright image, no permission to reprint

Anthocyanins have strong antioxidant capacity. Data show that different varieties of blueberries have different nutritional content, with the highest content exceeding 400 mg/100g. This is indeed relatively abundant in the fruit and vegetable world.

02

Relieve your thyroid?

Image source: Internet

Some netizens say that it can relieve thyroid problems. There are many cases where thyroid function changes, such as:

①Hyperthyroidism is an overactive thyroid gland. Common symptoms include increased appetite, sweating, tremors, and difficulty sleeping.

②Hypothyroidism is a decrease in thyroid function. Common symptoms include fatigue, drowsiness, constipation, muscle weakness, etc.

③Goiter is an irregular growth of the thyroid gland, which may appear as an overall enlargement of the thyroid gland, or it may appear as irregular cell growth leading to the formation of one or more lumps (nodules) in the thyroid gland.

④Thyroid nodules are caused by one or more abnormal mass structures in the thyroid gland due to various reasons such as genetics and environment. The cause is complex and has not yet been fully clarified.

It’s a grammatical error to say that blueberries can relieve the thyroid gland. Maybe she meant to say that they can promote thyroid health! There are indeed some studies that suggest that blueberries contain vitamin C, which can help promote thyroid health.

However, among fruits, blueberries are not particularly rich in vitamin C. Moreover, vitamin C is indeed a healthy nutrient, but it has no special effect on the thyroid gland. If you really have any thyroid disease, it is okay to eat some blueberries in a healthy diet, but you still need to follow the doctor's advice and take medicine at a reasonable time.

03

Whitening skin?

Image source: Internet

The reason why blueberries can whiten your skin is mainly because they are rich in vitamin C and have good antioxidant activity. They can inhibit the activation of tyrosine, so that tyrosine will not turn into melanin and can play a whitening role.

This statement makes sense, but there is actually no particularly sufficient evidence. However, vitamin C is also the raw material for the synthesis of collagen that makes up the skin, so it is still good for the skin. Therefore, it can be considered that supplementing with vitamin C may have certain benefits for the skin, but the whitening effect may not be as effective as you expect. If you want to whiten your skin, you should still do a good job of daily sun protection.

Moreover, vegetables and fruits are rich in vitamin C. Just pay attention to eating more vegetables and fruits. Besides, vegetables and fruits themselves are good for health. If you want to supplement vitamin C, just buy the cheapest one.

04

Will my eyesight improve?

Image source: Internet

The reason why eating blueberries improves eyesight is mainly because of the anthocyanins they contain.

Indeed, studies have found that anthocyanins promote the growth of retinal pigment epithelial cells, suggesting that they may also have a potential role in protecting vision.

However, there is currently insufficient evidence to prove the benefits of anthocyanins for vision, and blueberries cannot prevent or treat myopia. The European Food Safety Authority once evaluated the health claims of another fruit containing anthocyanins, blackcurrant, and concluded that its health claim of "improving vision and promoting dark vision" was insufficiently supported.

05

Would you like some blueberries?

As a fruit, blueberry has the advantages of other fruits, as well as its own characteristics. It tastes good too. If you like it, of course you can eat it.

However, if you believe in the exaggerated health benefits of blueberries, then I advise you not to hold your hopes too high.

In fact, the various health benefits of blueberries are basically derived from the "antioxidant" effect of anthocyanins, and there is no direct clinical trial data. Moreover, the claimed health benefits are suspected of being exaggerated.

Moreover, the more anthocyanins you consume, the better. Anthocyanins are a powerful antioxidant that can protect the body from damage by free radicals. However, too much anthocyanin can also hinder the absorption of minerals. People with anemia and zinc deficiency should not eat too much anthocyanin. People with poor gastrointestinal tract are also not recommended to eat too much.

Blueberries are not cheap. Usually a small box costs more than 10 yuan or even more. A small box usually only contains 100 grams, which means that one pound usually costs more than 50 yuan. No wonder some people say that eating a box every day will make you poor. I think this is really possible. I suggest that you choose fruits according to your actual situation.

Even if you want to get anthocyanins, you have many choices. Basically, any food that is red, purple, black, or blue will contain anthocyanins. Anthocyanins in some fruits and vegetables are found in the peel, such as purple eggplant, crimson apples, purple cabbage, mulberries, purple sweet potatoes, etc. If you just want to take in anthocyanins, there is really no need to eat only blueberries. Considering the cost-effectiveness, foods such as purple sweet potatoes and purple eggplant peels will be cheaper.

References:

[1] Ge Cuilian, Huang Chunhui, Xia Sijin, et al. Analysis of main nutrients and pigment contents of 10 blueberry varieties[J]. China Southern Fruit Trees, 2012, 41(4): 33-35.

[2] Zhu Jinyan, Wang Yuehua, Zhang Jianli. Study on nutritional components and anthocyanin types of different varieties of blueberries[J]. New Agriculture, 2016(9):10-14. DOI:10.3969/j.issn.1002-4298.2016.09.003.

[3] Yin Haisong, Tang Weihua, Zhang Renkuan, et al. Analysis of nutrients and antioxidant effects of wild and cultivated blueberries[J]. Food Research and Development, 2015, 36(18): 39-41. DOI: 10.3969/j.issn.1005-6521.2015.18.010.

[4] Zhou Xiaoli, Chen Li, Wang Rui, et al. Comparative analysis of conventional nutrients and active substances in different parts of blueberry[J]. Food Industry Science and Technology, 2016, 37(9): 363-366. DOI: 10.13386/j.issn1002-0306.2016.09.063.

[5] Yan Yamei, Dai Yanman, Ran Linwu, et al. Comparison of anthocyanin composition and in vitro antioxidant activity in Lycium barbarum and five kinds of fruits and vegetables [J]. Food Industry Science and Technology, 2014, 35(16): 133-136.

[6] Chinese Nutrition Society Scientific Consensus Working Group on the Use of Nutrient Supplements. Scientific Consensus on the Use of Nutrient Supplements[J]. Journal of Nutrition, 2018, 40(6): 521-525. DOI: 10.3969/j.issn.0512-7955.2018.06.001.

[7] Dietary Guidelines for Chinese Residents (2022) Miyake, S., Takahashi, N., Sasaki, M. et al. Vision preservation during retinal inflammation by anthocyanin-rich bilberry extract: cellular and molecular mechanism. Lab Invest 92, 102–109 (2012). https://doi.org/10.1038/labinvest.2011.132

[8]Gonçalves AC, Nunes AR, Falcão A, Alves G, Silva LR. Dietary Effects of Anthocyanins in Human Health: A Comprehensive Review. Pharmaceuticals (Basel). 2021 Jul 18;14(7):690. doi: 10.3390/ph14070690. PMID: 34358116; PMCID: PMC8308553.

[9]Lem, DW; Gierhart, DL; Davey, PG Can Nutrition Play a Role in Ameliorating Digital Eye Strain? Nutrients 2022, 14, 4005. https://doi.org/10.3390/nu14194005

https://doi.org/10.2903/j.efsa.2011.2204

Author: Ruan Guangfeng, Director of the Science and Technology Department of the Kexin Food and Nutrition Information Exchange Center

Review | Zhang Na, Associate Researcher, Doctoral Supervisor, Peking University School of Public Health

The cover image and the images in this article are from the copyright library

Reproduction of image content is not authorized