What will happen if you eat one carrot every day? Will your eyesight really improve? Will your immunity really become stronger?

Carrots are considered a healthy food in everyone's mind, especially for office workers and students who frequently look at mobile phones and computers every day, they are the guardian of eye health.

The health effects of eating carrots every day are not just about protecting your eyes, there are many more! In this article, we will talk about carrots.

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01

What are the benefits of eating carrots regularly?

1. Protect your eyes

The key nutrient in carrots is beta-carotene. The beta-carotene content of carrots is 2653 micrograms per 100 grams, which is higher than that of green leafy vegetables such as leeks, 1.4 times that of leeks, and 631 times that of Chinese cabbage. The beta-carotene content of Xinjiang carrots can reach 5739 micrograms per 100 grams. [1]

This ingredient can be converted into vitamin A in the body, also known as provitamin A, which is beneficial for eye and skin health .

Vitamin A is particularly important in protecting vision. It is a component of the photosensitive material in visual cells. It is necessary to ensure that it is adequately consumed in order to maintain the synthesis of rhodopsin and the entire dark vision process. Deficiency can lead to night blindness, and in severe cases, it can cause dry eyes and even blindness . At present, the rate of vitamin A deficiency in China is relatively low, but it is still necessary to pay attention to supplementation. [2]

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Although vitamin A is important, excessive intake is not good. Vitamin A poisoning can damage multiple organs such as the skin, bones, brain, and liver. Fortunately, it is very safe to supplement vitamin A by eating foods rich in carotene. This is because beta-carotene can be stored in the liver and can be gradually converted into vitamin A according to the body's needs. There is no need to worry about the toxic effects of excessive vitamin A.

In addition, carrots also contain lutein and zeaxanthin, both of which are important components of macular pigment in the human cornea. They can protect the retina from damage by blue light and improve visual sensitivity .

2. Enhance immunity

Adequate vitamin A is not only good for eye health, but also important for skin health and immunity. It can maintain the integrity of the skin and mucous membranes, and a lack of it can cause the skin to become rough, dry, and easy to peel.

Vitamin A is also a regulator of immune metabolic cells, can promote the differentiation of epithelial tissue, may enhance the activity of macrophages and natural killer cells, and change the growth and differentiation of lymphocytes.

It plays an important role in maintaining the normal function of human epithelial cells, preventing respiratory and digestive tract infections, and improving immunity. For example, vitamin A deficiency can lead to atrophy and dryness of the respiratory mucosal epithelium, a reduction in cilia, and a weakening of disease resistance; increase the risk of respiratory diseases; and make it easier to develop symptoms such as dry throat, itching, and coughing; and make it difficult to recover from respiratory diseases. [2] Because of its function, it is also called an "anti-infection" vitamin.

3. Prevent constipation

The dietary fiber content of carrots is quite good. According to the data from the U.S. Department of Agriculture Nutrition Database, the total dietary fiber content of carrots is 2.8 grams per 100 grams, which is nearly three times the total dietary fiber content of Chinese cabbage. [3] It can not only enhance satiety, but also promote gastrointestinal motility, prevent constipation, and help the proliferation of beneficial intestinal bacteria.

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4. May Prevent Cancer

There are many studies on the relationship between β-carotene and cancer, such as its ability to prevent lung cancer, breast cancer, oral cancer, etc. However, many conclusions are inconsistent. Molecular level studies have shown that carotene has the functions of preventing or delaying the progression of cancer, anti-oxidation and regulating cell growth; epidemiological research results show that cancer risk is related to carotenoid intake, but it is limited by individual differences and measurement methods. [4] At present, clinical evidence on whether supplementing β-carotene can prevent cancer is still controversial.

However, for smokers, taking β-carotene supplements will aggravate the DNA oxidative damage caused by cigarette smoke condensates, causing changes in cell proliferation and apoptosis pathways related to tumor suppressor genes, thereby increasing the risk of cancer. In other words, for smokers, additional β-carotene supplements will increase the risk of lung cancer , especially for those who smoke and drink more. This may be related to the dose of β-carotene consumed, which is often high. [4]

02

What is the best way to eat carrots?

Carotene is a fat-soluble vitamin and needs to be combined with fat to promote better absorption, so many people think that it must be fried with cooking oil to eat.

Actually, it is not like that. Although it needs to be paired with fat, it does not mean that it must be fried with oil. Food is digested and absorbed in the small intestine of the human body. As long as carotene and fat can meet in the small intestine, it is fine . When eating foods rich in carotene, you can also eat them with foods rich in fat, such as meat, nuts, and stir-fried dishes with cooking oil. Try to chew slowly to release the carotene better.

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It is also important to pay attention to the cooking method. Studies have shown that cooking and heating are beneficial to improving the bioavailability of carotenoids in dark vegetables . Different cooking methods will also lead to differences in the retention rate of β-carotene. Although carrots need fat to assist in absorption, cooking with oil as the medium will increase the loss of carotene.

Experiments have shown that the retention rate of β-carotene in carrots will be significantly reduced when cooking with oil, stir-frying or deep-frying. For example, when carrots are stir-fried for 2 minutes and then stewed for 8 minutes, the retention rate is 75%. Deep-fried carrots have a retention rate of 76%. Boiled carrots have a higher retention rate, with a retention rate of up to 91% for 7 minutes. [5] In addition, the carotene mixed in the soup on the plate is often thrown away, causing further losses.

Therefore, it is not recommended to cook carrots by frying first and then stewing them. Instead, it is more recommended to steam them directly, which not only has a high absorption and utilization rate but also reduces losses .

03

How much should you eat if you don’t want to turn yellow?

Although eating carrots has many health benefits, eating too many of them can really turn you into a "minion"! This is because you consume too much beta-carotene, which prevents it from being quickly converted into vitamin A in the small intestinal mucosal cells . Increased levels of carotene in the blood cause yellow pigmentation in the skin and subcutaneous tissue, which manifests as yellowing of the skin, most notably on the tip of the nose, nasolabial folds, forehead, palms, and soles of the feet. This condition is called "hypercarotenemia." [2] But don't worry, it won't harm your health. Just stop consuming large amounts of rich vitamins.

If you eat foods containing beta-carotene, the symptoms will disappear on their own after 2 to 6 weeks and your skin will gradually return to its original color.

If you want to eat carrots every day without turning your skin yellow, you just need to control the amount. A population intervention study showed that taking 30 mg of beta-carotene from food every day can cause your skin to turn yellow within 25 to 42 days. [2]

For example, Xinjiang carrots are rich in beta-carotene. One 200-gram carrot contains about 12 mg of beta-carotene. To prevent yellowing, it is best to limit the number of carrots to 2 per day , but you can also eat less. After all, beta-carotene is not only found in carrots, but also in common dark-colored fruits and vegetables, such as spinach, broccoli, chicory, pumpkin, mango, cantaloupe, papaya, etc.

Your eyes must be tired, so let’s have some carrots as a snack today~

References:

[1] Yang Yuexin. Chinese Food Composition Table 6th Edition Volume 1[M]. Peking University Medical Press, 2018

[2] Yang Yuexin, Ge Keyou. Chinese Nutrition Science Encyclopedia 2nd Edition (Volume 1)[M]. People's Medical Publishing House, 2019

[3]https://fdc.nal.usda.gov/fdc-app.html#/food-details/170393/nutrients

[4] Zhai Yanli, Hui Bodi, Cai Jin, Liu Rui, Wang Yingming. Study on the correlation between carotenoids and cancer risk[J]. Food Science, 2013, 34(13): 307-313

[5] Wang Lu, Fan Zhihong, Chen Ran. Effects of cooking on carotenoids in dark vegetables[J]. Chinese Food and Nutrition, 2013(6):82-85

Author: Xue Qingxin, one of the first nutrition instructors of the National Health Commission, and a registered nutritionist in China

Reviewer: Zhang Na, Associate Researcher, Doctoral Supervisor, Peking University School of Public Health