When you think of "walnuts", what do you think of?Many people may have two words in their minds - "replenish the brain"!What exactly is the nutrition of walnuts?Can eating more walnuts really "replenish the brain"?Let's talk about it in detail today. 
Gallery copyright**, use may lead to copyright disputesStick to eating walnuts for 6 months
The brain has really changed!
In April 2023, a 6-month randomized controlled nutrition intervention trial was published in the well-known medical journal The Lancet, which gave us a preliminary answer to the question of "whether eating walnuts can replenish the brain". The study included 942 secondary school students aged 11 16 years, and after screening, 771 adolescents were included in the analysis and randomized – the control group did not receive any form of intervention;The experimental group would receive a sachet containing 30g of walnut kernels per day, about 3 4 walnuts, and eat 1 sachet per day for 6 months. After observation, the researchers found that 133 people had good compliance, ate walnuts for 100 days (not necessarily every day), and the red blood cell-linolenic acid status of these adolescents was slightly higher, and their attention was enhanced, which significantly improved the behavior of some adolescents with symptoms of attention deficit hyperactivity disorder, which was manifested in the increase in paying more attention to the teacher in the classroom and fluid intelligence-related functions, such as perception, memory, calculation speed, reasoning ability, etc. In this way, for teenagers who insist on eating walnuts for 6 months and have good compliance, walnuts do play a role in "tonifying the brain". Researchers also believe thatEating walnuts on a regular basis (more than 3 servings per week, about 10 walnuts) may lead to improvements in sustained attention, fluid intelligence, and ADHD symptoms, although there is no significant effect on neurodevelopment in healthy adolescents. Research aside, walnuts do contain a lot of nutrients that the brain needs, such as protein, which is a component of the brainCarbohydrates provide energy for the functioning of the brain;Linolenic acid, a polyunsaturated fatty acid, is converted into DHA in the body and contributes to brain health. But I should be reminded that although the above research shows that eating walnuts for a long time is somewhat useful for "nourishing the brain", don't expect to increase your IQ by eating walnuts!
Gallery copyright**, use may lead to copyright disputesWhat are the nutrients of walnuts?
Walnuts, also known as walnuts, are widely cultivated in China, and as of 2020, China's walnut planting area ranks first in the world, which shows how popular walnuts are in China. It can make art, play with walnuts, and eat them, killing three birds with one stone!If you want to talk about the nutritional value of walnuts, it is really good, it has the reputation of "longevity fruit" and "health treasure".
Proteins
Walnuts have a protein content of 149g 100g, although it is not very good among nuts, but it is still rich in amino acids. Studies have shown that walnut protein contains 18 kinds of amino acids, of which 8 are essential amino acids, accounting for 26% of the total amino acids98%~30.38%, which is conducive to growth and development.
Unsaturated fatty acids
Walnuts have a high fat content of 588g 100g, mainly polyunsaturated fatty acids, the content accounts for about 762%, linolenic acid and linoleic acid accounted for 122% and 64%. Although the linolenic acid content in walnuts is not as high as that of flaxseeds, it is much higher than that of other nuts. This ingredient can be converted into DHA in the body, which is beneficial for brain and retinal health, but the conversion rate is generally low.
Vitamin E
Walnuts have a more prominent vitamin E content among nuts, up to 432mg 100g, which is nearly 1 of hazelnuts2x. Vitamin E has strong antioxidant properties, is also an essential nutrient for maintaining fertility, and can also maintain normal immune function.
Antioxidants
Walnuts are rich in antioxidants, including total phenols and flavonoids. Phenolic substances and flavonoids were analyzed on the seed coat of fresh walnuts, and it was found that the phenolic substances had the highest content of gallic acid and the lowest content of ferulic acidRutin is the most abundant flavonoid. andThe vast majority of antioxidants are found on the seed coat of walnut fruitsThese ingredients are antioxidants that help our body fight inflammation and scavenge excess free radicals. However, the seed coat of walnut fruit has a high level of astringency, so it has an obvious astringency. If acceptable, it is best to eat it with the skin. In addition, it has to beA reminder: walnuts ≠ pecans。The walnut we usually talk about is a nut of the genus Juglans, and the pecan is not a "walnut in the mountains", it is also called a small walnut, which is a member of the genus Hickory. Pecans are much smaller than walnuts and have a thicker skin and lower edible parts, with 43% of walnuts and only 24% of pecans. 
Source: iPlant Plant There is no small difference between the two in nutrition, compared with walnuts with higher content of linolenic acid, dietary fiber, potassium and selenium, and pecans with higher content of protein, vitamin E and magnesium. 
Note: Pecan linolenic acid data is cooked pecans Source: Made by the authorWalnuts in addition to "brain supplementation".
What other benefits are there for the body?
Walnuts are so nutritious, don't just think about whether you can "nourish your brain" when you eat them, eating walnuts often has a lot of other benefits for the body!
Improves blood lipids
A 2018 analysis of 26 clinical trials involving 1059 participants found that a diet supplemented with walnuts was associated with a significant reduction in plasma triglyceride (TG) levels compared with a control group that did not eat walnuts daily552%, LDL cholesterol (bad cholesterol) levels decreased 373%, total cholesterol level decreased by 325%。The decrease in these indicators is of great significance for the prevention of hyperlipidemia, and can also further reduce the risk of atherosclerosis and cardiovascular disease. A 2022 meta-analysis of 13 intervention trials involving the United States, Germany, Iran, the United Kingdom, Spain, and Chinese populations** examined the effect of walnut intake on blood lipid levels. The study found that walnut intake was significantly associated with improvements in serum triglycerides, total cholesterol, and bad cholesterol levels. The consumption of walnuts in the study was 15 64g per day for healthy people and 30 99g per day for people with overweight, obesity and dyslipidemia comorbidities.
Prevent diabetes
A study in the American Journal of Clinical Nutrition mentions that a high consumption of nuts, especially walnuts, has been linked to a reduced risk of diabetes, as well as a lower risk of obesity. Therefore, it is possible to stick to regular (about 1 time a day) nuts as part of a healthy diet to prevent obesity and type 2 diabetes.
May promote sleep
Melatonin is a hormone secreted by the pineal gland of the brain, which can naturally induce sleep, but due to physical or work reasons, many people's melatonin secretion has been affected, resulting in difficulty in falling asleep. Walnuts are melatonin-rich foods, and some studies have found that the amount of melatonin in the blood of animals can be 4 times higher after feeding them walnuts. People who don't sleep well usually eat walnuts, which may help with sleep, so you might as well give it a try.
Relieves anxiety
Among nuts, walnuts have an excellent -linolenic acid content. Studies have shown that -linolenic acid has a neuroprotective effect and can reduce anxiety symptoms, relieve emotional tension and reduce stress. 4 tips for eating walnuts
Although eating walnuts is good for health, it is important to choose the most correct way to eat them. Regarding eating walnuts healthily, here are 4 tips that you must check!
Choose plain walnuts
Now there are many walnut flavors on the market, such as sweet amber walnut kernels, salty salt and pepper walnut kernels, this kind of walnut kernels are generally high in sugar or salt, and eating them often is not good for health, which will increase the risk of dental caries, obesity, hypertension and other diseases. The most recommended ones are plain walnuts or whole shelled walnuts.
It is best eaten with the skin on
Under normal circumstances, the surface of walnut kernels has dark brown walnut skin, the taste is a little bitter, many people do not like to eat, and there are also peeled walnuts on the market, which are white and clean. If you want to get more of the antioxidants in walnuts, eat them with the skin.
Pay attention to how you save it
Walnut kernels are rich in polyunsaturated fatty acids, which are easy to oxidize rancidity and have a hala taste. Therefore, it is recommended to buy less each time and keep it sealed and refrigerated. If you can buy the shelled one, it is better to store it in a cool and dry place, and eat it freshly opened. Don't eat moldy walnuts!
Keep the amount under control
Although eating nuts regularly can help prevent obesity, you should not eat too much. The Dietary Guidelines for Chinese Residents recommend eating 50 70g of nuts per week, with an average of 10g per day, which is equivalent to 1 large paper nut or 2 3 pecans. If you eat too much, then appropriately reduce the amount of cooking oil, or use walnuts to replace part of pork and beef, so as to achieve polyunsaturated fatty acids to partially replace saturated fatty acid intake, which can reduce the risk of coronary heart disease. 
The weight of 1 paper walnut is about 9g, source: The author provides small walnuts with big benefits!Eating walnuts every day will make you have healthier blood lipid levels, better weight maintenance, no more anxiety, less stress, and may also make you more focused, better memory, and stronger reasoning skills. Let's start eating walnuts!References
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2] Wu Ping, Zhou Jisong, Deng Qianchun, et al. Structure, nutritional value, preparation, functional properties and application of walnut protein in food[J ol].Food Science: 1-12[2024-01-05].
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4] Zhang Pengfei, Zhao Zhiyuan, Song Yuqin, Liu Yaling, Liu Qunlong. Analysis of total phenol content in walnut fruit[J].Journal of Shanxi Agricultural University:Natural Science Edition,2013,33(4):324-327341
5]guasch-ferré, marta et al. “effects of walnut consumption on blood lipids and other cardiovascular risk factors: an updated meta-analysis and systematic review of controlled trials.” the american journal of clinical nutrition vol. 108,1 (2018): 174-187. doi:10.1093/ajcn/nqy091
6] alshahrani sm, mashat rm, almutairi d, mathkour a, alqahtani ss, alasmari a, alzahrani ah, ayed r, asiri my, elsherif a, alsabaani a. the effect of walnut intake on lipids: a systematic review and meta-analysis of randomized controlled trials. nutrients. 2022 oct 23;14(21):4460.
7]jackson, chandra l, and frank b hu. “long-term associations of nut consumption with body weight and obesity.” the american journal of clinical nutrition vol. 100 suppl 1,1 (2014): 408s-11s. doi:10.3945/ajcn.113.071332
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Planning and production
This article is a work of popular science China-Star Project.
Produced by丨Popular Science of China.
Producer丨China Science and Technology Press***Beijing Zhongke Galaxy Culture Media***
Author丨Xue Qingxin is a registered dietitian.
Audit丨Ruan Guangfeng, Deputy Director of Kexin Food and Health Information Exchange Center.
Planning丨Lin Lin.
Editor-in-charge丨Lin Lin.