Nutrient requirements are

Nutrient requirements refer to the minimum dose of nutrients that the human body must obtain through diet during a specific period in order to maintain basic physiological functions and maintain a healthy state. Below this threshold, the body will suffer from varying degrees of functional impairment, and even induce nutritional deficiency diseases.

You must have read popular science such as "Adults should eat one pound of vegetables and half a pound of fruits every day" and "Drink 300ml of milk every day to supplement calcium." Do you occasionally wonder: I sit in the office fishing every day and run to the construction site every day to carry goods, is it really appropriate to eat the same amount? This is actually a misunderstanding of the applicable scenarios of "nutrient requirements".

Most of the general demand data we can find now are real results accumulated through large-sample population intervention experiments in the past few decades. Take vitamin C as an example. Researchers at that time found a group of volunteers who ate a diet that did not contain vitamin C for several weeks. They recorded the time when different people developed early symptoms of scurvy such as gum bleeding and subcutaneous ecchymosis. They then calculated backwards that to avoid the disease, one must eat at least 10mg of vitamin C every day - this is the basic requirement of vitamin C. Oh, yes, the Dietary Reference Intake (DRI) system we often call is built on this basic value.

However, precision nutrition has become a big trend in recent years, and many scholars feel that this "average data" is too rough. After all, everyone’s age, gender, physical activity level, genes and even intestinal flora are different, so the requirements vary greatly. Let me tell you a real story that I encountered before. Last year, I helped a fitness blogger who had just undergone meniscus surgery to make a post-operative diet plan. According to the general standard, it is enough for adults to eat 0.8-1.0g of protein per kilogram of body weight per day. However, he wanted to prevent muscle loss and promote tissue repair. The final amount given was 2.0g per kilogram of body weight, which was more than double the difference. Not to mention that expectant mothers in the third trimester need 200mg more calcium than ordinary women, and people working at plateaus need 30% more vitamin C than on plains. It is impossible to rely on a universal standard to meet the needs of these special circumstances.

Many people tend to confuse "required amount" and "recommended intake". In fact, the difference is quite big. For example, the required amount is the low battery alarm line of your mobile phone. If it falls below 20%, it may automatically shut down. ； The "100 mg of vitamin C a day" we often see in Copley is the recommended intake, which is equivalent to leaving a safety margin of almost 10 times the required amount. It takes into account the part that is lost due to heating when you stir-fry vegetables and the part that is not easily absorbed by the gastrointestinal tract. Even if you only eat half a catty of vegetables today, it is enough to reach the passing line of the required amount, so there is no need to worry.

Of course, the academic community has not yet fully reached a consensus on the requirements for many nutrients. The most typical one is saturated fat. The traditional nutritional view is that the human body can synthesize enough saturated fat to meet metabolic needs, so the dietary requirement is 0. The less daily intake, the better. ； However, in recent years, some scholars in the field of sports nutrition have come up with experimental data, saying that for people who train for more than 10 hours a week, appropriate intake of saturated fat can help maintain the levels of testosterone and other hormones, but completely cutting it off will affect exercise performance. Both views have support, and there is no absolute right or wrong yet.

I have been doing public nutrition science for almost 6 years, and the most common questions I encounter are asking with a nutrition calculator, "Did I eat 100 mg more sodium today?" "Did I lose 5 mg of vitamin C and not eat enough?" To be honest, most ordinary people really don’t need to be so meticulous. As long as they can eat more than 20 kinds of ingredients every week, including meat, eggs, milk, vegetables, fruits and whole grains, they can basically hit the bottom line of the required amount. There are really special circumstances - such as preparing for pregnancy, having to stay up all night for a week to prepare for an exam recently, or just having surgery and needing nutritional supplements. Just ask a registered dietitian to calculate the specific amount. Don't make meals feel like a task is completed just for the sake of a few milligrams difference, but lose the fun of eating.