Recently, many circles of friends are discussing a BBC show "The Truth About Healthy Eating" because the claims are quite "subversive":

Scrambled eggs are not as healthy as fried eggs.

Boiled vegetables are not as healthy as fried vegetables.

Breakfast of omelette and meat is healthier than milk with oats.

The nutritional value of wolfberry is not as good as that of strawberry.

Quinoa is not much more nutritious than other cereals.

... sounds quite different from everyday cognition.

This program claims to invite "top universities" to conduct experiments and evaluate based on the results of the experiments.

After reading it, I felt deeply: It seems that the evaluation of the nutritional value of food really needs to be popularized. The price of food and nutritional value may not be directly proportional. "Healthy food" does not necessarily bring health improvement to people. I support these claims with both hands, and I have written science popularizations many times.

However, the judgment standards of some food experts on the nutritional value of British universities are really shocking ...

(For the correct understanding of the nutritional value of food, I have compiled several textbooks for this part, and I will focus on teaching students daily, and have also done two related professional trainings.)

Today, I would like to use the content of this program as a case to share with you a few questions.

——I may not be a top expert at a top university, but I hope you can calmly think about the logic of thinking as I said and see if I can convince you. (I respect the top universities in the UK, but I love the truth ...)

In this article, let me first talk about the absurd evaluation of wolfberry in this BBC program.

The show said that wolfberry is much more expensive than ordinary fruits, and the British think it is a nutritious food. However, after eating it, the vitamin C content of volunteers increased much less than eating strawberries. Therefore, eating wolfberry just contributes to China's GDP.

I was a little stunned, actually speaking from the mouth of a scholar.

Can dried wolfberry and fresh strawberry compare together?

First, wolfberry is a dried fruit product. Strawberries are fresh fruits.

It is known that most of the vitamin C in fruits is lost when dried, just like fresh dates with a vitamin C content of 200 ~ 500mg / 100g. After drying into dried dates, the vitamin C content is lost by more than 90%.

If the strawberry is dried, it will also have a significant decrease in vitamin C content. The same is true for other dried fruits such as dried apricots, raisins, and cranberries, unless vacuum freeze-drying is used.

I consulted the Chinese research literature, and the vitamin C contained in fresh wolfberry is also quite rich, and it is not inferior to fresh strawberry.

The literature shows that the vitamin C content in fresh wolfberry fruit is 40 ~ 80mg / 100g, which is higher than the average level of strawberry (Zhang Ying et al., 2009). Some measured data compared the vitamin C content of fresh fruit and dried wolfberry in the same horticultural field, indicating that the vitamin C content of 100 grams of fresh wolfberry was 42.6 mg, and the dried wolfberry was 21.4 mg. At the same time, the vitamin C content of wolfberry produced in Zhongning County was measured and it was 18.4 mg (Qi Zongshao et al., 1986).

In other words, the dried vitamin C content of wolfberry is lower than that of strawberries (in the Chinese food ingredient table, the vitamin C content of strawberries is 47mg / 100g). After long-distance transportation and storage, the content may drop further when it is in the hands of British consumers. However, vitamin C of fresh goji berries is roughly equivalent to that of strawberries.

So the host reminded the audience: there is no need to spend money to buy Chinese wolfberry, because it is not worth the high price.

Secondly, from the perspective of antioxidants, the advantage of dried orange wolfberry is that carotenoids, including carotene and lutein, are particularly rich. This is beyond the reach of strawberries, because strawberries only have a small amount of anthocyanins, while carotenoids are minimal.

Chinese research data found that fresh wolfberry is rich in carotene, the content is 19.6mg / 100 g, and the dried wolfberry content is 8.9 mg / 100 g after drying (Ma Jianjun et al., 2009), which is higher than that in carrots.

Dried Chinese wolfberry is rich in lutein. The content of monohydroxy and xanthophyll in the dried Chinese wolfberry in Zhongning County is 10.1 and 60.3 mg / 100 g (Ma Jianjun et al., 2009), far higher than other common foods!

Β-carotene in dried wolfberry can be converted into vitamin A, which is beneficial for the prevention of dry eye and echinoderma; and lutein is useful for preventing cardiovascular diseases, cataracts and macular degeneration. Therefore, our country traditionally believes that wolfberry is good for eyesight.

Regarding the huge advantage of rich wolfberry carotenoids, the BBC program did not mention a word.

At the same time, the program did not compare the differences in B vitamins between the two fruits. From the nutrient density of B vitamins, dried wolfberry is higher than most fruits, but the sugar content is not the highest.

Wolfberry also crushes most fruits in the B vitamins project, because the B vitamins in fruits and dried fruits are generally very low.

According to the data in the "Basic Ingredients Data Sheet of Chinese Functional Food Raw Materials", 100 grams of Chinese wolfberry (dry product) contains 0.35 mg of vitamin B1, 0.42 mg of vitamin B2, and 4 mg of niacin. In comparison, the content of vitamin B1 in 100 grams of raisins is 0.09 mg, and vitamin B2 is too small to be detected. The content of vitamins B1 and B2 in fresh strawberries is 0.02mg and 0.03mg, respectively. I am afraid that it will be impossible to detect when dried.

In addition, wolfberry is also rich in flavonoids, betaine (0.77g / 100g), wolfberry polysaccharides (55.7g / 100g) and other health active ingredients. Lycium barbarum polysaccharides, in particular, have been shown to have a variety of health effects.

——Use the dried wolfberry product and fresh strawberry than vitamin C, and then say that it is not worth eating. If the brain of the expert is not a problem, it will deliberately cooperate with the TV station to make a speech.

The most important question is: Do people eat dried wolfberry to get the vitamin C in it?

The obvious answer is no.

When evaluating the nutritional value of a food, a certain unified index cannot be used to judge arbitrarily. Because there are dozens of nutrients in food, there are more varieties of health ingredients. As long as this food can supplement the nutrients you lack in your current diet, or if some of its health ingredients meet your body's needs, it is good food.

Just as a person has many aspects of abilities and qualities, whether a student can become a useful talent and contribute to society cannot be evaluated uniformly with the results of math classes.

Of course, dried wolfberry is not irreplaceable, and it is no problem if you don't eat it for a lifetime.

In addition to the lycium barbarum polysaccharides, carotene can be obtained from cooked carrots, lutein from spinach, and vitamin B1 and vitamin B2 from whole grains.

The show says strawberries are only £ 6, but wolfberry is much more expensive. In terms of price, wolfberry is not expensive. If you count by dry goods, dried strawberries will not be cheaper than dried wolfberries, because 4 to 5 pounds of fruit are needed to make one pound of dried fruit. If you transport it to the United Kingdom thousands of miles, the price will not be low.

In fact, strawberries are not the cheapest source of vitamin C.

For example, eating steamed potatoes instead of staple foods, often eating raw cabbage, tomatoes, and some oranges can easily get a lot of vitamin C, which is much cheaper than eating strawberries. It is cheaper to drink orange juice with VC, or take vitamin C tablets directly.

But can we say that strawberry is not worth eating?

Therefore, if you add a small amount of wolfberry every day when you cook porridge, soak water and cold dishes, you don't have to stop just because you watched this program. One hundred grams of wolfberry is only ten or twenty yuan. How much is a few grams of wolfberry? It can provide a variety of nutrition and health care ingredients, especially the carotenoids, which are good for our tired eyes.

If you want to save money, eat less snacks and desserts, drink less sweet drinks, eat less clothes, buy unnecessary clothes and accessories, and slow down the update of electronic products ... it will make more sense.