The eagle strikes the sky, the fish soars to the shallow bottom, and all kinds of frost are free. As a member of the natural biosphere, although from the perspective of diversity, many times we do not particularly emphasize the superiority of one organism over other organisms, after all, the survival of the fittest, each organism adapted to the environment, has its own uniqueness, however, from the perspective of the entire biosphere, and even extended to the entire ecosystem, we will find that human beings, a single species, are undoubtedly the strongest brother in the field of biosphere. In the 4.5 billion years of the earth's history, there has never been such a powerful and changeable species, whether it is the birth of life 3.8 billion years ago, or the Cambrian explosion, or the Mesozoic Era led by reptiles, the cause of these great changes is the joint efforts of countless species, and Homo sapiens such a species that appeared 200,000 years ago, in a short period of time, the changes to the earth have reached a standard sufficient to divide the new geological era, so that geology experts not only call the era of entering the agricultural age from 12,000 years as Holocene, but also separate a separate concept from the Holocene - the Anthropocene, in order to describe this unique era.
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It can be said that, to some extent, we are superior in biological evolution, but these superiorities do not come without a price.
01, disappearing vitamin C
In 1497, the Portuguese navigator Vasco da Gama circumnavigated Africa to India, and the crew of the ship fell seriously ill, which was "a pain all over the body, purple spots, swollen gums, and ...... of the gums", which became known as scurvy, and more than 100 of the ship's 160 crew members died as a result. This scene was repeated in the following Age of Sail, and even two centuries later, until Captain Cook of England found a solution to the problem, which was to eat plenty of fruit and vegetables on board.
Of course, today you and I are very clear that the core factor behind scurvy is vitamin C, and fruits and vegetables contain a lot of vitamin C. Nowadays, we are accustomed to the existence of this vitamin, after all, whether it is in various dietary guidelines or nutrient supplements, vitamin C is a well-deserved "important person".
So, have you ever wondered why humans need vitamin C supplementation?
The answer seems simple: humans cannot synthesize vitamin C. However, when you take a closer look, you will find that this truth does not seem to be so simple, because animals are not unable to synthesize vitamin C, and our human ancestors can actually synthesize vitamin C. Our close relatives, such as lemurs, can synthesize vitamin C [1].
So, when did humans lose the ability to synthesize vitamin C? One theory says 25 million years ago [2]. Vitamin C synthesis requires a key enzyme, LGO, and this is the point in time when mammals truly stand on the stage of the planet and become the new niche rulers. And our ancestors, in this new world, naturally began to pursue higher evolutionary advantages, including the gradual weakening of vitamin C's ability to synthesize. The disadvantage of the weakened ability to synthesize vitamin C is that we must obtain vitamin C through food, especially fruits and vegetables rich in vitamin C. But other possibilities also emerge.
The loss of vitamin synthesis in primates occurs simultaneously with the loss of the ability to break down uric acid [3,4]. People often go to the hospital for physical examination will know that there is a uric acid index, which the human body cannot decompose, often eat a lot of seafood and meat or drink less water will lead to high uric acid! Uric acid is a very important strong reducing agent. The time of human uridase gene inactivation is roughly the same as that of vitamin C. From this perspective, it may be possible to partially explain the weakening of vitamin C's ability to synthesize.
One of the important roles of vitamin C is antioxidant, and when primates have passed the initial difficult moment, the decrease in vitamin C leads to an increase in oxidative free radicals in the body, and the presence of excess free radicals increases the likelihood of free radical-induced genetic mutations that eventually drove hominants from primates [5].
It can be said that the loss of the ability to synthesize vitamin C promoted evolution, and these changes continued to accumulate over the years that followed, until one day, a real group of "highly intelligent" humans appeared in Africa, which we call "Homo sapiens".
02, not just vitamin C
Not only vitamin C, but in fact, most vitamins we can't synthesize.
In the huge family of vitamins, the human body can directly synthesize very little, only vitamin D and a small amount of vitamin K, B12, etc., and the rest must depend on eating.
And these vitamins are not optional. For example, vitamin E, a fat-soluble vitamin, is the body's main antioxidant. Inhibition of cholesterol synthesis may lead to increased oxidative damage to cell membranes and other factors when vitamin E is deficient, leading to metabolic disorders in the body [6]. In addition, vitamin E itself is a fertility-related vitamin, and vitamin E deficiency may lead to a decrease in sperm production in men [7], while in women, vitamin E deficiency may be related to ovarian secretion of estrogen, resulting in regression of ovarian function or premature aging [8]. For this reason, vitamin E is also known as tocopherol. However, this important vitamin cannot be synthesized by the human body and needs to be supplemented by eating.
Another example is vitamin A, which is a bioactive compound of retinol and has a variety of biological functions in the human body. It not only participates in the normal growth of bones and the functional development and maintenance of vision, but also plays an important role in animal reproduction and immune function [9]. In addition, vitamin A also has a corresponding effect on oxidative damage in the body, and can effectively control the oxidative stress response caused by the formation and metabolism of arachidonic acid in the body, and play an antioxidant function [10]. However, the human body is also unable to synthesize vitamin A.
Vitamin B, this is a relatively large family, there are many familiar faces in it, such as vitamin B1, vitamin B2, vitamin B6, vitamin B12, folic acid (B9), niacin (B5), etc., which are familiar names to most people, and are also common dietary supplement ingredients. The reason why B vitamins are so common is that they are involved in the fundamental processes of the body's metabolism and are important participants in the conversion of sugars, fats, and proteins into energy supply in the body [11]. For example, the familiar folic acid, which is vitamin B9, plays an important role in neurodevelopment, so it is recommended by many doctors during pregnancy. In fact, B vitamins in general belong to the type of rapid metabolism and therefore need to be consumed constantly.
Faced with the fact that the human body cannot directly synthesize essential vitamins, as omnivores, humans have many advantages in obtaining food. Especially after we are at the top of the food chain and have developed agriculture, human beings can actually supplement various nutrients by enriching their diets. So most of the time, we don't have to worry about not getting enough vitamins.
And what really deserves attention is the change in dietary structure.
03, Dietary crisis
The dietary crisis here is not a lack of food, but a change in the structure of our diet. In human history, especially in the era of civilization after the emergence of agriculture, most of the time, the main food of human beings is plant food, and these foods are often rich in various nutrients that need to be supplemented, including vitamins and other components, such as various minerals, such as calcium, iron, zinc, selenium, etc., so we are not actually very deficient in these nutrients.
In recent centuries, especially after the emergence of chemical fertilizers and pesticides, the development of agriculture has been greatly promoted, and the industrial revolution has also brought great changes to the development of agriculture. However, these great changes have brought about changes in the structure of human diet.
The food structure of some people has changed from plant food to meat food, which will lead to the deficiency of some vitamins and other nutrients from plants. In addition, some people are picky eaters and picky eaters, which will also increase the risk of nutrient deficiencies...... All of these factors combine to make our diet today unreasonable.
(http://www.chyxx.com/research/201607/429709.html)
And unreasonable, there is a price, and now many of us are still lacking in these vitamins, minerals, etc. These ingredients themselves are essential for the body's function, and the adverse effects of vitamin deficiency have been mentioned above, as well as the lack of mineral elements. For example, the familiar calcium is not only an important part of our bones, but also a structural substance of cell physiology, biochemical metabolism, and if the body lacks calcium, it will lead to fragile bones.
In the face of the frequent occurrence of modern sub-health, various countries have issued various dietary guidelines to guide people to work towards a healthy diet.
But in today's society, people's diet is often limited by a variety of reasons, such as young people in the workplace, who can only order takeout to solve three meals, and there are many other reasons why people cannot eat healthily. Therefore, many people are now facing the situation of insufficient vitamin supplementation, which also deserves the attention of people in the field of nutrition and medicine.
With the continuous development of the economy and society, our dietary structure may continue to change in the future, and how to advocate a healthy diet and encourage the masses to eat a reasonable diet has become a question worth pondering.
[1] Marie-Berengere Troadec， Jerry Kaplan，Some Vertebrates Go with the GLO，cell.2008.03.005
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[3] Johnson R J, Gaucher E A, Sautin Y Y, et al. The planetary biology of ascorbate and uric acid and their relationship with the epidemic of obesity and cardiovascular disease[J]. Medical hypotheses, 2008, 71(1): 22-31.
[4] Wu X W, Lee C C, Muzny D M, et al. Urate oxidase: primary structure and evolutionary implications[J]. Proceedings of the National Academy of Sciences, 1989, 86(23): 9412-9416.
[5] Bánhegyi G, Braun L, Csala M, et al. Ascorbate metabolism and its regulation in animals[J]. Free Radical Biology and Medicine, 1997, 23(5): 793-803.
[6] Wang, Xiaoyuan, and Peter J. Quinn. "Vitamin E and its function in membranes." Progress in lipid research 38.4 (1999): 309-336.
[7 ] Suleiman, S. Ali, et al. "Lipid peroxidation and human sperm motility: protective role of vitamin E." Journal of andrology 17.5 (1996): 530-537.
[8 ] Das, Padma, and Mridula Chowdhury. "Vitamin E-deficiency induced changes in ovary and uterus." Molecular and cellular biochemistry 198.1-2 (1999): 151-156.
[9] Mora JR, Iwata M, von Andrian UH (September 2008). "Vitamin effects on the immune system: vitamins A and D take centre stage". Nature Reviews. Immunology. 8 (9): 685–98.
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