Beware of Hidden Hunger: Eating Enough Is Not the Same as Eating Well
China's total grain output has achieved “eleven consecutive years of growth”, and people eating their fill is basically no longer a problem, but eating enough is not the same as eating well. The insufficient intake of trace elements and vitamins through food is called “hidden hunger”. The latest "Report on the Nutrition and Health Status of Chinese Residents" survey shows that nutritional imbalance, malnutrition and micronutrient deficiency are quite widespread among China's population. About 45% of our country's total population lacks vitamin A, 49% have insufficient zinc intake, the proportion of iron deficiency anemia among children under five years old is as high as 22%, and iron deficiency anemia among adults also accounts for 11%, etc.
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The nutritional content of fruits and vegetables has indeed declined
Countries such as the United Kingdom, the United States, Germany and Japan, by analyzing food nutritional content over several decades, found that the problem of declining nutritional content in fruits and vegetables and other foods does indeed exist. For example, Japanese food nutrition analyses from 1950 to 2000 showed that the vitamin A in every 100 grams of spinach dropped from 8000 IU to 700 IU, vitamin C dropped from 150 mg to 35 mg, and iron dropped from 13 mg to 2 mg; the vitamin A in carrots dropped from 13500 IU to 1500 IU, vitamin C dropped from 10 mg to 4 mg, and iron dropped from 2 mg to 0.2 mg.
American scholar Donald · Davis analyzed the 13 nutrients and yields of 43 horticultural crops recorded by the United States Department of Agriculture from 1950 to 1999, and found that the protein, calcium, phosphorus, iron, riboflavin (vitamin B2) and vitamin C content of these fruits and vegetables had “indeed declined” over the past half century: the iron content of carrots fell by 24%, the vitamin C content of eggplants fell by 44%, the calcium content of broccoli decreased by 37%, and the riboflavin content of winter melon had already fallen sharply by 52%. Davis said: “The minerals in vegetables in today's grocery stores have declined by an average of 5% to 40% compared with 50 years ago.” According to United Nations estimates, the global population with hidden hunger is as high as 2 to 3 billion people.
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How hidden hunger arises
The human body needs 13 vitamins and 16 trace elements. Most vitamins and mineral elements cannot be synthesized by the human body itself and can only come from food. For humans, apart from some aquatic products, these nutritional elements mainly “rely” on the soil.
The uneven distribution of elements on the Earth's surface can cause hidden hunger, and even disease. For example, the soil in Keshan County, Heilongjiang, contains very little selenium. In the 1990s, although people ate their fill, the selenium they took in was only 6 to 8 micrograms per day, and so “Keshan disease” occurred. Compared with the former, the deficiency of vitamins and mineral elements in agricultural products brought about by intensive modern agricultural cultivation has caused more widespread hidden hunger, mainly for the following two reasons.
Genetic dilution effect. Modern agriculture is committed to breeding new varieties to improve crop yields, resistance to pests and diseases, and adaptability to climate. Low-yield varieties are continuously eliminated, and high-yield new varieties are carried on. When farmers switch to a higher-yielding crop variety, they mainly use nitrogen fertilizer to stimulate faster growth, and in theory the roots also need to absorb trace elements at a faster rate. But for the same soil, the soil supply of trace elements or the absorption by plant roots cannot keep up in sync, which leads to crops absorbing more water and synthesizing a greater amount of carbohydrates, while the concentration of trace elements decreases.
Environmental dilution effect. Under modern intensive agricultural production methods, severe soil erosion will carry away the minerals in the topsoil, and after years of cultivation, the soil will become compacted, making it difficult for roots and water to extend downward; the large-scale production of modern agriculture favors the application of chemical fertilizers while applying little or even no organic fertilizer, and takes the above-ground harvest away from the fields, so trace elements cannot be replenished from external sources, while the excessive application of pesticides reduces the ability of microorganisms to transform soil minerals. In addition, soil pollution also easily causes antagonism among some trace elements, leading to a decrease in the content of certain trace elements in agricultural products. Some simulation studies have shown that as the greenhouse effect intensifies, the concentration of trace elements in agricultural products may be further diluted.
Dr. Curie, a Nobel Prize winner in medicine, pointed out: “Barren soil and chemical pollution cause plants to lose their original nutrients. When animals eat these plants, their meat, milk and eggs also cannot have their original nutrients. Even if a nutritionist understands nutritional combinations, they cannot eat their way to health.”
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How to eliminate hidden hunger
Food fortification is a direct means of eliminating hidden hunger. Clearly scarce elements are added to human food, such as iodized salt, zinc-fortified or vitamin A-fortified wheat flour, etc. Dietary diversification is an effective method to alleviate hidden hunger, and eating whole grains rather than deeply processed foods helps reduce the possibility of hidden hunger. This is because in deeply processed rice and flour, mineral elements and vitamins will be greatly reduced; for example, after fine processing of rice, iron, calcium and phosphorus are lost by 63%, 40% and 48% respectively, and vitamin B1, B2 and B6 are lost by 77%, 63% and 61% respectively.
To eliminate hidden hunger at the source, there are mainly two methods:
Soil fortification. Applying to the soil or directly spraying onto crop leaves is the main means of raising the level of mineral elements in crops. The soils of countries such as Denmark and Norway are clearly deficient in selenium. Starting in 1984, these countries implemented action plans for applying selenium to farmland. The selenium content of wheat in Norway has risen from 0.01 mg/kg to a stable 0.25 mg/kg, thereby improving the nation's selenium intake. Soil testing and formulated fertilization has been implemented in China for many years, mainly targeting the supplementation of nitrogen, phosphorus and potassium, with the aim of increasing yields. In the future, as soil testing and formulated fertilization develops in depth, it is hoped that its field will be broadened to mineral elements, so that while increasing grain yields, their “quality” is also improved.
Biofortification. Through breeding methods, the content of micronutrients that can be absorbed and utilized by the human body in existing crops is increased, reducing and preventing the globally widespread problems of human malnutrition and micronutrient deficiency, especially in developing countries (among poor populations). The zinc content in iron-fortified wheat varieties bred by the International Institute of Tropical Agriculture is 60 mg/kg, 2.4 times that before breeding; the iron content of excellent wheat lines bred by the International Maize and Wheat Improvement Center is 47 mg/kg and the zinc content is 55 mg/kg, nearly double that of varieties currently planted on a large scale. China's biofortification project began in 2004, breeding new crop varieties or lines such as rice, wheat and corn rich in micronutrients (iron, zinc, carotenoids). Iron- and zinc-rich wheat has iron and zinc as high as 749 mg/kg and 135 mg/kg respectively, which is 4 to 20 times that of ordinary wheat and general wheat.