Everyone knows that food is based on soil

Everyone knows that "food is based on soil." Let's hope everyone can gain a deeper understanding that soil is also the foundation of human health! Every single patch of soil in the world is extremely complex and harbors numerous biological communities. A handful of fertile soil contains a number of microorganisms equivalent to the global population. Essentially, a small patch of soil should have the same value as the Earth's tropical savannas, forests, and marine systems. Soil possesses and preserves most of the Earth's genetic diversity. Therefore, it's easy to understand that soil also determines human health.

The impact of soil on human health is often overlooked, but its effects on us can be positive or negative. Soil indirectly affects our health through all six ecological soil functions described. Soil and its components (such as soil composition, mineral elements, and microorganisms) also directly affect our health when we come into contact with it by handling the soil or the food we eat, the water we drink, and the air we breathe.

It's the food we eat; the composition of our food reflects the nature of the soil in which it grows. Zinc, involved in the function of hundreds of enzymes in our bodies, is one example: insufficient dietary intake can lead to symptoms such as hair loss and impaired immune system function, fertility, and sexual function. Approximately half of the world's agricultural soils are zinc-deficient, and about half of the world's population (primarily in the same geographical region) lacks this micronutrient in their diets. Similarly, low-sulfur soils, such as those in parts of Africa, Asia, Australia, and North America, may produce wheat (or beans, etc.) lacking methionine and cysteine-sulfur-containing amino acids essential for the body to utilize protein from food. Foods grown in certain regions often reflect low levels of iodine and selenium in the local soil, two elements not needed by plants but generally deficient in human nutrients (leading to goiter and Keshan disease, respectively).

Of the millions of organisms that inhabit the soil, a few can cause illness or even death in humans. Among the more notorious soil-borne pathogens is Clostridium, which causes tetanus and anthrax; its spores can survive in the soil for decades. This soil-borne infectious bacterial disease causes millions of deaths each year, including many infants and mothers born in unsanitary conditions. The soil fungus Blastomyces sp. can cause a less common but still potentially fatal soil-borne disease when it infects skin wounds or is inhaled into the lungs.

The therapeutic effects of soil discussed above do not mean we shouldn't hike in forests or gardens without rubber gloves (although gloves are a good idea if you have an open wound on your hand). On the contrary, the natural balance in most soils is highly beneficial to organisms that provide ecosystem services vital to human well-being.

Many people are unaware that plants growing in the soil are the source of most medicines-both traditional herbs and modern drugs-that prevent, alleviate, or cure many ailments and chronic diseases that plagued and often killed our ancestors. The story of paclitaxel beautifully illustrates this. This highly regarded anti-cancer drug was first discovered in the bark of a rare yew tree that grows in the soils of the Pacific coast of Oregon and Washington. Before scientists learned to use molecular culture and gene transfer techniques to create the drug from other organisms, demand for it led to the destruction of 500,000 yew trees.

Soil microbes themselves are the source of most of our life-saving antibiotics. Drugs such as penicillin, ciproxaxine, and neomycin originate from certain soil bacteria (such as streptococci) and fungi (such as penicillin), which produce these compounds as part of a defense strategy against competing soil microbes.