Over the past year, discussions on the nutritional value of food have been all the rage. Previously, it was said that eating fruits and vegetables with their skins on meant too much pesticide exposure, which could promote cancer. Now, it's said you must eat them with the skins to prevent cancer, leaving the public confused. Is something as simple as a fruit peel really that complicated?
Every component in plants has a certain physiological effect on the human body. This includes important minerals like potassium, calcium, and magnesium; vitamins C and carotenoids; "phytochemicals" such as flavonoids and anthocyanins, which are important antioxidant factors in the diet; and soluble dietary fiber like pectin, which helps lower the rise in blood sugar, blood lipids, and cholesterol. The insoluble fiber promotes intestinal peristalsis and helps prevent colorectal cancer.
In most fruits that can be peeled, the peel and the flesh just beneath it are often the parts richest in antioxidant components. This is true for apples, plums, and grapes, and the pattern is similar across them. This is because the parts richest in antioxidants are usually the parts most exposed to sunlight; and a natural reddening of the color also signifies an increase in antioxidants—because natural pigments like carotenoids, lycopene, and anthocyanins are the main force of antioxidants in the diet. At the same time, the outer parts usually contain higher levels of vitamins and minerals, and the dietary fiber in the peel is also very beneficial to the human body.
If you can eat apples with their skins on, it is naturally a more ideal approach. In fact, for fruits with soft skins, such as tomatoes, apples, pears, peaches, and apricots, eating them with the skin on provides more flavor and a good texture. The skins of ripe pumpkins, mangoes, and persimmons, as well as the skins of some grape varieties, are also not difficult to eat.
So, what about the issue of pesticides? In reality, consumers need not be overly worried about pesticides for three reasons: First, Chinese regulations do not permit the use of highly toxic pesticides on fruits, vegetables, and other foods that are eaten directly; recently, a batch of moderately and highly toxic pesticides was also banned. Second, the organophosphate pesticides commonly used in China today have a short residual period and decompose within a few days. According to relevant regulations, no pesticides are permitted to be used on fruits and vegetables for about a week before harvest. Third, most fruits are eaten several days or even months after harvesting, by which time the pesticides have basically decomposed. For example, it is now May, but apples were harvested last September and have been stored in cold storage all along. Fruits and vegetables like tomatoes are also among the varieties with the lowest pesticide residues. Therefore, the risk of acute or chronic pesticide poisoning from eating washed fruits and vegetables with their skins on is very small.
Some people may still ask with concern: Aren't there any pesticides with high residues that are difficult to decompose? Indeed, organochlorine pesticides, which were banned over 20 years ago, fall into this category; their residues can last for hundreds of years and can still linger in farmlands and orchards. However, these pesticides are mainly absorbed into the plant from the soil and cannot be removed by peeling. Purchasing fruits and vegetables with "green food" or "organic food" certification can ensure that all pesticide residues are below national limits. Of course, chemical preservatives and waxing may be used during storage, but their content is limited, and many of these components are not highly toxic.
However, if one were to extrapolate from this and think that all fruits and vegetables must be eaten with their skins, that would be going to extremes. While the peels of fruits and vegetables are non-toxic, if they contain too much hard, coarse fiber, they can cause mechanical damage to the gastrointestinal tract. For example, the sharp, hard pineapple peel might damage the esophagus and stomach wall. In the past era of eating coarse grains and simple vegetables, dietary fiber was abundant and antioxidant levels were also quite high, but people did not seem to be particularly healthy. Epidemiological surveys have shown that a diet of only refined, soft, and fine foods increases the risk of colon and rectal cancer; while a diet of only coarse, hard, and tough foods also increases the risk of stomach and esophageal cancer. No single food component is ever "the more, the better," and dietary fiber is no exception to this rule.
Because fiber stimulates intestinal peristalsis, people with gastrointestinal diseases, such as gastric ulcers, gastritis, and various chronic enteritis, need to be very careful when eating fruit peels and not consume too much fiber to avoid aggravating their condition. If you feel unwell after eating a fruit peel, you should stop immediately.
Just as cooking spinach can never be perfect, eating fruit can also have its regrets. If you are worried about the preservatives added during storage, or simply don't like the taste of the peel, what does it matter? We can completely get our fiber and antioxidants from other foods, such as whole grains, legumes, vegetables, and nuts. Peel the fruit a little thinner, increase the variety of foods in your diet, and life can be just as healthy. Why be so hung up on the fruit peel and be unhappy about it?