Guide You Out of Health Myths: Eliminate Dangerous Factors Around You

Author: Pan Shanying (Compiler)
Publisher:
Publishing Date: 2002-02-01
Features: Vegetable oils contain a large amount of linoleic acid. It helps reduce cholesterol levels in the human blood. However, vegetable oils are unsaturated fats, and if consumed in excess, they are easily oxidized in the body to form peroxides. Peroxides can accumulate in the body, leading to conditions such as cerebral thrombosis and myocardial infarction. They may even induce cancer. Scientific studies show that each person needs 4 to 5 grams of linoleic acid daily. Based on this standard, consuming about 25 grams of vegetable oil per day is sufficient. Additionally, the human body requires a small amount of animal fat daily, with the ideal amount being half that of vegetable oil. If vegetable oil and animal oil are consumed in a 2:1 ratio, this lipid balance is quite beneficial to health.
"Reusing oil used for frying" Some households prefer to store and reuse oil used for frying food, unaware that this practice can harm health. When oils are used repeatedly over a long period, a series of chemical reactions occur. Unsaturated fatty acids in the oil polymerize, producing dimeric, trimeric, and other substances. These compounds can have toxic effects on the human body, posing health risks. Some households and organizations mix used frying oil with new oil. When new oil comes into contact with old, degraded oil, its decomposition products trigger a chain reaction, further degrading the oil quality. To enjoy delicious fried foods without adverse health effects, it is best to avoid using old oil; frying temperatures should not be too high, and frying times should not be excessive. Used oil should not be used for frying or stir-frying. Additionally, if the oil turns black, becomes thick, foams, or has an odor, it should no longer be used.
"Frying in boiling oil is better" Many people believe that to stir-fry vegetables properly, the heat must be strong and the oil temperature high. As a result, many households often heat the oil until it smokes before adding the vegetables. This is not scientific. First, when oil smokes, its temperature generally exceeds 200 degrees Celsius. At such high temperatures, not only are the fat-soluble vitamins in the oil destroyed, but essential fats are also oxidized in large quantities, reducing the nutritional value of the oil. Meanwhile, when food comes into contact with high heat, vitamins in the food, especially vitamin C, are severely damaged. Second, high oil temperatures cause the oxidation of fats, producing peroxides. Scientists have found that peroxides are not only harmful to the human body but also significantly damage vitamins in food in the stomach and intestines. They also interfere with the absorption of proteins and amino acids. Long-term consumption of peroxides, which accumulate in the body, can damage certain metabolic enzymes, leading to premature aging.
Vegetables "Vegetables are fresher with water" Many people believe that "vegetables are fresher with water." In reality, this is a misconception. Green leafy vegetables primarily absorb water through their roots, not their stems and leaves. After washing, the osmotic pressure outside the stem and leaf cells changes, and cellular respiration is altered, causing the cells to die and rot quickly, shortening storage time. If the water is dirty, it also increases the risk of contamination. Therefore, it is not advisable to wash green leafy vegetables before storing them.
"The fresher the vegetables, the better" People generally believe that the fresher the vegetables, the better. However, this is not always true. From a modern scientific perspective, fresh vegetables also have "drawbacks": with current preservation technology still quite backward, fresher vegetables may contain higher levels of pesticide residues. Some vegetable farmers, failing to follow national regulations, may still spray pesticides on vegetables just one or two days before they go to market. Eating such "fresh" vegetables can lead to acute pesticide poisoning. Therefore, it may be better to let some vegetables sit for two or three days until the pesticide residues degrade before washing and consuming them.
"Deformed fruits and vegetables are harmless" In fruit and vegetable markets, it is common to see deformed fruits and vegetables with unappealing appearances, such as strawberry-like "twins," tomatoes with varying colors (purple or yellow), or tangerines with long tails. Many people think these deformed fruits and vegetables are harmless, just unattractive, and can be eaten without concern. In fact, this is not the case. The formation of deformed fruits and vegetables is due to the influence of plant growth regulators. Generally, plant growth regulators have low or even minimal toxicity, but improper use or excessive application can lead to potential toxicity. The deformed fruits in vegetables are a result of plant growth regulators, often appearing as tumor-like, peach-shaped, navel-split, or oval fruits, which affect both eating quality and commercial value. Therefore, it is best to consume deformed fruits and vegetables sparingly.
"Cook until fully cooked" Many people believe that "vegetables must be fully cooked to be edible." However, this is not always true and depends on the specific situation. Meats should naturally be cooked thoroughly, but some uncontaminated green leafy vegetables do not need to be overcooked. Some households prefer to cook vegetables for long periods, resulting in poor color and loss of nutrients. Because vitamins C and B in green leafy vegetables are sensitive to heat and prolonged cooking, excessive cooking or simmering after stir-frying can lead to significant vitamin loss. It is best to cook vegetables over high heat, which not only improves flavor but also minimizes nutrient loss.
"Squeezing vegetable juice improvesflavor" Some people like to squeeze vegetable juice dry when making fillings. This practice can cause more than 70% of the vitamin content to be lost. Vegetables are a primary source of vitamin C in the diet. However, vitamin C is highly unstable, easily soluble in water, and prone to oxidation, making it easily destroyed during heating. Therefore, cooking methods are crucial. When making fillings, people often wash vegetables, blanch them in water, chop them, and then squeeze out the juice. This process causes most of the vitamin C to be wasted. Would you be willing to sacrifice significant nutrients just for flavor?
"Adding vinegar to stir-fried greens enhances flavor" Adding a small amount of vinegar while cooking can help preserve vitamins, but not all vegetables are suitable, such as green leafy vegetables. This is because chlorophyll in green leafy vegetables is highly unstable under acidic conditions during heating. The magnesium ions in chlorophyll molecules can be replaced by oxygen ions in the acid, forming a dull, olive-colored de magnesium chlorophyll with greatly reduced nutritional value. Therefore, it is not advisable to add vinegar when cooking green leafy vegetables.
"Fish bile clears heat" Using fish bile as a "cooling remedy" is very dangerous. Fish bile contains "bile toxins," which are heat-resistant and not easily broken down by alcohol. Whether swallowed raw, cooked, or taken with alcohol, fish bile poisoning can occur. Symptoms of fish bile poisoning include nausea, vomiting, abdominal pain, diarrhea, bloating, liver pain, anorexia, and aversion to oil. Severe cases may lead to coma, convulsions, hypotension, arrhythmia, kidney failure, bleeding, and even death.