Can you drink lemon water for beauty? Is it better to drink during the day or at night?
Many people like lemonade and think that lemonade is good for health. Lemonade is rich in vitamin C and various minerals, which is good for whitening and skin. However, there are many "interesting" sayings on the Internet. Facts and rumors coexist. This paper introduces the relationship between lemonade and health to see what is effective and what is just a rumor.
lemonade can't be drunk during the day?
lemonade can only be drunk at night, and it is easy to get tanned by the sun when you drink it during the day. This statement is very popular on the Internet. I did a brief search, and many professionals really agreed.
The reason why lemonade is considered easy to tan is probably not related to the vitamin C it contains. Otherwise, the rumor should be that you can't eat oranges, kiwis or VC effervescent tablets mixed with water during the day ... The reason why lemonade is not suitable for drinking during the day is because it contains "photosensitive substances", mainly coumarin.
coumarin has an aromatic smell and has three structures: simple coumarin, furocoumarin and pyranocoumarin. Coumarin exists in citrus plants (orange oil, lemon oil, grapefruit, bergamot and so on). ), mostly furan coumarin. Coumarin has photosensitivity, which makes the skin black and seriously damages the skin.
The following are various mechanisms of coumarin (psoralen) affecting skin blackening. Simply put, it is to increase melanin synthesis, increase skin's sensitivity to ultraviolet rays, increase melanocyte density, promote melanocyte growth, and protect melanocytes from being removed ... < P > Coumarin is easy to cause skin blackening and even skin poisoning. Lemon oil is an extract of lemon, which has been widely used in cosmetics, but it is banned in many countries because of its side effects. In recent years, it has been widely used in aromatherapy massage because it contains coumarin, which has the characteristics of photosensitivity and melanogenesis. In 21, a case study described two patients who received aromatherapy oil massage and then were exposed to ultraviolet rays. Bullous phototoxic skin reaction occurs after 48 ~ 72 hours, that is, "bullous skin" appears on the skin. Researchers believe that exposure to ultraviolet rays containing this citrus essential oil after massage will lead to health crisis [2].
Not only does coumarin in citrus essential oil cause problems to the skin, but citrus juice or vegetables containing coumarin can also cause problems if they are directly exposed to the skin and exposed to ultraviolet rays for a long time. There is a so-called Margarita Burn abroad, but it should be officially called "phytodermatitis". Margaret is a cocktail with lime, which contains several times as much coumarin as lemon. When Margaret adds freshly squeezed lime juice in summer, she will inadvertently let her hands occupy the lime juice, and then exposure to ultraviolet rays for several hours may cause local skin burns. After exposure to lime or other citrus and vegetables (such as celery), there are many cases of ultraviolet burn or sunburn.
Citrus essential oil and juice can easily cause sunburn or sunburn when they come into direct contact with the skin. Can drinking lemonade also cause sunburn? In 217, the coumarin concentration of various citrus fruits and juices was studied and analyzed. Except concentrated lemon juice, the concentration of lemon itself is not high, 329ng/g, which is one-third of that of lime and less than 2% of that of grapefruit. Based on about 5 grams of lemon, it contains about 16,5 milligrams or 16.5 micrograms of coumarin.
besides citrus, celery (252ng/g), parsley (23214ng/g), carrot (68ng/g), parsley (334ng/g), coriander (258ng/g) and other vegetables all contain more coumarin.
in a study published by the Swiss federal public health office in 1991, [7] four subjects were tested and celery containing coumarin was eaten. Subjects ate 3 grams of celery root, which contained about 28.2 mg of coumarin, and then irradiated with ultraviolet light, and their skin had no phototoxic reaction at all, but only one of them had a skin blackening reaction at the level of 1 mg of coumarin. It takes about 6 lemons to get a tan.
In a research paper published in Germany in 21, [8] the daily drinking of citrus drinks and vegetables was tested, and it was concluded that coumarin in diet was not phototoxic. It is reported that the phototoxicity of coumarin in diet should reach 45 mg, but the risk of direct skin contact will be greater.
Brown University published two epidemiological studies in the past five years, and a prospective study in 215 [23] analyzed the data of more than 1, people, and found that people who eat more citrus fruits are more likely to develop basal cell carcinoma and squamous cell carcinoma, but how much higher? If you eat 1.5 oranges a day for 25 years, basal cell tumor and squamous cell carcinoma will increase by 16% and 21% respectively. A cohort study published in 22 [24] analyzed the data of about 12, people for 27 years, and found that furocoumarins were not related to squamous cell carcinoma, but positively related to basal cell tumor, and the risk increased by 16%. These are all related studies for your reference.
So far, no clinical trial has found that drinking lemon juice or lemonade can easily lead to sunburn or increase the risk of skin cancer. So from the research evidence, direct contact with citrus juice is easy to cause sunburn, but drinking lemon juice has not found the same effect.
is lemonade acidic or alkaline?
Lemon juice has a pH of about 2 to 3, which is an acidic substance, while lemonade is an alkaline diet, which can increase the alkalinity of urine, that is, reduce the acid load (or DAL) in the diet.
Whether food is acidic or alkaline has nothing to do with the pH value of the food itself. It depends on whether the "products" after digestion and metabolism in the stomach are acidic or alkaline. In the past, there was a so-called Ash Analysis, which tested the acid load of food and divided it according to the ash produced after the food was completely burned and the acidity and alkalinity of the solution dissolved in water. This method is very inaccurate and is basically no longer used in the study of food acid load. At present, the standard for evaluating food acid load is "potential renal acid load" (PRAL), that is, tracking various minerals in food, such as potassium, magnesium, calcium, phosphorus, protein, etc., and calculating the pH value when the food reaches the kidney after metabolism. Food in protein is generally acidic, while fruits and vegetables contain more minerals, so they are alkaline. Lemon juice contains more minerals, so the PRAL value is about -2.5, which belongs to alkaline food.
diet changes urine pH, but has no obvious effect on blood ph. The pH value of human blood is regulated in the kidney and strictly controlled between 7.35 and 7.45. To affect the pH value of blood, you need to eat 8 kilograms of oranges to increase the pH value of blood by .2. Therefore, the influence of diet on blood pH can be ignored.
It is found that increasing alkaline food is related to improving various health problems. A literature review in 219 found that increasing alkaline foods such as vegetables and fruits is related to improving insulin resistance, diabetes, hypertension, chronic kidney disease and bone health. However, the study also pointed out that the combination of alkaline diet is very similar to DASH diet specially designed to improve hypertension, that is, the correlation between alkaline diet and health is not necessarily.
According to the research evidence, there is no clinical study to prove that PRAL with potential renal acid load can directly affect health, and lemonade is only one of many alkaline foods, and its alkalinity level is not high, so there is not enough evidence to prove that it affects health through alkalinity.
lemonade is anti-aging?
Animal experiments show that drinking water containing lemon polyphenol antioxidant for a long time can not only resist aging, but also prolong life. A study published in Japan in 219 found that the polyphenol antioxidant lemon polyphenol contained in lemon can resist aging. In this study, mice were divided into two groups. One group drank water containing lemon polyphenols throughout its life cycle, while the other group drank ordinary water. It was found that the average life span of mice drinking lemonade was prolonged by 3 weeks, equivalent to 4% of the life span of mice, and the mice drinking lemonade delayed the aging time. After further analysis, it was found that lemon polyphenols may change the intestinal flora of mice and have anti-aging effect.
In another animal experiment, it was found that the wrinkles, thickness and aging of the skin of the mice drinking lemonade decreased, while the collagen of the skin increased after ultraviolet irradiation compared with the mice not drinking lemonade. The results showed that the activities of various antioxidant enzymes, GPx, SOD and CAT in the cells of mice drinking lemonade increased. People think that drinking lemonade may help prevent premature skin aging caused by oxidative stress.
Up to now, no human clinic has found that lemonade can help to improve aging. However, taking more vitamin C is related to reducing skin wrinkles. An epidemiological study based on 425 British women in 28 found that more vitamin C in the diet was inversely proportional to facial wrinkles and dry skin.
topical vitamin c can improve skin aging. [16] In a double-blind controlled clinical trial conducted in France in 23, the subjects were treated with ointment containing 5% vitamin C.. After 6 months, dermatologists and subjects scored by themselves, and the skin of subjects who used vitamin C improved obviously, wrinkles decreased and skin elasticity increased. The conclusion is that ointment containing 5% vitamin C can effectively improve skin aging caused by ultraviolet rays. In another double-blind controlled clinical study in 1999, it was also found that the use of external lotion containing vitamin C was helpful for skin anti-aging. This time, the subjects used a topical lotion containing vitamin C and a placebo. It is found that vitamin C lotion can significantly improve skin aging after 3 months.
Therefore, animal experiments have found that drinking lemonade is helpful to anti-aging, but no similar findings have been found in human clinic. A certain amount of vitamin C helps to improve skin aging, but a lemon only contains about 3 mg of vitamin C. If you want to supplement vitamin C, eating a big orange (1 mg) or taking vitamin C supplements directly may be more effective.
Lemonade can improve other health problems
Lemonade can improve kidney calculi-the research paper points out that lemonade can significantly reduce the risk in kidney calculi. Lemon can prevent kidney calculi. In addition to lemon diuresis to increase urine excretion, potassium and citric acid are helpful. Citric acid can combine with calcium in urine to reduce calcium saturation in uric acid, and citric acid can combine with calcium oxalate to prevent crystal stones. There is a clinical study. Twelve patients with low calcium kidney calculi citrate excretion drank about 113 grams of lemon juice mixed with 2 liters of water (almost 4 lemons) every day for 6 days. The results showed that the average citrate excretion of subjects increased by 69%. Among them, 7 patients (58%) recovered to normal citrate excretion. The conclusion of this study is that lemonade can be used as an auxiliary method to treat calcium oxalate kidney calculi with low citrate excretion. However, some scholars disagree that lemonade can prevent or treat kidney calculi. However, lemonade may increase the water consumption of patients in kidney calculi, which may reduce the risk in kidney calculi.
Lemon juice helps to reduce uric acid —— A pilot clinical study in 215 divided 75 subjects into gout group, hyperuricemia group and healthy control group. Subjects drank 2 liters of freshly squeezed juice and 2 lemons every day for 6 weeks. Results: The serum uric acid of all subjects decreased, with an average of 1.6 mg/dl in gout group, 1.3 mg/dl in hyperuricemia group and 1.3 mg/dl in healthy control group. From the experimental results, lemonade not only reduces uric acid, but also reduces the risk of uric acid and gout in kidney calculi by increasing the pH value of urine. In 217, researchers from Huazhong Agricultural University in China also concluded that lemonade can help reduce uric acid in mice and small-scale clinical trials.
summary
from the research evidence, we really need to be careful not to expose your skin to the sun after direct contact with lemon juice and lemon essential oil, but after drinking lemonade, sunbathing will not make you more likely to tan.
Lemon contains vitamin C, lemon polyphenols and other beneficial substances, which is helpful to improve health, including reducing uric acid, and may reduce the risk of kidney calculi. However, there is not much evidence about the anti-aging and other health problems of lemonade in human clinical research.
Perhaps the biggest influence of lemonade on us is to replace sugary drinks, especially in summer, which may make us drink more water, which is helpful to our health.