I drank milk after eating oranges and went to the emergency room in the middle of the night! The truth about why milk and oranges cannot be eaten together is this

Expert in this article: Dr. Tian Jing, attending physician, Southern Theater Command Center for Disease Control and Prevention

Reviewer of this article: Chen Haixu, Deputy Director and Master Supervisor of the Second Medical Center of PLA General Hospital

Recently, the news that a woman was sent to the emergency room due to vomiting and diarrhea after eating orange and milk together has caused heated discussion.

There are even reports that doctors have diagnosed that the two cannot be eaten together.

Is it true that oranges and milk cannot be eaten together? Let's find out today.

Can't oranges and milk be eaten together?

Mixing milk and orange juice will produce flocculent precipitation, which proves that milk and oranges cannot be consumed together? Wrong!

Milk is rich in protein, 80% of which is casein. The isoelectric point of casein is around pH 4.8 (slightly acidic). When the pH value of the solution is close to the isoelectric point, casein aggregates.

Fruits contain many organic acids, inorganic acids, acid salts and acidic organic compounds. The pH value of fruits is the main reason why we can taste the sour taste of fruits.

The pH value of orange juice is between 3.0-4.0, which is obviously acidic. When orange juice is added to milk, the pH value of the milk gradually decreases. When it approaches the isoelectric point of casein, the casein aggregates and precipitates in the milk.

In comparison, the pH value of our gastric juice is between 0.9-1.5, which is a strongly acidic environment, much higher than the acidity of oranges. Casein is completely denatured and decomposed under the action of gastric acid and pepsin to form polypeptides that are easily absorbed by the human body. The free calcium in milk is also dissolved in gastric acid, which helps the subsequent absorption of these substances in the small intestine.

Therefore, the flocs caused by mixing milk and orange juice are mostly "sensory" discomfort. In the beverage industry, it is often possible to improve aggregation by adding some hydrophilic colloids and other substances to produce "orange juice" milk. However, from the perspective of food safety, there is no safety concern about consuming milk and oranges together.

Does eating oranges and milk together affect calcium absorption?

Consuming milk and green vegetables can provide the human body with sufficient calcium. In the human body, only calcium in a dissolved state can be absorbed by the small intestine, and calcium in a precipitated state cannot be absorbed.

The phosphopeptide released by the hydrolysis of milk casein under the action of pepsin can keep calcium ions in a stable state all the way to the end of the small intestine, which helps the absorption of calcium. Therefore, milk is considered to be a good calcium supplement.

Generally, some fruits and vegetables contain many organic and inorganic acids, among which oxalic acid, phytic acid, tannic acid, etc. can combine with calcium to form insoluble complexes that affect calcium absorption; large amounts of cellulose and light methyl pectin can also hinder calcium absorption.

The main acid in oranges is citric acid (accounting for 85%), and the rest are malic acid and succinic acid, which are not easy to form insoluble precipitates with calcium. Orange juice also contains a large amount of vitamin C, which can effectively promote the absorption of calcium to a certain extent, so eating oranges and milk together will not reduce the absorption of calcium.

Why does drinking milk cause diarrhea?

During infancy, the human intestine contains an enzyme that can break down the lactose in milk to help infants digest and absorb dairy products.

As people age, their demand for dairy products decreases and the lactase content in adults decreases. As a result, many adults experience symptoms such as diarrhea and abdominal pain after drinking milk. This is lactose intolerance.

Such people can choose to consume milk in small amounts and multiple times to slowly re-establish lactose tolerance, or directly choose commercially available lactose-free milk or yogurt.

However, there is another group of people whose immune systems mistake the casein and whey proteins in milk as harmful invaders when drinking milk, and thus fight against them, causing a "milk" allergy reaction with symptoms similar to food allergies.

"Milk allergy" can cause symptoms to appear after a few hours or days, such as skin hives, eczema, digestive tract abdominal pain and diarrhea, or shortness of breath, asthma, etc. People in this group need to completely avoid drinking milk.

Is raw milk more nutritious and should be drunk directly?

Because milk is rich in protein, lipids and sugar, it is a natural breeding ground for various microorganisms.

Although milk itself contains some beneficial bacteria, such as lactobacillus, bifidobacterium, etc., they also exist in the intestines of healthy people. These beneficial bacteria can help the human body digest food and improve resistance to other pathogens.

However, the industrial production of milk and dairy products will inevitably be contaminated by pathogenic bacteria.

Mycobacterium tuberculosis, Staphylococcus A, Staphylococcus B, Salmonella, Escherichia coli O157:H7, Listeria, Campylobacter and Brucella can all be transmitted to humans through non-sterilized raw milk and dairy products, which may cause different symptoms such as vomiting, diarrhea, abdominal pain, fever, headache, and in severe cases, death.

Therefore, please be aware of the purchase channels and refuse to drink raw milk! All commercially available milk must be sterilized by pasteurization. Do not drink raw milk sold by individual merchants.

Here are some things to remember when drinking milk:

1. Refuse to drink raw milk and do not buy milk and dairy products sold privately.

2. Patients with lactose intolerance should not drink milk on an empty stomach to reduce the stimulation of lactose on the intestines and avoid discomfort, or they can gradually build up tolerance. People who are allergic to milk should avoid drinking milk.

3. Avoid consuming milk at the same time as tea, fruits and vegetables with high oxalic acid content. Eat more foods rich in vitamin C, appropriately supplement vitamin D, and get more sun exposure to promote the absorption of calcium in milk.

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