Why do I feel nauseous after taking dietary supplements?

The vast majority of cases of nausea after taking dietary supplements are either caused by the irritating ingredients of the supplements or the wrong way of taking them. Only a few are caused by underlying diseases or allergies to ingredients, and are not some mysterious "detoxification reaction" at all.

A while ago, I followed the trend and bought a high-content iron supplement purchased from overseas. I took two pills while catching the subway on an empty stomach in the morning. I squatted in the corner of the platform feeling sick after two stops, and my face turned pale. Later, I asked my friend in the nutrition department to find out that it contains high-dose iron, zinc, unesterified vitamin C, and lipids. Ingredients such as soluble vitamins A and E are inherently irritating to the gastric mucosa. There is no food in the stomach to buffer them on an empty stomach. High concentrations can easily trigger a stress response in the gastrointestinal tract. The urge to vomit is actually a signal sent by your body to remind you that your stomach cannot handle such strong ingredients at this time. I also encountered this pitfall two years ago when I took high-containing B-complex. I felt nauseous soon after eating it on an empty stomach, and my mouth felt bitter. Later, I switched to swallowing it with the food at lunch, and I never had this problem again.

In addition to the problems with the ingredients themselves, many people may not pay attention to the small details of taking them and they are prone to vomiting. For example, the large-capacity fish oil capsules themselves have a faint fishy smell. If you don’t drink enough water when swallowing, the capsules will stick to the lower half of the throat, with that oily smell. The taste slowly comes back. Not to mention people who are prone to pharyngitis, ordinary people have to frown and vomit twice. Some people are used to saving the vitamins, liver protection tablets, fish oil, etc. they need to take for a day until they are empty in the morning. Dozens of ingredients are piled up in an empty stomach. It would be strange if they don't have acid reflux and nausea.

Recently, I saw many bloggers saying that "the body is detoxifying and it is an effective reaction" when taking supplements. I checked the relevant clinical data and asked senior students who are doing nutrition research. There is currently no evidence to support this statement. On the contrary, the discomfort is more likely to be that the dosage of the supplements you bought exceeds the standard - many overseas versions of supplements are designed according to the dietary structure of the locals. For example, the B group content in some multivitamins is several times the recommended daily intake for Chinese people. Excessive intake of B group can also cause gastrointestinal discomfort, dizziness and nausea. Some people are intolerant to fillers in supplements. For example, people with gluten allergies will not only feel vomiting but may also have diarrhea for several days after taking supplements with wheat flour as excipients.

Of course, this does not mean that all nausea is caused by supplements or how you eat them. People with chronic gastritis or gastroesophageal reflux may experience discomfort due to irritation from the capsule shell or a small amount of active ingredients, even if they take supplements with proper dosage and with meals. I used to have a friend who suffered from reflux esophagitis. He had acid reflux after taking ordinary vitamin C tablets. Later, he changed to effervescent tablets and drank them with warm water. If you vomit every time you take a certain supplement, don't insist on talking about detoxification. Either try it at a different time with a meal, or stop and check if you are intolerant to a certain ingredient. Supplements are the icing on the cake, and you don't have to suffer for them.