Are dietary supplements toxic?

The toxicity of dietary supplements cannot be generalized. Taking regular qualified products according to the recommended dosage has almost no risk of toxicity. However, excessive abuse and taking of substandard products will have no less toxic risks than taking random medicines.

Nowadays, it is easy for people to go to extremes in their understanding of supplements. They either think that they are "purely natural health products" and have only benefits and no harm no matter how much they are taken, or they think that they are all an IQ tax and that eating them will damage the liver and kidneys. In fact, both views are quite one-sided.

I met Aunt Zhang when I was doing nutrition education in the community two years ago. After listening to the lecture, I spent several thousand to buy deep-sea fish oil, which is said to be "original and natural from abroad." The salesman said, "Eat more to open your blood vessels." So she took 6 pills a day, which was twice the recommended amount on the product label. She had nosebleeds every now and then for three months, and her coagulation function was abnormal when she went to the hospital. Later, when she sent the bottle of fish oil for testing, she found out that the concentration of the active ingredient omega3 was more than three times higher than the standard, which was equivalent to almost ten times more than what she consumed every day. It was strange that there was no problem.

Of course, this does not mean that supplements are out of the question. The low-dose iron supplements we usually prescribe to people diagnosed with iron deficiency anemia, as long as they are taken according to the doctor's instructions, have basically no side effects except occasional constipation. Many people's hemoglobin returns to normal levels after two or three months of supplementation, and there is no toxic reaction at all. There are also many parents who are afraid that supplementing their children with vitamin D will cause poisoning, so they stop taking daily supplements. In the end, many of their children are found to be calcium deficient or even prone to rickets. In fact, domestic OTC vitamin D is only 400IU per pill. If you take one pill a day according to the recommended amount, you will not risk cumulative poisoning even if you take it for several years. On the contrary, some people buy so-called "powerful vitamin D" overseas, and one pill contains tens of thousands IU, which may cause problems after a week or two.

Many people have a misunderstanding, thinking that the labeling of "dietary supplement" and "plant extract" means no side effects. In fact, silymarin in many liver-protecting supplements can indeed help repair liver damage at normal doses. However, if you eat three or four times the amount at a time with the mentality of "eat more, take more supplements", it will put extra metabolic burden on the liver. When I was an intern in the nutrition department, I met two young men in the morning. They both took three times the dose of liver-protecting tablets to "replenish" after staying up late every day. The final physical examination showed that the transaminases increased to two or three times the normal value, which is typical of excessive supplementation.

If you really want to worry about whether supplements are safe or not, it is better to find out whether you are deficient or not. If you are not sure, ask a doctor or registered dietitian for evaluation first. When buying, choose blue hat or accurate brand products from regular manufacturers. Keep an eye on the recommended dosage before taking it and don’t increase the amount randomly. You will basically avoid the pitfalls of toxicity.