What are the side effects of nutritional supplements?

In recent years, a series of large-scale clinical and epidemiological studies have found that nutritional supplements are not effective in preventing chronic diseases such as cancer and heart disease, and vitamin C supplements are ineffective in preventing and treating influenza and colds. At the same time, there are more and more reports of side effects from taking nutritional supplements.
Although nutritional supplements are not structurally different from the vitamins, minerals and other nutrients in food, nutritional supplements are purified and highly concentrated, and the body's metabolism and absorption of them is different from that of direct ingestion from food, or even different from the low amounts of vitamins and minerals added to fortified foods. In addition, nutritional supplements often affect the absorption of other medications.
Based on the results of these studies, the international community emphasizes the need to obtain necessary nutrients from food, supplemented by fortified additives. Even if there is insufficient intake, efforts should be made to change the dietary structure. Nutritional supplements are only an auxiliary means because the effects of nutritional supplements, compared with their side effects, largely do more harm than good. Overemphasizing the effects of nutritional supplements will give people the impression that nutritional supplements are omnipotent, and instead make people ignore the importance of eating more foods rich in nutrients such as vitamins and minerals. They will not work hard to develop good eating habits, let alone do their best to correct bad eating habits.
Most experts who promote nutritional supplements are unaware of their side effects, let alone spread the knowledge about them.
Let’s take a closer look at some of the side effects of several major nutritional supplements.
Calcium tablets:

The widespread use of calcium tablets is related to the prevention of osteoporosis. At the beginning of the year, the U.S. Preventive Services Task Force analyzed and summarized 135 related studies and found that calcium tablets cannot prevent fractures in postmenopausal women. An analysis of 15 studies found that taking calcium supplements without vitamin D increased the risk of myocardial infarction by 30%. Results of a large study showed that women's risk of myocardial infarction increased by 24%, regardless of whether they took vitamin D with it. Another study found that calcium supplements could increase male smokers' risk of death from cardiovascular disease by 20%. This most likely happens because calcium from nutritional supplements accumulates in the arteries. In addition, calcium tablets will have an impact on patients with kidney disease, and may also affect the efficacy of certain antibiotics, osteoporosis drugs and thyroid drugs. Calcium supplements may also increase the risk of kidney stones, while calcium obtained from the diet does not. Vitamin A:

Vitamin A deficiency is common in poor countries, especially among children, and can cause vision problems such as night blindness or even complete blindness. Adding vitamin A to food and using genetic engineering to create vitamin A-rich golden rice are solutions to vitamin A deficiency in these countries. If your diet contains enough fortified foods, dairy products, fruits and vegetables, there is no need to take vitamin A tablets. Side effects of vitamin A include mouth ulcers, chapped lips, cracked nails, worsening of psoriasis, eye pain, peeling, hair loss, skin irritation, dryness, pain or redness, diarrhea, indigestion, fatty liver, chronic hepatitis, cirrhosis, cough, fever, respiratory tract infection, increased mother-to-child transmission of HIV, and death. Taking large amounts of vitamin A in the short or long term can cause poisoning, especially for people with liver disease and heavy drinkers. Alcohol, tetracycline, anticancer drugs, etc. will increase the side effects of vitamin A. If you smoke, drink and take vitamin A tablets, the risk of lung cancer increases. If pregnant women take excessive amounts, it can cause birth defects. Vitamin A also increases the risk of bleeding, so patients with blood diseases should pay attention. Vitamin C :

In the past, vitamin C was taken to prevent scurvy, but now that vitamin C deficiency is rare, vitamin C tablets are taken for reasons that have been proven to be unfounded, such as preventing colds. Vitamin C tablets are relatively safe, with rare side effects including nausea and vomiting, heartburn, abdominal discomfort and headache. Overdose may cause symptoms such as kidney stones, severe diarrhea, gastritis and nausea. Long-term use of large doses of VC may lead to hypotension if the dose is suddenly reduced, so the dose should be reduced gradually. Vitamin C also affects blood sugar. Currently, vitamin C taken from food is safe for pregnancy and breastfeeding, but research on vitamin C supplements is not sufficient to prove their safety. Some studies have found that pregnant women taking vitamin C supplements increase the risk of premature birth. Vitamin D:

Vitamin D helps with calcium absorption and is the only nutritional supplement some experts recommend as worthwhile. Vitamin D is mainly synthesized by subcutaneous fat through sunlight. If you don't get enough sunlight, such as living in a cold zone, you may be deficient. Vitamin D tablets are relatively safe, but taking too much may increase the risk of falling due to fractures, urinary tract infections, reduced appetite, weight loss, hypercalcemia, and an increased risk of cancer. Vitamin D can lower blood sugar levels, so people taking hypoglycemic drugs should be careful. It will also lower blood pressure, so people with low blood pressure should also pay attention. Vitamin E:

Vitamin E deficiency is rare, and vitamin E supplements became popular because of their antioxidant properties. However, several large studies have found that not only are they ineffective, but people who took vitamin E supplements are more likely to suffer from heart failure. They also found that taking more than 400 international units of vitamin E supplements per day increases mortality by 4%. If taken with other supplements, the amount increases by 6%, so vitamin E supplements are one of the nutritional supplements that should least be taken, especially by patients with heart disease. Taking vitamin C supplements during pregnancy can cause low birth weight in babies, and taking it alone may also cause congenital heart defects. fish oil:

Recent studies continue to disprove the effectiveness of fish oil. A paper published in July this year replicated the results of another study two years ago and found that men who took fish oil supplements could increase their risk of prostate cancer by 43%. Taking this supplement may cause nausea, diarrhea, constipation, loss of appetite and vomiting. It may also cause loss of short-term memory, headaches, hemolytic anemia, depression, increased risk of colon cancer, aggravated asthma symptoms, and increased blood pressure. Fish oil can also increase LDL cholesterol levels. Long-term use of fish oil can lead to vitamin E deficiency and increase the likelihood of vitamin A and vitamin D poisoning.
Glucosamine sulfate: Its effect on osteoporosis has not been confirmed, and side effects include dizziness, insomnia, headache, constipation, nausea, diarrhea, heartburn, etc. Because there is no scientific evidence, it is not recommended for pregnant women to take it.
In short, nutritional supplements have reached the point where they are useless and harmful.

<<: Eight kinds of fruits will cause miscarriage if eaten by pregnant women

>>: Revealing the six "lies" about drinking. Does a red face mean you won't get drunk easily?