Avoid Taking These 3 Supplements Too Casually as They May Increase Cancer Risk

Beta-carotene, vitamin E, and B vitamin supplementation may increase the risk of cancer.

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Globally, there is a rising trend of people taking nutritional supplements, particularly vitamins. ​However, some studies suggest a potential association between certain supplements—specifically beta-carotene, vitamin E, and B vitamins—and an increased risk of cancer.

Beta-Carotene

A meta-analysis published in Nutrition Reviews in 2023 analyzed eight randomized controlled trials and found that taking beta-carotene supplements showed no overall beneficial or harmful effects on cancer incidence but may increase lung cancer risk, particularly among smokers. Therefore, beta-carotene supplementation is not recommended for cancer prevention.

Additionally, a systematic review and meta-analysis published in Nutrients in 2022 established a 16 percent increase in lung cancer risk associated with beta-carotene supplementation, with smokers and asbestos workers facing an even greater risk of 21 percent.

When comparing medical professionals with people in other professions, beta-carotene supplementation had no significant effect on health care workers, while it increased the risk by 18 percent in other occupational groups. Researchers believe this may be because medical professionals typically pay more attention to maintaining a healthy lifestyle.

A 2020 review study published in Antioxidants proposed that beta-carotene can be both an antioxidant and a pro-oxidant in the human body and that beta-carotene can exacerbate the carcinogenic effects of ultraviolet rays.

The U.S. Preventive Services Task Force (USPSTF) recommends against using beta-carotene supplementation for the prevention of cardiovascular disease (CVD) or cancer.

A study published in 2023 by Newcastle University in the UK found that eating more carrots is related to a reduced incidence of cancer, but taking beta-carotene had no such effect.

The dosage of one single nutrient supplement is often higher than in foods, Lin Shi-hang, a nephrology specialist nutritionist in Taiwan, told The Epoch Times. Eating foods rich in beta-carotene, such as carrots, spinach, pumpkin, citrus, cantaloupe, and bell peppers, is safe, provides antioxidants, and helps you absorb more nutrients from those fruits and vegetables.

Vitamin E

Vitamin E is an antioxidant, effective in eliminating free radicals, promoting anti-aging, and improving immunity. However, a randomized controlled trial found that vitamin E supplementation significantly increased the risk of prostate cancer in healthy men. More than 30,000 participants from the United States, Canada, and Puerto Rico took a daily dose of 400 IU of vitamin E for seven to 12 years, revealing a 17 percent higher risk of prostate cancer than the placebo group.

A study published in Cell in 2019 found that long-term supplementation of vitamin E and the antioxidant N-acetylcysteine may further promote lung cancer metastasis.

The USPSTF does not recommend using vitamin E supplements to prevent CVD or cancer, citing a comprehensive analysis of nine randomized trials that demonstrated no benefits.

Although vitamin E is a good antioxidant, too much of it can cause gastrointestinal bleeding and other conditions, Dr. Tzung-Hai Yen, a professor in the Department of Nephrology and director of the Clinical Poison Center at Chang Gung Memorial Hospital in Taiwan, told The Epoch Times.

This is especially the case for people with chronic diseases, Yen said. They need to be more cautious because many health products might not suit them. They should first seek advice from a physician before taking vitamin E supplements.

Vitamin B in High Doses

A large U.S. study found that men who took high-dose vitamin B6 (at least 20 mg/day) or B12 (at least 55μg/day) supplements had almost double the risk of lung cancer compared with those who did not take them.

Published in the Journal of Clinical Oncology, this study involved 77,118 Americans aged 50 to 76 and found that men supplementing with either vitamin had a 30 to 40 percent increased risk, particularly among smokers.

However, there was no association between vitamin B6, B9 (folic acid), and B12 supplementation and lung cancer risk in women. Data showed that the participants’ intake of both B6 and B12 far exceeded the U.S. government’s recommended daily intake of 1.3 mg/day and 2.4 mcg/day.

Supporting evidence from a case-control study with 5,183 case-control pairs published in the International Journal of Cancer linked higher vitamin B12 levels with an increased overall lung cancer risk. The study also analyzed genetic data from 29,266 lung cancer cases and 56,450 controls and reached the same conclusion.

The study’s conclusions are observational and cannot be treated as a cause-and-effect relationship, Chen Xiaowei, a registered dietitian in Taiwan, told The Epoch Times.

Modern-day people’s diets are more diversified, and there is no danger in supplementing extra vitamins as long as they are not excessive, Chen noted. People who are at risk of cancer or have a family history of cancer should be careful when taking vitamins. Whether it is vitamin B12 or other nutrients, it is best to follow the recommendations of medical professionals.

Natural Foods Are the Best Health Products

Yen Tzung-hai emphasized that supplements manufactured from artificial vitamins often contain additives known as excipients, and many include artificial colors to enhance appeal, leading people to inadvertently take more.

Although these are all legal additives, doctors usually do not recommend taking them, except for patients on kidney dialysis, patients with severe malnutrition, and patients who are unable to eat on their own. He emphasized that the best healthy food is always natural food.

Traditional Chinese medicine (TCM) aligns with this philosophy, promoting health and the intake of diverse nutrients through natural foods. Ritsugaku Ken, a TCM expert at Japan’s Kyushu Kampo Research Association, told The Epoch Times, “Natural food is rich in vitamins needed by the human body, and these vitamins work synergistically with other nutrients to make them more easily absorbed and utilized by the body.”

According to Yen, TCM does not have vitamins as a modern scientific term. TCM states that the subtle substances produced by food metabolism are enough to nourish the human body, maintain vitality, promote the movement of energy in the body, enhance the function of the internal organs, prolong life, and improve the ability to resist disease. This is like the concept of vitamins in modern nutrition.

He said that TCM advocates the intake of five flavors (sour, bitter, sweet, pungent, and salty) and five colors (green, red, yellow, white, and black) of food. They correspond to the five key organs and energy systems in the body. Attending closely to a diversified diet can regulate the body and enhance immunity. When this is done, most people do not need supplements.