The American Task Force on Preventive Services issued a statement of recommendation in June 2022 on the use of over-the-counter vitamin supplements. Based on its independent expert panel’s review of existing scientific evidence, the task force recommended against the use of beta-carotene or vitamin E supplements for the prevention of cancer and cardiovascular disease, two leading causes of death in the United States.
The task force’s new statement is an update to its 2014 recommendation, which reached the same conclusion. In the most recent analysis, the expert panel looked at six other randomized controlled trials for beta-carotene and nine for vitamin E.
The Conversation asked Katherine Basbaum, clinical dietitian specializing in cardiovascular disease, to explain what this recommendation means for the general public, especially those currently taking or considering taking dietary supplements for cancer and disease prevention. cardiovascular. In our Q&A with Basbaum, she interprets the data behind the task force’s conclusion.
1. What was the basis for the task force’s recommendation?
The US Task Force on Preventive Services evaluated and averaged the results of several studies investigating the health outcomes associated with beta-carotene and vitamin E supplements. Beta-carotene is a phytonutrient – or plant chemical – with a red-orange pigment; beta-carotene and vitamin E are found in many fruits and vegetables such as carrots, sweet potatoes, kale, spinach, Swiss chard and avocados, to name a few.
The expert panel concluded that when it comes to preventing cardiovascular disease or cancer, the harms of beta-carotene supplementation outweigh the benefits and that there is no net benefit to beta-carotene supplementation. vitamin E supplementation for these purposes. Their recommendation applies to adults who are not pregnant and excludes those who have chronic conditions, are hospitalized or have a known nutritional deficiency.
Beta-carotene and vitamin E are powerful antioxidants, substances that can prevent or delay cell damage. They are commonly taken as dietary supplements for their potential health and anti-aging benefits, such as to combat age-related vision loss and inflammation associated with chronic disease. It has also been shown that vitamin E help support the immune system.
Our body needs beta-carotene and various nutrients for a variety of processes, such as cell growth, vision, immune function, reproduction, and normal organ formation and maintenance. But it is important to point out that more than 95% of the American population receives adequate levels of vitamin A, vitamin E, and beta-carotene by the foods they eat. Therefore, the average healthy adult probably does not need additional supplementation to support the processes mentioned above.
The task force did not focus on other potential benefits of vitamin supplementation. He noted that “there may be other benefits of certain supplements that were not covered in this review due to their focus on cardiovascular disease and cancer prevention.”
2. What risks has the working group flagged?
Based on their review of the evidence, the expert panel concluded that beta-carotene supplementation likely increases the risk of lung cancer incidence, especially in people at high risk of lung cancer, such as people who smoke or are occupationally exposed to asbestos. He also found a statistically significant increased risk of death from cardiovascular disease associated with beta-carotene supplementation.
In one of the clinical trials reviewed by the task force for their recommendation statement, people who smoked or had been exposed to asbestos at work were increased risk of lung cancer or death from heart disease at doses of 20 and 30 milligrams per day of beta-carotene. This dosage is higher than the standard recommendation for beta-carotene supplementation, which ranges from 6 to 15 milligrams per day.
3. Why were these supplements historically considered beneficial?
Antioxidants like beta-carotene and vitamin E can help fight inflammation and oxidative stress, two of the main contributors to the development of cancers and heart disease. Oxidative stress can trigger cell damage; when this happens, the cells can become cancerous.
Since cancer and cardiovascular disease are the two leading causes of death in the United States, it’s only natural that so many people choose to seek out dietary supplements to potentially boost prevention. Moreover, since only 1 in 10 Americans meets the federal recommendation for fruit and vegetable intake – 1.5 to 2 cups of fruit and 2 to 3 cups of vegetables per day – people often turn to dietary supplements to make up for this deficiency.
There is strong evidence that a diet rich in fruits and vegetables is beneficial overall health and disease prevention. Researchers also suggest this could be largely due to their high antioxidant content. The dose of antioxidants received by eating an abundance of foods rich in beta-carotene and vitamin E are not as high as the doses available in supplement form.
4. Should people be worried about taking any type of dietary supplement?
Rigorous testing is required before a drug is approved by the Food and Drug Administration. However, this is not the case with dietary supplements, which are regulated as a food and not as a drug. The FDA therefore not the authority to approve dietary supplements for their safety and effectiveness – or to approve their labeling – before the supplements are sold to the public.
The size of the global dietary supplements market was valued at US$151.9 billion in 2021. According to data from the 2017-2018 National Health and Nutrition Survey, approximately 60% of American adults took some form of dietary supplement, including vitamins, minerals, multivitamins, plants and herbs, probiotics , nutritional powders, etc.
Consumers should be careful when purchasing and consuming dietary supplements as they may contain ingredients that could negatively interact with a prescribed drug or medical condition. It should also be noted that products containing hidden drugs are also sometimes falsely marketed as “dietary supplements”, which can still put consumers at risk.
This year, the FDA began working to strengthen the regulation of dietary supplements and has wrote a proposal change its current policies.