The United States Food and Drug Administration, Office of Inspections, Compliance, Enforcement, and Criminal Investigations, monitors supplement products for accuracy in advertising and labeling, and when finding violations, warns manufacturers of impending enforcement action, including search and seizure, injunction, and/or financial penalties, such as for a Maine supplement company in 2017. The United States Federal Trade Commission, which litigates against deceptive advertising, established a consumer center to assist reports of false health claims in product advertising for dietary supplements, and, in 2017, successfully sued nine manufacturers for deceptive advertising of dietary supplements.
When it comes to omega-3 fatty acids (omega = ω) such as EPA and DHA, children may be given cod liver oil and served fish and/or other seafood 2-3 times a week. It is important to check the dose of vitamin A supplied, as it can be toxic in high doses, especially for children. One problem with cod liver oil today is that vitamin D has been removed during processing, thus changing the natural ratio of the two vitamins so that we ingest relatively too much of vitamin A. 
Anemia can deplete your energy, leaving you feeling weak, exhausted, and out of breath after even minimal physical activity. Iron deficiency can also impact your mood, causing depression-like symptoms such as irritability and difficulty concentrating. While a simple blood test can tell your doctor if you have an iron deficiency, if you’re feeling tired and cranky all the time, it’s a good idea to examine the amount of iron in your diet.
For instance, foods rich in vitamin E and beta-carotene are healthy and can help reduce cancer risk. However, the U.S. Preventive Services Task Force (USPSTF) and the American Academy of Family Physicians (AAFP) recommend against taking vitamin E or beta-carotene for the prevention of cardiovascular disease. People who smoke or are at risk for lung cancer also should avoid beta-carotene. It can increase their risk of lung cancer.