(OMNS Sept 12 2018) One of the most vitamin-restrictive countries in the world is Norway. There, authorities limit potencies to only slightly higher than RDA (Recommended Dietary Allowance) levels for dietary supplements sold outside of pharmacies. The traditional reasoning is that most people receive the nutrients they need from a "balanced diet."  The authorities are also obsessively concerned that some vitamins and minerals are harmful in high doses. And, since an intake of water-soluble vitamins in excess of needs is excreted in the urine, Norwegian "experts" advise that taking supplements is a waste of money. Accordingly, the argument goes, the public should be protected not only from possible harm, but also from wasting money on unnecessary nutrients. The official policies on nutritional supplements vary within OECD (Organization for Economic Cooperation and Development) countries. Some are more liberal, while others are even more restrictive.
In the United States, it is against federal regulations for supplement manufacturers to claim that these products prevent or treat any disease. Companies are allowed to use what is referred to as "Structure/Function" wording if there is substantiation of scientific evidence for a supplement providing a potential health effect. An example would be "_____ helps maintain healthy joints", but the label must bear a disclaimer that the Food and Drug Administration (FDA) "has not evaluated the claim and that the dietary supplement product is not intended to "diagnose, treat, cure or prevent any disease," because only a drug can legally make such a claim. The FDA enforces these regulations, and also prohibits the sale of supplements and supplement ingredients that are dangerous, or supplements not made according to standardized good manufacturing practices (GMPs).
Another spin on the 80/20 rule, says Dr. Lipman: stopping eating when you're 80% full. That means slowing down and checking in periodically throughout the meal about what your body is saying. Does the food no longer taste great? Are you getting that "I don't really need any more feeling"? Thinking 80/20 as you eat can help slow you down and be more mindful. Being in tune with your body prevents overeating, he says.
^ Jump up to: a b c Schwingshackl, L; Boeing, H; Stelmach-Mardas, M; Gottschald, M; Dietrich, S; Hoffmann, G; Chaimani, A (2017). "Dietary Supplements and Risk of Cause-Specific Death, Cardiovascular Disease, and Cancer: A Systematic Review and Meta-Analysis of Primary Prevention Trials". Advances in Nutrition: An International Review Journal. 8 (1): 27–39. doi:10.3945/an.116.013516. PMC 5227980. PMID 28096125.
The FDA does not have authority over dietary supplements in the same way it does prescription medicines. The Federal Government does not regularly test what is in dietary supplements, and companies are not required to share information on the safety of a dietary supplement with the FDA before they sell it. The companies are responsible for making sure the supplement is safe, but the FDA does not evaluate the safety of the product before the supplement is sold. So, just because you see a dietary supplement on a store shelf does not mean it is safe, that it does what the label says it will, or that it contains what the label says it contains.
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.