Vitamins can be natural or synthetic. Natural vitamins are extracted from food sources, while synthetic vitamins are formulated in laboratory processes. The only vitamin for which there is a noted difference between the natural and synthetic forms is vitamin E. The natural form is labeled d-alpha-tocopherol while the synthetic form is named dl-alpha-tocopherol, with the extra "l" signifying laboratory production. Natural vitamin E has been shown to be slightly more absorbable by the body than the synthetic version, although for other vitamins no significant differences in absorption have been noted.
Consumers can make wise choices for nutritional supplementation by consulting professional nutritionists and naturopathic physicians. Nutritional supplements are best added into the diet slowly, starting with small dosages and working up to the manufacturers' recommended amounts over time. Also, some supplements, such as herbal medications that may stimulate processes in the body, are best taken intermittently, allowing the body occasional rest periods without the supplement. To avoid unfavorable interactions, nutritional supplements are best used moderately and individually, rather than taking handfuls of capsules and tablets for various needs and conditions at the same time. Finally, consumers should be wary of excessive or grandiose health claims made by manufacturers of nutritional supplements and rely on scientific information to validate these claims.
Processing of food reduces its nutritional content, and the finished products are often based on fractions of the original foods. One example is milling grain to make white flour,  which has a lower nutritional density than whole grain flour. The reduction in nutritional value has accelerated since whole foods are now divided into pieces, for example, boneless chicken breast. When meat is injected with saline to increase the volume, the relative level of essential nutrients is reduced. In the United States, many supermarkets in low-income rural and inner city areas have a limited selection of nutrient-dense foods, compared with high-income areas. 
Dietary supplements are complex products. The FDA has established good manufacturing practices (GMPs) for dietary supplements to help ensure their identity, purity, strength, and composition. These GMPs are designed to prevent the inclusion of the wrong ingredient, the addition of too much or too little of an ingredient, the possibility of contamination, and the improper packaging and labeling of a product. The FDA periodically inspects facilities that manufacture dietary supplements.
We live in a modern world with amazing advancements in technology, yet our soil lacks minerals that it once contained causing whatever grows out of it (i.e. fruits, vegetables, and whole foods) to be significantly lower in minerals than it once was. Not only is our soil different, but our food takes a long time to get to us! Unless we’re growing our own whole food in our gardens, picking it out with our bare hands, and washing it off before eating, most likely our produce has been picked weeks before it reaches your grocery store and is purchased by you. This entire process can take weeks and cause nutrients to be depleted from the whole food (2).
Considering average dietary needs and the prevalence of certain health conditions, some basic guidelines may provide the foundation for the effective use of nutritional supplements. First, a high quality, broad-spectrum multivitamin and mineral supplement, taken once per day, is recommended to provide a range of nutrients. This should contain the B-complex vitamins B6, B12, and folic acid, which may help prevent heart disease, and the minerals zinc and copper, which aid immunity. In addition to a multivitamin, antioxidants can be added to a supplementation routine. These include vitamin A (or beta-carotene), vitamin C, and vitamin E, and the mineral selenium. Antioxidants may have several positive effects on the body, such as slowing the aging process, reducing the risks of cancer and heart disease, and reducing the risks of illness and infection by supporting the immune system. Coenzyme Q10 is another antioxidant in wide usage, as studies have shown it may improve the health of the heart and reduce the effects of heart disease. Essential fatty acids, particularly omega-3, are also recommended as they are involved in many important processes in the body, including brain function. Calcium supplementation is recommended for the elderly and for women, to strengthen bones and prevent bone loss. Calcium supplements that are balanced with magnesium have a less constipating effect and are better absorbed.
Over the period 2008 to 2011, the Government Accountability Office (GAO) of the United States received 6,307 reports of health problems (identified as adverse events) from use of dietary supplements containing a combination of ingredients in manufactured vitamins, minerals or other supplement products, with 92% of tested herbal supplements containing lead and 80% containing other chemical contaminants. Using undercover staff, the GAO also found that supplement retailers intentionally engaged in "unequivocal deception" to sell products advertised with baseless health claims, particularly to elderly consumers. Consumer Reports also reported unsafe levels of arsenic, cadmium, lead and mercury in several protein powder products. The Canadian Broadcasting Corporation (CBC) reported that protein spiking, i.e., the addition of amino acids to manipulate protein content analysis, was common. Many of the companies involved challenged CBC's claim.
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.