A variety of deficient illnesses paved the way for the discovery of the micronutrients we now call “vitamins.” A clear intervention, still in the form of foods and supplements at the time, alleviated symptoms and treated diseases like limes and scurvy, unpolished rice and beri beri, and cod liver oil and rickets. Nowadays, diseases are not defined by a lack of nutrients; rather, overconsumption of foods is the leading cause of chronic diseases such as cardiovascular disease, diabetes, and cancer. These lifestyle diseases are complex, with diet/nutrients playing a role in disease development; nevertheless, treating or preventing them requires more than a restricted focus on micronutrients.
The balance between the intake of supplements
Nonetheless, dietary supplements remain popular in the general community, with supplement users dubbed the “worried well.” Positive attitudes toward supplements, such as “Help me to be healthy,” “Stop me from getting sick,” “Do not harm me,” and “Be the best I can do for myself,” have been noted among supplement consumers in the United Kingdom. So, do dietary supplements play a role? Should we have to strike a balance between food and supplements even though health recommendations discourage the use of dietary supplements?
The continued use of supplements implies that the general population gets nutrients from both foods and supplements, and the supplement contribution may be large. In the case of suboptimal nutrient status or food intake, supplement use is thus an exposure that cannot be ignored in relation to (i) nutrient deficiency, sufficiency, and toxicity, (ii) biomarker associations, and sometimes (iii) disease (e.g., fish vs. fish oil and the association with cardiovascular disease).
Dietary supplements have been governed in Europe since 2002 by the directive 2002/46/EC, which defines them as: “Foodstuffs with the purpose of supplementing the normal diet and which are concentrated sources of nutrients or other substances with a nutritional or physiological effect, alone or in combination, marketed in dose form, namely forms such as capsules, pastilles, tablets, pills, and other similar forms, sachets of powder, ampoules of liquids, drop dispensing bottles, and other similar forms of liquids and powders designed to be taken in measured small unit quantities.”
It has been noted that different American polls have different definitions of what constitutes “dietary supplements” or even certain sorts of supplements. Definitions are also lacking in UK studies, despite the fact that participant response categories or the examples provided in the questionnaires provide an idea of the subject matter. In order to compute what is known as “total nutrient intake” (TNI), or the sum of food-sourced intake and supplements, prescribed drugs (as sources of folate, calcium, iron, and vitamin E) might be included. Additionally, separating derived medications from dietary supplements (or even food intake from dietary supplement intake) may reveal more information about reverse causality or confounding by indication, which may obscure the association with biomarkers or illness. For instance, using ferrous sulfate as prescribed for anemia, which itself may be brought on by an underlying illness or treatment, will be associated with health differently than ferrous sulfate.
The distribution of nutrients is shifted to the right by supplement intakes, but in most cases, food sources alone may provide enough already. The (small) decrease in the proportion of people at risk with the addition of supplements varies on the nutrient as well as how the supplements are grouped. When supplement intake is taken into account (among those who use that nutrient as a supplement), there is a slightly increased chance of exceeding the upper limits.
By indicating the “internal dose,” or absorption, objectively tested nutritional biomarkers can help to verify self-reported nutrient consumption. However, with regard to dietary supplements as a source of nutrient intake, a few things stand out with regard to how they may affect biomarkers. These issues are discussed in length elsewhere. The first benefit is a larger range of nutrient intake, and different dose-response relationships may be found with TNI compared to intake solely from food sources. Second, whereas a dose-response association is distinct and some of these results may be contradictory with regard to the “internal dose,” the statistical criteria selected in observational research are primarily intended to create correlations and quantify the reclassification of individuals.
Thirdly, colinearity in supplement nutrient ingestion exists (e.g., use of MVMM-type supplements), just as diets include several nutrients that may interact (e.g., fat-soluble vitamins as antioxidants in high-fat foods). As a result, indicators other than the nutrients under study (such as tocopherol concentrations and vitamin C supplement use) may be impacted.
What have nutrients provided?
The nutrients provided have the ability to increase plasma concentrations of the respective nutrients, particularly vitamins and fatty acids. Supplements at medicinal levels may produce strong correlations between consumption and biomarker; nevertheless, dose-response associations suggest saturation. A biomarker can be influenced by many other factors (for example, see Proc Nut Soc McMillan); additionally, higher circulating concentrations do not always indicate better health or functionality, because circulating biomarkers may not reflect nutrient storage or effectiveness in an organ.
In what ways does the scale tip in favor of supplements over foods? Because supplements are being consumed by an ever-increasing percentage of the population, it is necessary to keep an eye on how they affect dietary patterns, health, and disease. Traditionally, essential nutrients have been studied in relation to health. However, despite the fact that micronutrient deficiencies are still prevalent in the population of the UK, the relatively high nutrient intake may not be an indicator of healthy food choices. This is evidenced by the low consumption of fruit, vegetables, and fish that is found in national surveys.
Solving the problem of bad eating habits by consuming micronutrient supplements is a solution that is too narrow in scope. In today’s world, dietary recommendations for public health take into account not only the function of the nutrient in question but also its food source and its position within the diet. It seems that the significance of supplements in this context is now limited to specific age groups, living conditions, or disorders associated with reduced nutrient absorption (7,108). The methodology of observational research presents a number of challenges, the most significant of which are the evaluation and description of nutrient intake in the general population, as well as the determination of the role, if any, that nutritional supplements play in the primary disease prevention process.