Mineral Composition of Dietary Supplements-Analytical and Chemometric Approach

Abstract

There is a lack of data on the actual composition and effectiveness of beetroot-based dietary supplements. The research aimed to determine the profile of 22 elements (Na, K, Ca, Mg, P, Fe, As, Se, Zn, Cu, Ag, Co, Ni, Mo, Al, Mn, Sr, Cr, Ba, Li, Pb, Cd) in beetroot and its supplements by the microwave plasma atomic emission spectrometry (MP-AES) method. The analytical procedure was optimised and validated. The composition of both groups was compared, assessing compliance with the recommended daily doses for the chosen elements, and the health risk was estimated. Furthermore, chemometric analysis was applied. Beetroots constituted a significant source of elements, especially K, Na, Mg, Ca, P, in contrast to supplements which contained their negligible amounts except from iron-enriched products which provided notable amounts of Fe (38.3–88% of the Recommended Dietary Allowance for an adult male from 19 to 75 years old). Some products were significantly contaminated with toxic elements (As, Cd). Factor and cluster analyses were helpful in the differentiation of beetroot and its supplements in view of their type (vegetable, supplement, iron-enriched supplement), origin, type of cultivation (conventional, organic), and form (capsule, tablet) based on their mineral composition. The obtained results indicate the need for more stringent control of supplements, as they may pose a significant health risk to consumers.

Root Vegetables—Composition, Health Effects, and Contaminants

“…Beetroot ( Beta vulgaris L.) is of great interest to consumers in the 21st century due to its pleiotropic health-promoting properties [ 50 ]. Among all root vegetables, beetroot is characterized by high quantities of carbohydrates (9.56 g/100 g) and fiber (2.8 g/100 g) [ 51 ]. Beetroot is commonly considered a source of iron (Fe), but among root vegetables, it is parsley that contains greater amounts of this microelement [ 6 ].…”

“…The most abundant element is K (356 mg/100 g in organic beetroots). Moreover, it has been reported that organic beetroots are characterized by higher contents of mineral compounds, such as K, phosphorus (P), Mg, and Ca, than conventional ones [ 51 ]. The composition of conventional beetroot is presented in Table 1 .…”

“…One of the characteristic features of beetroot is the presence of betalains, i.e., betacyanins (e.g., betanin, betanidin, and isobetanin) and betaxanthins (vulgaxanthin I and dopamine–betaxanthin) [ 52 , 53 ]. Higher concentrations of these substances were found in the peel than in the flesh of the beetroot [ 51 ]. Besides their antioxidant potential and anti-inflammatory activity, betalains determine the color of beetroot and can be used as a food pigment [ 54 ].…”

“…Due to the presence of nitrates, beetroot and supplements made from this vegetable are recognized for their support in improving the respiratory and cardiovascular systems [ 51 , 120 ]. However, the consumption of beetroot has better health properties than supplementation with nitrates [ 51 ]. Beetroot juice may support the treatment of asthma and psychological stress by protecting against respiratory infections [ 121 ].…”

Assessment of the Mineral Composition and the Selected Physicochemical Parameters of Dietary Supplements Containing Green Tea Extracts

“…The determination of trace elements in plants by ICP-MS or FAAS allows rapid analysis with good precision and accuracy. Results from published works show that dietary supplements based on plant extracts contained elements in the μg/g range, and their concentrations varied widely [ 33 ]. The use of appropriate statistical methods has frequently aided in the interpretation of the results.…”