You, like millions of others, probably take daily vitamin and mineral supplements to complement your diet. Yet you might not get what you pay for.
Fluorescence spectroscopy, carried out by Gene Hall has uncovered these supplemental deceits. He is a Ph.D. and an analytical and physical chemist at Rutgers University in New Jersey. Hall found that the contents on the labels do not always match the ingredients.
Hall focused on examining the contents of fish oil, which boasts the healthy benefits of eating fatty fish without eating fish.
Anchovy, salmon, tuna, and menhaden usually go into dietary fish oils. Hall analyzed a number fish oil samples using a HORIBA Aqualog spectrofluorometer, which simultaneously measures both absorbance spectra and fluorescence Excitation-Emission Matrices. It gives the researcher a fingerprint of the sample under study in fast succession.
The Aqualog characterized the substance in the fish oil capsules. He found that some manufacturers used diluted fish oil or other substances to mimic fish oil. These did not actually contain omega-3 fatty acids in their natural triglyceride form. Instead, the common, or usual name, “fish oil” declared as a dietary ingredient in the supplement facts panel had been chemically altered, and could no longer claim “fish oil” as a dietary ingredient or dietary supplement.
His team found that manufacturers chemically altered about 80 percent of the products tested without notifying the consumer of a change in the common name of the supplement. This is a violation of the Food and Drug Administration’s regulations. Unfortunately, the FDA does not monitor these changes.
The Aqualog spectrofluorometer, vital in Hall’s analysis, presents a fingerprint of the sample on a three-dimensional graph using proprietary fluorescence software.
“The nice feature about the Aqualog is that you can have this simultaneous excitation and emission, and capture all that data into one nice visual interpretation,” Hall said. “You can actually see on the computer monitor some nice features with contour plots which can allow you to visualize differences or similarities between samples. It has a unique fingerprint. If two samples are very similar, they should have the same excitation emission fingerprint based on all of the many hundreds of compounds that are present in the sample.”
Since the Federal Drug Administration does not police dietary supplements, counterfeit vitamins and minerals are only subject to voluntary scrutiny.
“It leaves it to private industry or the research sector,” Hall said. “The industry polices itself, so it's basically on the honor system, but nobody's checking the dietary supplement companies. We're one of the few labs that are actually checking these companies.”
Researchers have found some substitute ingredients contain synthetic products that can damage a person’s pancreas and other vital organs. Others contain fatty acid ethyl esters, which doctors do not recommend for pregnant women.
Krill oil is one of the most heavily misbranded and adulterated dietary supplements, Hall said.
“Many products are labeled as Krill oil, but they have no Krill oil in them,” he said.
Krill oil’s benefits include polyunsaturated fatty acids. The industry is heavily publicizing the dietary supplement. Unfortunately, it does not live up to the amounts of EPA and DHA, both omega-3 fatty acids, in the Krill oil he tested.
“If you eat a normal diet, you get about maybe 10 times more EPA and DHA,” Hall says, “The dietary supplements to me are useless.”
Hall also studied salmon oil. Many products sold on the market as a dietary supplement say it has salmon oil.
“The nice feature (of the Aqualog spectrofluorometer) is that you can look for this special pigment, astaxanthin ,” he said. “Natural salmon oil has this very beautiful red pigment, which fluoresces very nicely with (HORIBA’s Aqualog). “So we went out and bought a whole bunch of salmon oil dietary supplements and analyzed it on the Aqualog.”
Hall found gross mislabeling, and plans to publish his results on these different adulterated dietary supplements in the near future.
Hall also uses analytical chemistry instrumentation, including Fourier-transform infrared spectroscopy (FTIR), energy dispersive X-ray fluorescence (EDXRF), and Raman spectroscopy from HORIBA Scientific to characterize the ingredients in these products.
“All natural” food products have grown in popularity with the increased health awareness of the U.S. population. Yet some product labeled “all natural” of supplements for weight loss have contaminants not listed on the product’s ingredient label. Those have included steroids, synthetic and non-synthetic drugs and other synthetic and non-synthetic adulterants that could be harmful to a person. Many such adulterants, like nitrogen rich melamine are a growing public health concern.
Raman is a technique for fast, nondestructive and spatially relevant localization of adulterants in powders. Researchers also combine Raman spectroscopy with direct mass spectroscopy to confirm the presence of a contaminant.
Raman and other spectroscopy techniques are well suited for melamine, analogue, and other adulterant identification, especially when used as an imaging technique, as spatially relevant data can help locate individual particulates. The localization and identification of these trace particles can then be extracted using a nanomanipulator.
The growing demand for whey protein supplements has made it the target of adulteration with cheap substances. Raman spectroscopy along with chemometrics and multivariate analysis in particular can simultaneously detect and quantify three common adulterants – creatine, L-glutamine and taurine.
Researchers have applied surface-enhanced Raman scattering (SERS) techniques to melamine and its analogues using gold nanoparticles for identification of these substances.
Scientists have used Fourier transform infrared (FTIR) spectroscopy with attenuated total reflectance (ATR) for detecting of known adulterants within dietary ingredients.
Researchers typically conduct the analysis of toxic heavy metals in supplements using an emission spectrophotometer or atomic adsorption spectrophotometer. Yet these techniques require time-consuming preparation procedures. Scientists can conduct the measurement using an X-ray fluorescence spectrometer, which permits easy sample preparation. Using an EDXRF spectrometer, quantitative analysis of heavy metals in dietary supplements were possible.
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