The dietary supplement industry is expanding, but it still remains far less regulated than the pharmaceutical industry, resulting in inconsistent quality control. Limited research has been performed in the U.S., particularly regarding the quantification of omega-3 fatty acids like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The aim of this study was to quantify the omega-3 fatty acid content in fish oil capsules and liquids purchased from major stores and a grocery chain and compare the results to their label claims. A total of 6 out of 15 were found to have EPA levels ±20% and 10 out of 15 were ±20% outside of the label claim for DHA. One product did not have a label claim for EPA and DHA, but did have a claim for total omega-3 content. These discrepancies indicate that consumers may unwittingly be consuming higher or lower quantities of omega-3 fatty acids than expected, potentially affecting their health outcomes.

Rhus is a genus of shrubs that produces strong aromatic essential oils. These oils have numerous applications, including treating urinary infections, flavoring food, and alleviating gastrointestinal ailments. We conducted an experiment to track the essential oil yield and composition of two Rhus species, Rhus aromatica Aiton and Rhus trilobata Nutt., over the course of the growing season. The essential oil yield and composition were examined over four weeks from May to June 2023. We found that higher ambient temperature lowered the total yield of essential oils. Yield decreased in both species over the course of the experiment, with a yield of 0.21% in week 1 and 0.07% in week 4. The composition of oils changed as the outside temperature increased. Some of the lighter hydrocarbons, such as limonene, decreased, while other heavier hydrocarbons, including β-caryophyllene and germacrene D, increased as the outside temperature rose. Limonene was also shown to be the main component of R. aromatica essential oil at an average of 86.2% area, with >98% of that being the enantiomer D-limonene. Additionally, the effect of different drying methods on the yield and composition of the essential oils was investigated. The results show that when drying the plant material in the oven, a greater yield of 0.31% is obtained, whereas the shade- and sun-dry methods yield 0.09% and 0.02%, respectively. The main component of R. trilobata was α-pinene compared to the D-limonene in R. aromatica. This study helps to understand more of the correlation between outside temperature and essential yield/composition in the species R. aromatica, particularly during the May–June sampling period. To compare two Rhus species that get commonly grouped together as the same species, SPME Headspace was used to determine that the main component of R. trilobata was α-pinene compared to D-limonene being the main component in R. aromatica.

The dietary supplement industry is a growing market with a variety of suppliers, producers, and distributors in terms of size and quality. Because of the little amount of regulation placed on the dietary supplement industry compared to the pharmaceutical industry in the United States, there is less pressure on supplement companies ensure that their labels accurately reflect the actual product’s content. There are few studies on the quality of fish oil sold in the U.S., particularly about quantitation of ω-3 fatty acids, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The aim of this study was to compare the amount of ω-3 fatty acids found in fish oil capsules and liquids bought from local stores to their label claim. Of the 16 fish oil products tested, 6 were ± 20% outside of the label claim for EPA and 10 of 15 were ± 20% outside of the label claim for DHA. One product did not have a label claim for DHA. The large variance in the amount of omega-3s from the product label could mislead consumers to ingesting significantly more or less than expected.