Saturation Diving Alters Folate Status and Biomarkers of DNA Damage and Repair

Exposure to oxygen-rich environments can lead to oxidative damage, increased body iron stores, and changes in status of some vitamins, including folate. Assessing the type of oxidative damage in these environments and determining its relationships with changes in folate status are important for defining nutrient requirements and designing countermeasures to mitigate these effects. Responses of humans to oxidative stressors were examined in participants undergoing a saturation dive in an environment with increased partial pressure of oxygen, a NASA Extreme Environment Mission Operations mission. Six participants completed a 13-d saturation dive in a habitat 19 m below the ocean surface near Key Largo, FL. Fasting blood samples were collected before, twice during, and twice after the dive and analyzed for biochemical markers of iron status, oxidative damage, and vitamin status. Body iron stores and ferritin increased during the dive (P<0.001), with a concomitant decrease in RBC folate (P<0.001) and superoxide dismutase activity (P<0.001). Folate status was correlated with serum ferritin (Pearson r = −0.34, P<0.05). Peripheral blood mononuclear cell poly(ADP-ribose) increased during the dive and the increase was significant by the end of the dive (P<0.001); γ-H2AX did not change during the mission. Together, the data provide evidence that when body iron stores were elevated in a hyperoxic environment, a DNA damage repair response occurred in peripheral blood mononuclear cells, but double-stranded DNA damage did not. In addition, folate status decreases quickly in this environment, and this study provides evidence that folate requirements may be greater when body iron stores and DNA damage repair responses are elevated

Effect of storage temperature on Vitamin C, total phenolics, UPLC phenolic acid profile and antioxidant capacity of eleven potato (Solanum tuberosum) varieties

Storage of potato tubers at low temperature affects their metabolism and may alter their phytochemical properties. There is a need to elucidate the changes in antioxidant compounds, activity and enzymes during storage of tubers. Eleven Indian potato varieties were evaluated for antioxidant parameters, after 0, 30, 60 and 90 days of storage at room temperature, 15 °C and 4 °C. Total phenolics (0.0786–0.1546 mg gallic acid equivalents⋅g−1 FW) and vitamin C content (0.0828–0.2416 mg⋅g−1 FW) varied among the varieties and were different with storage temperature; their levels fluctuated during storage but remained above the initial level until the last day of observation. Phenolic acid profiling by UPLC identified 12 compounds among which the most abundant was chlorogenic acid followed by gallic acid, sinapic acid and ellagic acid. Except para-coumaric acid which decreased at 4 °C, all the phenolic acids increased with storage. Caffeic acid, chlorogenic acid, protocatechuic acid and gallic acid mostly correlated with total phenolic content (r = 0.456, 0.482, 0.588 and 0.620, respectively). Antioxidant activity against both DPPH and ABTS radicals increased during the initial days of storage and then dropped to a level comparable or lower than the original value, irrespective of the storage temperature. Correlation study revealed that chlorogenic acid, gallic acid and ferulic acid mostly contributed to antioxidant activity. Activity of both antioxidant enzymes, superoxide dismutase and ascorbate peroxidase, increased initially but then decreased to values lower than the initial level and were not influenced by storage temperature. Correlation with antioxidant activity indicated that the enhancement of reactive oxygen scavenging species in cold stored tubers could result mainly from ascorbate peroxidase activity. Our results demonstrate that storage temperature adversely influences the metabolism and the content of antioxidant compounds in potato tubers, with subsequent increase on their antioxidant capacity

Bioavailability of the Polyphenols: Status and Controversies

The current interest in polyphenols has been driven primarily by epidemiological studies. However, to establish conclusive evidence for the effectiveness of dietary polyphenols in disease prevention, it is useful to better define the bioavailability of the polyphenols, so that their biological activity can be evaluated. The bioavailability appears to differ greatly among the various phenolic compounds, and the most abundant ones in our diet are not necessarily those that have the best bioavailability profile. In the present review, we focus on the factors influencing the bioavailability of the polyphenols. Moreover, a critical overview on the difficulties and the controversies of the studies on the bioavailability is discussed

Assessment of B-group vitamins in oat gluten-free products

Celem badań było oznaczenie zawartości witamin z grupy B: witaminy B₁, B₂, B₆ i PP we wszystkich dostępnych w 2013 roku na polskim rynku owsianych produktach bezglutenowych. Materiał doświadczalny stanowiło 7 owsianych produktów bezglutenowych, takich jak mąki i mieszanki do wypieku chleba i ciastek oraz płatki. Produkty poddano hydrolizie enzymatycznej z użyciem taka-diastazy oraz hydrolizie kwasowej z zastosowaniem kwasu solnego. Zawartość witamin z grupy B oznaczono metodami wysokosprawnej chromatografii cieczowej. Średnia zawartość witamin B₁, B₂, B₆ (jako sumy pirydoksalu, pirydoksaminy, pirydoksyny) oraz PP we wszystkich produktach wynosiła odpowiednio 0,184, 0,050, 0,159, 0,544 mg·100 g⁻¹ produktu. Największą zawartość witaminy B₁ stwierdzono w płatkach owsianych, a pozostałych witamin w musli owsianym z owocami. Owsiane produkty bezglutenowe charakteryzowały się zróżnicowaną zawartością witamin B₁, B₂, B₆ i PP. Najbogatszym źródłem analizowanych witamin były płatki owsiane oraz musli owsiane z owocami.Oat gluten-free products are a new category on the Polish market of foods for particular nutritional use. Oats which was the subject of numerous studies on its safety for use in the diet of patients with coeliac disease, was introduced on Polish market in 2012. Results of clinical trials in patients suffering from coeliac disease, indicate the occurrence of nutritional deficiencies, including deficiencies of B-group vitamins. Due to the fact that nutritional deficiencies refer both to the patients who do not comply with the recommendations, as well as to those on a gluten free diet, quality assessment of gluten-free food plays a significant role in the efficient treatment of coeliac disease. Oat products are an alternative to the commonly consumed cereal gluten-free products. The aim of this study was to determine the content of B-group vitamins: vitamin B₁, B₂, B₆ and PP in all glutenfree oat products available on the Polish market in 2013. Seven oat gluten-free products: flours, bread mixes, cookies mixes and flakes were purchased in the local health food stores. The concentration of B-group vitamins was determined by high performance liquid chromatography (HPLC) after prior enzymatic and acid extraction of sample. The content of thiamine ranged from 0.049 ±0.011 (oat mix for chocolate muffins) to 0.276 ±0.010 mg in 100 g of product (oat flakes) with a mean of 0.184 mg·100 g⁻¹. The most valuable source of vitamin B₂ was oat musli with fruits (0.085 ±0.001 mg·100 g⁻¹), the least valuable was gluten-free flour with oat (0.031 ±0.001 mg·100 g⁻¹). The average content of vitamin B₆ was 0.158 mg·100 g⁻¹ with the lowest content in gluten-free flour with oat (0.039 ±0.008 mg·100 g⁻¹) and the highest in oat musli with fruits (0.569 ±0.019 mg·100 g⁻¹). The niacin content in all selected products ranged from 0.269 ±0.023 (mix for oat cookies) to 1.084 ±0.103 mg·100 g⁻¹ (oat musli with fruits) with an average content of 0.544 mg in 100 g. High content of vitamins in oat muesli is a result of fruits content. Tested gluten-free products significantly differed in vitamin B₁, B₂, B₆ and niacin contents. The richest source of analyzed vitamins were oatmeal and oat muesli with fruits

Interactions between components of dietary supplements: a case of quercetin and vitamin C

W pracy przedstawiono wyniki badań nad wpływem pH środowiska na aktywność przeciwrodnikową kwercetyny w obecności witaminy C (kwasu askorbinowego). Stwierdzono, że aktywność przeciwrodnikowa kwercetyny, zmierzona w teście TEAC (Trolox Equivalent Antioxidant Capacity), ulega znacznemu obniżeniu w pH 4,5-9,0 w wyniku interakcji z kwasem askorbinowym. Wykonano odpowiednie obliczenia kwantowo-chemiczne w celu wyjaśnienia obserwowanego antagonistycznego oddziaływania pomiędzy tymi przeciwutleniaczami.In the present study, the effect of pH of the surrounding medium on the radical-scavenging activity of quercetin in the presence of vitamin C (ascorbic acid) was investigated. It was found that at pH 4.5-9.0 radical-scavenging activity of quercetin in the TEAC (Trolox Equivalent Antioxidant Capacity) assay is strongly reduced by ascorbic acid as a result of their interactions. Some relevant quantum-chemical calculations were performed to get some insight into the mechanism of observed antagonistic interaction between these two popular antioxidants