1.
Changes in Lutein Status Markers (Serum and Faecal Concentrations, Macular Pigment) in Response to a Lutein-Rich Fruit or Vegetable (Three Pieces/Day) Dietary Intervention in Normolipemic Subjects.
Olmedilla-Alonso, B, Rodríguez-Rodríguez, E, Beltrán-de-Miguel, B, Sánchez-Prieto, M, Estévez-Santiago, R
Nutrients. 2021;(10)
Abstract
Lutein is mainly supplied by dietary fruit and vegetables, and they are commonly jointly assessed in observational and interventional studies. Lutein bioavailability and health benefits depend on the food matrix. This study aimed to assess the effect of dietary intervention with lutein-rich fruit or vegetables on lutein status markers, including serum and faecal concentrations (by high pressure liquid chromatography), dietary intake (24 h recalls ×3), and macular pigment optical density (MPOD) and contrast threshold (CT) as visual outcomes. Twenty-nine healthy normolipemic subjects, aged 45-65 y, consumed 1.8 mg lutein/day supplied from fruits (14 subjects, 500 g/day of oranges, kiwi and avocados) or vegetables (15 subjects, 180 g/day of green beans, pumpkin, and sweet corn) for four weeks. Serum lutein concentration increased by 37%. The effect of the food group intervention was statistically significant for serum lutein+zeaxanthin concentration (p = 0.049). Serum α- and β-carotene were influenced by food type (p = 0.008 and p = 0.005, respectively), but not by time. Serum lutein/HDL-cholesterol level increased by 29% (total sample, p = 0.008). Lutein+zeaxanthin/HDL-cholesterol increased, and the intervention time and food group eaten had an effect (p = 0.024 and p = 0.010, respectively) which was higher in the vegetable group. The MPOD did not show variations, nor did it correlate with CT. According to correlation matrixes, serum lutein was mainly related to lutein+zeaxanthin expressed in relation to lipids, and MPOD with the vegetable group. In faecal samples, only lutein levels increased (p = 0.012). This study shows that a relatively low amount of lutein, supplied by fruit or vegetables, can have different responses in correlated status markers, and that a longer intervention period is needed to increase the MPOD. Therefore, further study with larger sample sizes is needed on the different responses in the lutein status markers and on food types and consumption patterns in the diet, and when lutein in a "pharmacological dose" is not taken to reduce a specific risk.
2.
Short-term effects of a high nitrate diet on nitrate metabolism in healthy individuals.
Bondonno, CP, Liu, AH, Croft, KD, Ward, NC, Puddey, IB, Woodman, RJ, Hodgson, JM
Nutrients. 2015;(3):1906-15
Abstract
Dietary nitrate, through the enterosalivary nitrate-nitrite-NO pathway, can improve blood pressure and arterial stiffness. How long systemic nitrate and nitrite remain elevated following cessation of high nitrate intake is unknown. In 19 healthy men and women, the time for salivary and plasma nitrate and nitrite to return to baseline after 7 days increased nitrate intake from green leafy vegetables was determined. Salivary and plasma nitrate and nitrite was measured at baseline [D0], end of high nitrate diet [D7], day 9 [+2D], day 14 [+7D] and day 21 [+14D]. Urinary nitrite and nitrate was assessed at D7 and +14D. Increased dietary nitrate for 7 days resulted in a more than fourfold increase in saliva and plasma nitrate and nitrite (p < 0.001) measured at [D7]. At [+2D] plasma nitrite and nitrate had returned to baseline while saliva nitrate and nitrite were more than 1.5 times higher than at baseline levels. By [+7D] all metabolites had returned to baseline levels. The pattern of response was similar between men and women. Urinary nitrate and nitrate was sevenfold higher at D7 compared to +14D. These results suggest that daily ingestion of nitrate may be required to maintain the physiological changes associated with high nitrate intake.
3.
Processing of vegetable-borne carotenoids in the human stomach and duodenum.
Tyssandier, V, Reboul, E, Dumas, JF, Bouteloup-Demange, C, Armand, M, Marcand, J, Sallas, M, Borel, P
American journal of physiology. Gastrointestinal and liver physiology. 2003;(6):G913-23
Abstract
Carotenoids are thought to diminish the incidence of certain degenerative diseases, but the mechanisms involved in their intestinal absorption are poorly understood. Our aim was to obtain basic data on the fate of carotenoids in the human stomach and duodenum. Ten healthy men were intragastrically fed three liquid test meals differing only in the vegetable added 3 wk apart and in a random order. They contained 40 g sunflower oil and mashed vegetables as the sole source of carotenoids. Tomato purée provided 10 mg lycopene as the main carotenoid, chopped spinach (10 mg lutein), and carrot purée (10 mg beta-carotene). Samples of stomach and duodenal contents and blood samples were collected at regular time intervals after meal intake. all-trans and cis carotenoids were assayed in stomach and duodenal contents, in the fat and aqueous phases of those contents, and in chylomicrons. The cis-trans beta-carotene and lycopene ratios did not significantly vary in the stomach during digestion. Carotenoids were recovered in the fat phase present in the stomach during digestion. The proportion of all-trans carotenoids found in the micellar phase of the duodenum was as follows (means +/- SE): lutein (5.6 +/- 0.4%), beta-carotene (4.7 +/- 0.3%), lycopene (2.0 +/- 0.2%). The proportion of 13-cis beta-carotene in the micellar phase was significantly higher (14.8 +/- 1.6%) than that of the all-trans isomer (4.7 +/- 0.3%). There was no significant variation in chylomicron lycopene after the tomato meal, whereas there was significant increase in chylomicron beta-carotene and lutein after the carrot and the spinach meals, respectively. There is no significant cis-trans isomerization of beta-carotene and lycopene in the human stomach. The stomach initiates the transfer of carotenoids from the vegetable matrix to the fat phase of the meal. Lycopene is less efficiently transferred to micelles than beta-carotene and lutein. The very small transfer of carotenoids from their vegetable matrices to micelles explains the poor bioavailability of these phytomicroconstituents.
4.
Arrowroot as a treatment for diarrhoea in irritable bowel syndrome patients: a pilot study.
Cooke, C, Carr, I, Abrams, K, Mayberry, J
Arquivos de gastroenterologia. 2000;(1):20-4
Abstract
OBJECTIVES Arrowroot is an old-fashioned remedy for diarrhoea, but no clinical studies have been done to evaluate its effectiveness. The aim of this pilot study was to assess its efficacy as a treatment for diarrhoea in 11 patients, all of whom had irritable bowel syndrome with diarrhoea as a feature. METHODS The patients were interviewed and a questionnaire completed on entry into the trial. They then took 10 mL arrowroot powder three times a day for one month and discontinued the treatment for the subsequent month. Questionnaires were completed after one month on treatment and at the end of the trial after one month off treatment. RESULTS Arrowroot reduced diarrhoea and had a long-term effect on constipation. It also eased abdominal pain. CONCLUSION Arrowroot is an effective treatment for diarrhoea. Its action could be explained by several theories which relate to an increase in faecal bulk and thus a more efficient bowel action. The number of patients was small, and further studies are needed to substantiate preliminary results.