Bioavailability of Lutein in Chlorella Powder: A Single Ingestion of Chlorella Powder Raises Serum Lutein Concentrations in Healthy Human Volunteers

Abstract

Chlorella powder (CP), a dietary supplement made from a green alga, contains abundant lutein (2.8 mg/g), but the bioavailability of lutein in CP has not been evaluated. In the present study, we assessed the effect of a single ingestion of CP (3 or 6 g) in tablet form on serum lutein concentrations in humans (n = 21). At 1 d, serum lutein concentrations increased from baseline values by 34% (25.6 nM/mg-lutein intake) after 3 g CP and by 66% (21.4 nM/mg-lutein intake) after 6 g CP. These results suggest that lutein in CP is highly bioavailable.Keywords: bioavailability, Chlorella, green alga, lutein *To whom correspondence should be addressed. E-mail: shinya-shibata@yakult.co.jp IntroductionLutein is the most abundant carotenoid in nature, and green leafy vegetables are the most popular source of dietary lutein. Lutein and zeaxanthin exist in the lens of the eye and the macular region of the retina (Krinsky et al., 2003). Many studies have indicated that the consumption of lutein-and zeaxanthin-rich food is associated with a reduced risk of agerelated macular degeneration (AMD) and cataracts (Moeller et al., 2000;Seddon et al., 1994). Seddon et al. (1994) have reported that daily intake of 6 mg of lutein was associated with a reduced risk of AMD. Richer et al. (2004) reported that a daily intake of 10 mg of lutein improved the vision of AMD patients.During the absorption of carotenoids from food, the carotenoids are initially transferred from the intact food matrix into emulsified lipid droplets. Subsequently, they are mixed into micelles, as are other dietary lipids, and then absorbed by the small intestine. These processes are influenced by various characteristics of the food; for example, fat facilitates the absorption of carotenoids, whereas dietary fiber inhibits it (van het Hof et al., 2000). Thus, to consume adequate amounts of vegetables and fruits in order to ensure sufficient intake of carotenoids, we must determine the bioavailability of carotenoids in food, not just the carotenoid content of the food.Chlorella species are unicellular green algae with high photosynthetic efficiency, and are rich in protein, essential nutrients, and plant pigments. Some Chlorella species are widely used as a dietary supplement in many countries, especially in East Asia (e.g., Japan, Taiwan, Korea). Chlorella regularis has been reported to potentially prevent lifestylerelated diseases (Shibata et al., 2003;Shibata and Sansawa, 2006;Shibata et al., 2007). Chlorella powder (CP) made from C. regularis contains large amounts of carotenoids such as lutein, α-carotene, and β-carotene (approx. 2.5 mg/g, 250 μg/g, and 500 μg/g, respectively). Thus, the ingestion of CP could improve low dietary intake of lutein due to low consumption of vegetables and fruits, because only a few grams of CP can supply 6 to 10 mg of lutein. However, to our knowledge, there is no available information about carotenoid bioavailability of CP.The aim of the present study was to determine the bioavailability of lutein from CP in humans. We assessed the e...

A Single Dose of Marine Chlorella vulgaris Increases Plasma Concentrations of Lutein, β-Carotene and Zeaxanthin in Healthy Male Volunteers

“…Results showed that for all carotenoids, the values of AUC and C max were significantly different from zero ( p < 0.01), indicating that a single dose of marine Chlorella vulgaris (6 g) increased plasma concentrations of lutein, β-carotene and zeaxanthin in healthy subjects. For lutein, the major carotenoid identified in marine Chlorella vulgaris ( Table 2 ), the C max achieved in this study per mg of ingested lutein (2.88 µg·L −1 ) was lower than the value reported by Shibata and Hayakawa (7.23 µg·L −1 ) [ 24 ], and this difference could be explained by the absence of olive oil in the meal. When compared with other food matrices rich in lutein, the range of C max obtained herein per mg of lutein intake (0.7–12.2 µg·L −1 ) are within the values reported for a dose of broccoli (200 g) (5.0 µg·L −1 ) and spinach (150 g) (10.5 µg·L −1 ) [ 27 ].…”

“…The bioavailability of carotenoids from a single dose of Chlorella vulgaris in humans was only reported by Shibata and Hayakawa, who demonstrated that 3 g or 6 g of this microalga increased the serum concentration of lutein by up to 66% for 3 days after the intake [ 24 ]. The high serum lutein concentration observed could be related to the simultaneous administration of olive oil, which has already been described to improve the intestinal bioaccessibility, absorption kinetics and bioavailability of carotenoids in vivo [ 25 , 26 ].…”

Chlorella is an Effective Dietary Source of Lutein for Human Erythrocytes

“…Chlorella algae contains high amounts of lutein 11 , and a previous study suggested that Chlorella intake influences serum lutein levels 12 . With a single oral dose of Chlorella a 6 g Chlorella tablet, containing 15 mg lutein , serum lutein concentration reportedly increased about one and a half-fold, but erythrocyte lutein concentrations were not investigated.…”

“…1 and Table 2 . Considering the results of previous studies 12,18,19 and our findings Fig. 1 and Table 2 , daily intake of Chlorella leads to increased plasma lutein in normal subjects.…”

“…single oral dose of 6 g Chlorella tablets containing 15 mg lutein to healthy volunteers, blood serum lutein concentration increased and reached a maximum of average 850 pmol/mL serum about one and a half-fold from the fasting conditions 12 , and the concentration was maintained over a 3-day period. Chlorella, therefore, appears to be a good dietary source for improving lutein bioavailability.…”