Nutritional and clinical relevance of lutein in human health

Abstract

Lutein is one of the most widely found carotenoids distributed in fruits and vegetables frequently consumed. Its presence in human tissues is entirely of dietary origin. Distribution of lutein among tissues is similar to other carotenoids but, along with zeaxanthin, they are found selectively at the centre of the retina, being usually referred to as macular pigments. Lutein has no provitamin A activity in man but it displays biological activities that have attracted great attention in relation to human health. Epidemiological studies have shown inconsistent associations between high intake or serum levels of lutein and lower risk for developing cardiovascular disease, several types of cancer, cataracts and age-related maculopathy. Also, lutein supplementation has provided both null and positive results on different biomarkers of oxidative stress although it is effective in increasing macular pigment concentration and in improving visual function in some, but not all, subjects with different eye pathologies. Overall, data suggest that whereas serum levels of lutein have, at present, no predictive, diagnostic or prognostic value in clinical practice, its determination may be very helpful in assessing compliance and efficacy of intervention as well as potential toxicity. In addition, available evidence suggests that a serum lutein concentration between 0·6 and 1·05 mmol/l seems to be a safe, dietary achievable and desirable target potentially associated with beneficial impact on visual function and, possibly, on the development of other chronic diseases. The use of lutein as a biomarker of exposure in clinical practice may provide some rationale for assessing its relationship with human health as well as its potential use within the context of evidence-based medicine.

Watercress supplementation in diet reduces lymphocyte DNA damage and alters blood antioxidant status in healthy adults

“…In support for this concept, a similar observation was also made in a previous study, in which plasma lutein and ␤-carotene status increased more markedly in nonsmokers than in smokers as a result of green vegetable supplementation (41). Furthermore, the elevated plasma lutein in particular may provide additional health benefits to watercress consumers in terms of cardiovascular risk (42) and macular degeneration (43). A recent prospective study also reported that high plasma concentrations of carotene (including ␤-carotene) were associated with a reduced risk of mortality from cancers and cardiovascular diseases (44).…”

Carotenoid deficiency in chronic pancreatitis: the effect of an increase in tomato consumption

“…Above all, serum and tissue lycopene levels have been found to be inversely related to the incidence of several types of cancer, including breast cancer and prostate cancer. More recently, individual carotenoids have attracted much attention because of their potential nutritional and clinical relevance; for example, the effectiveness of lutein in increasing macular pigments and in improving visual function; the in vitro animal and human evidence suggesting a unique anabolic effect on bone calcification and prevention of osteoporosis from b-cryptoxanthin; and the beneficial role of lycopene in prostate cancer, bone resorption and oxidative stress (Granado et al, 2003;Rao et al, 2007).…”

Improvement of Lentigines by Oral Crocetin Administration and Examination of Its Mechanism of Action

“…However, it is not believed that crocetin showed its effect via vitamin A-like action on lentigines because crocetin is not converted into vitamin A in the body. In addition, previous research reported no side effects of vitamin A overdose, without lutein being converted to vitamin A [25]. It is, therefore, believed that there are no side effects accompanied by vitamin A overdose because water solubility of crocetin is higher than that of lutein, it does not accumulate in the tissue, and is not converted to vitamin A.…”