Lutein supplements may enhance benefits of low-calorie diet: RCT
Data published in the British Journal of Nutrition indicated that 10 weeks of the low-calorie diet (LCD) plus 20 mg per day of lutein led to greater decreases in body fat compared to low calorie diet alone.
In addition, the lutein supplemented group displayed a preservation of their free fat mass (also known as lean body mass), while this decreased in the placebo group.
And only the lutein group experienced statistically significant improvements in total cholesterol and LDL-cholesterol levels, reported researchers from the Tabriz University of Medical Sciences in Iran.
“The major conclusion was that lutein can be considered as an adjuvant to an LCD in a weight loss programme for the obese older adults who not only are at high risk of age-related macular degeneration but also are prone to sarcopenia and metabolic disorders,” they wrote.
The study adds to an ever-growing body of science supporting the benefits of the carotenoid lutein, which is most associated with eye health. The link between lutein and eye health was first reported in 1994 by Dr Johanna Seddon and her co-workers at Harvard University, who found a link between the intake of carotenoid-rich food, particularly dark green leafy vegetables like spinach, and a significant reduction in age-related macular degeneration (AMD) (JAMA, Vol. 272, pp. 1413-1420).
In recent years, numerous studies with data from primates, children, middle-aged people, and the elderly also support the importance of lutein in brain health, which is unsurprising given that the eyes and the brain are connected.
The new study indicated for the first time, according to the researchers, that the carotenoid may also offer benefits for body composition and cholesterol levels when consumed in combination with a low-calorie diet in middle-aged obese people.
The Iran-based scientists recruited 48 obese middle-aged people to participate in their double-blind, randomized controlled trial. Subjects were assigned to a low-calorie diet with either a placebo or the lutein supplement for 10 weeks.
At the end of the study, both groups equally displayed significant reductions in body weight and waist circumference. However, the decrease in the percentage of body fat was greater in the lutein group, said the researchers.
While fat-free mass significantly declined in the placebo group, no such losses were recorded in the lutein group, said the researchers. Additionally, “visceral fat and serum levels of total cholesterol (TC) and LDL-cholesterol were significantly decreased only in the lutein group”, they added.
Commenting on the potential mechanism(s) of action, the researchers noted that “lutein could improve body composition was primarily based on the interaction of lutein with the nuclear receptors such as retinoic acid receptor, retinoid X receptor and PPAR and subsequent increase in energy expenditure.”
Regarding the improvements in lipid levels, they added: “The possible mechanisms by which lutein could improve lipid profiles were mainly based on the incremental effects of lutein on LDL-cholesterol receptor and scavenger receptor class B type 1 which involved in the elimination of LDL from plasma and removal of cholesterol from peripheral tissues towards the liver, respectively, and thereby caused a reduction of plasma levels of cholesterol.”
The researchers called for longer studies in different age groups to further strengthen the links reported in their paper.
Source: British Journal of Nutrition
Volume 126, Issue 7, Pages 1028-1039. doi:10.1017/S0007114520004997
“Lutein supplementation combined with a low-calorie diet in middle-aged obese individuals: effects on anthropometric indices, body composition and metabolic parameters”
Authors: F. Hajizadeh-Sharafabad et al.