Background and aims: Carotenoids may reduce diabetes risk, due to their antioxidant properties. However, the association between dietary carotenoids intake and type 2 diabetes risk is still unclear. Therefore, the objective of this study was to examine whether higher dietary carotenoid intakes associate with reduced type 2 diabetes risk.
Methods and results: Data from 37,846 participants of the European Prospective Investigation into Cancer and Nutrition- Netherlands study were analyzed. Dietary intakes of β-carotene, α-carotene, β-cryptoxanthin, lycopene, lutein & zeaxanthin and the sum of these carotenoids were assessed using a validated food frequency questionnaire. Incident type 2 diabetes was mainly self-reported, and verified against general practitioner information. Mean (SD) total carotenoid intake was 10 (4) mg/day. During a mean (SD) follow-up of 10 (2) years, 915 incident cases of type 2 diabetes were ascertained. After adjustment for age, sex, diabetes risk factors, dietary intake, waist circumference and BMI, higher β-carotene intakes associated inversely with diabetes risk [Hazard Ratio quartile 4 versus quartile 1 (HRQ4): 0.78 (95%CI:0.64,0.95), P-linear trend 0.01]. For α-carotene, a borderline significant reduced risk was observed, with a HRQ4 of 0.85 (95%CI:0.70,1.03), and P-linear trend 0.05. β-cryptoxanthin, lycopene, lutein & zeaxanthin, and the sum of all carotenoids did not associate with diabetes risk.
Conclusions: This study shows that diets high in β-carotene and α-carotene are associated with reduced type 2 diabetes in generally healthy men and women.
Alex’s Notes: This study is very straightforward. Carotenoids are plant pigments that provide the yellow, orange, and red colors of fruits and vegetables. Β-carotene is the well-researched and well-known carotenoid, but others include α-carotene, β-cryptoxanthin, lycopene, and lutein & zeaxanthin. The current study investigated the association between dietary intake of these six carotenoids and the incidence of type-2 diabetes in persons participating in the European Prospective Investigation into Cancer and Nutrition- Netherlands (EPIC-NL) cohort.
Overall, 37,846 persons were included in the analysis. The average age was 49 years and 74% were female. Dietary intake was determined with a 178-item food frequency questionnaire about the past year, and all nutrient values were adjusted for total energy intake. Type-2 diabetes was confirmed through a general health practitioner diagnosis.
Β-carotene and lycopene were the largest contributors to carotenoid intake in the cohort. As total intake rose, so did the average age and intake of vitamin C, E, & fiber. The higher quartiles of intake also had a lower waist circumference, higher education, more physical activity, and less current smokers.
Of the entire cohort population, only 915 (2.4%) developed type-2 diabetes, and there was indeed an inverse association between β-carotene intake and incidence. Compared to the lowest quartile of intake, the highest quartile had a 22% reduced risk of diabetes, which translates into a reduction of 0.52 persons per 100 who develop type-2 diabetes as a result of low β-carotene intake. None of the other carotenoids showed a significant association.
There are far more important things to consider with type-2 diabetes than carotenoids.