The research supported by the Intramural Research Program of the NIH Biomedical Research, National Institute of Aging is the first review and meta-analysis to look at the relationship of serum retinol, retinyl esters and carotenoids with cardiometabolic risk factors
A systematic review and meta-analysis published in the journal Nutrition Reviews, suggested that total mixed carotenoids as well as individual carotenoids were inversely related to metabolic syndrome (MetS), but no association was observed between retinol (also known as vitamin A) and MetS.
This research was supported by the Intramural Research Program of the NIH Biomedical Research, National Institute of Aging and is the first review and meta-analysis that comprehensively reviewed the relationship of serum retinol (vitamin A), retinyl esters, and carotenoids with cardiometabolic risk factors known as metabolic syndrome (MetS).
To choose for eligible studies to be included into the systematic review and meta-analysis respectively, a thorough literature search was done to select the research papers published from 1 January, 1997 to 31 March, 2017.
The starting year 1997 was selected since there was a lack of studies conducted on MetS prior to 1997. Thirty-three studies were included in the qualitative synthesis (systematic review), meanwhile, eleven studies were included in quantitative synthesis (meta-analysis).
From the systematic review, an inverse association was found between higher total carotenoid intake and the presence of MetS.
In regards of meta-analysis, all the 11 studies selected were published between 2003 and 2016, where 10 studies included adults of varying age ranges, whereas, 1 study included adolescents. The cumulative sample of studies included in the meta-analysis consisted of 29, 673 participants.
A clear net inverse association between serum total mixed carotenoids and MetS was observed from the 11 studies. In fact, this inverse association was also observed for all individual carotenoids, with beta-carotene showing the strongest putative protective effect, followed by alpha-carotene and beta-cryptoxanthin.
It is suggested that individuals with MetS have elevated oxidative stress markers, which explain the necessity to increase the requirements for antioxidants such as pro-vitamin A carotenoids. In contrast, serum retinol (vitamin A) was not associated with MetS in most selected cross-sectional studies, particularly those conducted among adults.
The researchers recommended that establishing an adequate recommended daily intake (RDI) may be necessary and beneficial for future studies since a typical Western diet has low level of carotenoids, especially beta-carotene and alpha-carotene – the two main carotenoids found in carrots.
“Metabolic syndrome (MetS) is one of the major threats to public health because it increases disability, healthcare cost and mortality rates. The prevalence of MetS has also increased over the past decades. The putative role of serum carotenoid in regulating the risk for MetS has been evidenced in this meta-analysis that collected and reviewed research from the past 20 years linking serum carotenoids to MetS,” said Diyanah Roslan, Nutritionist of ExcelVite.
“The current vitamin A and multivitamin products are mostly formulated with pure beta-carotene ingredient (either synthetic, fungus, or alga origin with more than 95% beta-carotene). Based on the thorough review, it’s recommended to take products with natural carotenoids, such as beta-carotene, alpha-carotene, lycopene and other carotenoids found in fruits and vegetable for healthy metabolic system."
"ExcelVite’s EVTene is a natural mixed-carotenoid extract from sustainably-sourced palm fruits containing high level of alpha- and beta- carotene with some amounts of other carotenoid such as gamma-carotene and lycopene.
The carotenoid composition in EVTene is similar to that found in carrots and can be incorporated into various type of food and beverage products as well as dietary supplement, hence providing a convenient way to acquire high level of alpha- and beta-carotene in our daily diet,” said Bryan See, Business Development Manager of ExcelVite.