Abstract: Oxidative stress is increased in patients with metabolic syndrome (MS). Antioxidants, including carotenoids, are decreased in MS. We hypothesized that a low skin carotenoid score (SCS), calculated using resonance Raman spectroscopy, would correlate with the presence of MS. We retrospectively reviewed consecutive patients referred for dietary assessment between 2010 and 2012. For each patient a nutrition history, medical history and SCS were recorded. Chi square and Student’s t-test were used to determine factors associated with MS. Multivariate logistic regression was used to identify factors associated with MS. 155 patients were included. The mean age was 54.1 ± 13.1 years and the mean body mass index (BMI) was 28.3 ± 6.1 kg/m2. MS was present in 43.9% of patients. The mean SCS was 28,084 ± 14,006 Raman counts (RC), including 23,058 ± 9,812 RC for patients with MS and 32,011 ± 15,514 RC for patients without MS (p = 0.0001). In a multivariate analysis, SCS <25,000 RC (OR 3.71, 95% CI 1.36–10.7, p = 0.01) was independently associated with MS. A higher number of MS components was associated with a progressively lower SCS (p = 0.004). In a consecutive sample of patients referred for dietary assessment, a non-invasively measured skin carotenoid score was lower among patients with MS.
Alex’s Notes: The basic premise of this study is simple. Metabolic syndrome is characterized in part by excessive oxidative stress. Antioxidants reduce oxidative stress, and carotenoids are an important dietary source found in a wide-range of vegetables. Those who consume a diet enriched in carotenoids have a lower prevalence of MS. Thus, the authors hypothesize that,
“A skin carotenoid score (SCS), calculated non-invasively using RRS [Resonance Raman spectroscopy], would correlate with the presence or absence of MS.”
The study sample included a cohort of 155 patients with an average age and BMI of 54 years and 28 kg/m2, respectively, and 44% were male, 78% were Caucasian, 33% had a BMI greater than 30, 39% had impaired fasting glucose of type-2 diabetes, and 46% had hypertension. Additionally, 44% had MS defined as,
“three or more of the following at the time of SCS measurement: (1) BMI ≥30 kg/m2, (2) triglycerides ≥150 mg/dL or on medication for hypertriglylceridemia, (3) HDL-C <40 mg/dL in men or <50 mg/dL in women or on medication for low HDL-C, (4) systolic blood pressure ≥130 mmHg, diastolic blood pressure ≥85 mmHg or on antihypertensive medication, (5) fasting glucose ≥100 mg/dL, or on diabetic medications.”
The clinical procedure to determine SCS is beautifully simple, quick, and accurate. The authors state at least three times how this procedure could greatly benefit clinical practices. Using a Biophotonic Scanner, each patient underwent a single measurement of skin carotenoids from the palm of their hand. Blue laser light from the scanner excites the major carotenoids within the skin, scattering them within a narrow wavelength range (440-450 nm) that generates a peak absorbance signal used to calculate the SCS, reported in Raman counts (RC).
This was then analyzed against the metabolic parameters of the subjects, as well as self-reported vegetable and fruit intake (cutoff of >5 servings/day), exercise (cutoff at >3 hours/week), and alcohol, tobacco, and dietary supplement intakes. For both men and women, those with MS had roughly 28% lower SCS than those without MS, despite the groups not having any difference in vegetable and fruit intake or activity levels (although I would bet this is the result of self-reporting errors). The overall values for MS and no-MS were 23,000 RC and 32,000 RC, respectively, and having an SCS below 25,000 RC was associated with a 271% increased risk of MS. Finally, there was a significant trend for less SCS as the number of MS factors increased.
So based on this study, it seems prudent to eat your veggies. Just hope you don’t develop carotenemia like I have (at least twice) in the past, it isn’t fun.