Funding: This work was supported by the Southeast Norway Regional Health Authority, the Norwegian Cancer Society and Oslo University Hospital.
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Noon Best Time to Get Vitamin D From Sun for Minimal Cancer Risk
Article first published online: 6 NOV 2015
DOI: 10.1111/ijd.13065
© 2015 The International Society of Dermatology
Issue
International Journal of Dermatology
Early View (Online Version of Record published before inclusion in an issue)
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Conflicts of interest: None.
Abstract
Background
Solar ultraviolet (UV) radiation varies with latitude, time of day, and season. Both spectral UV composition and ambient UV dose lead to different health outcomes at different latitudes. Finding the optimal time for sun exposure, whereby the positive effects of UV exposure (vitamin D) are facilitated and the negative effects (skin cancer, photoimmunosuppression) avoided are the most important consideration in modern skin cancer prevention programs.
Objectives
This paper focuses on the latitude dependency of UVB, UVA, vitamin D production, and skin cancer risk in Caucasians.
Methods
Biologically effective UVB (280–315 nm) and UVA (315–400 nm) doses were calculated using radiative transfer models with appropriate climatologic data for selected locations. Incidences of squamous cell carcinoma (SCC) and cutaneous melanoma (CM) were retrieved from cancer registries and published articles.
Results
Annual doses of UVA radiation decrease much less with increasing latitude than annual doses of UVB. Incidences of CM also decrease less steeply with increasing latitude than incidences of SCC. As SCC is caused mainly by UVB, these observations support the assumption that UVA plays an important role in the development of CM. The variations in UVA (relevant to CM) and UVB (relevant to vitamin D production) over 1 day differ: the UVB : UVA ratio is maximal at noon.
Conclusions
The best way to obtain a given dose of vitamin D with minimal carcinogenic risk is through a non-burning exposure in the middle of the day, rather than in the afternoon or morning.
Healthy Diets Modulate Gut Microbes and Improve Insulin Sensitivity in the Obese
Abstract
This abstract is available on the publisher’s site.
CONTEXT
Gut microbiota, which acts collectively as a fully-integrated organ in the host metabolism, can be shaped by long-term dietary interventions following a specific diet.
OBJECTIVE
To study the changes in microbiota after one year’s consumption of a Mediterranean diet (Med diet) or a low-fat, high-complex carbohydrates diet (LFHCC diet) in an obese population.
DESIGN
Participant swere randomized to receive Med diet (35% fat, 22% monounsaturated) and LFHCC diet (28% fat, 12% monounsaturated).
SETTING AND PARTICIPANTS
The study was conducted in 20 obese patients (men) within the CORDIOPREV study, an ongoing prospective, randomized, opened, controlled trial in patients with coronary heart disease.
MAIN OUTCOME MEASURE
We evaluated the bacterial composition and its relationship with the whole fecal and plasma metabolome.
RESULTS
The LFHCC diet increased Prevotella and decreased the Roseburia genera while the Med diet decreased Prevotella and increased the Roseburia and Oscillospira genera (P=0.028, 0.002, and 0.016, respectively). The abundance of Parabacteroides distasonis (P=0.025) and Faecalibactrium prausnitzii (P=0.020) increased after the long-term consumption of the Med diet and LFHCC diet, respectively. The changes in the abundance of 7 out of 572 metabolites found in feces, including mainly aminoacids, peptides and the sphingolipid metabolism, could be linked to the changes in the gut microbiota.
CONCLUSIONS
Our results suggest that a long-term consumption of the Med and LFHCC diets, exert a protective effect on the development of type 2 diabetes by different specific changes in the gut microbiota, increasing the abundance of the Roseburia genus and Faecalibacterium prausnitzii, respectively.
Mediterranean Diet and Brain Structure in the Elderly
TAKE-HOME MESSAGE
- High-resolution structural MRI scanning was completed in a cohort of 674 elderly multiethnic people (mean age, 80.1 years) with no history of dementia. Participants completed a food frequency questionnaire to determine adherence to a Mediterranean-type diet (MeDi). Those who showed higher adherence to a MeDi had a larger total brain volume (TBV), total gray matter volume (TGMV), and total white matter volume compared with people who showed a lower adherence to a MeDi. There was an association seen between higher fish and lower meat intake and larger TGMV as well as lower meat intake and larger TBV. Higher fish intake also showed an association with increased mean cortical thickness.
- MeDi adherence in the elderly is associated with significantly less brain atrophy. The key elements of the MeDi appear to be a higher fish intake combined with a lower meat intake.
OBJECTIVE
To determine whether higher adherence to a Mediterranean-type diet (MeDi) is related with larger MRI-measured brain volume or cortical thickness.
METHODS
In this cross-sectional study, high-resolution structural MRI was collected on 674 elderly (mean age 80.1 years) adults without dementia who participated in a community-based, multiethnic cohort. Dietary information was collected via a food frequency questionnaire. Total brain volume (TBV), total gray matter volume (TGMV), total white matter volume (TWMV), mean cortical thickness (mCT), and regional volume or CT were derived from MRI scans using FreeSurfer program. We examined the association of MeDi (scored as 0–9) and individual food groups with brain volume and thickness using regression models adjusted for age, sex, ethnicity, education, body mass index, diabetes, and cognition.
RESULTS
Compared to lower MeDi adherence (0–4), higher adherence (5–9) was associated with 13.11 (p = 0.007), 5.00 (p = 0.05), and 6.41 (p = 0.05) milliliter larger TBV, TGMV, and TWMV, respectively. Higher fish (b = 7.06, p = 0.006) and lower meat (b = 8.42, p = 0.002) intakes were associated with larger TGMV. Lower meat intake was also associated with larger TBV (b = 12.20, p = 0.02). Higher fish intake was associated with 0.019 mm (p = 0.03) larger mCT. Volumes of cingulate cortex, parietal lobe, temporal lobe, and hippocampus and CT of the superior-frontal region were associated with the dietary factors.
CONCLUSIONS
Among older adults, MeDi adherence was associated with less brain atrophy, with an effect similar to 5 years of aging. Higher fish and lower meat intake might be the 2 key food elements that contribute to the benefits of MeDi on brain structure.