title: Vitamin D-rich marine Inuit diet and markers of inflammation - a population-based survey in Greenland.
abstract: The traditional Inuit diet in Greenland consists mainly of fish and marine mammals, rich in vitamin D. Vitamin D has anti-inflammatory capacity but markers of inflammation have been found to be high in Inuit living on a marine diet. Yet, the effect of vitamin D on inflammation in Inuit remains unsettled. This led us to investigate the association between vitamin D and markers of inflammation in a population with a high intake of a marine diet. We studied 535 Inuit and non-Inuit living in West and East Greenland. Information concerning dietary habits was obtained by interview-based FFQ. Blood samples were drawn for analysis of 25-hydroxyvitamin D, high-sensitivity C-reactive protein (hsCRP) and chitinase-3-like protein 1(YKL-40). Participants were divided into three groups based on degree of intake of the traditional Inuit diet. The diet groups (Inuit diet/mixed diet/imported foods) were associated with vitamin D levels in serum (74·2, 69·8 and 52·9 nm; P < 0·001), hsCRP (1·6, 1·4 and 1·3 mg/l; P = 0·002) and YKL-40 (130, 95 and 61 ng/ml; P < 0·001), respectively. YKL-40 level decreased with rising vitamin D level in Inuit (Inuit diet P = 0·002; mixed diet P = 0·011). YKL-40 was lower in groups with higher vitamin D levels after adjusting for other factors known to influence inflammation (P < 0·001). This was not seen for hsCRP. In conclusion, vitamin D and markers of inflammation vary in parallel with the intake of the marine Inuit diet. Vitamin D levels were inversely associated with YKL-40 levels, but no association with hsCRP was found. The hypothesised anti-inflammatory effect of vitamin D was not supported. Other factors in the marine diet may be speculated to influence inflammation.
authors.affiliation: Department of Public Health, Centre for Arctic Health, Aarhus University, Aarhus, Denmark; Department of Clinical Medicine, Arctic Health Research Centre, Aalborg University, Aalborg, Denmark; Endocrine Research Unit, Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: L K
authors.initials: LK
authors.lastname: Schæbel
authors.affiliation: Department of Public Health , Centre for Arctic Health , Aarhus University , Aarhus , Denmark.
authors.forename: E C
authors.initials: EC
authors.lastname: Bonefeld-Jørgensen
authors.affiliation: Endocrine Research Unit , Department of Clinical Medicine , Aalborg University , Aalborg , Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Laurberg
authors.affiliation: The Novo Nordisk Foundation Center for Basic Metabolic Research , Section of Metabolic Genetics , Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark.
authors.forename: H
authors.initials: H
authors.lastname: Vestergaard
authors.affiliation: Department of Clinical Medicine, Arctic Health Research Centre, Aalborg University, Aalborg, Denmark; Department of Geriatric and Internal Medicine, Aalborg University Hospital, Aalborg, Denmark; Department of Internal Medicine, Queen Ingrid's Hospital, Nuuk, Greenland.
authors.forename: S
authors.initials: S
authors.lastname: Andersen
keywords: Arctic Greenland; CRP, C-reactive protein; Dietary surveys and nutritional epidemiology; Inflammation; Inuit marine diet; POPs, persistent organic pollutants; Population-based studies; Vitamin D; YKL-40, chitinase-3-like protein 1; hsCRP, high-sensitivity CRP