Functional diversity of indigenous diets in coastal Papua New Guinea: Role in the nutrition transition and noncommunicable disease risk

Simplification of diets and reduced consumption of traditional foods and medicines play an important role in the increased prevalence of noncommunicable disease (NCD) in developing countries undergoing the nutrition transition. Empirical evidence on the consequences of reduced dietary diversity and exposure to functional dietary elements is sorely lacking in the literature. To address this, a food frequency and ethnomedical survey of 365 participants stratified according to age, gender and area of residence was conducted in coastal Papua New Guinea (PNG), and anthropometry, blood pressure and fasting blood glucose (FBG) recorded. Our results support the hypothesis that reduced food variety, especially in the fruits and vegetables group, is associated with increased obesity, hypertension and FBG, particularly in urban people. Application of the quantitative index for dietary diversity (QUANTIDD) showed that this was a superior indicator of nutrient adequacy and was more closely associated with reduced NCD risk. To test the effects of food functionality, a new compound indicator, the dietary functionality index (DFI) was developed. Application of the DFI to our population showed significant trends with improved health parameters, providing novel support for the functionality of indigenous foods towards health maintenance.;Our findings suggest that communities who consume more plants that possess antiatherogenic and/or antidiabetic functionality, which in itself is contingent on adequate dietary diversity, may be protected from NCD risk. This has important implications for public health policies aimed at reinforcing traditional food habits as a strategy to lessen the NCD burden that is usually associated with economic development.;From comparative ethnobotanical surveys, five plant species that were used in one community significantly more often than another were selected for laboratory analysis to assess whether differential consumption patterns might explain disparate rates of NCD. Crude extracts of betel quid (BQ), comprised of areca nut (AN; Areca catechu L.) and Piper betle L. inflorescence (PBI), guava bud (GB; Psidium guajava L.), noni (Morinda citrifolia L.) and mangrove bean (MB; Bruguiera gymnorrhiza (L.) Lam.) were tested for their ability to mediate glucose transport in cultured 3T3-L1 adipocytes, their antioxidant activity, their capacity to prevent Cu2+-catalyzed low density lipoprotein (LDL) oxidation or reduce the cytotoxicity of oxidized LDL (oxLDL) towards cultured bovine aorta endothelial cells (BAEC). Our results demonstrate that BQ and its constituents AN and PBI inhibit insulin action while GB and noni mimic or potentiate it, suggesting that consumption of the latter offsets the diabetogenicity of the former. Betel quid was also highly toxic towards BAEC and exacerbated oxLDL cytotoxicity, despite being a potent free radical scavenger. In contrast, GB and the root of noni (NR) were able to inhibit LDL oxidation and effectively protected BAEC.