RESUMEN
BACKGROUND: Safe and effective weight control strategies are needed to curtail the current obesity epidemic worldwide. Increasing dietary fibre has shown positive results with weight loss as well as in the reduction of metabolic syndrome risk factors. However, fibre can act as an inhibitor to the bioavailability of micronutrients in the gastrointestinal tract. While there is a substantial amount of scientific research into psyllium fibre, PolyGlycopleX (PGX®) is a novel fibre and as yet the effects of PGX® on micronutrient status is not well researched. AIM: To determine whether 3-months' supplementation with 15 g of psyllium or PGX® fibre daily affects micronutrient status of overweight and obese adults. METHODS: Overweight and obese individuals with a BMI between 25-40 kg/m2 and aged between 18 and 65 years, but otherwise healthy, were instructed to consume a 5 g sachet of psyllium, PGX® fibre or a rice flour placebo three times a day for 52 weeks as part of a larger long-term study. Blood sample data for the first 3 months were analysed for associations between serum micronutrient levels and psyllium fibre and/or PGX® supplements. RESULTS: No significant differences between fibre supplement groups and micronutrient status were found after 3 months at p > 0.05. Dietary intake of vitamin C was significantly lower for PGX® at 3 months compared to baseline and compared to control (p < 0.05). Folate was significantly lower in the control group after 3 months (p < 0.05). In the psyllium group, folate, sodium, zinc and magnesium intake decreased after 3 months (p < 0.05). A limitation of dietary intake data (tertiary measure) is the potential for inaccurate self-reporting, although reduced nutrient intake could be due to the satiating effect of dietary fibre. CONCLUSIONS: There were no significant between group differences in serum micronutrient concentrations after a 3-month psyllium fibre or PGX® supplementation intervention of 15 g per day. Fibre supplementation is unlikely to compromise the nutritional status of overweight and obese individuals in the short term. Further research is recommended to monitor micronutrient status over a longer period or with a higher fibre dosage.
RESUMEN
The persistent obesity crisis, with its increased risk for the metabolic syndrome (MetS), type 2 diabetes, and cardiovascular disease (CVD), continues to damage the health of populations globally, including children. Diets rich in the fiber provided by fruit and vegetables support good metabolic health, although few adults and children achieve the recommended daily target. Daily fiber supplementation, particularly with soluble fiber products, such as psyllium, oat bran, or a newer product such as PolyGlycopleX, may provide a convenient solution. Literature searches were conducted to identify original research articles, systematic reviews, and meta-analyses with the search terms psyllium, oat bran, PolyGlycopleX, and PGX, AND adults and children AND overweight, obesity, and metabolic syndrome. Data source was Embase and PubMed from 1980 to 2017. The results show that the addition of a soluble fiber product, most notably psyllium, improves blood lipid profiles, particularly total and low-density lipoprotein cholesterol, as well as glycemic response, and increases satiety, and by thus improving MetS and CVD risk factors, may augment the processes initiated by weight reduction diets. Although less studied than psyllium, the available evidence has shown that ß-glucan present in oat bran has a beneficial effect on MetS and CVD risk factors, particularly blood lipids and glycemia. Early research has found PolyGlycopleX to provide similar benefits to other soluble fiber products, and suggest it may also assist with weight loss. This critical review demonstrates that soluble fiber supplements used as an adjunct to dietary and lifestyle modifications may assist with the treatment of CVD and MetS risk factors. More research is needed to further clarify the benefits of PolyGlycopleX in particular, as well as to develop safe and efficacious recommendations for fiber supplementation of all types for children in general.