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Abstract

The intake of certain types of resistant starch (RS) has been associated in some studies with increased whole‐body insulin sensitivity. This randomised, cross‐over pilot trial evaluated the effect of consuming cooked, then chilled potatoes, a source of RS, compared to isoenergetic, carbohydrate (CHO)‐containing control foods, on insulin sensitivity and related markers. Nineteen adults with body mass index 27.0‐39.9 kg m−2 consumed 300 g day−1 RS‐enriched potatoes (approximately two potatoes; ~18 g RS) or CHO‐based control foods, as part of lunch, evening and snack meals, over a 24‐h period. After an overnight fast, insulin sensitivity, CHO metabolism markers, free fatty acids, breath hydrogen levels and appetite were assessed for up to 5 h after the intake of a standard breakfast. The primary endpoint was insulin sensitivity, assessed with the Matsuda index. P < 0.05 (one‐sided) was considered statistically significant. Insulin sensitivity was not significantly different between the potato and control conditions. The potato intervention resulted in higher postprandial breath hydrogen (P = 0.037), lower postprandial free fatty acid concentrations (P = 0.039) and lower fasting plasma glucose (P = 0.043) compared to the control condition. Fullness ratings were significantly lower after potato versus control (P = 0.002). No other significant effects were observed; however, there was a trend toward lower fasting insulin (P = 0.077) in the potato versus the control condition. The results of this pilot study suggest RS‐enriched potatoes may have a favourable impact on carbohydrate metabolism and support the view that additional research in a larger study sample is warranted.

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References

  1. Sanders LM, Dicklin MR, Palacios OM, Maki CE, Wilcox ML, Maki KC. Effects of potato resistant starch intake on insulin sensitivity, related metabolic markers and appetite ratings in men and women at risk for type 2 diabetes: a pilot cross‐over randomised controlled trial. J Hum Nutr. 2020. doi: 10.1111/jhn.12822.
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Abstract

The terms “high- and low-quality carbohydrate” are often ascribed to individual foods as a means of describing the healthfulness of the food in question, without any empirical definition of what constitutes high or low quality. This article summarizes the views of experts on the concept of carbohydrate quality and the numerous factors that should be considered when assessing the quality of a carbohydrate-containing food or meal.

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References

  1. Kanter, M. (2019). High Quality Carbohydrates: A Concept in Search of a Definition. Nutrition Today. doi:10.1097/NT.0000000000000377
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Abstract

(1) High-fat (HF) diet leads to gut microbiota dysbiosis which is associated with systemic inflammation. Bacterial-driven inflammation is sufficient to alter vagally mediated satiety and induce hyperphagia. Promoting bacterial fermentation improves gastrointestinal (GI) epithelial barrier function and reduces inflammation. Resistant starch escape digestion and can be fermented by bacteria in the distal gut. Therefore, we hypothesized that potato RS supplementation in HF-fed rats would lead to compositional changes in microbiota composition associated with improved inflammatory status and vagal signaling. (2) Male Wistar rats (n = 8/group) were fed a low-fat chow (LF, 13% fat), HF (45% fat), or an isocaloric HF supplemented with 12% potato RS (HFRS) diet. (3) The HFRS-fed rats consumed significantly less energy than HF animals throughout the experiment. Systemic inflammation and glucose homeostasis were improved in the HFRS compared to HF rats. Cholecystokinin-induced satiety was abolished in HF-fed rats and restored in HFRS rats. HF feeding led to a significant decrease in positive c fiber staining in the brainstem which was averted by RS supplementation. (4) The RS supplementation prevented dysbiosis and systemic inflammation. Additionally, microbiota manipulation via dietary potato RS prevented HF-diet-induced reorganization of vagal afferent fibers, loss in CCK-induced satiety, and hyperphagia.

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References

  1. Klingbeil, E.A., Cawthon, C., Kirkland, R., de La Serre, C.B. (2019) Potato-Resistant Starch Supplementation Improves Microbiota Dysbiosis, Inflammation, and Gut-Brain Signaling in High Fat-Fed Rats. Nutrients. doi:10.3390/nu11112710
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Abstract

Carbohydrate (CHO) ingestion is an established strategy to improve endurance performance. Race fuels should not only sustain performance, but also be readily digested and absorbed. Potatoes are a whole-food based option that fulfills these criteria yet their impact on performance remains unexamined. We investigated the effects of potato purée ingestion during prolonged cycling on subsequent performance versus commercial CHO gel or a water-only condition. Twelve cyclists (70.7 ± 7.7 kg, 173 ± 8 cm, 31± 9 years, 22 ± 5.1 % body fat; mean ± SD) with average peak oxygen consumption (VO2PEAK)of 60.7 ± 9.0 mL/kg/min performed a 2 h cycling challenge (60-85%VO2PEAK) followed by a time trial (TT, 6kJ/kg body mass) while consuming potato, gel, or water in a randomized-crossover design. The race fuels were administered with U-[13C6]glucose for an indirect estimate of gastric emptying rate. Blood samples were collected throughout the trials. Blood glucose concentrations were higher (P<0.001) in potato and gel conditions when compared to water condition. Blood lactate concentrations were higher (P=0.001) after the TT completion in both CHO conditions when compared to water condition. TT performance was improved (P=0.032) in both potato (33.0 ± 4.5 min) and gel (33.0 ± 4.2 min) conditions when compared to the water condition (39.5 ± 7.9 min). Moreover, no difference was observed in TT performance between CHO conditions (P=1.00). In conclusion, potato and gel ingestion equally sustained blood glucose concentrations and TT performance. Our results support the effective use of potatoes to support race performance for trained cyclists.

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References

  1. Salvador, A.F., McKenna, C.F., Alamilla, R.A., Cloud, R.M.T., Keeble, A.R., Miltko, A., Scaroni, S.E., Beals, J.W., Ulanov, A.V., Dilger, R.N., Bauer, L.L., Broad, E.M., Burd, N.A. (2019). Potato ingestion is as effective as carbohydrate gels to support prolonged cycling performance. Journal of Applied Physiology. doi:10.1152/japplphysiol.00567.2019
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Abstract

Resistant starch (RS) has been shown to improve postprandial glycemia and insulin sensitivity in adults with metabolic syndrome. RS is found naturally in potatoes, where the amount varies based on cooking method and serving temperature. Thirty females with a mean BMI of 32.8 ± 3.7 kg/m2, fasting glucose of 110.5 mg/dL, and insulin of 10.3 µIU/L, completed this randomized, crossover study. A quantity of 250 g of boiled (low RS) and baked then chilled (high RS) russet potatoes were consumed on two separate occasions. Glycemic (glucose and insulin) and incretin response, subjective satiety, and dietary intake were measured. Results showed that the chilled potato elicited significant reductions at 15 and 30 min in glucose (4.8% and 9.2%), insulin (25.8% and 22.6%), and glucose-dependent insulinotropic peptide (GIP) (41.1% and 37.6%), respectively. The area under the curve for insulin and GIP were significantly lower after the chilled potato, but no differences were seen in glucose, glucagon-like peptide-1, and peptide YY, or overall subjective satiety. A higher carbohydrate and glycemic index but lower fat diet was consumed 48-hours following the chilled potato than the boiled potato. This study demonstrates that consuming chilled potatoes higher in RS can positively impact the glycemic response in females with elevated fasting glucose and insulin.

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References

  1. Patterson MA, Fong JN, Maiya M, Kung S, Sarkissian A, Nashef N, Wang W. Chilled Potatoes Decrease Postprandial Glucose, Insulin, and Glucose-dependent Insulinotropic Peptide Compared to Boiled Potatoes in Females with Elevated Fasting Glucose and Insulin. Nutrients. 2019; 11(9):2066, doi:10.3390/nu11092066.
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Abstract

The white potato is a concentrated source of carbohydrate, dietary fiber, and resistant starch and continues to be the staple food of choice for many cultures. The white potato is also a concentrated source of vitamin C and potassium. Two of the nutrients in white potatoes, dietary fiber and potassium, have been designated as nutrients of concern in the 2010 Dietary Guidelines for Americans. Potatoes are often maligned in nutrition circles because of their suspected link to obesity, and popular potato foods often contain more fat calories than carbohydrate calories. Some food guides do not include potatoes in the vegetable group because of their association with high-fat diets. However, potatoes should be included in the vegetable group because they contribute critical nutrients. All white vegetables, including white potatoes, provide nutrients needed in the diet and deserve a prominent position in food guides.

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References

  1. Janet C. King, Joanne L. Slavin, White Potatoes, Human Health, and Dietary Guidance, Advances in Nutrition, Volume 4, Issue 3, May 2013, Pages 393S–401S, https://doi.org/10.3945/an.112.003525
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Abstract

Vegetables are universally promoted as healthy. Dietary Guidelines for Americans 2010 recommend that you make half of your plate fruits and vegetables. Vegetables are diverse plants that vary greatly in energy content and nutrients. Vegetables supply carbohydrates, dietary fiber, and resistant starch in the diet, all of which have been linked to positive health outcomes. Fiber lowers the incidence of cardiovascular disease and obesity. In this paper, the important role of white vegetables in the human diet is described, with a focus on the dietary fiber and resistant starch content of white vegetables. Misguided efforts to reduce consumption of white vegetables will lower intakes of dietary fiber and resistant starch, nutrients already in short supply in our diets.

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References

  1. Joanne L. Slavin, Carbohydrates, Dietary Fiber, and Resistant Starch in White Vegetables: Links to Health Outcomes, Advances in Nutrition, Volume 4, Issue 3, May 2013, Pages 351S–355S, https://doi.org/10.3945/an.112.003491
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Abstract

Potatoes are rich in phenolic compounds which have been reported to impact starch digestion and intestinal glucose transport in model systems through phenolic-starch interactions. While these effects are well documented for pigmented potatoes and in model systems, the relevance of phenolics to the glycemic properties of processed colorless potato-based foods under naturalistic conditions remains unclear. This study assessed impacts of processing on phenolic concentrations, resistant starch content and glycemic properties of Russet Burbank and Shepody potatoes. Product forms included French fries, shredded (hash browns) and diced (home fries) produced through commercial processing as well as parallel in-home techniques. Commercial products had significantly higher concentrations of resistant starch (p < 0.05, 1.48-6.57 vs. 1.23-2.22 g/100 fresh weight, FW) and resistant starch/total starch ratio (5.42-18.3 % vs. 3.58-7.62 %) compared to freshly prepared counterparts, while statistically lower total caffeoylquinic acid content (2.94-10.9 vs. 11.5-25.2 mg/100 FW). Glucose release and intestinal transport assessed using an in vitro digestion/Caco-2 cell monolayers model demonstrated a reduction in d7-glucose intestinal transport from commercially processed products relative to fresh prepared counterparts (p < 0.05, 31.3-61.2 % vs. 79.3-110 % at 60 min). Commercial Russet Burbank potato products including French fries, home fries and hash browns were then selected for clinical assessment of glycemic response and appetite rating by 23 participants (11 male and 12 female). The three products presented a subtle but discernable ascending trend (French fry ≥ home fry ≥ hash browns) for incremental area under the curve (IAUC, 95.2 ± 12 vs. 105 ± 10 vs. 107 ± 14 mM•min, p < 0.05) at 2 h post breakfast and for appetite rating (45.2 ± 6.3 vs. 52.4 ± 4.1 vs. 57.7 ± 7.2 for hunger) at 4 h post breakfast with no significant difference from the control (whole wheat pancake). These results suggest that potato phenolics have only a modest influence on acute glycemic responses.

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References

  1. Li M, George J, Hunter S, Hamaker BR, Mattes R, Ferruzzi MG. Potato product form impacts in vitro starch digestibility and glucose transport but only modestly impacts 24h blood glucose response in humans. Food Funct. 2019; 10:1846-1855. doi:10.1039/C8FO02530D.
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Abstract

Dietary carbohydrates have been shown to influence cognitive performance and satiety in children. However, it remains unclear whether the carbohydrate source is a primary determinant of cognitive performance and satiety. The objective was to compare the effects of white potatoes and other carbohydrate-containing foods on cognitive performance, glycemic response, and satiety in children. On six separate mornings, in random order, children (n=22) consumed 50 g of available carbohydrates from microwaved mashed potatoes (prepared from fresh potatoes then frozen), deep-fried potato strips (French fries), hash browns, white rice, white beans, or skipped a meal. Cognitive performance, glycemic response and satiety were measured over 180 min. Cognitive performance was measured using a battery of tests assessing verbal declarative memory, spatial memory, short-term memory, working memory, and information processing speed. Although cognitive performance after the treatment meals did not differ from meal skipping, children recalled more words after French fries (9.1±0.4 words) compared with mashed potatoes (8.2±0.3 words; p<0.001) and white rice (8.4±0.3 words; p=0.04) on the verbal declarative memory test. Blood glucose concentrations were higher after white rice compared with white beans, mashed potatoes, and hash browns (p<0.05). Change from baseline subjective average appetite (mm/kcal) was lowest after mashed potatoes compared with all other treatment meals (p<0.05). In conclusion, verbal declarative memory was higher after French fries and subjective average appetite was lowest after mashed potatoes. Future longitudinal studies are needed to confirm these short-term findings and to elucidate the mechanism of action.

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References

  1. Lee. J. J., Brett, N. R., Wong, V. C., Zepetnek, J. O., Fiocco, A. J., & Bellissimo, N. Effects of Potatoes and Other Carbohydrate-Containing Foods on Cognitive Performance, Glycemic Response, and Satiety in Children. Appl Physiol Nutr Metab. 2019.
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Abstract

Health professionals universally agree on the importance of a balanced diet, and the fallacy of relying on any one or two food groups, as the means of achieving peak physical performance and health. A review of the existing sports nutrition literature indicates that different types of athletes and physically active people may have slightly different nutritional requirements, but the main tenets of sports nutrition have not changed much over the last 25 years. The specific combinations may vary, but carbohydrates, protein, and fluids are vital components of an active individual’s diet. Further, most available research supports the notion that optimal physical performance requires carbohydrate – and, specifically, high-quality, nutrient-dense carbohydrate from whole food sources, like potatoes. High- quality carbohydrate sources – foods that offer an array of macro- and micronutrients as well as energy, can help to build a strong nutritional foundation for the level of training, recovery, and adaptation that most physically active people seek to achieve. Low carbohydrate diets will not generally allow athletes to train at the intensity required to attain peak physical performance.

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References

  1. Kanter M, Elkin C. Potato as a Source of Nutrition for Physical Performance. Am J Potato Res. 2019; 96:201. doi:10.1007/s12230-018-09701-8.
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