Research Category: Cardiometabolic Health
Effect of potatoes as part of the DASH diet on blood pressure in individuals with and without type 2 diabetes: A randomized controlled trial
This randomized controlled trial evaluated different cooking methods of potatoes as part of the DASH diet on blood pressure (BP) and anthropometrics in people with and without type 2 diabetes (T2D). Participants were randomized into DASH-FP (fried potatoes), DASH-NFP (non-fried potatoes) or DASH-NP (no potatoes) groups. BP, weight, waist circumference and body composition were measured.
Change outcomes from baseline to 6 weeks showed no significant difference in the study outcomes, including diastolic BP (p = 0.12), systolic BP (p = 0.26), body weight (p = 0.11), waist circumference (p = 0.86) and body composition (p = 0.57) within study groups. A significant group T2D status interaction was found for waist circumference (p = 0.036). Results from pairwise comparisons between the groups for all outcomes were not significant; however, a positive trend was seen in DASH-NFP and DASH-FP diet groups in BP and anthropometrics.
Individuals with and without T2D that consumed potatoes and the DASH diet did not significantly change BP and anthropometrics by six weeks. Slight improvements in BP and anthropometrics were seen in non-fried and fried potato groups. This helps future investigations of popular foods for people with chronic conditions that can be incorporated in a healthy eating pattern.
Low-Energy Dense Potato- and Bean-Based Diets Reduce Body Weight and Insulin Resistance: A Randomized, Feeding, Equivalence Trial
We evaluated the effect of diets low in energy density (1 kcal/g) and high in either potatoes (Potato) or pulses (Bean) on blood glucose control in participants with insulin resistance. We hypothesized that the Potato and Bean diets would have equivalent effects. This was an 8-week randomized, parallel design, controlled feeding study comparing Potato and Bean diets (50–55% carbohydrate, 30–35% fat, 15–20% protein). Equivalence was prespecified as the mean change in the blood glucose concentration for Potato that was within ±20% of the Bean diet. Thirty-six participants (age: 18–60 years, body mass index: 25–40 kg/m2) with insulin resistance (homeostatic model assessment of insulin resistance [HOMA-IR] >2) were enrolled. Body weight was measured, and subjects underwent a mixed meal tolerance test at baseline and after 8 weeks. Intent-to-treat (ITT) and completer analyses were conducted. Equivalence between the two diets in the area under the curve for serum glucose was attained within ±10%, but the reduction from baseline was not statistically significant. For the Bean diet, insulin (area under the response curve: −2136.3 ± 955.5 mg/[dL∙min], P = .03) and HOMA-IR (−1.4 ± 0.6, P = .02) were lower compared with baseline. ITT and completer analyses were similar, except that HOMA-IR was also reduced by the Potato diet (−1.3 ± 0.6, P < .05). Compliance with the diets was 87–88%, and body weight was reduced in both diets (Potato: −5.6% ± 0.6%; Bean: −4.1% ± 0.6%, P < .001) with no significant difference between the two diets. Potato and Bean diets low in energy density were equally effective in reducing insulin resistance and promoting weight loss in individuals with impaired blood glucose control.
Potato consumption is not associated with cardiometabolic health outcomes in Framingham Offspring Study adults
Some consider potatoes to be unhealthy vegetables that may contribute to adverse cardiometabolic health outcomes. We evaluated the association between potato consumption (including fried and non-fried types) and three key cardiometabolic outcomes among middle-aged and older adults in the Framingham Offspring Study. We included 2523 subjects ≥30 years of age with available dietary data from 3-d food records. Cox-proportional hazards models were used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for hypertension, type 2 diabetes or impaired fasting glucose (T2DM/IFG), and elevated triglycerides, adjusting for anthropometric, demographic and lifestyle factors. In the present study, 36 % of potatoes consumed were baked, 28 % fried, 14 % mashed, 9 % boiled and the rest cooked in other ways. Overall, higher total potato intake (≥4 v. <1 cup-equivalents/week) was not associated with risks of T2DM/IFG (HR 0⋅97, 95 % CI 0⋅81, 1⋅15), hypertension (HR 0⋅95; 95 % CI 0⋅80, 1⋅12) or elevated triglycerides (HR 0⋅99, 95 % CI 0⋅86, 1⋅13). Stratified analyses were used to evaluate effect modification by physical activity levels and red meat consumption, and in those analyses, there were no adverse effects of potato intake. However, when combined with higher levels of physical activity, greater consumption of fried potatoes was associated with a 24 % lower risk (95 % CI 0⋅60, 0⋅96) of T2DM/IFG, and in combination with lower red meat consumption, higher fried potato intake was associated with a 26 % lower risk (95 % CI 0⋅56, 0⋅99) of elevated triglycerides. In this prospective cohort, there was no adverse association between fried or non-fried potato consumption and risks of T2DM/IFG, hypertension or elevated triglycerides.
French-fried potatoes consumption and energy balance: a randomized controlled trial
Background
Epidemiologic observations suggest increased potato consumption correlates with weight gain, adiposity, and diabetes risk, while nut consumption is associated with weight control and metabolic health. Randomized controlled trial (RCT) data indicate humans respond to changes in energy intake in single dietary components and compensate for extra energy consumed.
Potato Consumption is not Associated With Elevated Cardiometabolic Risk in Adolescent Girls
We examined the association between potato consumption in two different age periods during adolescence and risk of obesity and cardiometabolic dysfunction in White and Black girls. We used data from the biracial prospective National Growth and Health Study. Average potato consumption was derived from multiple 3-d food records in two age periods, 9–11 and 9–17 years, and included white and sweet potatoes from all sources. Multivariable logistic regression models were used to estimate OR for becoming overweight, developing prehypertension, elevated TAG levels or impaired fasting glucose (IFG) at 18–20 years of age according to the category of daily potato intake. We also stratified by cooking method (fried/non-fried) and race. ANCOVA was also used to estimate adjusted mean levels of BMI, systolic blood pressure, diastolic blood pressure, log-transformed TAG, the TAG:HDL ratio and fasting glucose levels associated with potato intake category. Higher potato consumption was associated with higher fruit and non-starchy vegetable intakes and higher Healthy Eating Index scores in Black girls. There were no statistically significant associations overall between moderate or higher (v. lower) intakes of potatoes and risks of overweight, prehypertension, elevated fasting TAG, high TAG:HDL ratio or IFG. Also, no adverse associations were found between fried or non-fried potato intake and cardiometabolic outcomes. Potato consumption has been the subject of much controversy in recent years. This study adds evidence that potato consumption among healthy girls during the critical period of adolescence was not associated with cardiometabolic risk.
Frequency of Boiled Potato Consumption and All-Cause and Cardiovascular Disease Mortality in the Prospective Population-Based HUNT Study
Few studies have assessed the association between potato consumption and mortality, especially cardiovascular disease (CVD) mortality. Our objective was to investigate the association between consumption of boiled potatoes and all-cause and CVD mortality in a Norwegian population. We used data from the population based HUNT3 study in Norway, with data on boiled potato consumption frequency in 2006-2008 from 49,926 males and females aged 20 years or above. All-cause and CVD mortality were identified during 10 years follow-up through the national Cause of Death Registry, which is virtually complete. We used Cox regression to estimate hazard ratio (HR) with a 95% confidence interval (CI) for death controlling for potential confounders, and conducted additional analyses stratified by sex, body mass index (BMI) ±25 kg/m2, and age ±65 years. There were 4,084 deaths and 1,284 of these were due to CVD. Frequency of boiled potato consumption was not associated with all-cause mortality, nor with CVD mortality. Compared to those individuals who consumed boiled potatoes less than once weekly, those who reported to consume boiled potatoes 1-3 times per week had an adjusted HR (95% CI) of 1.12 (0.89, 1.41) for all-cause mortality and 1.20 (0.78, 1.86) for CVD mortality. Individuals who consumed boiled potatoes 4-6 times per week had HRs of 0.97 (0.78, 1.21) and 1.03 (0.68, 1.55), for all-cause and CVD mortality, respectively, whereas those who consumed boiled potatoes more than once daily had HRs of 1.04 (0.83, 1.29) and 1.09 (0.73, 1.63) for all-cause and CVD mortality, respectively. There was no evidence of differential associations for males vs. females, nor between people with BMI ± 25 kg/m2. The associations between frequency of boiled potato consumption and all-cause mortality showed different patterns between those younger vs. older than 65 years, with a tendency of increased risk only in the oldest age group. In conclusion, frequency of consumption of boiled potatoes was not associated with all-cause or CVD mortality in the HUNT population in Norway.
Short-Term RCT of Increased Dietary Potassium from Potato or Potassium Gluconate: Effect on Blood Pressure, Microcirculation, and Potassium and Sodium Retention in Pre-Hypertensive-to-Hypertensive Adults
Increased potassium intake has been linked to improvements in cardiovascular and other health outcomes. We assessed increasing potassium intake through food or supplements as part of a controlled diet on blood pressure (BP), microcirculation (endothelial function), and potassium and sodium retention in thirty pre-hypertensive-to-hypertensive men and women. Participants were randomly assigned to a sequence of four 17-day dietary potassium treatments: a basal diet (control) of 60 mmol/d and three phases of 85 mmol/d added as potatoes, French fries, or a potassium gluconate supplement. Blood pressure was measured by manual auscultation, cutaneous microvascular and endothelial function by thermal hyperemia, utilizing laser Doppler flowmetry, and mineral retention by metabolic balance. There were no significant differences among treatments for end-of-treatment BP, change in BP over time, or endothelial function using a mixed-model ANOVA. However, there was a greater change in systolic blood pressure (SBP) over time by feeding baked/boiled potatoes compared with control (−6.0 mmHg vs. −2.6 mmHg; p = 0.011) using contrast analysis. Potassium retention was highest with supplements. Individuals with a higher cardiometabolic risk may benefit by increasing potassium intake.
Potato Consumption and Risk of Cardio-Metabolic Diseases: Evidence Mapping of Observational Studies
Background: Recent systematic review of clinical trials concluded that there was no convincing evidence to suggest an association between potatoes and risk of cardio-metabolic diseases. Objective: Summarize observational study data related to potato intake and cardio-metabolic health outcomes in adults using evidence mapping to assess the need for a future systematic review. Methods: We searched MEDLINE®, Commonwealth Agricultural Bureau, and bibliographies for eligible observational studies published between 1946 and July 2020. Included studies evaluated potato intake in any form or as part of a dietary pattern with risk for cardio-metabolic diseases. Outcomes of interest included cardiovascular disease (CVD), cerebrovascular diseases, diabetes, hypertension, blood lipids, and body composition. Results: Of 121 eligible studies, 51 reported two different methods to quantify potato intake (30 studies quantified intake as either grams or serving; 20 studies reported times per week; one reported both methods) and 70 reported potato as part of a dietary pattern and compared higher vs. lower intake, linear change, or difference in potato intake among cases and controls. Studies that quantified potato intake as either grams or serving reported the following outcomes: diabetes (8 studies); cerebrovascular stroke (6 studies); five studies each for CVD, systolic and diastolic blood pressure, and hypertension; three studies each for body mass index, body weight, CVD mortality; two studies for myocardial infarction; and one study each for blood glucose, HOMA-IR, and blood lipids. Higher potato intake was associated with an increased risk for blood pressure and body weight, and the results of all other outcomes observed no association. Potato consumption as part of dietary pattern studies reported a negative association between fried form of potato and all or most cardio-metabolic risk factors and diseases. Conclusion: Evidence mapping found sufficient data on the association between potato intake and cardio-metabolic disease risk factors to warrant for a systematic review/meta-analysis of observational studies.
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
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.