Author: Sherry Watkins

November 28, 2023

Study shows serving kid-friendly forms of potatoes with other vegetables in a cafeteria setting increases overall vegetable intake.

A new study published in Nutrients illustrates how potatoes may play a beneficial role in encouraging school aged children to eat more vegetables. The Dietary Guidelines for Americans currently recommends children ages 3-18 consume between 2.5-3 cups of vegetables per day to meet their total vegetable goals. Yet, the average school-age child eats only about 1 cup daily. “That’s why we wanted to learn more about how school meal offerings may influence kids’ eating behavior and possibly encourage greater vegetable consumption,” explains principal investigator Gene Ahlborn, PhD, Associate Professor, Department of Nutrition, Dietetics and Food Science, Brigham Young University.

The study found children ate more total vegetables when peas and carrots were served in combination with potato shaped smiley faces, suggesting that pairing kid-friendly forms of potatoes with other vegetables can promote greater overall vegetable consumption. Potato shaped faces are a potato product in the shape of happy faces, made with mashed potatoes and sunflower oil to create a slightly crunchy exterior and soft interior.

“Getting kids to eat their vegetables is always a challenge,” Ahlborn says. “Potatoes not only add nutrients, like potassium, directly to the plate, but they may also help encourage kids to explore other veggies that they’re served alongside and thereby help them get closer to their overall nutrition needs.”

Through controlled mealtime observation, the research team evaluated how different potato presentations and preparation styles impacted the amount of vegetables school-age children consumed in a cafeteria setting. While seasoned potatoes proved to be less appealing to the 7-13 year-old participants, and the potato shaped faces served separately from the peas and carrots did not encourage greater total vegetable consumption, meals in which potato shaped faces were served with the peas and carrots in the same bowl led to a measurable increase in total vegetables eaten.

Ahlborn and colleagues also found that serving potato shaped faces in a cafeteria setting led to reduced vegetable plate waste compared to the control meal. “This underscores the wide-reaching impacts of school menus. We want vegetables on school lunch trays to fuel kids’ bodies – not fill the trash can,” Ahlborn adds.

Considered together, these findings suggest serving kid-friendly preparations of potatoes with other vegetables could lead to cumulative benefits not only to students’ dietary patterns, but school cafeterias’ food waste reduction efforts.

These results align with other research findings showing that adolescents who consume potatoes are more likely to have higher diet quality, nutrient intake, and adequacy; therefore, encouraging potato consumption may be a sound strategy to improve nutritional status.¹

Study Details

Study Design

Dr. Ahlborn studied children’s dietary behaviors and consumption patterns during a series of mealtimes that took place within a controlled, simulated environment designed to mimic a school cafeteria. During each session, children were given a base meal that consisted of 2% milk, chicken nuggets, ketchup and applesauce, along with the experimental meal component (which reflected different presentations and preparations of mixed peas and carrots). Researchers weighed the food pre- and post-meal to assess plate waste and also analyzed total vegetable consumption.

The experimental meal component came in five variations of mixed peas and carrots (MPACs) including:

1. MPACs and a whole-wheat bread roll served separately (control condition)
2. MPACs and potato shaped faces served in separate bowls
3. MPACs and seasoned diced potatoes served in separate bowls
4. MPACs and seasoned diced potatoes served in the same bowl
5. MPACs and potato shaped faces served in the same bowl 

Results

These small changes to presentation and preparation style had measurable impact on participant vegetable consumption and were illustrated in study findings; when potatoes were on trays, children ate more peas and carrots than when they were served alongside a separate bread roll.

Participants consumed the most vegetables and calories when peas/carrots and potato faces were served in the same bowl (452 calories total, and 8.77g more vegetables than compared to when peas and carrots were combined with rosemary potatoes in the same bowl). This was a minor difference compared to the control meal, with just 21 additional calories and 5 additional grams of fat (all of which was unsaturated).

Strengths and Limitations

Strengths of the study included removal of parents from the immediate study environment to minimize potential bias during mealtime consumption, and food intake and plate waste was measured in real-time, compared to less accurate dietary recall methods. While researchers took steps to create a controlled environment mimicking a school cafeteria, the experiment took place in a food lab which did not account for duration of mealtimes, timing of lunch before or after recess, nutrition education, or other factors related to mealtime eating behaviors at school.

Full details can be found in the published article, “The effects of potato presentation on vegetable intake in school aged children’” in Nutrients (https://doi.org/10.3390/nu15214496). Funding was provided by the Alliance for Potato Research & Education; the funders did not play any role in the design, data collection, analysis, or interpretation of this research.

References

1. Agarwal S, Fulgoni VL. Intake of Potatoes Is Associated with Higher Diet Quality, and Improved Nutrient Intake and Adequacy among US Adolescents: NHANES 2001–2018 Analysis. Nutrients 2021, Vol 13, Page 2614. 2021;13(8):2614. doi:10.3390/NU13082614

October 25, 2023

Menu modeling shows swapping grains for starchy vegetables may lead to declines in fiber and potassium – two nutrients most Americans don’t get enough of.

A perspective recently published in Frontiers in Nutrition underscores the unique role starchy vegetables play as a vital vehicle for essential nutrients. The Dietary Guidelines for Americans currently recommend that most adults consume five to six cups (or cup equivalents) of starchy vegetables each week to help meet their total vegetable goals.¹ Yet, as confusion around “good versus bad carbs” persists among consumers, there is a risk of starchy vegetable avoidance in favor of other carbohydrate foods perceived as equally or more nutritious – or even carbohydrate avoidance all together.

Using menu model analyses, nutrition expert Keith Ayoob, EdD, RDN, Associate Professor Emeritus, Albert Einstein College of Medicine, demonstrates the real-world implications of eliminating starchy vegetables in the diet and swapping them for grain-based foods. The results? Replacing starchy vegetables with grain-based alternatives, including whole-grain foods, for one day led to a 21% decrease in potassium, a 17% decrease in vitamin B6, an 11% drop in vitamin C and a 10% reduction in fiber.

“It’s tempting to think of all carbohydrate foods as interchangeable,” says Ayoob. “But these foods are categorized within different food groups for a reason – perhaps most importantly, they tend to have vastly different vitamin and mineral contents.” Compared to grains, starchy vegetables like potatoes tend to be higher in potassium, designated a nutrient of public health concern by the Dietary Guidelines for Americans because inadequate intake is associated with increased health risks.¹ They can also provide an excellent source of vitamin C.²

Additionally, though neither group is considered a major protein source, the protein quality in potatoes is notably higher than the protein quality of grains, comparable in quality (as measured by “biological value”) to the protein in egg and milk.^3,4 And though food choices from both groups can help add fiber to the diet, grains offer unique nutritional benefits as well, typically offering more thiamin, zinc and vitamin E.

“As is so often the case in the world of nutrition, guidance comes down to balance, variety and moderation – which might sound boring, but all three would benefit most people’s eating styles,” Ayoob adds. “It’s important to get the right mix of vegetables and grains and include both starchy and non-starchy vegetables to help ensure we’re meeting both our macronutrient and micronutrient needs.”

In addition to demonstrating key differences in the nutrient contributions of starchy vegetables and grain-based foods, the perspective discusses distinctions in each food group’s chemical structure, culinary applications, economic benefits and cultural relevance.

Ayoob notes, “It’s also important to recognize that some cultural groups traditionally use certain carb-containing foods over others. That’s why more research is needed to understand how different carbohydrate food choices impact diet quality and what culturally appropriate foods should be encouraged to help close any nutrient gaps.”

Menu Model Details

Dr. Ayoob analyzed two, one-day menu models to assess the nutrient contributions from both starchy vegetables and grain-based foods to the daily diet.

A ~2,000-calorie “foundation” menu was used to reflect the dietary recommendations within the 2020-2025 Dietary Guidelines for Americans and in alignment with the USDA’s “Food Pattern Models.” This menu included both grain-based foods and white potatoes, as a nutritionally representative food from the starchy vegetable category.  In this foundational diet, white potatoes were included at breakfast in the form of hashbrowns and at dinner in the form of a baked potato.

A ~2,000-calorie menu with 100% of starchy vegetables replaced with grain-based foods was used as a comparison. This menu replaced the hashbrowns at breakfast with an additional slice of whole wheat bread and the baked potato at dinner with white rice.

Limitations of these menu modeling results include the fact that potatoes were the only starchy vegetable incorporated into the foundational menu, and modeling was limited to a single day. Additional modeling reflecting other culturally relevant starchy vegetable options and preparations over a longer period would help to further elucidate nutritional implications of starchy vegetable avoidance or carbohydrate food swapping behaviors.

Full details can be found in the published article, “Carbohydrate confusion and dietary patterns: unintended public health consequences of ‘food swapping,’” in Frontiers in Nutrition (https://doi.org/10.3389/fnut.2023.1266308). Funding was provided by Potatoes USA; the funder had no impact on the peer review process and final manuscript.

References

¹U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th Edition. December 2020. [Internet]. Available from: https://www.dietaryguidelines.gov/sites/default/files/2020-12/Dietary_Guidelines_for_Americans_2020-2025.pdf

²U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, 2019. fdc.nal.usda.gov/fdc-app.html#/food-details/170030/nutrients

³Camire, ME, Kubow, S, and Donnelly, DJ. Potatoes and human health. Crit Rev Food Sci Nutr. (2009) 49:823–40. doi: 10.1080/10408390903041996

⁴Hoffman, JR, and Falvo, MJ. Protein–Which is Best? J Sports Sci Med. (2004) 3:118

The Carbohydrate Food Quality Score offers a novel carbohydrate scoring strategy that is culturally inclusive and aligns with the Dietary Guidelines for Americans

March 23, 2023 – Despite the broad diversity of the U.S. population, dietary recommendations often overlook the positive contributions of cultural foods to build healthy dietary patterns. This is especially true when it comes to carbohydrate food guidance, where prevailing approaches have historically focused on only three components— carbohydrates, sugar, and dietary fiber—ignoring other important nutrient and cultural considerations. However, a new paper published in Nutrients highlights a more holistic approach, called the Carbohydrate Food Quality Score (CFQS), that is more culturally inclusive and aligns closer with the Dietary Guidelines for Americans.

“Unlike other approaches to evaluating carbohydrate quality, the CFQS evaluates the contribution of both under-consumed dietary components like potassium, dietary fiber and whole grains, and overconsumed nutrients like sodium, predominantly found in carbohydrate-containing foods, especially grains,” explained Judy Rodriguez, PhD, RDN, Professor Emerita in the Department of Nutrition and Dietetics at the University of North Florida, and coauthor of the study. “This nuance is significant, as it sheds light on the fact that carbohydrate-containing foods contain many important nutrients beyond carbohydrates. Furthermore, this tool is the only carbohydrate quality index that aligns with the Dietary Guidelines for Americans.”

How It Works

The development and validation of the CFQS is described in two previously published articles.^1,2 In brief, this new system is based on similar foundations of previously published approaches that focus on fiber, sugar and total carbohydrate content of foods. However, CFQS also acknowledges the heterogeneity, nutrient and cultural diversity across the carbohydrate food category by:

1) Including other nutrients like sodium, potassium, and whole grain (for grain-based foods) in the scoring system.   

2) Creating two distinct scoring systems: one for non-grain foods (CFQS-4), and one for grain-based foods (CFQS-5). CFQS-4 is scored on a 4-point scale based on the amounts of carbohydrates, sugar, sodium and potassium. CFQS-5 is scored on a 5-point scale, using the same 4 components as CFQS-4, plus whole grains.

“The new CFQS clearly recognizes that carbohydrate foods are not homogenous, and nuance is needed when communicating this to consumers. For example, while potatoes and grain-based foods are considered ‘carb foods’ and contribute important nutrients to the diet, their nutrient profiles and quality vary. The CFQS can help identify those foods that can be chosen frequently as dietary staples,” stated Dr. Rodriguez.

Not only do the metrics help to clarify and quantify carbohydrate food quality, but they also support health equity among all Americans as they can be applied across a variety of budgets, lifestyles, and cultures.

Why it Matters

Dietary guidelines continue to emphasize the importance of total dietary patterns and overall diet quality. However, many tools intended to help people build healthy dietary patterns continue to categorize individual foods as ‘good’ or ‘bad’. The CFQS is meant to break this cycle by providing a spectrum of carbohydrate food choices rather than assigning binary classifiers to food choices (e.g., good/bad, eat/avoid) and simplistic food classifications such as ‘eat a rainbow’ (e.g., dark green, red and orange, etc.) While such systems can be helpful, they are confusing when it comes to foods with neutral colors such as white cauliflower, daikon, jicama, potatoes, brown mushrooms, and black beans. Not only can the CFQS help eliminate confusion, but it aligns with the Dietary Guidelines for Americans as it recognizes other essential nutrients that are under- or over-consumed in the American diet and predominately delivered through carbohydrate-containing foods.

“The CFQS provides a vehicle that affirms with each individual’s values, socioeconomics, and food and cultural traditions, and provides a scale to help address nutritional concerns about the diet,” explained Julie Miller Jones, PhD, LN, CNS, professor emerita in the Department of Family, Consumer and Nutritional Sciences at the St. Catherine University in St. Paul, and coauthor of the study. “The CFQS can reassure consumers of the role of carbohydrate foods for constructing healthy eating patterns and while affirming equitable, nutritious, and culturally appropriate food choices to influence health.”

Disclosures: The Quality Carbohydrate Coalition (QCC) is a multi-stakeholder engagement of commodity groups across the food industry. Guided by the work of its Scientific Advisory Council (SAC), this group aims to support a collaborative, scientific dialogue around the unique and diverse roles that carbohydrate-containing foods play in healthful eating.  The council is made up of six world-renowned experts in carbohydrate research, nutrient profiling, cultural competency and epidemiology: Judith Rodriguez, PhD, RDN; Adam Drewnowski, PhD; Julie Miller Jones, PhD, LN, CNS; Joanne Slavin, PhD, RDN; Siddhartha Angadi, PhD; and Yanni Papanikolaou, MPH.  Potatoes USA provides the funding to support the research being conducted by the SAC. 

Additional Details on Study Design, Strengths, and Limitations

Three one-day menu models were developed to demonstrate the utility of the CFQS models when selecting carbohydrate foods as part of a healthy dietary pattern. Menu models adhered to nutritional requirements outlined in the following dietary patterns established by the 2020-2025 Dietary Guidelines for Americans:

• Healthy US
• Healthy Mediterranean-Style
• Healthy Vegetarian

A fourth menu model was developed in alignment with the USDA Thrifty Food Plan to demonstrate the utility of the CFQS in budget-conscious healthy eating.

All four menu models were created using ESHA Food Processor menu modeling software, and each menu adhered to a 2,000 kcal diet including three meals and two snacks. While carbohydrate foods with a CFQS of three or greater were prioritized, scores of one and two were also included to demonstrate their nutritional contributions to healthy, diverse, affordable and culturally appropriate food patterns.

Finally, four tables were created to reflect carbohydrate foods commonly found across the largest recorded ethnic groups in the United States:

• African American
• Latino/Latin America
• Asian American
• Native American

The purpose of these tables was to demonstrate how culturally inclusive food patterns can be integrated with DGA-recommended dietary patterns and the CFQS models.

The present modeling exercises demonstrate the feasibility of using carbohydrate food quality score models (CFQS-4 and CFQS-5) to better understand the value and variability of carbohydrate food quality across different food groups and different dietary patterns. The models were previously validated, and the current work demonstrates their applicability and utility across culturally and economically diverse eating patterns. However, the current work cannot show the effects of implementing CFQS models on specific health outcomes. Thus, future research will need to examine the health impacts of consuming higher scoring CFQS dietary patterns compared to lower scoring patterns.  Furthermore, while the CFQS metrics emphasize nutrients of public health concern, the scoring system omits other key factors associated with health, such as bioavailability of nutrients, content of other nutrients, and contributions from bioactive phytonutrients (e.g., antioxidants, prebiotics, and probiotics). Future research will inform further development of the existing models to reflect these important components.

References

1.         Comerford KB, Papanikolaou Y, Jones JM, et al. Toward an Evidence-Based Definition and Classification of Carbohydrate Food Quality: An Expert Panel Report. Nutrients. 2021;13(8). doi:10.3390/NU13082667

2.         Drewnowski A, Maillot M, Papanikolaou Y, et al. A New Carbohydrate Food Quality Scoring System to Reflect Dietary Guidelines: An Expert Panel Report. Nutrients. 2022;14(7). doi:10.3390/NU14071485

Pennington Biomedical Research Center

BATON ROUGE, Louisiana — When we think of healthy vegetables, we don’t think of potatoes, but we should. Potatoes have developed a reputation for causing weight gain and an increased risk for type 2 diabetes, and often find themselves on a list of foods to avoid, especially for individuals with insulin resistance. However, a new study from Pennington Biomedical Research Center, published in the Journal of Medicinal Food, says that potatoes actually did not increase that risk, are filled with key nutrients, and packed with health benefits.

Candida Rebello, PhD, an assistant professor at Pennington Biomedical, served as co-investigator of the study which examined how a diet including potatoes affects key health measures. Rebello, who is also a registered dietitian, said, “We demonstrated that contrary to common belief, potatoes do not negatively impact blood glucose levels. In fact, the individuals who participated in our study lost weight.”

“People tend to eat the same weight of food regardless of calorie content in order to feel full,” Rebello explained. “By eating foods with a heavier weight that are low in calories, you can easily reduce the number of calories you consume. The key aspect of our study is that we did not reduce the portion size of meals but lowered their caloric content by including potatoes. Each participant’s meal was tailored to their personalized caloric needs, yet by replacing some meat content with potato, participants found themselves fuller, quicker, and often did not even finish their meal. In effect, you can lose weight with little effort.”

The study involved 36 participants between the ages of 18 and 60 who were overweight, had obesity, or insulin resistance. Insulin resistance refers to a health condition in which the body’s cells do not respond well to insulin and glucose does not enter into the cells to make energy. Insulin resistance is linked to obesity, high blood pressure, high cholesterol, and type 2 diabetes

Participants were fed precisely-controlled diets of widely available common foods including either beans, peas, and meat or fish, or white potatoes with meat or fish. Both diets were high in fruit and vegetable content and substituted an estimated 40% of typical meat consumption with either beans and peas or potatoes. Previous studies have shown that eating beans and peas improves blood glucose levels in individuals with newly diagnosed type 2 diabetes. To increase the dietary fiber component of the potatoes, they were boiled with the skin intact and then refrigerated between 12 and 24 hours. Potatoes were incorporated into the main lunch and dinner entrées, such as shepherd’s pie and creamy shrimp and potatoes, and served together with sides such as mashed potatoes, oven-roasted potato wedges, potato salad, and scalloped potatoes with lunch and dinner entrees.

“We prepared the potatoes in a way that would maximize their fiber content. When we compared a diet with potatoes to a diet with beans and peas, we found them to be equal in terms of health benefits,” Rebello said. “People typically do not stick with a diet they don’t like or isn’t varied enough. The meal plans provided a variety of dishes, and we showed that a healthy eating plan can have varied options for individuals striving to eat healthy. In addition, potatoes are a fairly inexpensive vegetable to incorporate into a diet.”

Pennington Biomedical Research Center’s Executive Director John Kirwan, PhD, and Principal Investigator on the study said, “Obesity is an incredibly complex disease that Pennington Biomedical is tackling on three different fronts: research that looks at how and why our bodies react the way they do, research that looks at individual responses to diet and physical activity, and policy-level discussions and community programs that bring our research into strategies our local and global communities can use to live healthier lives. These new data on the impact of potatoes on our metabolism is an exciting addition to the arsenal of evidence we have to do just that.”

This work was supported in part by an investigator-initiated grant from the Alliance for Potato Research and Education and in part by a grant from the National Institute on Aging and from the National Institute of General Medical Sciences of the National Institutes of Health, which funds the Louisiana Clinical and Translational Science Center. The funders (Alliance for Potato Research and Education and the National Institutes of Health) had no role in the design, analysis, or writing of the manuscript. The content is solely the responsibility of the authors and does not necessarily represent the official views of the sponsors.

About LSU’s Pennington Biomedical Research Center

The Pennington Biomedical Research Center is at the forefront of medical discovery as it relates to understanding the triggers of obesity, diabetes, cardiovascular disease, cancer and dementia. The Center architected the “Obecity, USA” awareness and advocacy campaign to help solve the obesity epidemic by 2040. The Center conducts basic, clinical, and population research, and is affiliated with Louisiana State University. The research enterprise at Pennington Biomedical includes over 480 employees within a network of 40 clinics and research laboratories, and 13 highly specialized core service facilities. Its scientists and physician/scientists are supported by research trainees, lab technicians, nurses, dietitians, and other support personnel. Pennington Biomedical is located in state-of-the-art research facilities on a 222-acre campus in Baton Rouge, Louisiana. For more information, see https://www.pbrc.edu.

The latest findings show that overall diet and lifestyle mediate health outcomes associated with potato consumption, not potato preparation methods

Peer-Reviewed Publication

THE ALLIANCE FOR POTATO RESEARCH AND EDUCATION (APRE)

Although potatoes are a nutrient-rich vegetable, they are often singled out as a food to limit. In fact, despite the Dietary Guidelines for Americans’ recommendation to increase fruit and vegetable consumption, some health experts still recommend limiting or avoiding eating potatoes due to concerns that they may increase cardiometabolic risk. However, a newly published study in the Journal of Nutritional Science finds that advice may be unwarranted. Researchers at Boston University examined the influence of potatoes as part of overall diet and lifestyle patterns on cardiometabolic disease risk. They found no change in cardiometabolic risk factors associated with intake of either fried or non-fried potatoes in adults from the long-running Framingham Offspring cohort.

“In this study, we looked at the effects of higher intakes of potatoes on blood pressure, lipids, and glucose and we found that after accounting for other dietary and lifestyle factors, there was no increased risk of cardiometabolic disorders associated with potato consumption,” said lead study investigator Lynn L. Moore, DSc, MPH, associate professor of Medicine at the Boston University Chobanian & Avedisian School of Medicine. “In fact, we found that those in the highest potato intake category consumed 25% more total fruits and vegetables than those in the lower potato intake group. As a result, these participants who consumed more potatoes were more likely to meet the recommendations of the Dietary Guidelines.”

The findings from Moore’s research group observed no association between consuming 4 or more cup-equivalents of potatoes per week (both white and sweet, fried and non-fried) and type 2 diabetes (T2DM), impaired fasting glucose (IFG), hypertension, and dyslipidemia in a large population of healthy Caucasian adults. “We know that potatoes are rich in potassium, magnesium, and dietary fiber, all of which may be protective against the heart attacks and strokes that are a consequence of elevated levels of cardiometabolic risk,” explained Moore. “In fact, potatoes are one of the most important sources of potassium in the American diet.”

Meanwhile, the effects of fried potato consumption appeared to be modified by other diet and lifestyle factors. For example, those with higher intakes of fried potatoes and lower consumption of red meat had a 26% lower risk of elevated triglycerides. Additionally, more physically active adults who consumed higher levels of fried potatoes had a 25% lower risk of developing Type 2 diabetes. These findings underscore the importance of overall diet and lifestyle when it comes to cardiometabolic disease risk,” Moore added. “Public health messaging singling out potatoes, and even fried potatoes, is not supported by this evidence.”

These study results indicate that potatoes, both fried and non-fried sweet and white potato varieties, can be included as part of a healthy diet without impacting risk factors for cardiometabolic disease. Further, potatoes contribute to total fruit and vegetable intake, thus enabling consumers to more closely align with the Dietary Guidelines recommendations.

As Moore explained, “Previously published evidence on potato consumption has been conflicting. For example, some find higher potato intakes to be positively associated with elevated blood pressure while others find the opposite. In observational studies, it is important to try to separate out a food like potatoes from other dietary components. If the individuals consuming more potatoes, for example, also consume more refined grains or have other unhealthy lifestyle habits, then the adverse effect of potatoes may actually be a result of other things associated with diet and lifestyle.”

One strength of the current study is that diet was assessed with detailed dietary records, thus allowing the investigators to determine cooking methods. In addition, dietary records provide a more accurate assessment of the intake of most foods and nutrients than the food frequency questionnaires that have been used in many other studies.

The results of this study support the need for future randomized controlled trials to investigate the effects of potatoes as part of a healthy diet (including potatoes cooked in different ways) on cardiometabolic disease risk. In the interim, these data add to the evidence supporting a role for potatoes as part of a healthy lifestyle.

Study Design, Strengths, and Limitations 

Data from 2,523 offspring of the Framingham Heart Study, 30 years of age and older, were included in this prospective cohort study that began in 1971.

• Approximately 16,000 collective days of dietary records were collected from roughly 70% of participants during exams 3 (1983-87) and 5 (1991-95).
• The consumption of potatoes (both white and sweet potatoes) was derived from total vegetable servings. For these analyses, each participant’s usual potato intake was estimated as the mean from all days of diet records and grouped as follows: total potato intake (<1, 1-<2, 2-<4, and ≥4 cup-equivalents/week, and fried or non-fried (<1, 1-<2, and ≥2 cup-equivalents/week).
• Health outcome data were provided from regular examination visits.
• Researchers assessed the impact of both total potato consumption as well as fried versus non-fried potato consumption on hypertension, T2DM/IFG, and dyslipidemia risk.
• Researchers further assessed whether other diet and lifestyle factors modified the effects of fried and non-fried potato intakes on cardiometabolic risk.

In addition to the large sample size, the use of a prospective study design allowed for the assessment of large amounts of data from subjects in a free-living environment. For example, potato consumption was averaged over 8 years before the beginning of a 16-year follow-up. Furthermore, dietary intake was analyzed from an average of 6 days of dietary records, thus providing a more stable intake assessment. Further studies will need to assess more diverse populations, as this current sample of Caucasian adults is not broadly generalizable. Future studies will also benefit from consideration of cooking methods and by studying the specific effects of potatoes when consumed as part of a healthy diet.

This research was supported by the Alliance for Potato Research and Education (APRE). APRE had no influence on the study design, conduct, execution, or data analysis after approving the initial proposal for funding.

The article “Potato Consumption is not Associated with Cardiometabolic Health Outcomes in Framingham Offspring Study Adults” is published in the Journal of Nutritional Science (doi: 10.1017/jns.2022.65).

Journal: Journal of Nutritional Science

DOI: 10.1017/jns.2022.65

Article title: Potato Consumption is not Associated with Cardiometabolic Health Outcomes in Framingham Offspring Study Adults

Article publication date: 09/02/2022

---

JOURNAL

Journal of Nutritional Science

DOI

10.1017/jns.2022.65 

ARTICLE TITLE

Potato consumption is not associated with cardiometabolic health outcomes in Framingham Offspring Study adults

Read the Full Study Summary

The latest findings challenge outdated assumptions about the anabolic effects of plant-derived proteins

Peer-Reviewed Publication

THE ALLIANCE FOR POTATO RESEARCH AND EDUCATION (APRE)

Exercise enthusiasts have long presumed animal protein to be superior to plant-derived options for muscle protein synthesis due to its essential amino acid profile. While many plant proteins are deficient in one or more essential amino acids necessary for optimal muscle growth and repair, a new randomized controlled study published in Medicine & Science in Sports & Exercise shows that plant-derived proteins can still induce strong anabolic responses. Researchers at Maastricht University, The Netherlands, found that consuming 30 grams of potato-derived protein concentrate following resistance exercise strongly increased muscle protein synthesis rates to levels that did not differ from the response following the ingestion of an equivalent amount of milk protein concentrate.

“The anabolic response to exercise depends on the exercise stimulus and the postprandial increases in circulating amino acids,” said lead study investigator Luc J.C. van Loon, PhD, a professor of physiology of exercise and nutrition at Maastricht University Medical Centre. “In general, plant-derived proteins are considered to have lesser anabolic properties, due to their lower digestibility and incomplete amino acid profile. Our results show that ingestion of 30 g potato-derived protein will support muscle growth and repair at rest and during recovery from exercise.”  

The findings from van Loon’s research group demonstrate that potato-derived protein concentrate powder can be used to increase muscle protein synthesis rates both at rest and during post-exercise recovery in healthy, young men, at rates that do not differ from the ingestion of an equivalent amount of milk protein.

“The potato’s amino acid profile has no apparent deficiencies and ingestion of 30 g protein was shown to strongly stimulate muscle protein synthesis during recovery from exercise,” explained van Loon.

These study results are part of a growing body of literature that demonstrate the benefits of potatoes in physical activity and exercise recovery.^1-3 As van Loon explained, “Although further dose-response studies in broader populations are undoubtedly necessary, these data seem to support the use of potato-derived protein concentrate as an effective means to support muscle conditioning.”

Study Design, Strengths, and Limitations 

Twenty-four young, healthy males between the ages of 20-28 years volunteered to participate in this randomized, double blind, parallel group study.

• Participants completed resistance exercise on a seated knee-extension machine (randomized to complete with either their dominant or non-dominant leg) following a warm-up on a supine leg press machine.
• Participants rested for 10 minutes following their exercise session. Blood samples were drawn, and muscle biopsies were taken from each leg.
• Immediately after the biopsies, 12 participants ingested 30 grams potato-derived protein while the other 12 ingested an equivalent amount of milk-derived protein. 
• Blood samples were collected over a 5-hour period following ingestion to determine blood amino acid, glucose, and insulin concentrations.
• Second and third muscle biopsies were taken to determine muscle protein synthesis rates at rest and during recovery from exercise.

The strategic use of a randomized double-blind study design with a unilateral exercise protocol allowed for assessment of postprandial muscle protein synthesis in both exercised and non-exercised muscle. Further studies will need to assess dose-response relationships between smaller and larger doses of protein on muscle protein synthesis. Future studies will also benefit from assessing the effects of plant-derived protein concentrates on muscle conditioning after repeated bouts of exercise in larger and more diverse populations.

Nonetheless, the current data show “there is ample room for high quality plant-derived proteins in sports nutrition, such as protein from nutrient-dense sources like potatoes,” stated van Loon.

This research was supported by the Alliance for Potato Research and Education (APRE). APRE had no influence on the study design, conduct, execution, or data analysis after approving the initial proposal for funding.

The article “Potato Protein Ingestion Increases Muscle Protein Synthesis Rates at Rest and during Recovery from Exercise in Humans” is published in Medicine & Science in Sports & Exercise (10.1249/MSS.0000000000002937).

References

1. Oikawa SY, Bahniwal R, Holloway TM, Lim C, McLeod JC, McGlory C, Baker SK, Phillips SM. Potato Protein Isolate Stimulates Muscle Protein Synthesis at Rest and with Resistance Exercise in Young Women. Nutrients. 2020 Apr 27;12(5):1235. doi: 10.3390/nu12051235.
2. Flynn S, Rosales A, Hailes W, Ruby B. Males and Females Exhibit Similar Muscle Glycogen Recovery with Varied Recovery Food Sources. Eur J Appl Physiol. 2020. doi: 10.1007/s00421-020-04352-2
3. Salvador AF, McKenna CF, Alamilla RA, et al. Potato Ingestion is as Effective as Carbohydrate Gels to Support Prolonged Cycling Performance. J Appl Physiol. 2019;127(6):1651-1659. doi: 10.1152/japplphysiol.00567.2019

---

DOI

10.1249/MSS.0000000000002937 

METHOD OF RESEARCH

Randomized controlled/clinical trial

SUBJECT OF RESEARCH

People

Read the Full Study Summary

Peer-Reviewed Publication

THE ALLIANCE FOR POTATO RESEARCH AND EDUCATION (APRE)

A new study recently published in Frontiers in Nutrition has challenged the tendency in nutrition research to separate starchy vegetables from their non-starchy counterparts and categorize them with foods delivering lower nutritional value.

Whole grains, legumes, non-starchy vegetables, and fresh fruit are typically considered to be higher quality carbohydrate foods, yet starchy vegetables, including white potatoes, are typically categorized in nutrition studies with sweets, candy, and soda, when researchers assess subjects’ food intake and associations with health outcomes. This new study used five separate indices to assess carbohydrate quality to determine if this categorization of starchy vegetables is an accurate reflection of the foods’ nutritional value.

Four of those carbohydrate quality indices (CQIs), based on carbohydrate to fiber and sugar ratios, had been developed and validated in 2021 by researchers at Tufts University. The fifth index, the new carbohydrate food quality scoring system (CFQS-4) recently developed by scientists working with the Quality Carbohydrate Coalition, also incorporated potassium and sodium. All five indices had been previously published.

The new study screened more than 2,400 carbohydrate-containing foods for carbohydrate quality.  Recognizing that carbohydrates are present in a great variety of plant-based foods, the study expanded the range of food groups to include refined and whole grains, snacks and sweets, but also starchy and non-starchy vegetables, legumes and whole fruit. Starchy vegetables had not been tested before using the new carbohydrate quality metrics.

“Starchy vegetables are often not even viewed as vegetables and are routinely removed from high-quality food categories in nutrition research. That view is now challenged by the new nutrient profiling methods” said lead author Adam Drewnowski, PhD, researcher at the Center for Public Health Nutrition at the University of Washington. “Now that we have formal measures of carbohydrate quality that we can agree on, it is time to put starchy vegetables back where they belong.  There is no need to demonize ‘bad’ vegetables when the American diet could do with more produce of all kinds.”

“I certainly hope that the Dietary Guidelines Advisory Committee take note as they design a healthy diet at an affordable cost,” Dr. Drewnowski added

The four CQIs and the CFQS-4 had been published before but had not been applied to evaluating carbohydrate quality of legumes, vegetables and fruit.  The five indices were based on specific rations of carbohydrate, fiber, free sugar, potassium and sodium. Whereas potassium is under-consumed, sodium is consumed to excess. Both nutrients are recognized as ‘nutrients of public health concern’ in the Dietary Guidelines for Americans.

Based on the four CQI scores, nearly half of the 210 starchy vegetable foods analyzed in the study met the CQI definitions for high-quality carbohydrates, which were defined as those with evidence-based cut-off values for fiber and free sugar. Meanwhile, extremely few snacks and sweets (1-5%), candy and desserts (0-5%) and refined grain foods (10-12%) could be considered high-quality, according to the same CQI measures.

Based on the more comprehensive CFQS-4 model, which also accounts for foods’ potassium and sodium content, starchy vegetables scored most closely to non-starchy vegetables and fruit versus sweets and soda.

“I hope that this simple application of existing carbohydrate quality metrics to a wide spectrum of carb-containing foods will show that starchy vegetables belong with the high-quality carbohydrate foods” said Drewnowski. “Our application of other nutrient profiling has previously shown that potatoes and beans led the pack in terms of nutrients per penny. This latest demonstration clearly shows that all vegetables should remain together when it comes to both research and dietary guidance.”

Study Design, Strengths, and Limitations

More than 2,400 carbohydrate foods in the USDA Food and Nutrient Database for Dietary Studies were evaluated using four previously published CQIs, and one more recently created carbohydrate food quality scoring system (CFQS-4).

Specifically, the various CQI composites were:

• 10:1 Carbohydrate-to-Fiber model: at least 1 gram of fiber for every 10 grams of carbohydrate
• 10:1:1 Carbohydrate-to-Fiber-to-Free Sugars model: at least 1 gram of fiber and no more than 1 gram of free sugar for every 10 grams of carbohydrate 
• 10:1:2 Carbohydrate-to-Fiber-to-Free Sugars model: at least 1 gram of fiber and no more than 2 grams of free sugar for every 10 grams of carbohydrate
• 10:1|2:1 Carbohydrate-to-Fiber and Sugar-to-Fiber model: at least 1 gram of fiber for every 10 grams of carbohydrate and fewer than 2 grams of sugar per 1 gram of fiber
• The CFQS-4 model builds upon previous 10:1 and 10:1:1 ratios for fiber and free sugars relative to carbohydrate, but also assesses sodium (an over-consumed nutrient of concern) and potassium content (a shortfall nutrient of concern) according to the Dietary Guidelines for Americans.

Foods with at least 40% energy from carbohydrates per 100g dry weight were included in all analyses. The frequency and percentage of foods that met the CQI criteria were calculated for each food group. Carbohydrate quality scores were measured against the average energy densities of food groups and subgroups.

This study included a large, comprehensive data set using multiple nutrient profiling models. Further research to build upon these models, however, should continue to incorporate other vitamins and minerals in food quality assessments. Nonetheless, this study aligns with a broader, evolving body of literature showcasing the multi-dimensionality of carbohydrate foods and their role in human health. As Dr. Drewnowski explained, “Current efforts to inform dietary guidelines and regulatory frameworks would benefit from modern, comprehensive tools to define and assess carbohydrate food quality.”

This research was supported by the Alliance for Potato Research and Education (APRE) and by the Quality Carbohydrate Coalition (QCC), which is funded by Potatoes USA. Neither APRE nor Potatoes USA had an influence on the study design, conduct, execution, or data analysis after approving the initial proposal for funding. Dr. Adam Drewnowski is a member of the QCC-Scientific Advisory Council.

The article “Multiple metrics of carbohydrate quality place starchy vegetables alongside non-starchy vegetables, legumes, and whole fruit” is published in Frontiers in Nutrition (doi: 10.3389/fnut.2022.867378).

---

JOURNAL

Frontiers in Nutrition

DOI

10.3389/fnut.2022.867378 

Read the Full Study Summary

Newly published perspective examines the shortcomings of the glycemic index as a measure of carbohydrate food quality

Peer-Reviewed Publication

THE ALLIANCE FOR POTATO RESEARCH AND EDUCATION (APRE)

Today, many people struggle to make healthy food and beverage choices in line with the Dietary Guidelines for Americans (DGA). In fact, the average American under-consumes nutrient-dense fruits, vegetables, whole grains, beans and dairy foods – and more than half of American adults have at least one diet-related chronic disease.¹ To improve overall diet quality, Jill Nicholls, PhD, asserts in a recently published perspective in Frontiers in Nutrition, people need tools that are relevant, reliable and applicable – and evidence suggests the glycemic index (GI) falls short on all of the above.

“The GI is increasingly used and interpreted as a measure of overall carbohydrate food quality, with some proponents advocating for its broader adoption as a public health tool. However, the GI model doesn’t address nutrient density or translate well to healthy dietary patterns, and its narrow focus on just one dimension of carbohydrate-containing foods may divert public attention away from approaches to improving health that are accessible, affordable, culturally appropriate and environmentally sustainable,” stated Nicholls, owner of Food Context, LLC. “At best, it’s an incomplete gauge of carbohydrate food quality. At worst, it may be counterproductive to achieving the dietary recommendations set forth in the DGA.”

Intended for People with Type 1 Diabetes – Not the General Public

Developed in the 1980s as a blood glucose management tool for people with type 1 diabetes, the GI is a comparative measure of glycemic impact. The GI measures the ability of the available carbohydrate in a food to increase blood glucose. It is determined by measuring blood glucose after consuming 50 grams of carbohydrate from a single test food and normalizing to a comparable portion of a control food, typically pure glucose or white bread.²

Carbohydrate-containing foods are quite varied and make important contributions to dietary patterns, yet the GI measures only glucose response. It does not account for overall nutrient content, and research has shown it may not be an accurate predictor of overall diet quality. And because low-GI foods are not necessarily high in essential nutrients, over-reliance on GI values may lead to food choices that are inconsistent with current dietary guidelines. Energy-dense choices such as ice cream and candy bars, for instance, can have low GI values, while nutrient-dense choices that support healthy dietary patterns can also be high-GI foods, including carrots, potatoes and grains.

An Unreliable and Highly Individualized Measure of Glycemic Response

“The reliability of the GI has been scrutinized since its introduction more than 40 years ago, including critiques about methodology and questions about the relationship between a food’s GI value and true post-meal glycemic response,” said Nicholls.

Because GI values are calculated based on foods consumed in isolation and analyzed under standard laboratory conditions, their real-world application may be limited. “Under the GI model, fat, protein and fiber are treated as entirely independent variables, but that assumption is at odds with current views about our understanding of how eating patterns influence health based on all food and beverage contributions,” Nicholls explained.

Much of the research has demonstrated significant variability in both inter- and intra-individual glycemic responses to the same food. Thus, it remains unclear whether the GI is a property of foods or a characteristic of each unique individual consuming those foods. Emerging studies have found that glycemic responses are more similar within individuals than between them, and an array of factors in addition to meal composition can influence individual carbohydrate metabolism, including, meal timing, physical activity and sleep habits. ⁴

A Questionable Predictor of Health Outcomes

Research also indicates that the GI may not be the best carbohydrate food quality metric to assess diets and chronic disease prevention. In a landmark series of systematic reviews and meta-analyses, Reynolds et al. found that the association between the GI and risk of non-communicable diseases was low to very low compared to fiber or whole grains.⁵ Meanwhile, the dietary patterns emphasized in the DGA contain more whole grains and fiber-containing foods than Americans usually eat, along with higher amounts of fruits, vegetables, and dairy foods. These patterns are associated with lower risk for NCDs. Eating nutrient-dense whole foods as part of balanced meals during the day is an easy way to improve glycemic responses and improve diet quality without monitoring the GI of foods.

“The Mediterranean Diet is one example of a dietary pattern that has been associated with reduced disease risk; yet, not every food in a Mediterranean eating pattern is low GI,” Nicholls added. In addition, clinical trials have shown compelling evidence that high GI foods eaten within the context of high-quality dietary patterns can yield improvements in cardiovascular disease risk factors, and weight loss regimens may be less reliant on glycemic responses than expected.^6-7

“Evidence increasingly suggests that it’s the total diet that counts. Improving the overall quality of an individual’s dietary patterns can have beneficial effects on a variety of diet-related chronic disease, but the effect of any single food choice is mediated by the other foods and beverages eaten, physical activity and other lifestyle choices. While the GI may illuminate some narrow insights, it also keeps many of these relevant variables in the dark.”

The article, “Perspective: The Glycemic Index Falls Short as a Carbohydrate Food Quality Indicator to Improve Diet Quality,” is published in Frontiers in Nutrition (https://doi.org/10.3389/fnut.2022.896333). Funding was provided by the Alliance for Potato Research and Education.

References:

¹U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9^th Edition. December 2020. [Internet]. Available from: https://www.dietaryguidelines.gov/sites/default/files/2020-12/Dietary_Guidelines_for_Americans_2020-2025.pdf

²Wolever, T.M., Jenkins, D.J., Jenkins, A.L., & Josse, R.G. (1991). The glycemic index: methodology and clinical implications. The American journal of clinical nutrition, 54 5, 846-54

³Zazpe, I., Sánchez-Taínta, A., Santiago, S., De la Fuente-Arrillaga, C., Bes-Rastrollo, M., Martínez, J., & Martínez-González, M. (2014). Association between dietary carbohydrate intake quality and micronutrient intake adequacy in a Mediterranean cohort: The SUN (Seguimiento Universidad de Navarra) Project. British Journal of Nutrition, 111(11), 2000-2009. doi:10.1017/S0007114513004364

⁴Berry SE, Valdes AM, Drew DA, Asnicar F, Mazidi M, Wolf J, et al, Human postprandial responses to food and potential for precision nutrition. Nat Med. (2020) 26:964–73. doi: 10.1038/s41591-020-0934-0

⁵Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. (2019) 393:434–45. doi: 10.1016/S0140-6736(18)31809-9

⁶Sacks FM, Carey VJ, Anderson CAM, Miller ER III, Copeland T, Charleston J, et al. Effects of high vs. low glycemic index of dietary carbohydrate on cardiovascular disease risk factors and insulin sensitivity: the OmniCarb randomized clinical trial. J Am Med Assoc. (2014) 312:2531–41. doi: 10.1001/jama.2014.16658

⁷Gardner CD, Trepanowski JF, Del Gobbo LC, Hauser ME, Rigdon J, Ioannidis JPA, et al. Effect of low-fat vs. low-carbohydrate diet on 12-month weight loss in overweight adults and the association with genotype pattern or insulin secretion: the DIETFITS randomized clinical trial. J Am Med Assoc. (2018) 319:667–79. doi: 10.1001/jama.2018.0245

---

DOI

10.3389/fnut.2022.896333 

Read the Full Study Summary