Key Facts About Vitamin C

• Vitamin C plays an important role in collagen formation and immune function.
• As a potent antioxidant vitamin C stabilizes or eliminates free radicals in the body, thus helping to prevent cellular damage.
• Fruits and vegetables are the best and only natural source of vitamin C.
• A medium 5.3 oz potato with skin-on is an excellent source of vitamin C, providing 30% of the recommended daily value (DV). This is more vitamin C than one medium tomato (27% DV) or a sweet potato (20% DV).
• For men ages 19 years and older, the recommended dietary allowance (RDA) for vitamin C is 90 mg per day. For women ages 19 years and older, the RDA is 75 mg per day.

Functions of Vitamin C

Vitamin C is required for the synthesis of collagen, a structural protein that gives strength and elasticity to a variety of body tissues (e.g., skin, gums, tendons, ligaments and bone) and plays a vital role in wound healing. Vitamin C also functions as an antioxidant in the body, stabilizing or eliminating free radicals, thus helping to prevent cellular damage. Finally, vitamin C assists with the absorption of iron and is concentrated in a number of immune cells thereby helping to support the body’s immune system.¹

Vitamin C Recommendations

The current RDAs for vitamin C are based on its known physiological and antioxidant functions in white blood cells and, thus, have been set higher than the amounts needed to prevent the deficiency disease (scurvy).¹ For men ages 19 years and older, the RDA is 90 mg per day and for women ages 19 years and older the RDA is 75 mg per day.

References:

1. Institute of Medicine (US) Panel on Dietary Antioxidants and Related Compounds. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. 2000. Washington (DC): National Academies Press (US).
   2. Cotton PA, Subar AF, Friday JE, Cook A. Dietary sources of nutrients among US adults, 1994-1996. J Am Diet Assoc. 2004;104:921-930.
   3. O’Neil CE, Keast DR, Fulgoni VL, Nicklas TA. Food sources of energy and nutrients among adults in the US: NHANES 2003–2006. Nutrients. 2012 Dec 19;4(12):2097-120.
   4. USDA standard reference 28, based on Reference Amounts Customarily Consumed (RACC)

Key Facts About Potassium

• Potassium is an important electrolyte that aids in muscle, cardiovascular and nervous system function.¹
• Potassium helps maintain normal blood pressure. Research suggests diets high in potassium and low in sodium may reduce the risk of hypertension and stroke.²
• Potatoes with skin-on are a good source of potassium. This is more potassium in a medium 5.3oz skin on potato than in a medium-size banana.³
• Potatoes provide one of the most affordable sources of potassium, significantly more than those foods commonly associated with being high in potassium, including bananas, oranges and mushrooms.²

Functions of Potassium and Relevant Research

Research suggests diets rich in potassium and low in sodium reduce the risk of hypertension and stroke.⁵ In a scientific statement promoting dietary approaches to prevent and treat hypertension, the American Heart Association (AHA) reported that evidence from animal experiments, observational studies and more than 30 human clinical trials show a significant association between high potassium intakes and reduced blood pressure.⁶

Given their high potassium content, potatoes may contribute to a heart healthy diet. In fact, the Dietary Guidelines for Americans encourages people to increase potassium by focusing on food choices with the most potassium such as white potatoes, beet greens, white beans, plain yogurt, and sweet potatoes.⁵

Potassium Recommendations

Current recommendations for potassium intake are expressed as an “adequate intake,” or AI. For males 19-50 years of age, the AI for potassium is 3400 mg per day whereas for females 19-50 years of age it is 2600 mg per day.⁷

References:

1. Institute of Medicine. 2004. Dietary Reference Intakes: Water, Potassium, Sodium, Chloride, and Sulfate. Washington, DC: The National Academies Press. https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/
   2. Drewnowski A, Rhem CD. Vegetable cost metrics show that potatoes and beans provide most nutrients per penny. PLoS One, 2013;15;8(5).
   3. USDA Dietary Guidelines for Americans. Available at: https://health.gov/dietaryguidelines/2015/guidelines/chapter-2/a-closer-look-at-current-intakes-and-recommended-shifts/
   4. Potassium: Food Sources Ranked by Amounts of Potassium and Energy per Standard Food Portions and per 100 Grams of Foods. Available at: https://health.gov/dietaryguidelines/2015/guidelines/appendix-10/.
   5. Aaron KJ, Sanders PW. Role of dietary salt and potassium intake in cardiovascular health and disease: a review of the evidence. Mayo Clin Proc. 2013;88:987-995.
   6. Appel LJ, Brands MW, Daniels SR, Karanja N, Elmer PJ, Sacks FM. Dietary approaches to prevent and treat hypertension. A scientific statement from the American Heart Association. Hypertension. 2006;47: 296–308.
   7. National Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes for Sodium and Potassium. Washington, DC; The National Academies Press; 2019.

Key Facts About Carbohydrates

• One medium 5.3 oz potato with skin-on provides 26 grams of carbohydrates, or 9% of the daily value per serving.
• The brain + red blood cells require carbohydrates.
• Consume 130 grams of carbohydrates per day for central nervous system support.
• Choose carbohydrates high in “nutrient density”
• Fruits + vegetables are excellent carbohydrates

Functions of Carbohydrates

The primary function of carbohydrates is to provide energy to the cells of the body, particularly the brain. While most body tissues and organs prefer carbohydrate as their primary fuel source, some, like the brain, red and white blood cells, and certain parts of the kidney require it. ¹ Carbohydrates are also an important fuel for the muscles during exercise, particularly intense and/or prolonged exercise, and as such are key to optimal athletic performance. ² 

In fact, carbohydrates are so crucial to the body that if you don’t consume adequate amounts in your diet, your body will have to make them—a process known as “gluconeogenesis” (literally translated “to make new glucose”). The most common gluconeogenic substrates are amino acids derived from both dietary sources of protein and body proteins such as muscle and vital organs. ²  Thus, while the body can survive without carbohydrates; it does so at the expense of the body’s protein pool and consequently does not function optimally. ² 

Carbohydrate Classificaiton

Carbohydrates can be broadly classified as simple or complex, based on their chemical structure. Simple carbohydrates, as their name implies, have a simple chemical structure consisting of one or two sugar molecules. Examples include the monosaccharides (single sugars)—glucose, fructose, galactose—and the disaccharides (two sugars)—sucrose, lactose, and maltose. Most fruits and dairy products contain an abundance of simple sugars. Soft drinks, ice cream, sweets and pastries also contain significant amounts of simple sugars. ³

Complex carbohydrates, including starch, glycogen, fiber and resistant starch, have a more complex chemical structure, containing two or more sugar molecules linked together. ³ Glycogen is the body’s storage form of glucose, while starch is a plant’s storage form of glucose. Foods rich in starch include grains, cereals and most vegetables, particularly beans, peas, corn and potatoes. ³

Carbohydrate Recommendations

The current RDA for carbohydrates is 130 grams per day based on the amount needed to optimally support the central nervous system (i.e., the brain). ¹ If you engage in physical activity, you need more carbohydrate. How much more depends on the intensity and duration of your exercise. ⁴ The Food and Nutrition Board of the Institute of Medicine (the government body that sets the RDA) has recommended an acceptable macronutrient distribution range (AMDR) for carbohydrates of 45-65% of total daily energy intake. ¹

Some people hold the misconception that they need to cut out carbohydrates to manage body weight. But scientific consensus asserts that excess calories are to blame for weight gain, not diet composition. ⁵ Instead of restricting carbohydrates from your diet, practice common sense when selecting carbohydrate-rich foods—choose nutrient dense whole grains, fruits and vegetables.

References

1. Food and Nutrition Board, Institute of Medicine of the National Academies. Dietary Reference Intakes for Energy,Carbohydrate, Fiber, fat, Fatty Acids, Cholesterol, Protein and Amino Acids. Washington, DC. The National Academies Press. 2002; pp 265.
2. Burke LM, Hawley JA, Wong SH, Jeukendrup AE. Carbohydrates for training and competition. J Sports Sci. 2011; 29(Suppl 1): S17-27
3. Food and Nutrition Board, Institute of Medicine of the National Academies. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, fat, Fatty Acids, Cholesterol, Protein and Amino Acids. Washington, DC. The National Academies Press. 2002; pp 275-276.
4. Raatz SK, et al. Resistant starch analysis of commonly consumed potatoes: Content varies by cooking method and service temperature but not by variety. Food Chem. 2016 Oct 1;208:297-300.
5. U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015 – 2020 Dietary Guidelines for Americans. 8th Edition. December 2015. Available at http://health.gov/dietaryguidelines/2015/guidelines/.

Key Facts About Protein

• A medium-size 5.3 oz potato with skin-on provides 3 grams of plant-based protein.
• The 3 grams of protein in one skin-on 5.3 oz potato exceeds that of all other commonly consumed vegetables, except dried beans.¹
• The Dietary Guidelines for Americans recommend eating a variety of plant-based foods to improve overall health.³

Functions of Protein

Proteins play many important roles in the body including:

• Providing structure: Protein is a key component of muscle, tendons, ligaments and connective tissues like collagen. In addition, our skin, hair and nails contain significant amounts of protein.
• Regulating metabolic processes: Enzymes which catalyze chemical reactions, hormones which regulate metabolic processes and cytokines that bind to the surface of cells and influence their functions are all proteins.
• Transporting substances: Transport proteins carry important substances in the body. For example, hemoglobin and myoglobin carry oxygen, albumin carries several vitamins and minerals as well as fatty acids, and transferrin and ferritin carry iron.
• Balancing fluid and electrolytes: Proteins, especially those found in the blood, help regulate fluid balance. Amino acids can be either positively or negatively charged, thus allowing them to help the body achieve acid-base balance and optimal pH.
• Providing energy: Protein provides 4 calories per gram (similar to carbohydrate); however, under normal circumstances protein contributes little to energy production. Under stressful conditions (e.g., severe illness, starvation, diabetic ketoacidosis) protein becomes a more significant source of energy; but, to the detriment of health.

Protein Recommendations

The current recommended dietary allowance (RDA) for protein is .8 grams per kilogram of body weight and the acceptable macronutrient distribution range (AMDR) is 10%-35% of total daily energy intake from protein. One 5.3-ounce skin-on potato is a source of 3 grams of plant-based protein. Current dietary guidance, including the Dietary Guidelines for Americans, recommends substituting plant-based proteins for some animal-based proteins to improve overall health and support the environment.

References:

1. Woolfe JA. The Potato in the Human Diet. 1987. Cambridge University Press.
   2. McGill CR, Kurilich AC, Davignon J. The role of potatoes and potato components in cardiometabolic health: A review. Ann Med. 2013;45(7):467-73.
   3. U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015 – 2020 Dietary Guidelines for Americans. 8th Edition. December 2015. Available at https://health.gov/dietaryguidelines/2015/guidelines/.
   4. Gropper S,S Smith JL, Carr TP. Advanced Nutrition and Human Metabolism. 7th ed. 2018. Boston, MA. Cegage Learning.

Key Facts About Fiber

• A medium 5.3 oz potato with skin-on provides 2 grams of fiber, or 7% of the daily value per serving.
• Dietary fiber has been shown to have numerous health benefits, including improving blood lipid levels, regulating blood glucose, and increasing satiety, which may help with weight loss.¹
• A common misconception is that all of the fiber in a potato is found in the skin. While the skin does contain approximately half of the total dietary fiber, the majority (> 50 percent) is within the potato itself.³
• In the United States, recommendations for fiber intake are often made relative to calorie intake. The current recommend intake for fiber is 14g/1,000 kcal; thus, an average adult woman should consume 25 grams of fiber per day and the average male should consume 38 grams of fiber per day.²

Functions of Fiber

Dietary fiber has been shown to have numerous health benefits, including improving blood lipid levels, regulating blood glucose, and increasing satiety, (makes you feel full longer), which may help with weight loss.¹

Fiber Recommendations

The current recommended dietary allowance (RDA) for fiber is 25 g per day for women 19-50 years of age (28 g per day if pregnant or lactating) and 38 g per day for men 19-50 years of age.⁵

References:

1. Dahl WJ, Steward ML. Position of the Academy of Nutrition and Dietetics: Health Implications of Dietary Fiber. J Acad Nutr Diet. 2015;115:1861-70.
   2. Dietary Guidelines Advisory Committee 2015 Scientific Report. https://health.gov/dietaryguidelines/2015-scientific-report/Accessed December 27, 2018.
   3. Woolfe JA. The Potato in the Human Diet. New York: Cambridge University Press. 1987.
   4. Drewnowski A, Rehm CD. Vegetable cost metrics show that potatoes and beans provide most nutrients per penny. PLoS One. 2013;15;8(5).
   5. Institute of Medicine. 2005. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press. https://doi.org/10.17226/10490.
   6. Storey ML, Anderson PA. Contributions of white vegetables to nutrient intake: NHANES 2009-2010. Adv Nutr. 2013: 4: 335S–344S.
   7. https://www.accessdata.fda.gov/scripts/InteractiveNutritionFactsLabel/factsheets/Dietary_Fiber.pdf